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3rd International
Symposium on Turkey Diseases
Berlin, 14th - 17th
June 2000
This is the third meeting on turkey diseases organised at the same venue by Prof. Hafez. These are my notes of the presentations, grouped according to some of the subject areas rather than order of presentation. They are offered not as a transcript but as a "best effort" at a personal interpretation of the papers. This document is a very poor substitute for being at the meeting (maybe next time I can arrange a video-clip of the after-dinner entertainment!).
If you are an author and would like to correct any errors I may have made in this text please forward the specific correction by e-mail: (mailto:corrections@poultry-health.com)
The full proceedings will be available in a few months - see contact details at the bottom of this document.
Special congratulations to Dr Jane Cook to whom this meeting was dedicated on the occasion of her retirement. Dr Dick Jones did an excellent job at the beginning of the meeting outlining her many contributions to poultry disease research, and we all enjoyed the cocktail session in her honour.
Many thanks to Prof Hafez for organising this meeting and allowing us to make this available on the Poultry Health Services site. Thanks also to Bayer Animal Health for organising my participation in the meeting.
Paul McMullin
Thirsk, 6th July 2000
Food Safety
Ref Number : 310
19. Kasbohrer, A. New zoonoses directive:
Strategies and their consequences for turkey production.
TurkBerlin00 2000.
Keywords : zoonoses; turkey; production; Human; Salmonella;
control; Antibiotics; resistance; disease; Animal; risk; Chickens;
broiler; turkeys; chicken; Birds;
Notes : We are currently working under council directive 92/117/EEC.
This covers monitoring and reporting of zoonoses which pose a
threat to human health in particular dealing with Salmonella
control programmes. Over the past few years the Commission has
been preparing a new draft directive and regulation. The
directive will deal with monitoring and the regulation will deal
with the control. The draft documents are currently being
discussed in various working groups. The objectives establish
appropriate and sufficient monitoring of zoonoses, collecting
relevant information in member states, and analysing these. The
directive will have general rules for monitoring - to include
pathogens and monitoring of antibiotic resistance. It is intended
that the monitoring programme should be coordinated and that
epidemiological investigation of foodborne outbreaks of disease
be conducted. Regulation - to ensure that appropirate and
effective measures are taken to control the zoonoses. this will
include adoption of targets to reduce the prevalence of specified
zoonoses adoption of specific control programmes adoption of
specific rules applied to reduction of zoonoses. adoption of
rules concerning intra-community trade and imports form third
countries of specified animals Community targets - to reduce the
risk to public health posed by zoonoses. The annexe will specify
agents, animal populations, dates for achievement, requirements
with respect to trade. On Salmonella only serotypes of interest
to public health will be included - e.g. S.e. in laying hens,
more serotypes in chickens and broilers. Currently turkeys are
not mentioned with respect to breeding flocks. Targets to be
established by end of 2002 for chicken breeding flocks, 2005 for
turkeys - trade effects to start 1 year later. Control programmes
provide for the detection of zoonoses and agents thereof Define
responsibilities of food business operators Specify the control
measures to be taken Identify the means to re-evaluate the
programme. The programme must cover feedstuff production, primary
production of animals, processing and preparation of foodstuffs
of animal origin. General requirements - Aim - occurrence of the
zoonoses geographical area list of approved laboratories methods
used in the examination of the zoonotic agents, including
sampling schemes type of measures if zoonotic agents are detected
Current minimum requirements for broilers are to be day old and
slaughter, turkeys at slaughter. Originally vaccination of
breeding birds was to be banned, currently flexibility on this is
to be maintained at the discretion of the commission.
Laboratories must be specifically approved and participate in QA
schemes operated by national reference laboratories
Ref Number : 311
20. Borck, B., Pedersen, K. and Madsen,
M. Campylobacter in Danish turkeys. TurkBerlin00 2000.
Keywords : Campylobacter; turkeys; Human; Denmark; Salmonella;
broiler; infections; control; management; Germany; analysis; Meat;
risk;
Notes : The author is working on a 3 year study on campylobacter
in Danish turkeys. Camplyobacter is a leading cause of diarrhoea
in humans - in Denmark campylobacter hs overtaken Salmonella as a
cause. There is a constant increase in campylobacter cases since
1980, in Iceland and New Zealand this rise has been particularly
dramatic. The Iceland effect has been attributed to cessation of
mandatory freezing of broiler carcases. There is a marked annual
cycle of Campylobacter infection in both humans and broilers -
the cycles match very closely. This project aims to examine the
occurrence from "stable to table" It aims to look at
risk factors of infection and colonisation and identify critical
control points including slaughter and processing. Eventually the
project aims to evaluate methods of campylobacter detection and
assess their usefulness in process management. Currently about 1
million turkeys are produced in Denmark, imported as poults from
Germany and grown on 24 farms and slaughtered in a single plant -
standard houses except for a group of farms in Jutland. Material
& methods - 10 swabs taken from each batch, placed in BHI
broth. In the lab they are pooled in 3 ml of sterile water then
streaked onto CCDA plates, incubated in microaerophilic
athmosphere for 3 days. Isolates are colony selected and sub-cultured
until monocultures are obtained. This is the same method applied
for broilers in Denmark. Results to date were presented and show
60-90% positives except for march (20%) and April (5%) - May is
up again. The overall average is 50% of batches, 56% of flocks As
expected C.jejuni was dominant (90%) among the isolates - 3 C.lari
from a single farm in Furhter work will involve analysis of
slaughter and meat processing, quantitative studies of occurrence
in turkeys
Ref Number : 286
2. Horrox, N. Food Microbiology - Issues for
Reflection. TurkBerlin00 2000.
Keywords : control; poultry; veterinarian; food microbiology;
Salmonella; TVC; quality control; accreditation; legislation;
risk;
Notes : Quality control of food testing has progressed
significantly in recent years. The author speaks from the point
of view of a poultry veterinarian with a UKAS accredited food
testing laboratory. Major supermarkets now require independent
laboratories to be accreditied by UKAS - a laboratory can be
accredited even if only 1 test is accredited - both laboratory
and test need to be accredited. Accreditation helps tell us what
is happening in our laboratory and relates to how much faith we
have in the results. Interpretation of results: Negative - should
be replaced by "Not detected" We require a
representative number of samples collected and processed
appropriatedly. If we are testing a 25 g sample and can detect 1
organism - this equates to 40.000 in a tonne or a million per
wagon load! Even non-detection could allow up to 1 million
organisms per load. Internal/external challenge testing. The
following results refer to the Qm food testing now operating in
30 countries. Assessment of returned scores with respect to
expected results uses a Z statistic (perfect = 0, 2 or higher
unacceptable). Returned results tend to be normally distributed.
Laboratories spend 10-20000 dm/year in order to stay in this
scheme. UKAS does not remove labs on the basis of a single bad
result - requires continuous improvement of outliers. Different
laboratories perform differently on different test. Good
laboratories aim for Z stats of 1 or less. In a recent QA test
for Salmonella at 10 organisms/gram, 10% of laboratories failed
to detect. Recent British legislation tends to take food
poisoning out of the category of "absolute offence" -
the "due diligence defense". This may be relevant to
those of us running laboratories. The features of this defense
are: 1. were you aware of the risks? 2. have you taken measures
to remove or minimise risks? 3. are you regularly checking the
situation 4. Are we analysing results of checks and acting on
unacceptable results 5. Do we seek appropriate advice and
guidance.
Ref Number : 313
14. Schroeter, A. and Helmuth, R.
Resistance of salmonella isolations from turkey in Germany.
TurkBerlin00 2000.
Keywords : resistance; Salmonella; turkey; Germany; feed;
environment; Animal; turkeys; typhimurium; Incidence; Meat; DT104;
Notes : The authors' organisation examines annually 4-7000
salmonella samples- the range of species involved is fairly
similar from year to year. Samples come from feed, food and
environment as well as animals. Certain serovars are more common
from turkeys typhimurium, saintpaul, blockley, hadar, newport,
indiana. There is a moderate incidence group which includes S.e.
There are a large number of other isolates which occasionally
occur. Heidelberg seems to be a growing problem. For testing a
german standard method 58940 disk diffusion method is used.
Resistance tends to be high in S.typhimurium, and other high
prevalence Salmonellae. Multi-resistance was seen in many
isolated, though the percentage of isolations is dropping. The
serotypes on meat which are multi-resistant to 6 or more are S.newport
and typhiumurium in both years - the same is true for S.anatum,
in addition to newport and typhyimurium. Data were also presented
on MIC results on a sub-set of strains of S.heidelberg and S.anatum.
21 of 27 S.typhimurium isolates were determined to be DT104.
Ref Number : 312
15. Hafez, H.M. and Mazaheri, M
Bacteriological investigation on salmonella in meat turkey flocks.
TurkBerlin00 2000.
Keywords : Salmonella; Meat; turkey; consumer; legislation;
control; production; E.coli; Campylobacter; disinfection;
transport; Female; Male;
Notes : Safe food is a fundamental requirement for all consumers.
The expectation of the consumer may involve lack of immediate
health hazard, but long term health, correct composition, health
benefits and quality become additive demands. The current
legislation is not enough and industry must accept a greater
share of responsibility. The control must go all the way from
initial production through to the consumer. Processing plants are
not able to effectively decontaminate products. In this study 7
flocks which were negative on farm, frequently had salmonellae
after processing. A similar study demonstrated VTEC E.coli after
processing. Campylobacter jejuni can be readily identified on
farm but gross contamination in processing also occurs. Cleaning
and disinfection in processing plants was found to be highly
effective. Effort must be made to reduce contamination prior to
dispatch to processing. This needs to include knowledge of which
flocks are positive, processing logistics and transport. There is
currently no requirement for testing meat turkey flocks for
salmonella prior to slaughter. Currently there is debate between
producers and consumers. C&D must follow the slaughter of
known infected flocks. To date 9 cloacal samples have been taken
from each of 540 turkey flocks 3 weeks before processing. - only
9% were positive for Salmonella in 1999, 19% in 2000 to date. The
most frequently isolated groups were in groups B,C,D,E, Newport,
enteritidis, anatum, agona, heidelberg, bredeny - the rise in
2000 is related to heidelberg. There were 23.4% of farms positive
and only 6.2% were repeated positives - most were related to
successive depletions of females and males, the remainder were
mainly different serotypes. Results - Salmonella of serovars were
found - positive flocks were slaughtered at the end of the day
and meat use from them was adapted accordingly, hygieneic
measures were discussed with the company. Legislation alone will
not deal with this - the industry must take a greater
responsbility. Measures to reduce contamination pre and post
harvest are necessary
Ref Number : 314
17. Stephan, B., Reynolds, D.J., Gibson, S.A.,
Johnson, A.C. and Froyman, R. Direct challenge and floor pen
trials assessing the efficacy of Competitive Exclusion (Aviguard)
against different Salmonella serovars in turkeys. TurkBerlin00
2000.
