Onchocerciasis

Onchocerciasis is a chronic parasitic infection that primarily affects the skin and eyes, leading to severe itching, skin disfigurement, and potentially blindness, greatly impacting the quality of life and economic productivity in endemic areas.

Causative Agent and Transmission: Onchocerciasis is caused by the parasitic worm Onchocerca volvulus. It is transmitted to humans through the bite of infected blackflies (Simulium spp.), which breed in fast-flowing rivers and streams, primarily in Africa, as well as in some parts of Central and South America and the Middle East. The blackflies breed in fast-flowing rivers and streams, mostly in remote villages located near fertile land where people rely on agriculture.

Lifecycle and Infection: Once the larvae are transmitted to humans, they mature into adult worms within subcutaneous nodules in the body. These adults can live for up to 15 years. Female worms produce thousands of microscopic larvae (microfilariae) that migrate through the skin and eyes.

Skin Manifestations: The skin becomes heavily infested with the larvae, leading to severe itching, rashes, and skin discoloration. Over time, chronic skin changes such as thickening and loss of elasticity (often called "lizard skin") can occur.

Eye Disease and Blindness: One of the most severe effects of Onchocerciasis is eye disease, which can lead to visual impairment and ultimately blindness. The larvae migrate to the eyes, causing inflammation in different parts of the eye, leading to lesions on the cornea and, eventually, to irreversible blindness.

Nodules under the Skin: The presence of adult worms is often marked by palpable nodules under the skin, usually non-painful. These nodules can be surgically removed to reduce the number of circulating larvae.

Socio-Economic Impact: Like lymphatic filariasis, Onchocerciasis has significant social and economic impacts, especially in affected rural communities. The risk of blindness can hinder the ability to work and lead to increased dependency within communities.

Prevention and Control: Efforts to control Onchocerciasis focus on eliminating the blackfly vector through insecticide spraying and on mass drug administration, mainly with ivermectin, which kills the larvae, and prevents blindness.

Global Health Initiatives: There have been significant efforts by global health organizations to control and aim for the elimination of Onchocerciasis, especially in Africa. These programs have had considerable success in reducing the incidence of the disease and the associated blindness.

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Western Africa Cape Verde MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Kenya MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Equatorial Guinea MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Guinea Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Rwanda Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Burkina Faso MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Gabon MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Guinea-Bissau Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Seychelles Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Namibia MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Ethiopia MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Benin MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Niger MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Gabon MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Lesotho MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Kenya MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Zambia Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Comoros MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Togo MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Niger MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Togo MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Cote d'Ivoire MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Zimbabwe MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Madagascar MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Comoros MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa The Gambia MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Burundi MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Zambia MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Madagascar MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Sierra Leone MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Central African Republic Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Cameroon Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Nigeria MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Benin MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Lesotho MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Cote d'Ivoire MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Tanzania (Zanzibar) MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Senegal Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Burkina Faso MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Sierra Leone MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Malawi MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
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Southern Africa Malawi MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Republic of Congo MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Niger MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa eSwatini Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Gabon MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Botswana MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Sierra Leone MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Guinea-Bissau MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Cape Verde MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Niger MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Burundi MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Guinea MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
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Western Africa Nigeria MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Ghana MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
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Eastern Africa Kenya MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
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Western Africa Cote d'Ivoire MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
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Western Africa Nigeria MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Uganda MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Equatorial Guinea MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Cameroon MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Malawi MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Cote d'Ivoire MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Togo MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Central African Republic MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Democratic Republic of the Congo MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa Madagascar MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Eastern Africa South Sudan MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
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Southern Africa Botswana MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
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Central Africa Democratic Republic of the Congo MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa The Gambia MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Sierra Leone Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Burundi MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa South Africa MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Mali MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Sierra Leone MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Mali MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Republic of Congo MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Nigeria MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Angola Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Gabon Endemicity 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Ghana MDA/PC rounds (Geographic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Burkina Faso MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa South Africa MDA/PC rounds (Therapeutic coverage) 2013 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Liberia MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa eSwatini MDA/PC coverage (Geographic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Niger MDA/PC coverage (Therapeutic coverage) 2021 Download map png Download map pdf Download map png Download map pdf
Central Africa Cameroon MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Western Africa Guinea-Bissau MDA/PC rounds (Historical MDA) 2000 - 2021 Download map png Download map pdf Download map png Download map pdf
Southern Africa Malawi Endemicity 2021 Download map png Download map pdf Download map png Download map pdf

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