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ZOONOSES RISK FOR THE CONSUMER – RELEVANCE OF

TURKEY

AN EVALUATION OF THE INFORMATION FROM THE

EUROPEAN UNION ZOONOSES NETWORK

Annemarie Käsbohrer

Community Reference Laboratory for the Epidemiology of Zoonoses

BgVV, Berlin, Germany

Source of information

Within the European Union, in Council Directive 92/117/EEC the overall goal is

to prevent and reduce the appearance of zoonoses which pose a threat to

human health. In the future, information should provide for risk assessments

and risk management decisions. For this purpose, appropriate and sufficient

monitoring of zoonoses and agents thereof has to be implemented by all

countries. Currently, eleven different zoonotic diseases or agents are covered

by the system. As regards turkey, the current systems mainly deal with

salmonellosis. For the other zoonoses, only exceptionally data are provided

within the zoonoses reporting system.

To get some insight into the relevance of turkeys for zoonotic infections in man,

an evaluation was made on the data available in the zoonoses report

(Anonymous, 2002). For turkey, no compulsory monitoring programmes are

implemented on the level of the European Union. Information is based on

activities in the individual member states. In some countries, compulsory

monitoring programmes are implemented for Salmonella in breeding flocks.

Furthermore, information out of voluntary monitoring programmes, surveys and

from diagnostic examinations is used to get a rough estimate of the current

situation and the dominating Salmonella serovars in turkeys and products

thereof. As regards zoonotic infections in man, data are derived from the

national surveillance programmes. This is based either on a requirement for

physicians to notify cases or for laboratories to notify isolations from clinical

specimen.

Recent situation

The incidence rate of human salmonellosis is varying on a wide rage between

the countries. Nevertheless, a decreasing tendency of reported cases can be

observed over the last years. The main serotypes causing human disease are

given in Table 1. S. Enteritidis and S. Typhimurium are counting for 72% of all

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reported cases. There is much variation between the countries. In Austria and

Germany, more than 80% of all cases are caused by S. Enteritidis or

S. Typhimurium. This is different in Finland and Sweden, where less than 60%

of all reported cases are caused by S. Enteritidis and S. Typhimurium.

Some outbreaks of human salmonellosis were reported where turkey meat was

suspected or confirmed as the source of infection. In one of these, precooked

turkey meat was contaminated with S. Agona (Synnott et al., 1998). In the

United Kingdom, 4 to 5% of the reported outbreaks are associated with turkey

(Kessel et al. 2001). In Denmark, 5 to 8% of the human salmonellosis cases are

estimated to be caused by turkey and ducks (Anonymous, 2001).

Currently only very limited data are available on the Salmonella contamination

of turkey meat specifically. Usually, the poultry species the food is derived of is

not specified in the report.

The sampling scheme fixed in Directive 92/117/EEC is applied in turkey

breeders in Finland, Sweden and Norway already for several years now. The

Netherlands, Ireland and France have started a control programme in turkeys

too. Information from other countries is available too (Figure 1).

Routine testing of production flocks before slaughter of each flock is done in

Denmark, Finland, Sweden, the Netherlands, and Norway (Figure 2). Usually

these programmes aim to detect at least a Salmonella prevalence of 5 % in the

flock. Different approaches for sampling are applied: faecal samples are taken

in the flocks one to four weeks before slaughter or cloacal swabs are taken at

the slaughterhouse; neck skin or swabs of the carcass are taken at the end of

the slaughterline; or cuts of meat are tested for Salmonella. From some

countries, data are provided from diagnostic examinations.

In the countries, where control programmes are run, Salmonella positive turkey

breeding flocks were only sporadically detected.

Data on the production level show that turkey and turkey meat might be a

source of human infection. Salmonella prevalence is varying in a wide range

which might reflect the different approaches taken for sampling or a real

difference in the prevalence rate. There is no unique pattern on the serotypes

prevalent in turkeys. Depending on the country, S. Enteritidis, S. Typhimurium

or other serotypes are the dominating ones. In Tables 2 to 4, the frequency of

serotypes in turkey and humans is compared for Austria, Denmark and England

and Wales. In Denmark, five to eight percent of human salmonellosis is

attributed to turkey and ducks over the last years.

