Clinical manifestations of bancroftian filariasis in relation to microfilaraemia and diethylcarbamazine therapy.

We studied the clinical manifestations of Bancroftian filariasis in relation to microfilaraemia and diethylcarbamazine (DEC) therapy in three groups of individuals in Pondicherry. In 3170 persons examined in a door-to-door survey (Group I), the prevalence of disease was found to be independent of microfilaria (mf) status (the disease rate was 13.4% in mf carriers and 13.6% in amicrofilaraemic persons). There was no association between the occurrence of disease (and individual manifestations), and mf status and its intensity in 1103 mf carriers examined in the filariasis clinic (Group II). Clinical manifestations, however, were age and sex dependent in Group II. Change in mf status in a five-year period (1981 to 1986) with and without DEC therapy did not influence the clinical manifestations in 1024 individuals (Group III). Though the disease rate in mf carriers who discontinued DEC (22.2%) and in those who completed one course of DEC (14.8%) was higher than those who did not receive DEC (10.6%), statistical analysis did not show any significant difference between the groups. The study confirms that the dynamics of infection and filarial disease are complex, and other associated factors need to be investigated.