Keywords : Salmonella; turkeys; infections; turkey; Birds;
typhimurium; DT104; Chickens;
Notes : Since Nurmi and Rantala proposed the principle of
competitive exclusion in 1973 it has been widely accepted.
Efficacy of the competitive exclusion product Avigaurd for
Salmonella in turkeys has been reported in the literature. One
trial involved birds challenged with 10^4 S.kedugou and
evaluation 7 days later. Results must be assessed using the
calculation of the infection factor and from these values for
each group a log reduction ratio is calculated. This trial
involved 2 groups treated with the product by spray, 2 by oral
gavage with product and with adult turkey caecal contents -
reductions of 4-7 were achieved, highest in the turkey caecal
contents group. In a second floor pen trial seeder birds
challenged with S.livingstone and S. typhimurium were used.
Reductions achieved were 86% fopr DT104 and about 45% for S.livingstone.
Batch comparison data were examined with 2 levels of Salmonella
keduguou challenge (10^3 and 10^4) achieved about 5 log
reductirons. A dose titration study compared 1/10th and full dose
with 10 doses- 1/10th dose achieved little protection in chickens
and 2 log reduction in turkeys, compared to 6 in both species at
full dose. Overdosing did not boost efficacy. A previous paper (av
Dis, 1982 585-595) examined the relative protection of CE in
chickens and turkeys. The reviewed literature suggests that CE
products based on turkey flora have a wider protective effect
than those derived from chickens - Aviguard appears to have
higher log reductions in chickens than in turkeys but also it
produces better protection in turkey than other products which
have been tested.
Turkey Enteritis
Ref Number : 306
22. Saif, Y.M. Enteric viral infections of
turkey poults. TurkBerlin00 2000.
Keywords : infections; turkey; adenovirus; enteritis; Intestines;
histopathology; intestine; bacteria; culture; electron microscopy;
reovirus; epidemiology; resistance; virus; anatomy; turkeys;
disease; PEMS; growth;
Notes : Experimentally rotavirus, astrovirus, coronavirus,
enterovirus, adenovirus and possibly reoviruses can cause
enteritis experimentally. Diagnosis: Clinical signs and lesions
are not diagnostic but typically poults are affected between 1-3
weeks of age - noisy, diarrhoea, excessive drinking, low
mortality, high morbidity. Pathology: Caecae and intestines
distended. Gut walls flaccid, transparent and full of liquid
contents and gas. Caecae commonly have yellow frothy contents.
Histopathology - hypercellularity of small intestine lamina
propria, scalloping of surface and vacuolation of epithelium,
separation and desquamation of enterocytes, bacteria adherent to
villi, villus atrophy. On SEM villi are roughened due to
desquamation. Malabsorption/maldigestion is a common sequel and
secondary nutritional problems - abnormal feathering, skeletal
deformities etc. A major problem is that the viruses involved are
difficult or impossible to culture. Direct and immune electron
microscopy are useful - use acute and convalescent serum. Genome
electopherotyping is useful for rotavirus and reovirus.
Immunoflourescence and immunoperoxidase can be useful.
Epidemiology - enteritis is common in commercial flocks. Route of
transmission is faecal-oral. Combined infections are common.
Viruses vary in resistance to environmental conditions. Survey
results vary but typically Astro and Rotaviruses are most common
in both sick and normal but % prevalence much higher in affected
flock. Sampling 4 flocks in detail showed astrovirus in all
flocks, from as early as 4 days to 5 weeks. Rotaviruses may be
found in the same time frame. Adenoviruses are generally post 5
weeks and are HE virus. Anatomy - villus epithelium - mature
nonproliferative cells differentiated for digestion/digestion -
crypt cells are proliferating non differentiated and are more
involved in secretion. When there is extreme villus atrophy there
is secretion with reduced absorption - this is an important
mechanism of diarrhoea but not the only one. Different viruses
have predeliction for different parts of the gut - mixed
infections tend to be additive in effects Rotaviruses - four
serogroups - group D is most common. These are the most common
cause of early enteritis. Astroviruses - a recognised pathogen in
turkeys and some mammalian species Coronaviruses - the cause of
what used to be called bluecomb disease. A highly labile virus
which is probably the most devastating enteric viral infection in
turkeys. Used to be considered species specific, high rates of
mutation. Reoviruses - a controversial subject as to whether they
do cause enteritis - difficult to reproduce disease. PEMS: An
acute transmissible disease of turkey poults 1-4 weeks of age
characterised by diarrhoea, anorexia, growth depression, immune
dysfunction and high mortality. It has driven many people out of
business. It is a mixed viral enteritis. Investigations have
shown rotavirus in 72% of flocks, astrovirus (SRV) in 44% and
turkey coronavirus in 22% - mixed infections were common. The
disease can be readily reproduced by filtered bacteria free gut
contents. It causes a rapid onset depression and subsequent scour
and weight depression. The turkey coronavirus and astrovirus were
additive in weight depression effect. The astrovirus was detected
in many tissues including thymus, bursa and spleen. It reduced
the lymphoproliferative response to ConA and reduces circulating
CD8+ cells. Recent studies suggest that the Small round virus is
a newly emerged astrovirus. Bovine coronaviruses are similar to
turkey coronavirus - at least one isolate from calves has been
shown to cause disease in turkeys but not in chicks.
Ref Number : 307
21. Dobos-Kovacs, M., Dren, C.N.,
Tovari, J. and Vetesi, F Diagnostic problems of enteritis and
growth retardation in turkey poults in Hungary. TurkBerlin00 2000.
Keywords : growth; turkey; electron microscopy; enteritis; virus;
disease;
Notes : These are preliminary results on a new problem in Hungary.
Diagnosis - definition of the gross and microscopic lesions is
still the main criterion. Viruses may be isolated and detected in
other ways (electron microscopy, immune electron microscopy).
Work in this area is complex and even if the viruses are
identified there is the issue of the cause and effect
relationship. In principle immunocytochemistry is a possibility.
It is surprising that there is little work on the molecular
biological techniques which might overcome some of the current
problems. Materials and methods. Standard light and thin section
electron microscopy - immune electron microscopy - sera provided
by Dr Saif. Method followed as per AAAP manual. Samples are
prepared by homogenisation and sonication of complete intestinal
contents - filtered and pelleted. Results - Indirect
immunoflourescence - problem with non-specific reactions from
antibody producing cells. Pathology - marked enteritis and frothy
caecae. EM: Viral particles seen mainly in cells in the lamina
propria, usually in dense intracytoplasmic inclusions -
containing 29-33 nm particles. Immune IE shows partial clumping
with astrovirus antiserum. It appears that this problem is caused
by this virus - work is planned on the attempted reproduction of
the disease, hopefully the results will be available for the next
meeting.
Ref Number : 281
3. Jodas, S. and Hafez, H.M.
Litter management and related diseases in turkeys. TurkBerlin00
2000.
Keywords : management; disease; turkeys; poultry; production;
control; nutrition; environment; risk; dust; feed; chemical;
bacteria; Air; Birds; Incidence; Haemorrhagic enteritis;
enteritis; virus; PEMS; Coccidiosis; Temperature; Antibiotics;
infections; resistance;
Notes : For effective poultry production litter management is as
important as many other aspects of mangement and health control.
Litter dilutes faecal material, insulates from cold floors.
Bedding material must be stored in a dry area. Minimum depth
should be 5 cm, caked litter should be removed and new litter
added as required. Tilling litter may be helpful to achieve
moisture of 25-35%. Friable litter helps breakdown. Wet and caked
litter can arise over the course of a few days when diarrhoea is
severe. Various factors are involved - nutrition, disease,
physical environment. Increase ammonia can cause respiratory
disease, keratoconjnunctivits, and reduced immune response. High
moisture increases risk of a range of diseases. Litter moisture
below 20% increases risk of respiratory disease from dust. Fat
and nitrogen in faeces can cause contact dermatitis. Feed - any
mecanical, chemical, formulation problem can be involved -
ingredient quality, and formulation are critical. Deviations in
feed coomposition can result in poor feathering as well. Faecal
consistency is quite variable - varying wateryness, foamyness and
colour. Caecal faeces are mainly present in the morning and 10-12
hours later. Factors increasing water consumption - minerals (potassium,
chloride, soidum), raffinose, biogenic amines may be relevant.
Water quality is vital - pH 6.8-7.5, free from bacteria, nitrate
<50 ppm, nitrite, <0.1ppm, lack of chemical contamination.
Drinkers must be appropriate in numbers, working correctly etc.
Drinker fialures can directly cause wet litter, reduced weight
gain etc. They should be washed daily. Poor water hygiene affects
efficacy of vaccination by this route. Target environment RH 60-70%,
NH3 <30 ppm, air movement 0.3 m/sec, at bird level,0.5 m at
house level. Anderson et al compared ammonia and dust levels with
respect to airsacculitis - both factors increased incidence and
severity of airsacculitis, but especially dust - there were no
interactions confirmed. Exposure to ammonia at 40ppm dramatically
increases damage to the tracheal epithelium. House design - must
proctect against elements, satisfy bird requirements, provide
reasonable comfort. Must also facilitate management, and
maintenance and facilitate hygiene. Interactions - many
infectious and non-infectious problems can lead to wet litter.
Haemorrhagic enteritis virus leads to bloody droppings and severe
depression. "PEMS" causes marked diarrhoeas as does
coccidiosis. Enteric disease cause significant problems General
measures - raise temperature, decrease litter moisture,
antibiotics to combat secondary infections, electrolyes, and
improved hygiene. Hygiene measures have general effects. Other
measures - vaccination for HE, competitive exclusion,
coccidiostats, anti-histamonas etc. CE in conjunction with good
hygiene has been shown to markedly improve resistance to a range
of pathogens. All management practices affect each other and can
both promote or inhibit poultry health.
Pneumovirus - Turkey Rhinotracheitis
Ref Number : 303
23. Van de Zande, S., Nauwynck, H. and
Pensaert, M. Protection of avian pneumovirus (APV) vaccinated
turkeys against an APV-E-coli challenge. TurkBerlin00 2000.
