River Blindness

River Blindness Latest News

ZSI study on blackflies offers hope for river blindness control, Researchers worked on four species collected from eight locations in the central Himalayan region

Why in the News?

• A new study by the Zoological Survey of India (ZSI) has introduced DNA barcoding to accurately identify blackfly species—the carriers of Onchocerca volvulus, the parasitic worm that causes river blindness (onchocerciasis).
• This innovation is expected to enhance disease control and vector management, especially in vulnerable ecological zones like the central Himalayas.

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What is River Blindness (Onchocerciasis)?

• River blindness is a neglected tropical disease (NTD) caused by the parasitic worm Onchocerca volvulus.
• The disease is transmitted to humans through the bite of infected blackflies belonging to the genus Simulium, which breed in fast-flowing rivers and streams.
• Symptoms include intense skin itching, disfiguring skin changes, and in advanced cases, permanent vision loss or blindness.
• Globally, it is second only to trachoma in causing infection-related blindness, especially affecting rural populations in sub-Saharan Africa, Yemen, and parts of Latin America.
• Treatment relies on mass drug administration (MDA) using ivermectin, with a minimum 80% therapeutic coverage required for effective control.
• According to the World Health Organization (WHO), river blindness remains one of the most neglected tropical diseases, especially in remote and rural areas.
• Five countries have been officially declared free of the disease by WHO:
  • Colombia (2013)
  • Ecuador (2014)
  • Mexico (2015)
  • Guatemala (2016)
  • Niger (2025) – the first African country to achieve this milestone.

River Blindness FAQs

Q1. What is River Blindness?
Ans. Also known as Onchocerciasis, it is a neglected tropical disease caused by the parasite Onchocerca volvulus.

Q2. How is it transmitted?
Ans. By the bite of infected blackflies (genus Simulium), usually found near fast-flowing rivers.

Q3. What are the symptoms?
Ans. Severe skin itching, nodules under the skin, and permanent blindness in chronic cases.

Q4. Which region is most affected?
Ans. It is endemic to Sub-Saharan Africa, but also occurs in parts of Latin America and Yemen.

Source: TH