International travel and health

Onchocerciasis

Cause

Onchocerca volvulus (a nematode)

Transmission

Onchocerciasis (river blindness) is transmitted through the bite of infected blackflies.

Nature of the disease

Onchocerciasis is a chronic parasitic disease, occurring mainly in sub-Saharan western Africa, in which adult worms are found in fibrous nodules under the skin. They discharge microfilaria, which migrate through the skin, causing dermatitis, and reach the eye, causing damage that results in blindness.

Geographical distribution

Onchocerciasis occurs mainly in western and central Africa, also in central and South America.

Risk for travellers

Generally low, unless travel involves extensive exposure to vectors in countries or areas at risk.

Prophylaxis

None.

Precautions

Avoid exposure to the bites of blackflies in countries or areas at risk.

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