One in the eye for river blindness

Abstract

This Journal Club article also appears in Trends in ParasitologyChemotherapy is the principal intervention in the control of filariasis. For Onchocerca volvulus, the species responsible for ‘river blindness’, the current approach is to treat with ivermectin (Mectizan), a drug highly effective at clearing the juvenile microfilarial stage of the parasite, which lives in the skin awaiting transmission by the blackfly vector. Unfortunately, Mectizan has no effect on the survival of adult worms, which can live for a decade or more in subcutaneous nodules, giving birth to millions of microfilariae. Consequently, treatment has to be repeated on an annual basis for several years and cover sufficient numbers of people to have any hope of interrupting transmission. For years, scientists have been searching for that elusive drug that can kill or permanently sterilize the long-lived adult nematodes, but with little success. Recently, a new target for anti-filarial chemotherapy has emerged from the revelation that intracellular Wolbachia bacteria have evolved an obligate symbiosis with their nematode hosts. Treatment of filarial nematodes with the antibiotics tetracycline or rifampicin leads to the depletion of Wolbachia, and results in long-term sterility and inhibition of worm development and viability. In the few years since this discovery, the first clinical trial to test the effect of antibiotics on the depletion of Wolbachia in human onchocerciasis has been completed in Ghana 1xDepletion of Wolbachia endobacteria in Onchocerca volvulus by doxycycline and microfilaridermia after ivermectin treatment. Hoerauf, A. et al. Lancet. 2001; 357: 1415–1416Abstract | Full Text | Full Text PDF | PubMed | Scopus (167)See all