Onchocerciasis (“river blindness”), a parasitic disease that leads to debilitating and stigmatizing ailments, has been targeted by the World Health Organization for elimination. New drug treatments that kill or permanently sterilize female worms could accelerate this process. The DOLF team, together with our partners at the University of Health and Allied Sciences (UHAS) in Ghana compared the tolerability and efficacy of ivermectin plus diethylcarbamazine and albendazole (IDA) vs. a comparator treatment (ivermectin plus albendazole, IA) in persons with onchocerciasis. Results from this pilot study, that was funded by the Bill & Melinda Gates Foundation, was recently published in the journal PLOS Neglected Tropical Diseases.
While additional studies are needed, results from the Ghana study are promising and show that IDA was well tolerated after ivermectin pretreatment. They also suggest that IDA was more effective than the comparator treatment IA for killing or sterilizing female O. volvulus worms. No other short-course oral treatment for onchocerciasis has been demonstrated to have macrofilaricidal activity.
The DOLF team plans to build off these early results to better plan a follow-up study in Liberia – that will launch over the next several months – to explore the value of this and other new combination treatments for onchocerciasis. These two studies could improve chances for eliminating onchocerciasis in Africa.
Fig 1. Examples of nodules and worm sections analyzed by histology.
Panels B-D are H&E stained sections, E-H are APR stained sections; red staining indicates that the worms are alive. A: Paraffin block with a highly calcified nodule from. B: Nodule section with calcified (dead) worms. C: Erroneously excised lymph node. D-E: Consecutive sections with two living female worms stained with H&E and APR, respectively. F: Collapsed O. volvulus female that could not be evaluated for embryogenesis. G-H: Cross-sections of two different living O. volvulus females in the same nodule. Image G shows normal stretched microfilariae (arrow). The worm uterus in image H is filled with degenerated embryos (asterisk). Ut, uterus; I, intestine.