Keywords : pneumovirus; turkeys; vaccine; E.coli; Scoring;
bacteria; serology; virus; control; Birds;
Notes : Previous work has suggested good cross-protection between
types A and B at 3 weeks post vaccination, and only partial
virological protection at 11 weeks post challenge. This study
investigates whether a single vaccine could protect against a
mixed APV-E-coli challenge. Vaccination was by I/Nasal at 10^2.3
ciliostatic doses with Aviffa and Poulvac. Virulent strains of
pneumovirus and E.coli were from clinical cases. Both dual, APV
and E-coli only groups were derived from each treatment group.
The scoring system ranged from 0 to 7. Poults were antibody
negative and vaccinated at 3 weeks. Bacteria were isolated and
titrated. Serology was performed throughout using a SN test. The
challenge strain was A type. More virus was present in the B-A
group than in the A-A group at both 3 and 5 days post challenge (controls
were much higher). E.coli was generally not reisolated in the AA
group but in the BA had a sudden peak at 5 days - unvaccinated
challenged birds had massive E.coli invasion. Serology shows peak
antibodies at 5-7 weeks and a dramatic anamnestic response post-challenge.
Conclusions - Clincal signs were much worse in non vaccinated
birds, and there were 10^3 more virus and 10^7 E.coli. Cross
protection showed that protection was somewhat better in the A
group for A challenge.
Ref Number : 300
26. Bayon-Auboyer, M-H, Arnauld, C.,
Toquin, D. and Eterradossi, N Nucleotide sequence of the F, L and
G protein genes of two non-a/non-B avian pneumoviruses (APV)
reveal a novel subgroup of APV. TurkBerlin00 2000.
Keywords : pneumovirus; elisa; sequencing; genes; sub-types;
Notes : The avian pneumovirus the genome is smaller than
mammalian pneumovirus genome and some of the genes are in
different orders. In both groups the G gene is the main target
for sero-neutralizing antibody. Initially groups A and B were
identified by antigenic differences, Elisa, Mabs. When sequencing
was carried out it was found that there was only 38% amino acid
identity. To date a sequence of the American C type is not
available. This work was done with non-A/non-B isolates made in
1985. Cross-elisa testing suggests variation in antigenicity
which make them separate from both A, B and Colorado. One of the
strains F/85/1/APV was replicated in vero cells and was then
amplified and sequenced. It was found to have low conservation of
the SH-G and G-L intergenic regions - overall nucleotide
identitity was only about 56% for both A and B strains though the
two strains were nearly identical, only 31% identity for amino
acids. This paper should serve as an alert that avian
pneumoviruses are much more diverse than previously thought and
highlights the need for continuing vigilance of these infections.
Ref Number : 302
27. Worthington, K.J., Sargent, B.,
Davelaar, F.G. and Jones, R.C. Immunity to TRT in turkeys
following in-ovo vaccination. TurkBerlin00 2000.
Keywords : immunity; TRT; turkeys; Animal; Birds; stress; disease;
vaccine; elisa; incubation;
Notes : This forms part of a project supported by Fort Dodge
Animal Health. Why in-ovo? This provides an accurate individual
dose as compared to spray. Possible reduced bird stress, ease of
automation and possible earlier immunity. In-ovo administration
has been used in a number of diseases. There appear to be no
papers on the use of this technique in turkeys. It was planned to
evaluate safety and efficacy with Poulvac TRT a live attenuated
vaccine of normal spray dose 10^4.2 TCID. To evaluate safety eggs
were obtained from antibody negative parents and an overdose (10^1.3)
of vaccine was used. Hatchability and poults post hatch were
evaluated. A total of 72 eggs were used. Hatchability was
satisfactory. Nasal scores were recorded daily. Only 36% of the
vaccinated birds showed signs - maximum effect at 6 days post
injection. Signs were mild as compared to virulent TRT challenge.
Using an in-house Elisa there was a satisfactory response (as
compared to previous experience with eye-drop and spray) by 3
weeks of age. The next step was to test efficacy using antibody
positive eggs and a low dose of vaccine (10^1 below normal).
Injection was at 24 days of incubation. Challenge was conducted
at 3 or 6 weeks of age. There was no effect on hatchability in
this case. At 3 weeks both groups still had the same level of
antibody. On challenge antibody negative eggs given low dose were
fully protected, antibody positive eggs showed 77% protection.
Further work was shown on the use of eye-drop vaccine at day old
to provide protection for both type A and B challenge Summary:
Inoculation of a high dose of live attenuated TRT vaccine did not
affect hatchability and caused only mild clinical disease in a
small proportion of poults. A low dose in antibody positive eggs
provided 77% protection from challenge at 3 weeks.
Ref Number : 301
28. Jones, R.C., Worthington, K.J. and
Sargent, B.A. Some observations on serological responses to avian
pneumovirus in turkeys and chickens. TurkBerlin00 2000.
Keywords : pneumovirus; turkeys; Chickens; sub-types; elisa;
vaccine; infections; Birds; immunity;
Notes : In the UK there are sub-types A and B and various
commercial test kits based on Elisa. It is generally agreed that
there is good cross-protection between types A and B. What do we
expect from APV Elisas ? Ability to detect successful uptake of
vaccine and seroconversion in response to field infection. We
have direct Elisa's and competitive elisas and various antigens
are used. There can be any combination of A's and B's in the
antigen, vaccine, and field challenge. When birds are vaccinated
with one type and challenged with the other there seems to be
more consistent reactivity among different test kits. Chickens
often do not produce a detectable response after vaccination or
after challenge. It has been shown that IgA antibodies can be
found in tears but not a lot in trachea. Turkeys are much more
reactive than chickens to both attenuated vaccine and challenge.
Currently Elisas are probably no good in chickens to determine
response to vaccination, also may be misleading in diagnosis.There
are differences in response between chickens and turkeys. We
could think about double Elisas, bivalent Elisas, viral subunit
Elisas or IgM specific Elisa to confirm recent infection. It
would also be nice to have a simple test of cell mediated
immunity.
Ref Number : 298
29. Engstrom, B. Appearance and
disappearance of turkey rhinotracheitis in Swedish turkey farms -
a case report. TurkBerlin00 2000.
Keywords : turkey; report; poultry; production; density; broiler;
Denmark; elisa; PCR; disease; Newcastle; Newcastle Disease;
infections;
Notes : Poultry production in Sweden is relatively low density,
however it tends to be located in the south of the country. Two
broiler parent flocks were affected in the south west close to
Denmark - mild respiratory signs, low mortality - antibody
detected by a blocking Elisa. APV type A detected by PCR in four
flocks - determined to be type A. The index cases were in 2
different companies and all sera tested were strongly positive.
Given that this was a new disease further investigation revealed
4 more infected flocks. A stamping out process was adopted for
these 6 flocks and restrictions were put in place as for
Newcastle Disease. Serological monitoring continued. It was
difficult to find epidemiological links between the first 6 farms.
A single turkey farm about 20 km from the broiler parent farms
was also found to be positive although clinical signs were
minimal - believed to have been affected much earlier - this site
was multi-age and had an exhibition and processing plant with no
biosecurity. There started to be a large number of farms detected
so there was a change in policy - vaccination was allowed in
broiler parents. The disease seemed to spread without
identifiable contact over large distances. Strict biosecurity
failed to prevent this. On some farm spread was very slow. Even
though the turkey farm did not vaccinate the infection died out
and were antibody negative in 1999. One broiler parent company
stopped vaccinating and are antibody negative - the other still
vaccinates because of possible new introductions.
Ref Number : 297
31. Nagaraja, K., Shin, H.J. and
Halvorson, D.A. Avian pneumovirus of turkeys and its host range.
TurkBerlin00 2000.
Keywords : pneumovirus; turkeys; elisa; veterinarian; economics;
virus; Temperature; Chickens; Birds; disease; serology; PCR;
infections; control; broiler; Ducks; Pigeons;
Notes : Avian pneumovirus has been present in the USA at least
since 1997, when it was diagnosed in flocks from Colorado.
Development of an Elisa test allowed screening and identification
of its presence in Minnesota - some veterinarians believe it
started in 1995 or 1996. There are a very large number of
affected flocks and its economic effects are much greater than
those of low pathogenicitiy AI. Biosecurity as applied has not
prevented its spread. This particular virus appears not to affect
the trachea to any extent - it is mainly in the turbinates and
sinuses. This virus survives freeze-thaw cycles very well and at
room temperature for 2 weeks. Even in a conventional freezer it
will survive for at least 1 year. This is relatively resistant
for a pneumovirus. The first question addressed was what is the
host range. Most isolations in the literature are from chickens
and turkeys - it has been innoculated into a broad range of
species but only reisolated from chickens and turkeys. Antibodies
have been found in guinea fowl, ostriches (Zimbabwe) and seagulls
(Europe). This project examined mice, rats, waterfowl, wild birds,
chickens and other birds - in Minnesota there is no evidence of
disease or serology in chickens. Mice - 3, 5 7 week old
inoculated with 10^4 TID 50 All age groups were PCR positive at 4,8,14
days post infection and seroconversion occurred by day 14. PCR
positivity was found in droppings but not in bedding. When
control mice were put in contact there were some lung and rectal
swab positives. Similar results were found in rats although virus
was present for a shorter period - they also seroconverted. Both
rats and mice were laboratory strains Chickens - no infection
established in SPF leghorn chicks. When conventional broilers
were taken from the field at 14 days and infected orally or oculo-nasally
most birds showed signs by 8 days post infection. A similar study
on 2 week old ducks. Oculo-nasal challenge resulted in a broad
range of PCR positivity between 3 and 21 days PI - blood,lung,
trachea etc - similar results by oral challenge. This raised the
question as to the role of migratory waterfowl in the
transmission of APV - used sentinel ducks. On one pond they were
positive within 1 week of placing (only positive from choanal and
nasal swabs, not cloacal). (sero-conversion positive at 4 weeks)
- now virus isolation completed. In a second site it took 8 weeks
for the birds to go positive. Field samples from sparrows,
starlings, swallows, pigeon, kill deer, not grasshopper, frogs,
rats etc.
Ornithobacterium rhinotracheale
Ref Number : 305
24. Sommer, F. Detection of antibodies
against Ornithobacterium rhinotracheale in Austrian turkey flocks
by Elisa. TurkBerlin00 2000.
