Pathogen and transmission
Trichinellosis (also known as trichinosis) is an infectious disease that is caused by Trichinella, a kind of roundworm. Infection is through the consumption of raw or undercooked meat that contains the worm’s larvae. The disease occurs primarily with pork, and more rarely with horsemeat or game, and with sausage products made from such meats. It cannot be transmitted from person to person.
Pathology
The infection can be asymptomatic (i.e. free of any symptoms), mild or severe, depending on the number of larvae ingested. As a rule, the first initially unspecified symptoms such as diarrhoea, other gastrointestinal discomfort and/or a fever will develop 5 to 14 days after infection. As the disease progresses, the larvae may move to the muscular system via the bloodstream and cause muscle pain, swelling around the eyes and other more severe pathologies.
Trichinellosis can be treated with anthelmintic (i.e. anti-worm) drugs. These work best at the start of the disease, before the larvae and the worms can establish themselves in the muscular system.
Distribution and frequency of occurrence
Trichinellosis occurs worldwide, but is only occasionally seen in Switzerland: fewer than ten cases are reported to the FOPH per year. In many such cases, the persons concerned have been infected while abroad, or after eating food of animal origin obtained from outside Switzerland.
Prevention
Many countries (including Switzerland) require mandatory examinations of all animals intended for slaughter which could carry Trichinella (such as pigs, horses or wild boar) as part of their meat inspection regulations. This makes it unlikely that anyone will develop trichinellosis after consuming such meat products. But the possibility of wild boar meat or meat from outside Switzerland containing Trichinella cannot be entirely ruled out. In view of this, raw or undercooked fresh (pork) meat should never be consumed.