Existing Drug May Be Useful in Treating 37 Million with River Blindness

Researchers at The Scripps Research Institute, together with colleagues, have reported that a drug (closantel) currently used as the standard treatment for sheep and cattle infected with liver fluke may be useful in treating river blindness, a tropical disease that is the world's second leading infectious cause of blindness for humans (the leading cause is trachoma, caused by infection with Chlamydia trachomatis). Dr. Kim Janda, an author of the new report, said that there is an urgency to fighting the infection that leads to river blindness, which is also known as onchocerciasis. Despite several eradication efforts, the disease affects more than 37 million people in Africa, Central and South America, and Yemen. "Victims of onchocerciasis suffer severe skin lesions, musculoskeletal pain, and various stages of blindness," said Dr. Janda, adding that patients also experience decreased body mass index, decreased work productivity, and social stigmatization. The new research shows that clostanel has the potential to inhibit the molting process of the parasite (Onchocerca volvulus) that causes river blindness. "We think this finding holds terrific potential for the treatment of river blindness, one of 13 recognized neglected tropical diseases," said Dr. Christian Gloeckner, the first author of the study. River blindness is caused by thread-like filarial nematode worms, O. volvulus, which are transmitted among humans through the bite of a black fly. The worms then multiply and spread throughout the body. When the worms die, they cause a strong immune system response that can destroy surrounding tissue, including that of the eye. Currently, the only drug available for mass treatment of river blindness is ivermectin, and it now appears that resistance to that drug is emerging.