Keywords : Ornithobacterium; Ornithobacterium rhinotracheale;
turkey; elisa; management; disease; broiler; layers; ART; ORT;
Birds; turkeys;
Notes : Clincal signs are variable - an acute highly contagious,
duration and mortality variable. It requires synergism with
management faults and viruses. It is difficult to reproduce
disease without use of a "primer". This survey includes
6 broiler parent flocks, 16 broiler flocks (all in lay),turkeys
and layers (in lay). Half of the broilers were from sick flocks
most of the rest was routine monitoring. Positivity: Sera FLock
Broiler parents - 95% 100 Broilers 16% 47 Layers 100 In both
broilers and layers there were paralel high ART titres. Ort
titres and positive was higher in the sick broilers than in the
normal birds. In turkeys 56% of flocks were positive in the
Biocheck Elisa and 83% in the Idexx system. There were massive
differences in reactivity among the 2 test systems. There is not
a great correlation between clinical history and response to
either test. Between test reproducibility within manufacturer is
satisfactory but is very unsatisfactory between manufacturers.
Possible causes are the antigen strains, methods of antigen
extraction and judgement of suspect sera.
Ref Number : 304
25. Zorman, R.O., Zdovc, I. and
Bencina, D. Ornithobacterium rhinotracheale - current situation
in Slovenia. TurkBerlin00 2000.
Keywords : Ornithobacterium; Ornithobacterium rhinotracheale;
Male; Female; broiler; pneumonia; egg drops; serology;
pneumovirus; ORT; turkey; E.coli; enrofloxacin; Birds;
Notes : This paper describes outbreaks Flock 1 - 68 days old
clinical signs of depression, weakness, gasping an sneezing.
Morbidity was 50% in males, 20% in females - weekly mortality
rate was of the order of 1% Flock 2 - 72 day old severe clinical
signs in males - 3% mortality Flock 3 - 27 week old broiler
breeders - depression, weakness, gasping mortality 1.7% in 10
days - fibrinopurulent pneumonia, aircsacculitis, no egg drop.
Bacteriology - lungs, tracheas etc Serology for ND, AI,
Pneumovirus, Ort by ElisaM.g. M.s. M.m. Ort was isolate from
tracheal lungs and heart of the turkey flocks, E.coli was also
commonly isolated. Isolates were sensitive to amocycillin,
lincomycin, tetracycline but resistant to enrofloxacin etc. The
affected flocks sero-converted to Ort but was also positive for M.s.
Another unaffected flock was positive for antibodies to Ort and M.s.
but went M.s. negative. A fourth unaffected flock showed low
titres for Ort. The broiler parent case occurred in november and
it is surmised that the problem was related to M.s., and poor
ventilation. Ort antibodies are commonly present in imported
broiler parent chicks. Presence of antibody in healthy birds
suggests that this is a multifactorial problem.
Avian Influenza
Ref Number : 289
30. Capua, I, Mutinelli, F and Morneo-Martin,
A. The 1999-2000 avian influenza H7N1 epidemic in Italy.
TurkBerlin00 2000.
Keywords : Avian Influenza; veterinarian; poultry; production;
Birds; Meat; turkeys; broiler; turkey; layers; disease; enteritis;
feed; Chickens;
Notes : This epidemic has caused a massive amount of work for lab
staff, epidmeiologists and field veterinarians. On march 29th
1999 H7N1 LPAI was isolated and notified. This circulated for 9
months in industrial poultry production. The first suspicion of
HPAI was on December 13th, confirmed on the 17th. The last
outbreak was notified on April 5th. The LPAI infected area was in
Veneto and Lombardia, initially in the Verona area. In this area
250 million birds are slaughtered annualy - 10+ hatcheries and
processing plants. The great majority of identified LPAI cases
were in meat turkeys. Clinical signs - Broiler turkey breeder and
layers - fever, depression, drop in egg production (up to 80% in
turkey parents). The main PM finding was egg yolk peritonitis.
Morbidity was 100%, mortality 2-20%. Abnormal shell colour and
shape were common. Meat turkeys - birds under 40 days showed
respiratory disease with marked sneezing, coughing, sinusitis,
fibrin clots in the sinuses and trachea. In young birds
haemorrhagic/necrotic pancreatitis was seen, often followed by
enteritis. Mortality up to 97% occurred in young birds - swollen
heads and sinusitis. In older meat turkeys and broilers it was
milder, with severe loss of appetite, mortaliy generally of about
5% There were 413 outbreaks from December to April - mainly in
meat turkeys (177) and layers (121) - the total number of birds
affected (deaths/depopulated/preemptive slaughter) was about 17
million. There were a number of outbreaks in other areas,
including 1 in Sardinia and 1 in Sicily - related to bird
movements. HPAI clinical signs - Severe depression, no feed
consumption, cyanosis of comb, occasionally haemorrhages on the
shank (chickens), mortality approximating 100%. In caged layers
there was slow progression in the house but birds died suddenly.
Comments - LPAI should be diagnosed promptly in order to achieve
a stamping out policy in a limited number of flocks. Improved
biosecurity should be implmented at flock level. EU directive 92/40
which defines AI virulence should be extended to cover LPAI.
After all of this everybody was ready for a holiday - now we have
ND!
Ref Number : 299
33. Hess, M., Wenzel, R. and Hafez, H.M.
epidemiological investigation on avian pneumovirus in poultry
flocks using nested RT-PCR. TurkBerlin00 2000.
Keywords : pneumovirus; poultry; virus; serology; Birds; vaccine;
PCR; turkey; epidemiology; sub-types; sequencing; genes;
Notes : This virus belongs to paramyxoviridae, pneumovirinae,
Metapneumovirus is the proposed genus. Three sub-types have been
identified to date. Initially types were based on differing
serology. Sequencing of the glycoprotein gene allowed the
development of PCR's Type B is currently dominant in the UK and,
France, a non-a/non-b virus has been identified in France. The US
virus is designated C. In this work samples were taken by
practitioners from sick birds. Dried swabs were submitted for
examination. Use of Nobilis and Tervac vaccines allowed
comparison with field isolates of types A and B, though it was
not possible to distinguish vaccine and field challenge. Of the
flocks tested 31 samples were type A, This nested PCR detects up
to 25 TCID50. TRTC is widespread - 60% of turkey flocks. 50% of
non-vaccinated flocks were positive. Subtype A is the predominant
strain type (92%)
Ref Number : 295
34. Pittman, M. The current EU legislation
to control avian influenza as well at the future approach.
TurkBerlin00 2000.
Keywords : control; Avian Influenza; Influenza; Human; disease;
risk; infections; poultry; virus; surveillance; inspection;
culture; report; Animal; disinfection; review; Birds; density;
production; legislation;
Notes : For the adoption of legislation 2 procedures are used.
Regulations have to be immediately applied, directives need to be
put into national law and there is some leeway in their
application. A more complex procedure is the co-decision
procedure introduced by the Treaty of Mastricht and simplified by
the Treaty of Amsterdam. This is mainly used for public health
issues and requires 2 readings through the European Parliament.
The standing veterinary committee meet twice monthly on
veterinary and human health issues. Control and eradication of AI
92/40/EEC. Harmonisation was required because it is a list A
disease, it can cause high losses and can affect trade - i.e.
high socio-economic importance. Reduced border controls increase
the risk of disease spread - now relies on checks at source
rather than at destination. AI is defined as an infection of
poultry with an Influenza A virus of IVPI greater than 1.2 or
which have multiple basic amino acids at the cleavage site. When
this occurs there is a stamping out policy for affected flocks
and flocks with epidemiological/proximity links. When there is a
limited outbreak a protection zone of at least 3 km is
established - and surveillance of at least 10 km. A census is
carried out then veterinary inspections, epidemiological enquiry
with tracing, - restrictions on movement on poultry eggs, and
manure. Movements may be allowed by authorisation. Restricted
areas may be extended under the safeguard clause (90/425/EEC)
which requires intervention of the SVC when control is not being
achieved. The area may be defined on epidemiological and
topographic (rather than political) boundaries. This may be
applied to third countries and is in line with WTO and SPS
requirements. Control measures favour stamping out. Emergency
vaccination is allowed but the area affected is considered
infected - trade restrictions apply. There are contingency plans
to ensure compensation and resources to deal with a reasonable
outbreak. Member states have national laboratories and there is a
community reference lab which is a source of expertise, knowledge
and training. Prompt diagnosis is required with harmonised rules
for viral identification. There is characterisation of viruses
and maintenance of culture collections and reagents. The Food and
Veterinary office is based in Dublin and controls implmentation
of EU legislation by member states and third countries. There are
on-the-spot missions but concentrates of assessment of
effectiveness of veterinary structures and their control
functions. Its operations are transparent and reports are
published on their web site. Financial support by the community -
it is important in order to maintain farmer support - the
community covers up to 50% of member states costs for destruction
of animals, cleaning and disinfection and destruction of
contaminated materials. Future approach - the definition needs to
be reviewed on the basis of accumulated experience and taking
into account the risk of mutation from low to high pathogenicity.
The SVC has been asked to review the adequacy of the current
definition, as well as what action is appropriate for low
pathogenicity viruses. They have also been asked to review
policies on emergency vaccination and surveillance - monitoring
programmes and role of wildlife? General conclusions - a well-designed
targeted programme with industry support would provide a useful
early warning system, Conclusions - the industry needs to
reassess the wisdom of producing birds in areas of high bird
density. Structures for integrated production need to take into
account disease control. A high level of biosecurity is required.
Simulation exercises should be run to test readiness of the
control systems. Dedication is required from all involved.
Ref Number : 291
35. Ortrud, W., Teifke, J.P. and
Starick, E. Comparative studies of the pathogenicity of avian
influenza virus isolates in chickens and turkeys. TurkBerlin00
2000.
Keywords : Avian Influenza; virus; Chickens; turkeys; disease;
poultry; turkey; Birds; enteritis; genetics; Influenza; Germany;
Notes : Clinical severity of this disease in commercial poultry
varies from assymptomatic to 100% mortality. The main factor
affecting this is virus pathogenicity. Directive 92/40/EEC
defines the disease as caused by an influenza A virus with an
IVPI of 1.2 or more, or has multiple basic amino acids at the
cleavage sites. It is vital to know the pathogenicity for
chickens and turkeys, regardless of the source of the virus.
