Onchocerciasis history and symptoms

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Kalsang Dolma, M.B.B.S.[2]

Infected persons may be without symptoms. Those with symptoms will usually have one or more of the three manifestations: skin rash (usually itchy), eye disease, and nodules under the skin. The most serious manifestation consists of lesions in the eye that can lead to visual impairment and blindness.

It can take up to one year for the larvae (also called microfilariae) to develop into an adult inside the human body and between 10 and 20 months before larvae can be found in the skin. Each adult female worm, which can live from 10-15 years, can produce millions of larvae during her lifetime. As it is the larvae that cause most of the symptoms of onchocerciasis, most people feel well until after the adults start producing large numbers of new larvae. Some people do not experience symptoms while infected with O. volvulus, as the larvae can migrate through the human body without provoking a response from the immune system. Most symptoms of onchocerciasis are caused by the body’s response to dead or dying larvae. The inflammation caused in the skin, in addition to causing itching, can result in long-term damage to the skin. Onchocerciasis can cause

• Skin rashes
• Skin swelling
• Pruritus
• Dermatitis
• Non-painful swelling of lymph glands
• Vision changes
• The most serious manifestation consists of ocular lesions that can progress to blindness.

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