Progress report on the elimination of human onchocerciasis, 2017–2018. Weekly Epidemiological Record. WHO, 2018
Onchocerciasis, commonly known as “river blindness”, is a parasitic infection caused by the filarial nematode Onchocerca volvulus. The parasite is transmitted through the bites of blackflies of the genus Similium that breed along rivers and streams in areas where there is fast-moving water. Currently, 205 million people live in areas that are known to be endemic for onchocerciasis. Many of these people live in areas where there is little risk for onchocerciasis-related blindness or skin disease, as long as mass drug administration (MDA) with ivermectin continues.
Four countries have completed the WHO-recommended process for verification of the interruption of transmission of human onchocerciasis, and many others have stopped MDA, completed post-treatment surveillance (PTS) or both in at least one transmission area in their territory. Interrupting transmission would allow countries to protect the gains made by many years of effective MDA with ivermectin and to stop MDA permanently, freeing the resources for other health priorities. It would be a meaningful contribution to Sustainable Development Goal (SDG) 3.3, part of which calls for ending the epidemics of AIDS, tuberculosis, malaria and neglected tropical diseases (NTDs) by 2030.
Although interruption of transmission would make the gains permanent, it is more difficult to achieve and to demonstrate than is achievement of elimination as a public health problem. Interruption of transmission will require additional resources now in order to realize gains to be obtained in the future. The onchocerciasis community is ready for the challenge of eliminating transmission, and national programs for river blindness are well on their way towards this goal.