A long-term follow-up of asymptomatic amicrofilaraemic individuals living in a filaria-endemic region of Orissa, India: infection and disease status

A group of asymptomatic amicrofilaraemic individuals (endemic normals) aged > 12 years was identified in 2 filaria-endemic villages of Orissa, India in 1990 (Bajapur village, n = 40) and in 1994 (Olosingh village, n = 47). They were re-examined for microfilaraemia and disease status in the year 2000 after a 10-year and a 6-year period. Studies conducted at both villages yielded a similar pattern in the development of disease. Above 85% of the females remained normal, compared to 54% of males. Remaining individuals had acquired hydrocoele (males) and adenolymphangitis (both males and females). Only 1 individual converted to having asymptomatic microfilariae. No case of elephantiasis was observed. Results indicate that most females remained normal and males faced considerable risk of developing hydrocoele in these Wuchereria bancrofti-endemic areas.