February 2016

Silencing River Blindness

A visit to World Health Organization (WHO) headquarters in Geneva offers a stark reminder of the impact that parasites and vectoring insects can have on mankind as well as what mankind can achieve when it fights back. By the 1970s, in river-bordering villages of West Africa, frighteningly large percentages of adult populations were suffering from Onchocerciasis, or River Blindness, a disease brought on by infection from the filarial worm Onchocerca volvulus andthe blackflies that vector it.

Blackflies breed in habitats marked by fast flowing streams and rivers, commonplace in the eastern portion of the African continent. Notorious biters, the insects also transmit the indigenous parasiteO. volvulus from infected human hostsinto the bloodstreams of non-infected humans. Once inside the human body, these worms can grow as much as three feet in length and produce millions of offspring known as microfiliariae. Left untreated, these microscopic offspring migrate to the ocular region of the host causing itching, weakness, muscle pain, rashes and lesions, and ultimately blindness.

Robert McNamara
John F. Kennedy Presidential Library

As with most diseases, the impacts of River Blindness touch not only the afflicted, but have ramifications that spill over into the society at large. When U.S. Secretary of Defense Robert McNamara visited the region in 1972, while serving term as president of the World Bank, he was taken aback by the poverty and overall low quality of life in Onchocerciasis-affected communities. It was there that the enduring image of children leading blind adults around by sticks began to burn in the social-consciousness. disease.

Leveraging his position, McNamara helped to launch an international effort that would eventually become the Onchocerciasis Control Programme (OCP). Under the auspices of the World Bank, World Health Organization (WHO), the Food and Agriculture Organization of the United States, and the United Nations Development Programme, the OCP would operate from 1974-2002 and lead the charge to eradicate the insidious disease. Early efforts in the program were focused on the vector with anapproachcombiningorganophosphates with the Bacillus thuringiensis subsp. Israelensis.

Dr. William Campbell
Photo by Bengt Nyman

Then in 1978, a Merck & Co. veterinary researcher named Dr. William Campbell discovered an effective antiparasitic agent that would eventually become known as ivermectin (MECTIZAN®). Introduced in 1987, ivermectin attacked the disease rather than the vector. One to two doses per year of the new drug killed microfiliarae and sterilized female adult worms in hosts.

Dr. William Foege
CDC Public Health Image Library

The program got another boost when Dr. William Foege, director of the Carter Center – a non-profit founded by President Jimmy Carter to alleviate human suffering in underdeveloped areas, spearheaded funding for distribution of ivermectin throughout rural Africa through foundations, Ministries of Health, medical mission teams, and other foundations. Tagged as one of the largest public-private partnerships ever conducted, the Carter Center program would ultimately deliver more than 400 million annual treatments of MECTIZAN.

The final piece of the puzzle came in 1995 when a new organization call the African Programme for Onchocerciasis Control (APOC) extended the eradication effort to 19 countries outside the scope of the OCP. With funding from business, NGOs, and Merck & Co., these adjacent areas became covered under drug treatment programs to ward off any reinvasion of the disease.

Today, symbolic statues, depicting a child leading a blind elder by a stick andcommemorating the collaborative efforts to eradicate Onchocerciasis, have been erected in Burkina Faso, Africa, WHO headquarters in Geneva, World Bank headquarters in Washington D.C., the Carter Center in Atlanta, GA, and the Royal Tropical Disease Institute of the Netherlands in Amsterdam.


PATHOGEN Onchocerca volvulus
VECTOR Simulium spp.


Miles of West African rivers treated under the OCP.


The year the statue at WHO was dedicated.