Alternative screening and case finding methodology for HAT and introduction support for new diagnostic tools

Human African Trypanosomiasis (HAT) or sleeping sickness is a parasitic disease that causes immense suffering in Subsaharan-Africa. After a major epidemic during the 1990s, HAT is now again on the decrease in most affected areas. The disease was recently targeted by the World Health Organization (WHO) for elimination by 2020 and interruption of transmission by 2030. Until HAT transmission has been eliminated, there will be a need for active case finding and surveillance; the need for surveillance will continue even when there will be no more HAT cases in the community. The current approach to case finding and surveillance is based on mobile teams conducting exhaustive population screening. This approach is very costly and becomes less effective when HAT prevalence is low because people do not participate any longer (1). There is therefore an urgent need to develop a more affordable and sustainable mechanism for active case finding and surveillance, adapted to the environment of rural Sub-Saharan Africa. In addition there are populations currently not covered by the screening efforts because they live in locations that are not readily accessible for the mobile teams.

Apart from the introduction of the CATT screening test at the end of the 1980s not much has changed in HAT control since colonial times but some recent technological developments could open up new perspectives (2). Two new rapid tests have been developed that are easily applicable in the field and can be stored at ambient temperature (3,4). A new molecular test based on loop mediated isothermal amplification (LAMP), has been developed and is currently in the process of being evaluated(5). LAMP has been automated to such a degree that it can be used at the level of a district hospital. Outside the health field there have been other innovations that have not yet been used in HAT control. These include GPS technology and availability of mobile devices for communication and data registration.

In this project we will develop and evaluate an alternative approach to active case finding and surveillance in HAT that incorporates these recent technological developments. Rather than to send out a full-fledged mobile screening team as is currently done, we will send out a single health worker equipped with a PDA, rapid tests, and some cryotubes for blood sampling. The health worker will go from house to house and use his PDA to register all inhabitants and record the geographic coordinates of each house. For all those present during the survey he will conduct a rapid test. For those testing positive a small volume of blood will be collected on the spot in a cryo tube with stabilization buffer and stored at ambient temperature. Once every 2-4 weeks these samples will be delivered to a laboratory at district or provincial level and tested by LAMP. If positive, the subject will be invited for a full diagnostic workup and treated according to national guidelines. The district health management team will continuously analyze the information on new cases detected and decide on a village by village basis whether additional screening is required.