Onchocerciasis: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Onchocerciasis?
An infectious disease doctor, who treats infections from germs and parasites, usually leads care for onchocerciasis. An ophthalmologist, an eye doctor, helps when the eyes are affected. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is onchocerciasis?
Onchocerciasis is also called river blindness. It is a rare tropical disease caused by a parasite. A parasite is a living thing that lives in or on a person.
The parasite is a worm called Onchocerca volvulus. The adult worms live under the skin and produce larvae, which are very young worms. The disease affects the eyes and the skin.
Symptoms
Symptoms may start to appear at any time in life. Some people have no symptoms for many months.
Skin symptoms may include:
- Severe itching.
- A rash with small pimples, scarring, and thick, leathery skin.
- Patches of skin that are much lighter in color.
- Darkening of the skin and very severe itching.
- In most cases, lumps under the skin form around the adult worms.
Eye symptoms may include itchy eyes, red eyes, and sensitivity to light. Infection of the eye can lead to vision loss and eventually blindness.
Causes and who gets it
The worm spreads through the bites of infected blackflies. These flies breed in fast-flowing rivers and streams.
A fly picks up young worms when it bites an infected person. Inside the fly, the young worms grow into larvae that can infect the next person it bites.
Repeated bites from infected flies increase the number of adult worms and larvae.
The disease mostly affects rural communities in sub-Saharan Africa and Yemen. More than 99% of infected people live in Africa and Yemen. Smaller areas are found in parts of Latin America.
Long-term travelers and expatriates living in these areas are at greater risk. Infection generally takes repeated insect bites.
How doctors diagnose it
Infectious disease doctors use special lab tests of blood, tissue, or fluids to find the exact cause of an infection. They may also have experience with infections linked to recent travel to areas where certain infections are more common.
Eye doctors may use imaging, vision tests, and lab work to diagnose and guide treatment.
Treatment
The World Health Organization (WHO) recommends treating onchocerciasis with ivermectin at least once yearly for 10 to 15 years. Population-based treatment with ivermectin is also known as mass drug administration.
Another parasitic worm, called L. loa, is found in some countries. Treating people with high levels of L. loa in the blood can sometimes cause severe side effects. Where both worms are present, treatment plans may need to change.
When to see a doctor
Infected people may develop eye lesions, which can lead to visual impairment and permanent blindness. Severe itching and skin changes can also be signs of the disease.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Your primary care provider can be your main point of contact. They may order tests or refer you to specialists.
Common questions
Is river blindness the same as onchocerciasis?
Yes, river blindness is the common name for onchocerciasis. It is caused by the parasitic worm Onchocerca volvulus.
How do people get onchocerciasis?
People get it from the bites of infected blackflies. These flies breed in rapidly flowing rivers.
Can onchocerciasis cause blindness?
Yes, it can lead to permanent blindness.
How is onchocerciasis treated?
WHO recommends treating it with ivermectin at least once a year for 10 to 15 years.
Can onchocerciasis be controlled?
Yes, in west Africa, a control program brought it under control between 1974 and 2002. The program mainly sprayed insecticides against blackfly larvae. Large-scale distribution of ivermectin was added later.
Sources
- NIH Genetic and Rare Diseases Information Center - Onchocerciasis
- World Health Organization - Onchocerciasis
- CDC Yellow Book - Onchocerciasis (River Blindness)
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
