Zoonotic infections in Europe: trends and figures - a summary of the EFSA-ECDC annual report
1. European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
2. European Food Safety Agency (EFSA), Parma, Italy
3. EFSA’s Zoonoses Collaboration Centre, Copenhagen, Denmark
The 2006 annual Community Summary Report from the European Food Safety Authority (EFSA) and the European Centre for Disease Prevention and Control (ECDC) was released this week with the latest trends and figures on the occurrence of zoonotic infections and agents, antimicrobial resistance and food-borne outbreaks in the then 25 European Union Member States and five non-EU countries (Bulgaria, Iceland, Liechtenstein, Norway and Romania)*. The following is a background for the report and a summary of the principle findings.
When combined together, campylobacteriosis, VTEC and salmonellosis were estimated by a recent pilot study to carry a higher burden of disease in Europe than influenza and measles, yet less of a burden than HIV and tuberculosis . Worldwide, bacterial food-borne zoonotic infections are the most common cause of human intestinal disease, with Salmonella and Campylobacter accounting for over 90% of all reported cases of bacteria-related food poisonings . It is estimated that one third of populations residing in developed countries worldwide are affected by food-borne diseases every year, and the majority of these are thought to be caused by zoonotic agents . It is also predicted that about 1% of the inhabitants of Europe will be infected with Campylobacter every year . For these reasons and to comply with the “Zoonoses Directive” (Directive 2003/99/EC) , EFSA together with its Zoonoses Collaboration Centre and ECDC have produced the latest report on trends and sources of zoonotic infections in Europe. By identifying which animals and foodstuffs are the main sources of infection one can prevent diseases from occurring by improving and targeting control measures in the food production chain.
Main zoonoses trends in 2006
In 2006, as in the previous year, campylobacteriosis was the most commonly reported zoonotic disease in humans in the EU, with 175,561 cases, representing a small decrease in confirmed cases from 2005. Campylobacter was most commonly detected in fresh poultry meat where on average 35% samples were found positive. Campylobacter was also frequently found in live poultry, pigs and cattle.
Salmonellosis was the second most commonly reported zoonotic infection in 2006, with 160,649 human cases. This represents a statistically significant decrease in the number of cases over the past three years. Salmonella was most commonly found in fresh poultry and pork meat, where 5.6% and 1.0% of samples were found positive, respectively. In animals, Salmonella was most frequently detected in poultry flocks. The prevalence of Salmonella in laying hens and their breeding flocks has decreased significantly compared to the past few years, which is thought to reflect the success of the control measures taken in this sector. Similar trends, however, were not observed in broilers flocks.
Yersinia and VTEC
The number of cases of Yersinia infection in humans decreased from 9,533 in 2005 to 8,979 in 2006. In animals, Yersinia were found mainly in pigs.
A total of 4,916 confirmed cases of VTEC were reported in 2006, compared to 3,217 in 2005, yet representing a statistically significant and downward trend since 2004 when 4,085 cases were registered. The difference between 2005 and 2006 is mainly due to reports from the Czech Republic, accounting for 1,558 cases or 92% of the increase. No cases were reported by the Czech Republic in 2005. The data from the animal sector indicated that VTEC was detected mainly in cattle and products thereof.
The number of cases of listeriosis increased to 1,583 in 2006 compared to 1,427 in 2005. Furthermore, the incidence rates of this infection in Europe have shown a statistically significant increase over the past five years. Listeriosis is an important food-borne zoonosis due to the severity of the disease and high mortality. It is a significant risk factor in well-defined groups: immunocompromised individuals, pregnant women and neonates younger than four weeks . In 2006, the average mortality rate associated with food-borne listeriosis outbreaks was 14.2%. In 2006, as in the past, Listeria were most commonly reported above the legal safety limit from ready-to-eat fishery products, followed by cheeses and other ready-to-eat products.
Trends in other zoonoses
Compared to 2005, the occurrence of bovine tuberculosis slightly increased and that of bovine and sheep/goat brucellosis decreased in those Member States which are not free of these diseases. In humans 1,033 brucellosis cases were reported mainly by the same countries where the disease is present in animals.
Two parasitic zoonoses, trichinellosis and echinococcosis, caused 231 and 458 human cases, respectively. In animals, these parasites were mainly isolated from wildlife.
In 2006, no cases of rabies were reported in humans, whereas in animals, the majority of rabies infections were found in the Baltic states and some Eastern European countries.
In 2006, a total of 5,710 food-borne outbreaks were reported by the Member States. As in 2005, Salmonella was the most common cause of those outbreaks. For the first time, however, food-borne viruses were the second most frequent cause. The number of viral outbreaks is assumed to have been severely underreported in the previous years. The majority of the reported food-borne Salmonella outbreaks were associated with eggs while meat was the second most common source.
A high level of Campylobacter resistance to ciprofloxacin was observed, ranging from 30.6% to 56.7% in isolates from poultry meat, live poultry and pigs. Ciprofloxacin is the first-choice antibiotic in the treatment of human campylobacteriosis, and thus high levels of resistance to this drug may limit treatment options in humans.
The majority of Salmonella Enteritidis isolates from humans were fully sensitive to all antimicrobials tested. Compared to 2005, the resistance to nalidixic acid, sulphonamids and ampicillin increased to 14.8%, 8.0% and 8.1%, respectively. The resistance to ciprofloxacin remained at low level (0.6%) in EU. From the S. Typhimurium isolates, 39.7% were resistant to more than four of the antimicrobials tested, and there was an increase in resistance to sulphonamides and streptomycin to 46.5% and 40.1%, respectively. The resistance to ciprofloxacin in S. Typhimurium isolates was 0.7%. Nalidixic acid is an indicator for increasing resistance to fluoroquinolones (e.g. ciprofloxacin), antimicrobials regarded as critically important for treatment of human cases.
The 2006 Community Zoonoses Report has again identified Campylobacter and Salmonella as the two most common zoonotic infections in humans in Europe. Even though they are reported with less frequency than in years prior, they make up the overwhelming majority of all zoonotic infections and are believed to represent only a fraction of the true number of cases in the EU . Antimicrobial resistance, particularly of Campylobacter to ciprofloxacin is a cause for concern. A major foodborne source of both agents in Europe is fresh poultry meat, while eggs still remain the most important source for Salmonella infections. Salmonella remains the most common cause of reported food-borne outbreaks but viral food-borne outbreaks are on the rise. The number of Listeria cases is also increasing, and Listeria is most commonly found in ready-to-eat fishery products and cheeses. Control programmes aimed at lowering the risk of zoonotic infections have proven successful in the past , yet this report demonstrates that there is still room for improvement. Indicating the main sources of zoonotic infections in Europe, helps to identify areas where control measures in the food production chain should be applied.
* 25 EU MS and five non-EU countries reported human data for Salmonella, yet fewer reported for other zoonoses and animal data (i.e. 21 EU and four non-EU MS for Campylobacter and 22 EU and four non-EU MS for VTEC in humans). Most countries have now provided human data on most zoonoses for the past five years thereby affording an opportunity to perform trend analyses.