The first fully completed genome sequence for the parasite that causes river blindness has revealed a list of proteins that could be targeted with repurposed existing drugs, providing new starting points for treatment development, reports a paper published online in Nature Microbiology this week. Published with a second related paper, the two studies provide an unprecedented insight into the physiology and evolution of the river blindness parasite and its bacterial endosymbiont, Wolbachia, which lives within the parasite.
River blindness, caused by the parasitic worm Onchocerca volvulus, affects an estimated 17 million people throughout sub-Saharan Africa, Latin America, and Yemen. The O. volvulus larval parasites migrate through the skin and eyes and trigger an allergic-type immune response that can lead to dermatitis and corneal damage, potentially leading to vision impairment or blindness. Although targeting the larval form of the parasite with drugs has shown some success, there is currently a lack of drugs that kill adult parasites and no vaccine to prevent new infections.
In the first study, Elodie Ghedin and colleagues describe the full genome of O. volvulus, and its Wolbachia endosymbiont, and identify more than 12,000 protein-coding genes that are expressed across the eight stages of the parasite’s lifecycle. The authors suggest the genome and associated data sets will enable the development of new and urgently needed interventions against river blindness and other diseases associated with parasitic worm infection.
In the second study, Makedonka Mitreva and colleagues build on the new genome to describe the genomic diversity of O. volvulus. They identify variations in the nuclear, mitochondrial and endosymbiont DNA that will have important implications for ongoing control programmes and could boost efforts to characterize drug, vaccine, and diagnostic targets.