The comparative burden of salmonellosis in the European Union member states, associated and candidate countries

Abstract

Background: Salmonella is an infectious agents causing numerous cases of illness each year, and thereby having significant economic impact. Using returning Swedish travellers we estimated the burden of salmonellosis in different European countries.

Methods: From the Swedish database on notifiable communicable diseases 15,864 cases with travel-associated salmonellosis acquired in Europe from 1997-2003 were retrieved. These cases were compared to a dataset from the same years on 14,171 randomly selected Swedish residents, with a history of recent overnight travel in Europe. Distribution of salmonellosis in returning travellers and the distribution of Salmonella Enteritidis was analysed for different member states in the European Union, associated and candidate countries. The risk of being notified with a salmonella infection after return from each European country/region was calculated, and compared with official reporting data rom these countries. Using Norway as reference country, we could 1) construct comparable incidence estimates and 2) calculate the "under-reporting" in each country compared to Norway.

Results: The highest burden of salmonellosis was estimated for Bulgaria (2741/100,000), followed by Turkey with 2344/100,000 and Malta with 2141/100,000. S. Enteritidis is the dominating serotype, 66.9 % of all cases and phage type 4 accounts for 37.5 % of the S. Enteritidis cases.

Conclusion: Using returning tourists as a sentinel population can provide a useful base for comparison of disease burdens in different countries/regions. Focusing prevention of salmonellosis to prevention of egg and poultry associated S. Enteritidis infection will have a major impact from a public health perspective and will significantly lower the burden of disease in most European countries.

Figure 1

Proportion of Salmonella Enteritidis in returning travellers, plotted against the estimated incidence of salmonellosis. Proportion of Salmonella Enteritidis in returning travellers, plotted against the estimated incidence of salmonellosis. Each dot represents one country in the study.