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Zoonoses in the EU: Trends and Sources

by 5m Editor
21 January 2009, at 12:00am

Because zoonoses are infections and diseases that are transmissible from animals to humans, it makes it particularly important to keep these livestock diseases under surveillance and control, writes Adam Anson, reporting for ThePoultrySite.

In order to keep a track on the activity of these diseases within Europe, the European Food Safety Authority (EFSA) monitors the prevalence in each of the EU Member States (MS).

Infection via zoonoses can be acquired either by direct contact with infected animals, or by consuming contaminated food products. Consequently, to gain a true picture of how zoonoses affect the entire animal feed sector, EFSA have analysed data in human, animals and foodstuffs.

Once EFSA can adequately identify which animals and foods are the main sources of infections, it believes it will be will be better equipped to prevent them from occuring.

Most Common Zoonoses

The latest zoonoses analysis, released in January 2009, looks at data collected in the year 2007. According to the analysis, The Community Summary Report On Trends and Sources of Zoonoses and Zoontic Agents in the European Union in 2007, campylobacteriosis was again the most frequently reported zoonotic disease in humans in the European Union with 200,507 confirmed cases. Most of the Member States reported an increased number of cases of campylobacteriosis for that year.

The report says salmonellosis was still the second most commonly recorded zoonosis accounting for 151,995 confirmed human cases. However, the incidence of salmonellosis continues to decrease in the European Union with a statistically significant trend over the last four years.

In foods, the highest proportion of campylobacter-positive samples was once again reported for fresh poultry meat, where on average 26 per cent of samples were found positive. Campylobacter was also commonly detected from live poultry, pigs and cattle. The reported proportions of Campylobacter-positive samples remained at high levels and no overall decrease was apparent.

The reported notification zoonoses rates in confirmed human cases in the EU, 2007

Source: EFSA

Salmonella was most often found in fresh poultry and pig meat where proportions of positive samples, on average 5.5 per cent and 1.1 per cent, were detected respectively. Some Member States reported 0.8 per cent of table eggs positive for Salmonella, while dairy products, vegetables and fruit were rarely found to contain the bacterium. In animal populations, Salmonella were most frequently detected in poultry flocks.

2007 was the first year when EU Member States implemented the new Salmonella control programmes in poultry (Gallus gallus) breeding flocks on a mandatory basis and already 15 Member States reported prevalence below the Salmonella reduction target of one per cent laid down by Community legislation.

The number of listeriosis cases in humans remained at the same level as in 2006 with 1,554 confirmed cases recorded in 2007. A high fatality rate of 20 per cent was reported among the cases, especially affecting the elderly. Listeria bacteria were seldom detected above the legal safety limit from ready-to-eat foods but findings over this limit were most often found in smoked fish and other ready-to-eat fishery products followed by ready-to-eat meat products and cheeses.

At European Union level, the occurrence of bovine brucellosis remained largely unchanged compared to 2006, while that of bovine tuberculosis and sheep/goat brucellosis seemed to slightly decrease. In humans, 542 confirmed brucellosis cases were reported but the notification rate is decreasing.

A total of 2,905 confirmed verotoxigenic Escherichia coli (VTEC) infections were recorded in the European Union in 2007. Among animals and foods, VTEC was most often reported in cattle and bovine meat.

However, the importance of a zoonosis as a human infection is not dependent on incidence in the population alone. The severity of the disease and case fatality are also important factors affecting the relevance of the disease. For instance, despite the relatively low number of cases caused by VTEC, Listeria, Echinococcus, Trichinella and Lyssavirus (rabies), compared to the number of human campylobacteriosis and salmonellosis cases, these infections are considered important due to the severity of the illness and higher case fatality rate.

In 2007, the number of reported yersiniosis cases in humans was 8,792, and the bacterium was reported from pigs and pig meat. Two parasitic zoonoses, trichinellosis and echinococcosis, caused 779 and 834 human cases each in European Union Member States. In animals, these parasites were mainly detected in wildlife.

Salmonella

New salmonella control programmes in breeding flocks of chickens (Gallus gallus) were implemented on a mandatory basis for the first time in 2007. The aim of the programmes is to reduce the occurrence of S. Enteritidis, S. Hadar, S. Infantis, S. Typhimurium and S. Virchow to one per cent or less in adult breeding flocks comprising at least 250 birds by 31 December 2009.