Further developments

Further investigations are necessary on this topic. To face that problem, the

European Commission is currently adjusting the legislation. In August 2001, a

proposal (Document COM(2001) 452 final) was submitted which suggests a

directive for the monitoring of zoonoses and agents thereof as a tool for risk

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assessment and a regulation for the control of Salmonella and other zoonotic

agents transmitted by food. In the new directive, there will be a requirement for

the Member States to establish a monitoring programme for several zoonotic

agents according to the epidemiological situation. In the regulation, a control

programme to be implemented on Salmonella in turkey flocks is required in a

few years.

Conclusions

In summary, current data show that Salmonella are prevalent in turkey at

considerable rates. In consequence turkey meat is frequently contaminated with

this zoonotic agent. Those serovars isolated from turkey are also relevant in

human infection.

The current zoonoses network provides limited information on the monitoring

and control activities applied in 16 European countries and the results out of it,

the prevalence rates in feedingstuff, animals, food and the incidence rates in

man. Furthermore, the network allows to identify gaps in the current

approaches. It can be concluded, that harmonised monitoring schemes are

necessary to provide for valid data for risk assessments.

References

1. Anonymous, 2001: Annual Report on Zoonoses in Denmark 2000, Ministry

of Food, Agriculture and Fisheries.

2. Anonymous, 2002: European Commission Document SANCO/927/2002.

Report on ‘Trends and sources of zoonotic agents in animals, feedingstuffs,

food and man in the European Union and Norway in 2000’

3. Synnott MB, Brindley M, Gray, J, Dawson JK. An outbreak of Salmonella

agona infection associated with precooked turkey meat. Commun Dis Public

Health 1998, 1 (3), 176-9

4. Kessel AS, Gillespie IA, O’Brien SJ, Adak GK, Humphrey TJ, Ward LR.

General outbreaks of infectious intestinal disease linked with poultry,

England and Wales, 1992 – 1999. Commun Dis Public Health 2001, 4 (3),

171-7

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Figure 1: Salmonella monitoring and control programmes in turkey breeders

in the European Union and Norway in 2000

Figure 2: Salmonella monitoring and control programmes in turkey flocks on

production level in the European Union and Norway in 2000

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Table 1: Main Salmonella serotypes in human salmonellosis in the

European Union and Norway in 2000

Serotype %

S. ENTERITIDIS 59,14

S. TYPHIMURIUM 13,03

S. HADAR 1,77

S. VIRCHOW 1,36

S. INFANTIS 0,87

S. AGONA 0,75

S. BRANDENBURG 0,68

S. NEWPORT 0,53

S. BLOCKLEY 0,46

S. BRAENDERUP 0,43

Table 2: Main Salmonella serotypes in turkey and rank of this serotype in

human salmonellosis in Austria in 2000

AUSTRIA Turkey 1

Humans

Serotype % rank

S.SAINTPAUL 31% 9

S.HEIDELBERG 19%

S.READING 13%

S.ENTERITIDIS 6% 1

S.INFANTIS 6% 4

S.MONTEVIDEO 6%

S.AGONA 3% 10

S.AMSTERDAM 3%

S.KENTUCKY 3%

S.KOTTBUS 3%

1 Routine sampling

Table 3: Main Salmonella serotypes in turkey and rank of this serotype in

human salmonellosis in Denmark in 2000

DENMARK Turkey 2 Human

Serotype % rank

S.AGONA 25% 3

S.HEIDELBERG 25%

S.MONTEVIDEO 16%

S.RISSEN 11%

S.INFANTIS 9% 9

S.DERBY 7%

S.NEWPORT 2% 8

S.INDIANA 2%

S.HAVANA 2%

S.BRANDENBURG 2%

2 Compulsory ante-mortem examination

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Table 4: Main Salmonella serotypes in turkey and rank of this serotype in

human salmonellosis in Denmark in 2000

England and Wales Turkey 3 Human

Serotype % rank

S.DERBY 16%

S.TYPHIMURIUM 12% 2

S.AGONA 12% 8

S.NEWPORT 9% 6

S.FISCHERKIETZ 7%

S.ORION 6%

S.MONTEVIDEO 6% 9

S.SENFTENBERG 5%

S.KOTTBUS 4%

S.INDIANA 4%

3 Laboratory reports under Zoonoses order