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Overview of a Shameful Situation

GHF2006 - Parallel session PS03

Author(s): François Chappuis1
Affiliation(s): 1Travel and Migration Medicine Unit, Geneva University Hospitals, Geneva, Switzerland
Meeting challenges: Visceral leishmaniasis (or kala-azar) and trypanosomiasis (sleeping sickness and Chagas disease) are some of the most neglected diseases of mankind. Transmission of these diseases mostly occurs in rural areas of tropical countries where the vast majority of patients belong to the poorest strata of the society. As patients have no means to seek care in referral hospitals, which are generally located in distant urban centres, they are managed in local health facilities. The numbers, level of training, and technical competence of staff working in peripheral health structures are usually limited. It is therefore vital to have cheap, reliable, efficient, safe, and easy-to-use diagnostic and treatment tools available to manage these diseases in the field. These conditions are currently grossly unmet. RK39 antigen-based dipsticks have been validated in the Indian sub-continent for the field diagnosis of visceral leishmaniasis, but they are poorly distributed in the public sector. Moreover, currently commercialized rK39 dipsticks lack sensitivity in Sudan. In most endemic areas, treatment of kala-azar still relies on pentavalent antimonials, which are rather toxic and impractical to use. Other drug options are either too expensive (liposomal amphotericin B), under evaluation (paromomycin or miltefosine in East Africa), or wrongly distributed (miltefosine in the Indian private sector). The treatment of American trypanosomiasis still relies on benznidazole or nifurtimox, which should be given during or within years after acute infection, a phase that often remains undetected. Moreover, treatment is long and poorly tolerated. The diagnosis and staging of African trypanosomiasis due to T. b. gambiense is complicated by the lack of a screening test for individual use, the insufficient sensitivity of parasitological tests, and the absence of a practical staging tool. Consequently, diagnostic algorithms are too sophisticated to allow the integration of sleeping sickness activities within existing health structures. Efl ornithine has proven to be a much safer drug than the arsenic-derivative melarsoprol for treatment of advanced sleeping sickness, but its wider use is impaired by logistic (4 daily 2-hour infusions for 14 days) and human resources constraints.
Conclusion (max 400 words): The lack of field availability of practical, cheap, and easy-to-use diagnostic tests and drugs for neglected diseases such as human leishmaniasis and trypanosomiasis is primarily, but not exclusively, due to a lack of research on and development of better tools. New initiatives to by-pass this failure will be presented during the symposium.

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