A parasite prominent in sub-saharan African rivers called Onchocerca volvulus (pictured above) is one of the 17 neglected tropical diseases selected by WHO in 2003 for directed control or elimination. Transmitted by bites of Simulium blackflies that breed in rivers, the parasite causes 'river blindness'. Approximately 500,000 people are visually impaired by the disease, and many more have other symptoms of the disease. The WHO estimates that 205 million people in sub-Saharan Africa are at risk of infection.
The biggest barrier to treatment of the parasite is lack of proper diagnostic tools. Currently, an ELISA-based test that determines presence of an immune response specific for the parasite is used. However, this test does not discriminate between active and past infections, nor does it cover all potential markers for the parasite. As a result, it too-commonly returns false-negative readings.
A study led by scientists at the National Institutes of Health identified other biomarkers that can be used for more accurate detection of the parasite. Their test was able to determine whether the infection was old and recovered or active, and had more accurate results compared to the previous method.
The biomarkers they identified, along with others, could also be used in the future for more sensitive platforms for surveillance. The testing procedure found by this group has a sensitivity rate of 94% (meaning, it correctly identifies positive cases 94% of the time), and the researchers describe a way by which the test could even reach the WHO-recommended rate of 99%.