What are some of the problems with onchocerciasis treatment?

Diethylcarbamazine is effective treatment for the microfilarial stage, but a hypersensitivity reaction to large numbers of dying parasites in the anterior chamber of the eye may cause irreversible blindness and, in some cases, death. A safer course, in otherwise asymptomatic victims, is periodic “nodulectomy,” which removes the adult worms and significantly lowers the morbidity of onchocerciasis.