Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

Left/Right: Blackflies, the vector of onchocerciasis. Center: Microfilariae of O. volvulus from a skin nodule of a patient from Zambia, stained with H&E. Image taken at 1000x oil magnification.

Onchocerciasis, or River Blindness, is a neglected tropical disease (NTD) caused by the parasitic worm Onchocerca volvulus. It is transmitted through repeated bites by blackflies of the genus Simulium. The disease is called River Blindness because the blackfly that transmits the infection lives and breeds near fast-flowing streams and rivers and the infection can result in blindness. In addition to visual impairment or blindness, onchocerciasis causes skin disease, including nodules under the skin or debilitating itching. Worldwide onchocerciasis is second only to trachoma as an infectious cause of blindness.

Image: Left/Right: Blackflies, the vector of onchocerciasis. Center: Microfilariae of O. volvulus from a skin nodule of a patient from Zambia, stained with H&E. Image taken at 1000x oil magnification. Credit: WHO, DPDx, CDC

Explore

 
Contact Us:
  • Centers for Disease Control and Prevention
    1600 Clifton Rd.
    Atlanta, GA 30333
  • 1-800-CDC-INFO
    (1-800-232-4636)
    TTY: 1-888-232-6348
    Hours of Operation
    8am-8pm EST/ Monday-Friday
    Closed Holidays
  • Contact CDC-INFO
  • Page last reviewed: May 21, 2013
  • Page last updated: May 21, 2013
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC-INFO