Because SPF chickens are available these are used for IVPI
testing. In Germany various isolates of LPAI viruses have been
reported - these have IVPI of zero in six week old chickens in
spite of high mortality in turkeys. Should the IVPI be done in
turkeys? A range of isolates have now been tested by both methods
including German and Italian isolates. The multiple basic amino
acids were only seen in the 2 HPAI strains from Italy. The tests
were done in 5 week old Big 6 turkey poults or SPF 6 week old
Lohmann leghorn chickens. The method followed the method laid
down in the directive - 0.1 diluted allantoic fluid injected
intraveneously. Birds were examined for 10 days and scored normal,
sick, very sick or dead (0-3). Results ALl H6 and H9 had an IVPI
of zero in chickens - equivalent in turkeys ranged from 0 to 0.18
(3/5 non zero) - minor illness from which they recovered,
typically starting at day 4. The most prominent pm lesion at the
end was moderate pancreatitis, slight kidney swelling -lesions
more severe in turkeys. Enteritis and tracheitis were more
evident in the chickens. The LPAI H7 strain from Italy showed
zero IVPI in chickens but 0.67 in turkeys, another showewed 0.19
in chickens and 0.63 in turkeys - all diseased turkeys had marked
pancreatic enlargement with focal necrotic areas and associated
haemorrhage. Kidneys were enlarged and very pale. Lesions were
more severe in turkeys than in chickens. The turkeys which died
had fibrinous tracheitis. The HPAI strains had very high IVPI in
both chickens and turkeys (about 3) - some showed focal
mycoarditis, occasional sub-epicardial haemorrhage etc.
Conclusions - HPAI gives similar pathogenicity results in both
chickens and turkeys. LPAI tend to show increased IVPI in turkeys.
Turkeys are clearly more susceptible to influenza virus induced
pancreatitis and nephritis, at least in the genetic lines
commonly reared.
Ref Number : 294
36. Hafez, H.M., Prusas, C. and Lohren,
U. Serological investigation on avian influenza A in meat turkey
flocks in Germany. TurkBerlin00 2000.
Keywords : Meat; turkey; elisa; Swine; Influenza; Germany;
Notes : Fowl plague was first described by Perroncito in 1878 in
Piemonte, Italy. There have been cases in Australia, England, USA,
Ireland, Mexico, Pakistan, USA. After events in Italy the
awareness of the turkey industry has increased in many countries.
Voluntary investigations are ongoing. The German Turkey Producers
association has been testing all meat turkey flocks since the
middle of last year. A total of 533 flocks (10 samples/flock)
have been tested. A commercial Elisa (IDEXX) has been used -
positives are re-tested by HI for H5,H7 25 flocks (4.7%) are
Elisa positive (147 samples - 2.8%). All except 1 of the positive
flocks were from northern Germany. All positive samples were
tested for H5 and H7 by HI and all were negative. 9/12 of the
positive flocks were positive for H6. Sera tested and found Elisa
positive in other laboraties were H6 positive also. Conclusions
are that H5 and H7 are not circulating in Germany. There is some
H6 and H1, it is believed that at least some of this is of swine
origin.
Ref Number : 293
37. Starick, E. and Ortrud, W.
Detection and characterisation of recent German avian influenza
virus isolates by molecular biological methods. TurkBerlin00 2000.
Keywords : Avian Influenza; virus; PCR; turkeys; Germany;
sequencing;
Notes : H9N2 viruses were isolated in Germany in 1995 and 1996.
In the past 2 years most isolates have been various combinations
of H6. This project aimed to develop molecular biological methods
targeted at the haemagglutinin. PCR products were generated and
cloned for sequencing. All isolates originated from turkeys in
Germany in 1998 and 1999. Deduced amino acid sequences found
greater than 98% homology.
Ref Number : 288
38. Halvorson, D. The control of avian
influenza. TurkBerlin00 2000.
Keywords : control; Avian Influenza; chicken; disease; virus;
Temperature; poultry; Swine; Birds; turkeys; infections; turkey;
production; education; density; vaccine; risk; serology;
Influenza;
Notes : We are now in a new era in influenza control. The Hong
Kong incident with 18 people infected with HPAI of chicken origin
with a 30% mortality rate has led AI to be reclassified as a
zoonotic disease. This could raise food safety issues (in HK
chicken consumption dropped 70%). It is agreed that the best
control is to keep it out - where this is possible. Subtypes
refer to the surface antigens, pathotype on pathogenicity - not
all H5 and H7 ar HPAI. The virus can survive for a week at
ambient temperatures, months in winter. This virus requires a
dense population of susceptible hosts. It has a high mutation
rate and its segmented genome facilitates natural recombination -
potentially 255 combinations from any 2 viruses coinfecting a
cell. There are other reservoirs to consider in addition to
wildfowl - live poultry markets and swine. Minnesota has 10000
lakes and is the largest brooding area for wild waterfowl in the
US. Live bird markets are mainly a problem in the eastern US - e.g.
H7 in New York live bird markets for the past few years. The
trick is to avoid commercial poultry becomming a reservoir. In
Pensylvania in 1980's, Mexico and more recently in Italy when
LPAI became established HPAI eventually emerged. All influenza is
a serious problem in turkeys and the subtype does not really
matter for this. HPAI can emerge (this has not happened in
Minnesota). The author has seen 70% mortality in LPAI. There is
no uniform control programme for LPAI. The Minnesota industry has
decided that it must look for this infection, there must be an
immediate and energetic response - don't worry about finding HPAI
because federal government will be too slow to act anyway. If
HPAI and LPAI are circulating simultaneously it is very
complicated. Grower cooperation is key to all control programmes
- the producers interest must be kept at heart, programmes should
incentivate control. Since 1978 there have been more thatn 100
outbreaks in Minnesota, involving more than 1000 flocks. Every
flock which is grown or processed is checked serologically. Each
year there tend to be different subtypes from the previous year.
"Live with the introduction" rather than "live
with the disease". The worst outbreak was in 1995 - this and
the HK incident has reduced range turkey production from about 10%
to about 1%. The key points are to remember waterfowl, range
growing, unclean load out equipment and personnel, partial flock
removal, marketing of actively infected birds and inadequate
cleaning and disinfecting - this is the basis of the Minnesota
voluntary AI control programme. A major factor is to provide
education to prevent exposure and spread - annual meetings,
publications etc. We must keep in mind that turnover rates are
often high (e.g. catching crews). Monitoring is required to allow
responsible responses and appropriate vaccination. A responsible
response - concentrates in not causing inadvertent penalties -
asking to slaughter involuntarily encourages non-reporting. The
best thing to do for an infected flock is to delay marketing
until after the acute phase then progress to orderly marketing.
Scheduling of new stock onto the farm needs to be modified.
Spread reduction measures must target specific, most important
people (those with direct contact with the flock and its manure).
Catching crews and equipment are the main issue. Brood and move
is normal so this move is a good way to spread disease. What is
appropriate vaccination : killed injectable, aiming to reduce the
susceptible population where biosecurity is not enough (where
there is area spread due to high farm density) . It is unlikely
to be overused because of the difficulty - its important that it
be of the right type. Problems - as there is no compensation
programme - lack of a vaccine might encourage intentional
infection (e.g. in breeders). Effective vaccination reduces the
numbers of susceptible birds, reduces the number of infected
birds and the quantity of virus shed on challenge (by 99%). Lack
of a vaccine can cause financial disasters. USDA and EU have
expressed concerns about vaccination and it will not prevent
infection or transmission. However laboratory studies that it
reduces it substantially. Field results with approved vaccine in
the USA has not been associated with any homologous failures.
Vaccination crews are a risk but so are all crews. - it is a
manageable risk. Serological titres are indistinguishable - so
are they for ND - serology is identical for LPAI and HPAI.
Vaccination does not protect against transmission - this is
largely theoretical. "Use of vaccine sends the wrong message"
- is it preferable to allow LPAI to circulate freely? In
Minnesota - 45 million turkey population - only 1-5% are
vaccinated each year. The Utah 1995 outbreak demonstrated the
benefit of an effective vaccine. Lessons : Vaccine should be a
first resort not a last resort. Suggestion - conditional
licensing, controlled use, must be inactivated. Killed vaccines
are not a threat if used as part of an integrated control
programme - the advantage of reducing circulation of LPAI far
outweighs any disadvantages. If international agreements are a
problem we should change them. Serological monitoring relies
exclusively on the AGP test.
Ref Number : 287
39. Alexander, D.J. and Gough,
R.E. Avian Influenza in turkeys. TurkBerlin00 2000.
Keywords : Avian Influenza; turkeys; review; disease; Birds;
Human; virus; poultry; surveillance; density; turkey; production;
Ducks; infections; egg drops; Pasteurella; vaccine; control; feed;
Pig; Influenza; legislation;
Notes : This paper will review this disease in turkeys.Influenza
type A affects both birds and a broad range of mammals (esp
humans, pigs, horses), type B have been isolated from humans (recently
from seals) and type C have only been isolated on rare occasions
in humans or pigs. Influenza A virus are classified according to
their 2 major proteins, haemagglutinin (15 types) and
neuraminidase (9 types). All types have been found in birds, in
humans mainly types 1-3. Many years ago it was recognised that
there was an association between waterfowl and avian influenza.
Much of the early work was done in Canada and this demonstrated
association between migratory wildfowl and respiratory disease in
poultry. Surveillance showed a high proportion of samples,
especially from juveniles, to be positive for influenza viruses..
They have also been identified from psittacines in quarantine,
but mainly mallard (18.9%) and anseriformes (15%). Waterfowl can
occur at high density, especially on lakes on migratory flight
paths. Turkey production tends to be concentrated in particular
areas. In California and Minnesota there is overlap of high
concentrations of poultry and waterfowl. Sentinel ducks show that
isolation of AI in north america is seasonal and matches wildfowl
migration. The same subtype tends to be dominant in both
waterfowl and commercial turkey flocks. These findings encouraged
the housing of commercial turkeys in North America. There are 2
pathotypes of influenza in poultry - low pathogenicity induces
mild respiratory disease, depression, egg production problems and
may exacerbate other infections. High pathogenicity is associated
with severe disease, usually only H5 and H7 subtypes, mortality
close to 100%. In practice, in the field it can be difficult to
distinguish between the 2 types because of high mortality in LP
cases due to other diseases. In LP infection there are a variety
of factors affecting severity - the virus, host age (younger
birds more affected), and other pathogens. LPAI occurred in GO in
1979 - it affected 50 week old birds H7 showed only mild
respiratory disease - in various other cases there were white egg
shells, mishapen eggs, marked egg drops, sometimes low mortality.
