Trichinella and trichinellosis in Europe

Background: Trichinellosis, the proper term for the human zoonotic disease is caused by nematodes of the genus Trichinella. These zoonotic parasites show a cosmopolitan distribution in all the continents but Antarctica. They circulate in nature by synanthropic-domestic and sylvatic cycles that are correlated with each other. Today, nine species and three genotypes are recognized in this genus, all of which infect mammals, including humans, while one species also infects birds, and two other species also infect reptiles. Scope and Approach: To review the recent literature on these pathogens, which are unusual among the other nematodes in that the worm undergoes a complete developmental cycle, from larva to adult to larva, in the body of a single host, which has a profound influence on the epidemiology of trichinellosis as a zoonosis. When the cycle is complete, the muscles of the infected animal contain a reservoir of larvae capable of long-term survival. Humans and other hosts become infected by ingesting muscle tissues containing viable larvae. Key Findings and Conclusions: The main source of human infection is raw or under-cooked meat products from pig, wild boar, bear, walrus, and horses, but meat products from other animals have been implicated. Both pre-slaughter prevention and post-slaughter control can be used to prevent Trichinella infections in animals. The first involves pig management control in high containment level farms as well as continuous surveillance programs. Meat inspection is a successful post-slaughter strategy. However, continuous consumer education is of great importance in countries where meat inspection is not mandatory.