Pattern of community compliance with spaced, single-dose, mass administrations of diethylcarbamazine or ivermectin, for the elimination of lymphatic filariasis from rural areas of southern India

Current programmes to eliminate lymphatic filariasis (LF) are largely based on annual mass administrations of single doses of antifilarial drugs. The level and pattern of compliance by the target population are important determinants of the success of such mass drug administrations (MDA). Community compliance was therefore investigated during a study in southern India of the effects, on Wuchereria bancrofti microfilaraemia and transmission, of spaced MDA based on diethylcarbamazine (DEC) or ivermectin (IVM). During six rounds of MDA, the frequency of compliance in the target populations, in the five study villages given DEC and the five given IVM, ranged from 55%-77%. Analysis of the relevant cohort data indicated that about 30% of the villagers had complied with treatment during all six rounds, but 3.5% of those in the DEC arm and 4.0% of those in the IVM arm had never complied with treatment. Most of the villagers (>90%) had received treatment at least once, however, and >60% had each received treatment in at least four of the six rounds. Overall, there was a significant negative correlation (r=-0.78; P=0.008) between the size of the village, in terms of the number of villagers, and the mean frequency of compliance over the six rounds of MDA. The pattern of community compliance was found to be 'semi-systematic', laying between random and systematic. In terms of the elimination of LF, a semi-systematic pattern of compliance is worse than random compliance but better than systematic. The relevance of the levels and patterns of compliance to LF control or elimination is discussed.