Use of a live Pasteurella vaccine at the time of challenge
resulted in 10% mortality on 2 weeks in one case in the USA. HPAI
cases are relatively uncommon, only about 18 index cases recorded
since 1959 - equal numbers of H5 and H7 in turkeys, more H7
overall. There were as many cases in the 1990's as in the
previous 30 years - an emerging problem? HPAI in turkeys - sudden
high mortality, up to 100%, cessation of egg laying, respiratory
signs, oedema and cyanosis of the head, haemorrhages in tissues,
neurological signs. Control - the most effective method is to
prevent the virus entering a country, area, farm and flock. This
is easier to achieve in island countries. Legislation covers
issues such as vaccination, slaughter policies etc. On the farm
the main options are prevention of infection and vaccination.
Farm biosecurity : planning and design - all commercial farms and
flocks should be well separated, hatcheries should be isolated
from farms, separation of species by farm, ensure adequate fresh
water (not surface water). Basic house biosecurity should include
bird-proofing of houses, stores, water tanks, movements on and
off farms should be controlled, visits between different farms
should be carefully controlled. - vectors are caretakers, farm
owners, staff, feed lorries, hatchery vehicles. etc. AI vaccines
have been formalin or BPL inactivated vaccines in oil emulsions.
Ref Number : 290
40. Valentina, A.D., Fabris, G. and
Gavavzzi, L. Avian Influenza H7N1 in broiler breeders and meat
turkeys in the north area of italy: clinical and serological
investigations. TurkBerlin00 2000.
Keywords : Avian Influenza; broiler; Meat; turkeys; Birds; turkey;
production; elisa; feed; egg drops; Influenza;
Notes : Influenza viruses have been found repeatedly in various
avian species in Northern Italy over the years, 1970's, 1980's,
1994, 1997. Current series started in March 1999. Inappetance was
the most marked sign, also paralysis, gasping, sinusitis, sc
emphysema, pus in sinuses and the syrinx. In broiler parents
flaccid ovaries, and tracheitis were associated with peritonitis.
In commercial turkeys mortality was highest in birds of 20-60
days - on average morality was 10% above normal for all affected
flocks. One case in turkey parents affected at 32 weeks of age
resulted in a marked drop in production which persisted for the
life of the flock. In commercial turkeys HI titres were 1:16-1:128
Elisa tests were very sensitive - titres of around 1100. The
problem also reduced feed conversion by 200 grammes, reduced
weights at slaughter by 1.5kg, and increased condemnations by 3%
- egg drops ranged from 30 to 60% HPAI Devastating effects with
almost total losses, direct estimated damage is estimated at 210
million Euros. It is proposed that all H5 and H7 viruses should
be considered potentially highly pathogenic.
Ref Number : 292
41. Mutinelli, F., Capua, I., Bozza,
M.A., Grossele, B. and Furlattini, V. Comparative intraveneous
pathogenicity for turkeys and chickens of the low pathogenic
avian influenza A/ty/Italy/3675/99. TurkBerlin00 2000.
Keywords : turkeys; Chickens; Avian Influenza; Meat; chicken;
turkey; Birds; control; Feathers; growth; enteritis; virus;
Incidence; Influenza;
Notes : LPAI faced Italy from March to December 1999 - 199
outbreaks of which 164 in meat turkeys - a severe condition in
meat turkeys which led people to question the validity of using
the chicken test data. This project aimed to compare the results
of IVPI test performed in chickens and turkeys. 22 SPF chicks and
commercial turkey poults were divided in 4 experimental groups of
11 birds each. They were tested for seronegativity at 4 weeks for
a range of pathogens. Inoculation was in accordance with the
directive at 4 weeks of age.- 1 control group and 1 inoculated
per species. Birds were examined daily for clinical signs and
sacrificed at intervals. Birds were necropsied and selected
organs were collected for virology, histology and histochemistry.
Infected poults develped a clinical condition characterised by
depression, anorexia, ruffled feathers, diarrhoea and this
resulted in marked stunting growth while infected chickens
remained healthy. The gross lesions were of an acute haemorrhagic-necrotic
pancreatitis proceding to fibrosis and atrophy. There was
enteritis and mal-absorption as well. Virus was isolated up to
day 5 p.i. Influenza A antigen was demonstrated by
immunohistochemistry of the pancreas using the commercial "EnVision"
system. In chickens virus was isolated only until day 2 p.i.
There were low incidence lesions of pancreatitis and nephrosis in
chickens. Histochemistry was much more commonly positive in
turkeys than in chickens Conclusions - LPAI strain used appears
to replicate much more effectively in turkeys than in chickens,
the pancreas is a particular target.
Miscellaneous
Ref Number : 285
1. Szolgyenyi, W. Diagnosis of avian
mycoplasmosis by PCR and internal positive controls. TurkBerlin00
2000.
Keywords : PCR; control; serology; culture; Sensitivity and
Specificity; Mycoplasma; turkey;
Notes : From the University fo Vienna - using PCR for
supplementing the traditional approaches to diagnosis (Serology
and Culture). PCR provides high reliability, both respect to
sensitivity and specificity - economical as well. The MG product
of 16S rRNA covers 186bp - separatedy by pulsed gel
electrtophoresis, stained by ethidium bromide. PCR can also have
problems of false positives and negatives, e.g. laboratory
contamination of previously amplified products, or on the other
hand inhibition of taq polymerase. To achieve a detection level
usually about 30 cycles are required. Inhibition can grow also
with increasing cycles. Remember that reference strains are very
clean with no inhibiting materials. PCR optimization - inclusion
of positive and negative controls. Trials were carried out to
determine the optimal concentration of an IPC internal control.
Ref Number : 284
4. Gazdzinski, P. and
Hunter, B. Hypothyroidism in turkey breeder candidate hens.
TurkBerlin00 2000.
Keywords : turkey; Birds; Liver; biochemistry; control; disease;
feed; Temperature;
Notes : Description of syndrome - hens affected at 22 to 30 weeks
of age. Hens loose balance and flip onto their back in the dark
period. Most die after a couple of days - over an 8 week period
is 1-1.5% - highest in the winter months house temperature under
50 F. Morality rises steadily from 23 to 29 weeks. When they come
into lay the problem disappears. In this work PM's were conducted
on live and dead affected birds along with detailed biochemical
and hormonal profiling. Also did hormone profiles of
experimentally stressed (flipped over) hens, as well as thyroid
stimulation testing, histology and immunohistochemistry.
Initially there were no significant lesions on routine necropsy,
histology, bacteriology, virology. Affected birds tend to be
heavier than normal (also increased liver size and abdominal fat).
Surviving flipped-over hens are losing weight during the period
in question. There were no significant effects on blood gases.
Biochemistry profiles showed many differences - sodium, potassium,chloride,
blood protein low, uric acid and ketone bodies were high. However
it is now believed that these effects were due to hens lying on
their back. "Fresh flipovers" showed no significant
effects on these parameters. Thyroid hormones were 277 pcg/ml in
affected hens shortly after flipping, compared to 900+ in
controls (T3). A similar pattern was seen with T4 - recovery to
similar levels after a couple of days. Flipping birds
experimentally increased corticosterone 3 times but had no effect
on thyroid hormones. Histology showed variable intensity of
colour of matrix in the thyroid, degenerate follicles, sloughing
of epithelium, and an acute or chronic thyroiditis - mainly
lymphocytic infiltration. TSH stimulation testing showed a
response for T3 and T4 but levels were much lower than for normal
hens. Is this an autoimmune disease? Preliminary
immunohistochemistry has not revealed turkey antithyroid
antibodies. Detected changes initially were result of anorexia,
and dehydration/stress. The underlying disease is a thyroiditis
associated with low thyroid hormones and poor response to
stimulation. This problem has been seen to date only in BUT birds,
not Nicholas and Hybrid, at least as seen in this company to date.
The problem has not been seen in commercial birds. The problem
does not seem to be response to increasing levels of iodine in
feed. Water sanitation with iodine may be the next step.
Ref Number : 283
5. Panshin, A., Shihmanter, E.,
Weisman, Y., Orvell, C., Kydyrmanov, A., Sayatov, M., Asanov, M.,
Nyaga, P.N. and Lipkind, L.M. Comparative antigenic
characterisation of Newcastle disease virus strains isolated from
turkeys and chickens. TurkBerlin00 2000.
Keywords : Newcastle; Newcastle Disease; disease; virus; turkeys;
Chickens; poultry; vaccine; turkey; chicken;
Notes : Newcastle disease is a devastating viral disease of many
avian species, that can lead to substantial losses in poultry. It
is caused by paramyxovirus, both chickens and turkeys are
affected. In general it is felt that vaccines are more effective
in chickens than in turkeys. This work seeks to compare the
antigenicity of various ND strains isolated from chickens and
turkeys. A bank of monoclonal antibodies were developed against
Haemagglutinin, F protein and structural protein. These MAB's
bound to 20-96% . Schematic models were derived from the results
suggesting the relationship between the various epitopes. Most
binding patterns were isolated from both species. On dendrograms
turkey and chicken strains were quite intermixed.
Ref Number : 280
6. Faye, I. Intensive turkey production with a
particularly animal-firendly housing system. TurkBerlin00 2000.
Keywords : turkey; production; poultry; Meat; turkeys; Free range;
broiler; density; feed; Female; Male; Antibiotics; growth; Birds;
Swiss;
Notes : Optigal is a main poultry producer in Switzerland -
turkey meat consumption is very low, production is only 45 t/year.
This company has been in turkeys since 1987, free range turkeys
in 1998, is ISO 9001 and ISO 14001 certified. Produces 13 million
broilers, 60% free range, 350000 turkeys, all free range. Use T9
imported as day-old - rear on deep litter in whole-house brooding
- houses are equipped with roosts, no debeaking with daylinght
via windows. Legally 5 lux, in practice 15 lux, minimum 8 hours
consecutive night. Density is 36.5 kg/square metre - there are
patios and yards (available after 43 days - the end of quarantine).
Feed is expanded and contains only vegetable protein, no GMO or
GP's Females are killed at 3-4 kgs and males at 7-9 kg. Losses
are decreasing, typically now 6% in males, 3% in females,
antibiotic treatments are reduced on free range. There has been
now obvious changes in growth rate, slight increases in FCR.
Production of free range T9 turkeys is feasible and improves
welfare - no specific problems are noted. Flocks are 2200 birds,
half male, half female (in accordance with Swiss law).
