Health campaigns are winning the battle against African river blindness, study finds
A native of Sudan, Tarig Higazi has seen the impact of river blindness up close. The tropical disease, transmitted by black flies that breed on the banks of fast-flowing rivers and streams, infects people with a parasite that can live in the body for 15 to 20 years. In the southern part of the country where the disease is more virulent, those afflicted may lose vision by age 40.
“About 10 percent of the adults in a village may be blind,” he says. “They’re active but not productive.”
Higazi, an assistant professor of biological sciences at Ohio University’s Zanesville campus, has focused his career on examining river blindness in Sudan, where it can manifest as a vision or skin disease depending on the region. The World Health Organization (WHO) estimates that more than two million people are infected in the African nation.
In 1998, WHO and the non-governmental organization The Carter Center began supporting measures to reduce the incidence of river blindness in the country.
Individuals were given a pharmaceutical treatment, Mectizan, to kill the parasite larvae and stop transmission of the disease. The medicine, donated by the Merck corporation and distributed by local communities, must be taken over the course of 10-15 years to effectively control the condition.
New research published by Higazi and colleagues this year suggests that the long-term strategy has paid off. The team collected and tested 30,000 black flies in two regions in northern Sudan. They discovered that in Abu Hamed, transmission of river blindness has been suppressed significantly over the past decade. The scientists found an average of only 1 infected fly per 10,000.
“The amount of disease transmission we saw in the north is an indication that the disease is being eliminated,” Higazi says. “That’s something big.”
The study also examined the black fly population in Galabat in eastern Sudan, where only minor, largely undocumented medical treatment has occurred since 2007. Higazi and his team found a moderate transmission rate of the parasite in this area, about 7 infected flies per 10,000.
Galabat is near the border of Ethiopia, where river blindness also is pervasive. “There are no boundaries for disease—if you don’t treat it next door, it can spread again,” Higazi says of the need to expand treatment efforts.
If treatments continue for the next few years, there’s hope that WHO could declare the disease eliminated in northern Sudan, says Higazi, who collected new disease transmission data there this summer as a consultant with The Carter Center. That’s happened in several countries in South America, where a more benign version of the disease has been prevalent. The next challenge, Higazi notes, would be to tackle the problem in the southern region, which voted earlier this year to split from the north and establish itself as an independent nation.
By Andrea Gibson
This article will appear in the Autumn/Winter 2011 issue of Perspectives magazine, which covers the research, scholarship, and creative activity of Ohio University faculty, staff, and students.