Trichinosis: A recent outbreak in Northern Thailand.

During April, 1973, and outbreak of trichinosis occurred in Mae Sruay District, Chiang Rai Province, about 900 kilometers north of Bangkok, Thailand. Thirty-one persons were involved, of whom 27 (20 males, and 7 females), ranging in age from 9 to 72 years, were questioned. One adult female died before being brought to hospital. All subjects gave a history of having consumed raw pork in the form of "lahb" and "nahm", favourite dishes of the northern Thai. Beginning the third week after exposure, all developed fever and myalgia. Other less common complaints were diarrhoea and oedema of extremities and palpebral skin. Leucocytosis was revealed in 37% and 55% had eosinophilia exceeding 20%. Nineteen patients had hookworm and Opisthorchis infections. About 63% were skin test positive with Trichinella antigen. Eight patients were admitted to hospital; muscle biopsy was done on one serious case and trichina larvae were detected.