The data showed that already 15 MSs reported in 2007 a prevalence of these five target serovars that was lower than the target, whereas eight MSs reported prevalence of the five serovars ranging from 1.1 per cent to 15.4 per cent

Few MSs reported data from routine monitoring on the prevalence of Salmonella in pig herds or slaughter pigs in 2007. However, an EU-wide Salmonella baseline survey was carried out in slaughter pigs in 2006 to 2007. In total, 19,071 ileo-caecal lymph node samples were collected from slaughtered pigs and the EU weighted mean prevalence in pigs was 10.3 per cent ranging between 0 per cent and 29.0 per cent in MSs. Few MSs have active monitoring of Salmonella in cattle but two MSs both reported slaughter prevalence of 0.1 per cent in cattle.

Campylobacter

In 2007, as in previous years, the majority of data on Campylobacter in animals was from investigations of broilers but data from pigs and cattle was also reported.

The recorded prevalence of Campylobacter-positive broiler flocks was generally high: 25.2 per cent at EU level ranging from 0 per cent to 82.8 per cent in MSs. Lower prevalence in broiler flocks was reported by some Nordic and Baltic countries.

High prevalence was also observed from the monitoring of pigs, 56.1 per cent at EU level (ranging from 0.9 per cent to 78.5 per cent).

In cattle, reported occurrences were somewhat lower: 5.9 per cent on average in the EU but prevalence up to 70.5 per cent was reported by some MSs. However, Campylobacter contamination rates in pig and bovine meat typically decrease sharply following slaughter and remain low at retail. This was also demonstrated by the results reported in 2007.

Tuberculosis due to Mycobacterium bovis

Eleven MSs, two non-MSs as well as 15 provinces and three regions in Italy were officially bovine tuberculosis-free (OTF) in 2007. As in 2006, only Belgium, France and Germany out of the OTF MSs, reported few positive cattle herds in 2007.

Overall, a decrease in the proportion of cattle herds infected/positive for M. bovis was observed in the non-OTF MSs compared to 2006: 0.44 per cent vs. 0.66 per cent, respectively. However, this decrease was due to the inclusion of data from Romania that has a low occurrence of bovine tuberculosis in its large cattle herd population. When excluding the Romanian data, the proportion of cattle herds infected/positive at EU level remained the same as in the previous year. Of the 15 reporting non-OTF MSs, Ireland and the United Kingdom reported the highest prevalence (4.4 per cent and 3.3 per cent, respectively) in their national herds.

Brucella

In 2007, 12 MSs were officially free of brucellosis in cattle (OBF) and 16 MSs were officially free of brucellosis in sheep and goats (ObmF). Furthermore, 20 provinces and seven regions in Italy as well as four Azores islands in Portugal and Great Britain in the United Kingdom were OBF, whereas 64 departments in France, five provinces and eight regions in Italy, all the Azores islands in Portugal and two islands in the Canaries in Spain were ObmF.

At EU level, a marked decrease was observed in the proportion of existing cattle herds positive for, or infected with bovine brucellosis from 2006 to 2007. However, this decrease is only caused by the inclusion of data from Romania (MS since 2007), which has a large cattle population with no positive herds. In the Community co-financed non-OBF MSs, the prevalence of bovine brucellosis increased compared to 2006. This was specifically observed for Ireland, Italy and the United Kingdom (Northern Ireland).

In the case of small ruminant brucellosis, the proportion of existing herds either positive or infected at EU level has decreased from 2004 to 2007 even though the trend is not statistically significant.

Listeria

In 2007, 18 MSs reported data on L. monocytogenes in animals and the bacterium was reported from various animal species. In some MSs the detected proportion of positive samples reached a moderate level in cattle and in small ruminants.

VTEC

In bovine animals, the average VTEC prevalence in reporting MSs was 3.6 per cent and the proportion of VTEC O157-positive animals was 2.9 per cent. The reported occurrence of VTEC ranged from 0 per cent to 22.1 per cent in MS investigations.

Further Reading

- You can view the full report by clicking here.

January 2009