Variation in Onchocerca volvulus

Onchocerca volvulus, the filarial nematode that causes onchocerciasis, is widely endemic in sub-Saharan Africa and in partsof Latin America. The pathology ranges from sub-clinical symptoms to dermatitis and ocular disease, and epidemiologicalstudies have shown that blinding onchocerciasis is much more common in dry savannah regions than in rain forest regions ofWest Africa. To develop a comprehensive understanding of the population genetics and structure of O. volvulus, weinvestigated the genomic diversity within and between O. volvulus populations by analyzing whole-genome (nuclear,mitochondrial and Wolbachia) sequences of >30 clinical parasite samples. Of these, 20 were collected from seven countriesin Africa (forest or savanna) and 10 from Ecuador in South America. The study also provides new information on thegenetic variability of potential vaccine, drug, and diagnostic targets.