A new tool and protocol for testing for onchocerciasis (oncho, or commonly known as river blindness) promises more accurate and cost-effective testing for the disease. When widely deployed, the improved test will help scientists and health workers to better target critical treatments, while allowing resource-constrained health systems to spend more efficiently.
Oncho is a neglected tropical disease (NTD) that, according to the 2017 Global Burden of Disease Study, has caused vision loss for an estimated 1.15 million people – nearly all of them in Africa.
The new tool and protocol for testing was developed at Smith College and University Hospital Bonn, funded through the Coalition for Operational Research on Neglected Tropical Diseases at The Task Force for Global Health with support from the United States Agency for International Development (USAID).
In June a group of scientists from Africa and representatives from the U.S. Centers for Disease Control and Prevention (CDC) held a training session at Smith’s campus in Northampton, Massachusetts, to provide training and assess proficiency on how to use this next-generation method. Fifteen scientists from Benin, Burkina Faso, Cameroon, Tanzania, Ghana, Malawi and Mali attended the training, which was led by Gates Professor of Biological Sciences Steven Williams, who also led the group that developed the new protocol.
“Our team is the focal point for training because we developed the protocol using the new test,” Williams says. “We’re a relatively small group of people at Smith College, so we wanted to partner with the excellent scientists at the CDC so we could train a larger group of scientists from Africa faster than we could on our own.”
Small flies known as black flies spread oncho to humans through bites. To find out if the disease is present in a community, health workers catch flies, remove their heads and test the heads for DNA which indicates the presence of the parasite. The June training sessions kicked off with a demonstration of how to correctly separate a blackfly’s head from its body to do the test.
“Testing flies is a good proxy for testing people,” says Williams. “If the flies in an area have oncho, you know people there have it, too.”
Philip Kutjok, a fellow at The Task Force and U.S. CDC from South Sudan who attended the training, said the sessions were enhanced by relevant experience of the trainees.
“The other trainees brought a very high-level of skill to the sessions,” Kutjok said. “One of the scientists from Tanzania gave us all tips on how to separate the head from the body. I’d never done that before.”
Williams said the shared dialogue among the trainees helped him and his team update written testing protocols and standard operating procedures for the new diagnostic.
As with testing for the disease’s presence, treatment for the disease is conducted at a community and regional level. Where infected flies are present, treatment consists of mass administration of preventative drug treatment.
Williams said the new streamlined test’s sensitivity, accuracy and lower cost should help affected countries complete testing more quickly. This will help health teams make better-informed decisions about when to stop mass drug administration.
“When to stop [mass drug administration] in an area is the big question for this disease,” Williams explains. “You don’t want to stop treatment prematurely, while the disease is still present, because the disease will creep back, and you’ll have to start over with treatment.”
Kutjok said the test’s improved precision offers profound benefits for people and communities impacted by oncho.
“Better testing allows you to concentrate your efforts where they’re needed,” he said. “When you eliminate oncho from a community, you’re eliminating one of the barriers that prevents people from thriving. You’re making it easier for people to work and for children to go to school.”
Scientists and Contributors:
Training at Smith:
Dr. Mary Doherty, Smith College
Katarina Flöer, Smith College
Dr. Nils Pilotte, Quinnipiac University
Dr. Jessica Prince-Guerra, CDC
Dr. Stephen Lindstrom, CDC
Dr. Moukaram Tertuliano, CDC (our translator!)
Phillip Kutjok, Task Force for Global Health
Research Contributors:
Dr. Mary Doherty, Smith College
Dr. Nils Pilotte, Quinnipiac University
Dr. Thomas Unnasch, retired, University of South Florida
Dr. Thomas Nutman, National Institutes of Health
Dr. Peter Fischer, Washington University
Dr. Sara Lustigman, New York Blood Center
Dr. Kenneth Pfarr, University Hospital Bonn
and many others
