Lymphatic filariasis elimination — DTM&H MCQ

Correct answer: A — Annual mass drug administration with vector control and surveillance

The correct answer is A, annual mass drug administration with vector control and surveillance. Once mapping confirms Wuchereria bancrofti prevalence exceeds the WHO treatment threshold and there is no Loa loa co-endemicity (which would otherwise raise concern about severe adverse reactions to ivermectin or DEC), the Global Programme to Eliminate Lymphatic Filariasis strategy of repeated, community-wide MDA is indicated. This interrupts transmission by suppressing microfilaraemia across the whole reservoir population, not just symptomatic individuals, and is combined with vector control (targeting the mosquito intermediate host) and post-MDA surveillance to confirm interruption and detect resurgence. This integrated approach is the standard elimination pathway once a population crosses the mapping threshold and lacks contraindicating co-endemic infections. Why the other options are wrong: C. Treat clinically swollen limbs without community therapy: this manages morbidity in individuals already symptomatic but does nothing to reduce the asymptomatic microfilaraemic reservoir that sustains ongoing mosquito-borne transmission. E. Vaccinate schoolchildren against filariasis: no licensed vaccine exists for lymphatic filariasis, making this option not a real intervention. D. Use praziquantel as the main filarial drug: praziquantel is the treatment for schistosomiasis and some other flukes and tapeworms, not for filarial nematodes; it has no activity against Wuchereria bancrofti. B. Rely on surgery for hydrocoeles as prevention: hydrocoelectomy addresses established chronic morbidity in an individual but has no effect on transmission dynamics or community microfilarial load. Key point: once prevalence mapping exceeds the treatment threshold and Loa loa co-endemicity is excluded, annual community-wide MDA plus vector control and surveillance is the definitive elimination strategy, not individual case management.

Reference: WHO, Global Programme to Eliminate Lymphatic Filariasis: progress report and elimination strategy (mapping, annual MDA with albendazole plus ivermectin or DEC, vector control, and post-MDA surveillance), who.int/teams/control-of-neglected-tropical-diseases/lymphatic-filariasis