Ref Number : 279
7. Prusas, C. and Hafez, H.M.
Investigation on avian leucosis in commercial turkeys. TurkBerlin00
2000.
Keywords : leucosis; turkeys; Chickens; production; virus; Meat;
chicken; Liver; ALV-J; layers; culture; turkey; infections; elisa;
broiler; Germany;
Notes : Avian leucosis is the commonest B cell lymphoma of
chickens - associated with tumour production and reduced
productivity. Exogenous virus induces new infectious virus in
susceptible host cells - subgroups A,D and J are most common.
Endogenous virus (subgroup E) is integrated in the genome of
chickens. ALV-Subgroup J is a new subgroup first identified in
the UK in 1989 - it was associated with tumours and production
problems in meat type chicken breeders. There is evidence of
increasing virulence. Infection causes typical myelocytomas in
liver, spleen, bones. ALV-J appears to be a recombinant between
exogenous and endogenous ALV's. It is able to propagate in cells
resistant to subgroup A and E virus. Its main difference is
increased horizontal transmission and increased pathogenicity in
meat-type chickens (less in layers, opposite situation for
subgroup A). The target is myelocytes rather than B cells. Avian
species vary in susceptibility to sub-groups (based on avian
fibroblast cultures) - turkey cells are susceptible to all types.
This led to interest in investigating the presence of this
infection in turkey farms. Breeding and meat turkey flocks were
examined by P27 Elisa for antigen and GP85 for antibody - all of
16 flocks were negative in both tests. In further work a very low
positivity of antibody (0.7%) of 417 samples from 39 turkey
flocks. Equivalent figures for layers was 1.3% and 16.6% for
broilers. These reactions could be non-specific. Reactions are
insignificant in turkeys at present in Germany, though there is
evidence of its occurrence in broilers.
Ref Number : 282
8. Buda, S. Foot pad lesions and the influence
of biotin in turkeys. TurkBerlin00 2000.
Keywords : turkeys; density; management; Antibiotics; layers;
Birds; electron microscopy; Male;
Notes : Foot pad dermatitis is very common in growing turkeys -
they are at least uncomfortable and may be painful. What are the
factors ?- stocking density, type of litter and its management,
water system, and possibly biotin. According to the literature
the requirement is 275-325 mcg/kg. There are differences in
bioavailability in accordance with the raw material. There may be
interactions with drugs (antibiotics). Symptoms of deficiency are
dermatitis or cracking of foot pads. Avian skin has no skin
clands - composed of lipid-rich sebokeratinocytes - responsible
for the synthesis of keratoproteins and lipids in multi-granular
bodies. Layers are Stratum Corneum, Stratum Transitivum, Stratum
Spinosum, and. Lipid deficiency causes structural changes -
elongation of reticulate scales, proliferative hyperkeratosis,
decrease in cytokeratin filaments, etc. Experimental birds (10/group)
were supplmented with either 2000 mcg biotin or 300 mcg per kg.
Methods used were light microscopy, electron microscopy. There
were no differences between the groups with respect to gross
lesions - there were marked differences on electron microscopy
and light microscopy (less distinct than in clinical biotin
deficiency) - surfaces much smoother in supplemented birds.
Summary - 4 differences - morphology of reticulate scales, size
of dermal papillary layer, Most commercial flocks suffer from
foot pad lesions. Sufficient biotic is necessary to prevent skin
lesions. 300 mcg/kg is probably not optimal, especially for male
turkeys.
Ref Number : 277
9. Foulmann, A. and Glunder,
A. Induction of a humoral immune response after the immunisation
of turkey poults using an inactivated Bordetella avium vaccine.
TurkBerlin00 2000.
Keywords : turkey; vaccine; consumer; Antibiotics; elisa; disease;
infections; immunity; IgG; Birds; serology;
Notes : How can we respond to consumer demands to reduce use of
antibiotics - immunisation. Can we achieve specific protection ?
It is proposed to use inactivated vaccines to protect poults
between 3rd and 6th week of life. Bordetella avium was chosen
because the bacteium was available, a commercial Elisa test is
available and it has disease significance. The literature
suggests that infection or vaccination of turkey hens allows
protective maternal immunity for 3 weeks. Infection of turkey
poults results in a detectable serological response (IgA, IgG,
IgM) - some experiments have also been done with vaccines.
Materials - B.avium, ATTC 35096 10^10 CFU/dose formol inactivated
0.5%, and incomplete Freunds adjuvant. - 2 concentrations .2 ml
and .5ml dose. The birds were Big 6 bought at 1 day old. Serology
was conducted with the KPL kit. Application was s/c in leg 0.2 ml
up to 14 day, and 0.5ml up to 21 days. Various ages and
combinations were used. Sera were collected weekly and stored.
Results were similar in all groups - antibody response increased
on day 28 and peaked at 48 days (15-3000 titre). In each group
the response was homogeneous. Two applications resulted in a
slightly more rapid response but peaks were similar regardless of
the schedule (not statistically significant at 42-56 days, some
differences at 28-35 days. Conclusions - administration of
inactivated B.avium vaccine applied before 21 days of age is
immunogenic - 2 doses increases antibody more rapidly. The
serology to date is based on IgG Elisa - the authors plan to look
at agglutinins and examine effects of various adjuvants.
Ref Number : 278
10. Voelckel, K., Redmann, T., Bertram, E.,
Neumann, U. and Kaleta, E.F. Marek's disease in fattening turkeys:
Clinical signs, pathology, detection of causative agent (MDV
serotype 1) by PCR. TurkBerlin00 2000.
Keywords : Marek's; disease; turkeys; PCR; infections; virus;
Birds; Chickens; serology; elisa; rev; culture; Liver; Germany;
Notes : Turkeys are known to be susceptible to experimental
infection. Similar field disease has been identified, but the
virus involved is rarely identified. This work relates to 4 sites,
2 very small , 1 with 150 birds and 1 700/crop. It is believed
that all 4 had contact with chickens and/or other domestic or
wild birds in early life. The 2 larger sites were multi-species.
There was no direct contact between the farms. Virology was
conducted with CEF and CEKC, serology by VNT, AGP (HVT, MDV_1)
and Elisa (REV, REV). Histology of spleen was also counducted.
PCRs were conducted on tumour and buffy coat cells for MDV-1 (132-bp
repeat), REV and LPDV (proviral LTR). Clinical signs in affected
turkeys were non-specific. Older birds often died with no obvious
signs, some lesions were detected at slaughter. Livers may have
obvious tumours or be generally enlarged, spleens can have one
large or many small tumours. Histology shows pleomorphic
infiltration with mainly mononuclear cells. Only HVT was detected
in cell culture systems. All tested birds had HVT SN antibody.
MDV AGP was negative. The PCR identified the presence of
oncogenic MDV 1 in all 4 farms. Conclusions - turkeys are
susceptible to MDV-1 and develop tumours. We do not know why
infected turkeys become persistently viraemic and develop disease.
So far only small populations under non-industrial farming
conditions are affected in Germany. Circumstantial evidence
suggests lateral infection from MDV-1 infected chickens.
Ref Number : 276
11. Kin, E. and Samberg, Y. Use
of multicomponent vaccines against turkey diseases. TurkBerlin00
2000.
Keywords : vaccine; turkey; disease; turkeys; Newcastle; PMV; ORT;
serology; control; elisa; Birds; Pasteurella; immunity;
Notes : Efficient vaccination programmes play an important part
in the prevention of turkey diseases. In Isreal turkeys are
vaccinated against Newcastle Disease, PMV 3, Yucaipa, AE, ORT,
Erysipelas etc. All inactivated vaccines are adminstered by
individual IM injection. By combining vaccines it is possible to
reduce handling. Four multivalent experimental vaccines were
produced, ND+HE, ND+PMV2+PMV3, ND+Pasteurella, Ort+Pasteurella.
Titres are quoted in the abstract. Safety tests were carried out
with 10 susceptible turkeys, 10 doses/bird, and observed for 21
days. Most vaccines were applied to commercial flocks at 21 or 28
days and evaluated by subsequent serology. Control groups were
not included in field trials - serology was HI for ND, PMV2 and
PMV3, Elisa for Ort, and immunodiffusion for HE. Birds were also
challenged with ND, Pasteurella and HE. ND-HE combinations showed
a good serological response and challenge protection. The
trivalent PMV1-3 vaccine showed a good response for all serotypes
but in most cases ND titres were higher than for PMV2/3 - there
was satisfactory immunity post challenge. The ND/FC vaccine was
also effective in serology and challenge studies.
Ref Number : 274
12. Kaiser, P. and Shelly, L.
Developing turkey reagents: Cytokines and cell surface markers.
TurkBerlin00 2000.
Keywords : turkey; markers; immunity; chicken; production; growth;
macrophages; T cells; Human; elisa; virus; Chickens; assay;
turkeys; IgG; infections; TRT;
Notes : The acquired immune system may be split into cell
mediated and humoral immunity. Both systems are controlled by
cytokines, different cells for each system. Knowledge of the
system was originally acquired in mammals. Data to date on the
chicken suggests that it is similar, in the turkey less is known
for lack of reagents. This project was financed by BTF and aimed
to produce turkey cytokines and then look at their activity as
adjuvants and immune modulators (not covered here). This talk
will cover production and characterisation as well as the basic
reagent work. Previously only IFN gamma and type 1 IFN had been
characterised in turkey. It is pleiotropic and active in most
stages of the immune response, stimulates activation and growth
differentiation of T and B cells, macrophages, natural killers
and also epithelial cells - it is produced by NK and T cells. The
C-DNA for IFN gamma was cloned - there is only 30% identify
between chicken and human molecules - though much of the
structurally imporant parts are similar. Chicken and Turkey IFN
gamma are 97% identical. The prediction was that they would cross
react. A capture elisa for IFN has been developed in Belgium -
experiments used splenic cells stimulated by mitogens. Turkey
splenocytes produced IFN gamma detectable in the same system.
