Lymphatic filariasis (LF) is a deforming and disabling infectious disease that causes elephantiasis and genital deformity (especially hydroceles). The infection affects some 120 million people in 81 countries in tropical and subtropical regions with well over 1 billion people at risk of acquiring the disease.
LF is caused by Wuchereria bancrofti and Brugia spp. (B. malayi and B.timori), nematode parasites that are transmitted by mosquitoes. The adult worms live in lymphatic vessels where they cause damage that results in swollen and enlarged limbs and genital deformities. The World Health Organization (WHO) developed a plan for LF elimination that is based on using novel approaches to rapidly map endemic areas and 4 to 6 annual rounds of mass drug administration (MDA) with antifilarial medications. More than 3 billion doses of MDA have been distributed since 2000. Thus, the Global Programme to Eliminate Lymphatic Filariasis (GPELF) is the largest infectious disease intervention program attempted to date based on MDA.
MDA has worked better in some areas than others. A recent publication reviewed challenges faced by GPELF. These include (among others) inability to conduct MDA programs in areas of Africa where Loa loa is coendemic because of the unacceptable risk of Serious Adverse Events (SAE’s) with Ivermectin in persons with heavy L. loa infections, the limited macrofilaricidal activity of current MDA regimens (especially Ivermectin/Albendazole) that necessitate repeated annual rounds of MDA, and the difficulty of achieving high compliance rates for MDA over a period of years.