STROGHAT

The challenge

Enormous progress has been made in the control of human African trypanosomiasis (HAT), a potentially fatal infection with trypanosome parasites. Elimination is possible, but new approaches to disease control will be needed as cases become ever more rare.

Historically, the treatment of the most common form of HAT – gHAT, caused by infections with Trypanosoma brucei gambiense – relied on relatively toxic drugs such as melarsoprol. To avoid over-use of a potentially harmful drug, patients underwent a complex assessment procedure, based on screening for antibodies, microscopic analysis of blood samples to identify parasites and, to confirm late-stage disease, analysis of a lumbar puncture sample. As well as being complex and time-consuming, this approach also missed about half of all gHAT cases.

The development of less harmful drugs, including agents active against both early-stage disease and severe late-stage disease, have opened up the possibility of treatment based on simple screening. In particular, the drug acoziborole, developed by Novartis and the Drugs for Neglected Diseases Initiative, has been shown to have an efficacy of 98% against gHAT and a good safety record, and could form the basis of a ‘screen-and-treat’ approach to gHAT control, with at-risk populations screened for antibodies and immediately treated if they test positive.

The project

The STROGHAT project will assess whether a screen-and-treat approach is safe, effective and acceptable. Focusing on the Nord Equateur region of the Democratic Republic of the Congo (DRC), it will target 63 villages in which cases of gHAT have recently been identified. Mobile teams will offer to screen all people in these villages and offer acoziborole to those testing positive, without waiting for microscopy results. In addition, rapid diagnostic tests will be offered at 30 sites already taking part in gHAT surveillance. 

The approach will be applied for three years, with careful monitoring for adverse reactions, after which the incidence of gHAT will be reassessed. If it has been reduced below a certain threshold, this would indicate that the parasite is on the path to extinction.

Impact

The STROGHAT project will provide key evidence on the effectiveness and safety of an approach that could be adopted as the incidence of gHAT becomes very low and detecting cases becomes more challenging. It will:

• Demonstrate whether acoziborole is sufficiently safe to be used at the population level, without conclusive proof of gHAT infections, so that no cases are missed.
• Show whether the screen-and-treat strategy is effective in continuing the downward pressures on gHAT infections.
• Provide an indication of the cost-effectiveness of the screen-and-treat approach. 

Progress in reducing the gHAT burden has been a major success story, but eliminating it will require a shift in strategy. The STROGHAT project could authenticate an approach that ensures populations in Africa no longer need to fear a disease with potentially devastating consequences.