<prompt> River blindness is caused by:Onchocera-VolvulusSchistoma haematobiumFasciola hepaticaOpisthorchis-viverrini  <response>: onchocera - volvulus Ref: 1327-HI7thONCHOCERCIASIS: River blindness is caused by the filarial nematode O valvulus Pruritis and rash are the most frequent manifestations of onchocerciasis Visual impairment is the most serious complication of onchocerciasis. The most common early finding is conjunctivitis with photophobia Snow flake opacies is frequent in younger patients. Enlarged nodes may hand down in response to gravity hanging grom sometimes predisposing to inguinal and femoral hernias Mazzotti test is a provocative technique IVERMECTIN is the treatment of choice for onchocerciasis 