Epidemiology of Yersinia enterocolitica with special consideration of animal reservoir

Abstract

The Yersinia genus is Gram-negative rods that now comprises 18 species. Y. enterocolitica is a psychrotrophic rod. It is a pathogen with a number of virulence factors that allow both the adhesion to the surface of the epithelial cells and avoidance the host immune response. Y. enterocolitica is an etiologic agent of various forms of yersiniosis, including intestinal, parenteral and transgranular forms. The registration of yeriniosis cases in Poland was started in 2002 and the increase in the number of cases has been reported since 2007 and it was caused by the European Y. enterocolitica bioserotypes 4/O:3 and 2/O:9. In 2006, the first case of Y. enterocolitica bioserotype 1B/O:8 US lines was reported in Poland. The main source of Y. enterocolitica infection is consumption of contaminated water or food, particularly raw or undercooked pork meat. The most common animals reservoir for Y. enterocolitica in the world is considered slaughter pigs (Sus scrofa domestica). Among Y. enterocolitica strains isolated from slaughter pigs the 4/O:3 is the most predominant bioserotype. Wild boars (Sus scrofa) have recently been tested for Y. enterocolitica because of the increase in their populations. It turns out that wild boars may also be a reservoir for Y. enterocolitica with diverse biotypes. Currently, studies are being conducted to check the wildlife such as red deer and roe deer as reservoirs for this bacterium. Potential, not yet widely recognized Y. enterocolitica reservoir may be domestic dogs, monkeys and small rodents. Investigation of these atypical reservoirs is conducted towards understanding the incidence of Y. enterocolitica and determining the potential pathogenicity.