Onchocerciasis

2020 Target

Control

Global burden

Concerted control and elimination programs over the past 40 years have reduced the burden considerably. Since 1995, the African Programme for Onchocerciasis Control (APOC) has treated 90 million people annually in 19 countries, resulting in a 73% case reduction.

Onchocerciasis is a black fly-borne parasitic disease of the skin and eyes caused by a filarial worm. When the worms die, they release a symbiotic organism that can destroy eye tissue. The disease causes skin lesions, severe itching and visual impairment, including permanent blindness, and can shorten life expectancy by up to 15 years.

Strategy for Elimination / Eradication / Control

Preventative chemotherapy with ivermectin has been used in elimination and control efforts. Loa loa has also been a barrier to expanding the program in some sites in Africa with lower prevalence of river blindness. Treatment of all infected areas will likely be required to eliminate the disease and achieve the 2020 targets. Ivermectin targets the immature form of the worm, and must be given annually to prevent ongoing transmission until the adult worm dies naturally. Elimination efforts would be helped if a drug to kill the adult form of the worm was developed, which would alleviate the need to annually treat people for river blindness for many years. New drugs safer to use in Loa loa endemic regions would also be an important advance.

Control of onchocerciasis is defined as elimination in Latin America and Yemen by 2015; elimination in selected countries in Africa by 2020.