Researchers report onchocerciasis (river blindness) could make a comeback in Northwestern Uganda if annual drug distributions to fight the disease are stopped. The study, conducted in the endemic region of Nyagak-Bondo, showed that while there was a significant reduction in infection after 18 years of community-based treatment with the deworming medication ivermectin, transmission has not been interrupted.
Lead researcher Moses Katabarwa, PhD, of The Carter Center and Emory University and colleagues from the Uganda Ministry of Health found that children born even long after the drug distribution began in 1993 were still getting infected. A substantial number of adults were testing positive for microfilaria (worm larvae) as well.
"This study shows that there is truly no one-size-fits-all approach when it comes to stopping river blindness infection," Katabarwa said. "The amount of time and the frequency of treatment necessary to interrupt transmission and eliminate the disease could vary considerably among different areas because of environmental factors, the flies involved, the risk of drug resistance, or other issues."
While recent reports conducted in other West African nations (Mali and Senegal) suggested that there was no difference between 15-17 years of annual or semi-annual community-based treatment with the deworming medication ivermectin in eliminating transmission of the disease in those areas, annual treatments were not sufficient in the Nyagak-Bondo region. The authors report the data indicate that it may be necessary to increase the frequency of ivermectin treatments to twice per year to successfully interrupt transmission of the disease.