---
title: "Onchocerciasis (river blindness) | Eye Health Guide"
description: "What onchocerciasis is, how the WHO African Programme fights river blindness, symptoms, and community prevention with ivermectin."
url: https://eyehealthguide.org/conditions/onchocerciasis/
source: Eye Health Guide
licence: "General information only. Cite the URL and the named medical reviewer."
---

Condition

# Onchocerciasis (river blindness)

Medical reviewer [Mr Mohamed Mohyudin](https://eyehealthguide.org/reviewers/mohamed-mohyudin/)· Last recorded site review July 6, 2026

### About this review

This page inherits the site’s previous review record. A separate, current article sign-off has not yet been recorded.

[How review works](https://eyehealthguide.org/reviewers/) · [Official biography & credentials](https://mohamedmohyudin.co.uk/author/mohamed-mohyudin/)

Quick answer

Onchocerciasis, also called river blindness, is an infection caused by a parasitic worm spread by black fly bites near rivers in parts of Africa and other regions. It causes severe itching, skin changes and can scar the cornea and retina, leading to blindness. Mass treatment programmes have greatly reduced it worldwide.

### On this page ⌄

1. Your next step
2. What it is
3. Common symptoms
4. WHO prevention and control
5. Relevance elsewhere
6. Related conditions
7. Treatments & Surgery
8. Frequently asked questions

## What it is

Onchocerciasis is caused by the worm Onchocerca volvulus, transmitted by repeated black fly bites. Microfilariae migrate through skin and eyes, causing inflammation that can damage the cornea and optic nerve over years.

## Common symptoms

Symptoms build over years of exposure in endemic communities.

- Intense itching and skin nodules
- Thickened or leopard-spot skin
- Eye redness, pain and light sensitivity
- Progressive vision loss and blindness in untreated cases

## WHO prevention and control

WHO and partners run community treatment with ivermectin (Mectizan) to kill microfilariae and prevent transmission. Vector control near rivers also helps. The goal is elimination as a public health problem in affected countries.

## Relevance elsewhere

River blindness is rare in high-income countries. Travellers to endemic areas for long periods may need awareness, but tourist visits are very low risk. It illustrates why global eye health programmes matter alongside everyday conditions elsewhere.

## Related conditions

## Treatments & Surgery

## Frequently asked questions

### Is onchocerciasis still a cause of blindness?

Yes in some endemic regions, though WHO-led mass drug administration has dramatically reduced new blindness in many African countries.

### How is river blindness prevented?

Community treatment with ivermectin and fly control near rivers are the main WHO-backed strategies, repeated until transmission stops.

### Can onchocerciasis be treated?

Ivermectin kills microfilariae and reduces progression, but established eye scarring may be permanent, which is why prevention programmes focus on early community treatment.

Optional — donate

## Want to fund sight-restoring surgery?

Eye Health Guide does not take donations. If you want to give, World Aid Network funds cataract and other sight-restoring operations through locally licensed ophthalmologists in Pakistan, Indonesia and Malaysia.

[Donate at World Aid Network](https://worldaidnetwork.org/donate)[World Aid Network eye health](https://worldaidnetwork.org/eye-health)[Their page on this condition](https://worldaidnetwork.org/eye-health/trachoma)[How this site relates to the charity](https://eyehealthguide.org/support/)

Eye Health Guide and World Aid Network are related public-interest projects and share a medical reviewer. Donations go to World Aid Network. This website does not take a cut, and giving is never required to read a page.

Your next step

## Take this to your appointment

Write down what has changed, when it started, your current medicines and the questions you want answered. Take these to your eye-care appointment.

Sudden loss of sight, severe eye pain or a dark curtain across vision needs immediate assessment. Do not wait to complete a worksheet.

## Sources for this information

These references support the information on this page. Follow the linked source for its full context.

- [World Health Organization - Onchocerciasis](https://www.who.int/news-room/fact-sheets/detail/onchocerciasis)