Trichinellosis results from ingesting raw or under-cooked meat infected with Trichinella species nematode worms. It is characterized by fever, diarrhoea, peri-orbital oedema, myositis and eosinophilia.

The problem in Africa

Human trichinellosis is uncommon in Africa. Most reported cases have occurred as a result of eating domestic pig, warthog and wild boar (Pozio, 2007). Outbreaks have occurred in Kenya, Tanzania and Ethiopia; and particularly in predominantly Muslim African countries (Gottstein et al., 2009). Trichinella infection is common in wild and farmed animals across the continent, and has been isolated from exotics such as farmed ostrich and crocodile. Human disease typically occurs in localized outbreaks.

Life-cycle and pathology

Cysts of Trichinella species are ingested in under-cooked infected meat, and larvae are released on gastric digestion. These embed in the duodenal mucosa and develop into adult worms; females release hundreds of larvae within 5–7 days of infection.

Larvae are carried in the bloodstream and lymphatics to skeletal muscles, where they penetrate striated muscle cells. Larvae may survive in humans for up to 40 years, and cyst calcification may occur after 6 months (Gottstein et al., 2009).