This work went on to look at recombinant IFN gamma - production
was assayed by a macrophage/nitric oxide bioassay. Both
recombinant chicken and turkey IFN gamma stimulated NO2
production by macrophages. A turkey virus was based on a
continuous turkey cell line stimulated with CM for 48 hours. Both
chicken and turkey r-N gamma was detectable in this system. The
activity could be neutralised by monoclonal and polyclonal
antibodies against IFN. This work will be published later this
year. Interkeukin 2 - stimulates growth and differentiation of
many cells involved in immune response, - stimulates expression
of other cytokines and is produced mainly by TH1 cells. The DNA
of turkey IL-2 was cloned using turkey-specific primers and
genome walking. Again the identity with human IL2 was only 30%,
chicken and turkey commonality was 84% but only about 70% in
amino acids. In spite of this the main structure appears to be
reasonably conserved. Knowledge of the mammalian molecules helped
identify receptor structures, some are conserved between chickens
and humans, some not. The prediction based on this was that
chicken and turkey IL2 would not cross react. Tests were
conducted in various assay systems, e.g. chicken splenocytes
stimulated by ConA - in all assays there was a high degree of
cross-reactivity. However it is possible to produce monoclonal
antibodies which neutralise the bioactivity of chicken IL2 and
not turkey IL2. Reagents Do existing chicken reagents cross react
with the turkey reagents - this knowledge would speed up work on
turkeys. Chicken reagents - antibodies to CD3, CD4, CD8, CD28,
TCR and some others. Flourescent-activated cell sorting was used
- binding anti-chicken CD4 attached to an anti-mouse IgG and a
flourescent marker. Summarising the data - CD4. CD8, CD28, and
some TCR, Bcell and anti-macrophage showed good reactivitiy for
at least some monoclonals. Further work was carried out to
confirm that these response were specific (i.e. same epitope on
same molecule). Some infection studies have been carried out on
TRT showing virus levels in infected levels (including
quantitative RT-PCR) and hope to present this next year. There
are influxes of successive T-cells into the Harderian gland -
showed immuno-peroxidase sections.
Ref Number : 275
13. Sharma, J.M. and Silke, R.
Role of cytokines in haemorrhagic enteritis in turkeys.
TurkBerlin00 2000.
Keywords : Haemorrhagic enteritis; enteritis; turkeys; adenovirus;
control; colisepticaemia; infections; virus; T cells; growth;
intestine; macrophages; Birds; production; turkey; sheep;
Notes : HE is caused by Type II avian adenovirus - at one time
caused major losses and is now under control through vaccination.
Infected turkeys show splenomegaly and intestinal haemorrhages.
Mortality may be 1-60%. Its main problem is immuno-suppression,
death often is through colisepticaemia. Splenic enlargement is
obvious at about 4 days post infection - typically 100%+ increase
in weight. The virus seems to replicate in IgM bearing cells -
these drop to a trough at day 4 and stay lower than controls for
at least 20 days. Culturing in sorted cells showed that there was
no activity in T cells and growth was greatest in the IgM bearing
cells. In the intestine there is considerable destruction of
tissue but very little viral expression - low level of virus is
found in minimal (Background) levels in bursa, duodenum and
thymus, much more in caecal tonsil, and most of all in spleen.
Why is there so little virus in the affected intestine? It was
hypothesised that although it replicates in B cells (possibly
macrophages) - perhaps T cells are stimulated to produce
cytokines (e.g. TNF) which cause the gut damage. There is
evidence that CD4 cells increase in the acute phase, also T cells
in the spleen seem to be transiently less responsive to mitogen.
If the T cells are involved in the gut lesion can we moderate it
by moderating T cell activity with cyclosporin A. CsA have
reduced response to ConA after cyclosporin treatment, though
there was no effect on their ability respond with antibody to
sheep RBC and B. abortus. In the preliminary experiment gut
lesions were reduced from 50% to 0 (10 birds per group) but had
no effect on virus titre in spleen or splenomegaly. No inducing
factor was shown to be markedly increased in spleen cells from
virus infected birds treated with ConA. IL6-like factor and TNF
production were similarly increased. It is suggested that the
intestinal lesion is mediated by cytokines produced by T cells
and macrophages, probably mainly TNF (thalidomide inhibits
response). Further works needs to be done to characterise the
details of the cytokines involved. The main lesions are in the
duodenum - suggested that the duodenum is the target for the
shock syndrome in turkey.
Ref Number : 308
16. Heinen, E. and Pirro, F.
Enrofloxacin and difloxacin in turkeys: In vitro activity and
pharmacokinetics. TurkBerlin00 2000.
Keywords : enrofloxacin; turkeys; enzymes; E.coli; Birds;
Salmonella; report; resistance; chicken;
Notes : Enrofloxin and difloxacin are fluoroquinolones which act
on DNA gyrase enzymes. Enrofloxacin was the first fluoroquinolone
developed exclusively for veterinary use. Its efficacy has been
widely documented. Recently difloxacin was approved. There are no
published comparative data. There are small differences in
structure, however these have considerable effects on activity.
In the in-vitro studies both E.coli isolates obtained from
healthy birds at slaughter and those from clinically sick flocks
were used. Clinical isolates showed a range of mic's - 0.004 to
64 for enrofloxacin, and 0.015 to >128 for difloxacin. There
is a trimodal distribution of sensitivity suggesting a number of
mutations - not surprising given that it is likely that some will
be from treated flocks. For both E.coli and Salmonella the MIC's
for Difloxacin tended to be 2 dilutions higher. In Salmonella
there appears to be a bimodal distribution. There have been
reports from the UK of Salmonella resistance to Naladixic acid -
it is not entirely clear how this relates to fluoroquinolone
resistance and the role for clonal spread. When examining the E.coli
isolates from healthy birds there is a townward trend in mean MIC's
The equivalent chicken data have been published. Pharmacokinetics
- used BUT Big 6 - 1200-1500 g with n=4 per sampling. Commercial
products were administered either as a single oral dose or
continuous medication over 3 days. Both drugs were rapidly
absorbed - peak 0.9-2 mcg/g in enrofloxacin while 0.7-0.85 in
difloxacin. There is 100% + tissue concentration in enrofloxacin
but only 10-15% in difloxacin. Difloxacin depletion also occurred
much more quickly. With continuous medication peaks of .6-1.2
occurred rapidly - steady state 0.5, equivalent for difloxacin
was about .4-.6 and steady state less than 0.2.
Ref Number : 309
18. Irion, T. Turkey coccidiosis: Experiences
with Toltrazuril. TurkBerlin00 2000.
Keywords : turkey; Coccidiosis; toltrazuril; eimeria; Chickens;
turkeys; Geese; Pigeons; immunity; risk; control; anticoccidial;
Notes : Toltrazuril is a triazine trione formulated in
trithanolamine and highly soluble in water. It has been shown to
be effective for all important Eimeria species of chickens,
turkeys (adenoides and meleagrimitis) also geese, pigeons, etc.
Rapid elimination of the parasite is due to the high efficacy
against all intra-cellular stages. It achieves this without
inhibiting development of immunity - perhaps because the
trophozoites and merozoites are not affected (allowing docking
responses) and because the dead parasites can be detected in
cells for a number of days. Immunity, depending on timing of
treatment, may be enhanced. Toltrazuril may be used strategically
at periods of high risk (e.g. around 28 days). Results of field
trials in France were conducted with administration of
Toltrazuril at start of clinical signs. Most flocks had recovered
by 4 days post treatment - judged by clinical signs and lesion
scores. A comparative study between different compounds carried
out in 1991 was presented to show improved oocyst excretion
control and weight gain of toltrazuril compared to potentiated
sulphonamides. Treatment with toltrazuril 2 days before the HE
vaccination appears to reduce vaccinal reactions - even in
addition to the normal in-feed anticoccidials improved weights by
200 g and improved FCR by .02 - this more than paid for the cost
of medication. For successful water medication the dosage should
be calculated on the basis of mg/kg liveweight. 7 mg/kg is the
minimum dosage in turkeys.
Ref Number : 296
32. Mulling, C. Structure and function of
the respiratory system in poultry. TurkBerlin00 2000.
Keywords : poultry; Birds; Heat; Air; infections; turkey; Animal;
anatomy; respiratory system;
Notes : We start our journey with the nasal cavity, entering via
the nares which may be partly occluded by an operculum. There are
three conchae, anterior, medial, posterior - the anterior
surfaces are covered by stratified squamous epithelium. In the
middle area the conchae are covered by ciliated epithelium with
unicellular glands (typical of the respiratory system) - a
transverse section will show the infra-orbital sinus. A traverse
section in the posterior part will show the caudal chae and it is
covered by olefactory epithelium (area is proportional to sense
of smell). Lateral to this is the nasal gland, important for salt
excretion in marine birds. The nasal conchae have a heat exchange
function and recover 70% of the moisture in the expired air. The
infraorbital sinus is susceptible to infections and inflammations
- it is a triangular cavity and is only covered by skin laterally.
Functions of the nasal cavity are Filtration - cleaning of
inhaled air, olfaction thermoregulation - heat and water
exchanging system. The larynx consists of 4 cartilages and is
connected in front to the hyoid bone and the back to the trachea.
Birds have a long and relatively thick trachea compared to
mammals of the same bodyweight. Cartilage rings overlap
alternately above and below. The cavity is covered by respiratory
epithelium although there are many more and larger epithelial
glands so more mucus is produced. In birds the voice is produced
by the syrinx- a very complicated structure composed of modified
cartilaginous rings connected with lateral and medial elastic
membranes. In the middle is the Pessalus which is covered in
cornified epithelium. The tension of the membranes is regulated
by the syrngial muscles with resultant modulation of voice. There
is a complicated system of bronchi in birds which are named
according to the direction in which they run (e.g. medial-dorsal).
The parabronchi are an anastomising system of airways connecting
the secondary bronchi. Infundibula and atria connect the
parabronchus with air capillaries which are closely associated
with the ccirculatory system. The blood gas barrier is similar in
structure to mammal but only half as thick - the diameter of an
air capillary is 10% that of a mammalian alveolus. There is a
counter-current exchange system in which airflow and blood flow
are in different directions. In addition there are the air-sacs -
bellow-like structures. There are the cranial and caudal groups -
in the turkey the cervical clavicular sacs have fused so the
total is 7. There is a simple squamous epithelium and there is no
air exchange. On inspiration and expiration air always goes
through the parabronchi in the same direction. The thoracic cage
works as a pump handle. The overall effect is of a highly
efficient gas exchange system - the most efficient of all air
breathing animals.
Enquries
relating to proceedings and future meetings:
Prof.
Dr. H. M. Hafez
Institute
for Poultry Diseases,
Free
University, Berlin, Koserstr. 21, 14195 Berlin, Germany
Tel +49 – 30 83853862
Fax +49 – 30 83855824
E.-mail
: hafez@zedat.fu-berlin.de