The impact of lymphatic filariasis on inputs in southern India: results ofa multi-site study

A multi-site study was undertaken, in the rural areas of three districts in Tamil Nadu state, in southern India, to examine the impact of acute and ch ronic forms of lymphatic filariasis, caused by infection with Wuchereria ba ncrofti, on labour inputs. More than half of the acute episodes of adenolym phangitis (ADL) observed in the study communities caused total disability. The mean (S.D.) time that each ADL case was able to allocate to economic ac tivity each day during these acute episodes was much less than seen in the controls matched for sex, age and occupation [0.97 (2.36) v. 4.48 (3.82) h; P < 0.01]. The acute disease also severely affected domestic activities, w ith female ADL cases spending only 1.54 (2.12) h/day on domestic activity, compared with 4.18 (2.61) h by controls. The subjects with chronic filarias is also spent significantly less time in economic activity than their match ed controls [4.40 (3.79) v. 5.13 (3.83) h/day; P < 0.01). Although the acut e episodes have a dramatic effect on the productivity of the affected indiv idual, the labour loss caused by chronic disease is more serious, as the ma nifestations of chronic disease mostly affect the most productive age-group s, persist for life and are mostly irreversible. The adverse impact of acut e and chronic filariasis was observed in males and females, farmers and non -farmers and during the rainy, winter and summer seasons. It is estimated t hat about 3.8% of the potential labour inputs of the men and 0.77% of those of the women were lost because of lymphatic filariasis. In addition to thi s loss, the total economic burden of the disease must include the costs of treatment and other health care and of the resources spent on control progr ammes. Estimates of the disease burden are likely to be useful in determini ng the costs and benefits of the recently launched campaign to eliminate ly mphatic filariasis.