Endemic filariasis on a Pacific island. I. Clinical, epidemiologic, and parasitologic aspects

The clinical and parasitologic aspects of filariasis were investigated in 459 inhabitants of a South Pacific island endemic for subperiodic Wuchereria bancrofti filariasis. Episodes of filarial fevers, usually with concomitant lymphangitis and/or lymphadenitis, were experienced by 26%. Lymphobstructive lesions, manifest in the later decades of life, were present in 12 with elephantiasis and 24 with hydroceles. Microfilaremia was detectable by membrane filtration of 1 ml of blood in 33% of persons, with a quarter of these having less than 50 microfilariae/ml. Microfilaremia and filarial fevers were more frequent in males than females and in residents of the most inland villages. Neither presence nor magnitude of lymphadenopathy correlated with other manifestations of filariasis except that markedly enlarged inguinal-femoral nodes were more common in those with elephantiasis or hydroceles. A history of filarial fevers did not correlate with presence of microfilaremia. Over 70% of adults had microfilaremia and/or historical or physical manifestations of filariasis. The absence of detectable microfilaremia in many residents with clinical evidence of filariasis and the presence of asymptomatic microfilaremia emphasize the limitations in relying only on microfilaremia rates or clinical findings in the study of the prevalence or manifestations of filarial infection.