Trichinella

Trichinella is a genus of parasitic nematodes in the family Trichinellidae. Species in the genus infect a wide range of carnivorous and omnivorous hosts, including humans, and are responsible for the zoonotic disease trichinellosis. Notable species include Trichinella spiralis, T. britovi, T. nativa, T. murrelli and T. pseudospiralis.

Humans and other hosts acquire infection by ingesting meat containing encysted larvae. In the small intestine, larvae molt into adults; female adults release new larvae that enter the bloodstream and migrate to striated muscles, where they encyst and remain viable for years. The cysts form nurse-cell complexes, and muscle tissue harbors the infectious larvae for the next host if eaten. The parasite has a broad host range including pigs, bears, wild boar, seals, and rodents.

Clinical features vary; many infections are mild or asymptomatic. Early symptoms may include nausea, diarrhea, and abdominal pain, followed by fever, myalgia, periorbital edema, and eosinophilia as larvae migrate to muscles. Severe disease can involve myocarditis, pneumonia, or neurological complications, especially with heavy infection. Diagnosis relies on serology (antibody tests), clinical and epidemiological evidence, and sometimes muscle biopsy or direct observation of larvae in muscle tissue. Treatment involves anthelmintic therapy such as albendazole or mebendazole; corticosteroids may be used to control inflammatory symptoms in moderate-to-severe disease.

Prevention focuses on food safety. Proper cooking of meat to safe internal temperatures (for example, 71°C/160°F) kills larvae; freezing may not reliably kill larvae for all Trichinella species. Meat from pigs and wild game should be tested or inspected where applicable, and meat handling practices should minimize cross-contamination. Public health guidelines emphasize avoiding the consumption of raw or undercooked meat.