Human African Trypanosomiasis Diagnosis in First-Line Health Services of Endemic Countries, a Systematic Review

Abstract

While the incidence of Human African Trypanosomiasis (HAT) is decreasing, the control approach is shifting from active population screening by mobile teams to passive case detection in primary care centers. We conducted a systematic review of the literature between 1970 and 2011 to assess which diagnostic tools are most suitable for use in first-line health facilities in endemic countries. Our search retrieved 16 different screening and confirmation tests for HAT. The thermostable format of the Card Agglutination Test for Trypanosomiasis (CATT test) was the most appropriate screening test. Lateral flow antibody detection tests could become alternative screening tests in the near future. Confirmation of HAT diagnosis still depends on visualizing the parasite in direct microscopy. All other currently available confirmation tests are either technically too demanding and/or lack sensitivity and thus rather inappropriate for use at health center level. Novel applications of molecular tests may have potential for use at district hospital level.

Diagnostic Accuracy of Loopamp Trypanosoma brucei Detection Kit for Diagnosis of Human African Trypanosomiasis in Clinical Samples

“…For diagnostic purposes all were subjected to parasitological confirmation, irrespective of CATT results. Trypanosomes were detected by examination of lymph node aspirate (in subjects with swollen cervical nodes) or by blood examination (all study subjects) with the capillary centrifugation technique (CTC) [12], mAECT on whole blood [8], and mAECT on buffy coat [5]. For patients with parasites detected in the lymph or blood, or with a plasma CATT end titer ≥1∶8 a lumbar puncture was done.…”

“…They can be performed on various specimen types such as whole blood, blood stored on filter paper and CSF. However, the need for laboratory instruments for nucleic acid extraction, amplification and visualization are obstacles to their application in clinical settings in HAT endemic areas [8]. Isothermal reactions such as nucleic acid sequence-based amplification (NASBA) and loop mediated isothermal amplification (LAMP) have recently been developed for the diagnosis of HAT [7], [9].…”

Cattle trypanosomosis: the diversity of trypanosomes and implications for disease epidemiology and control

“…Although the VSG can be a useful diagnostic substrate for clonal trypanosome species/strains in which there is limited diversity and relative conservation of the content and usage of the VSG repertoire (e.g. VSGs are the target for the CATT test for T. b. gambiense [78] and RoTat 1.2-based diagnosis of T. b. evansi), such an approach is unlikely to be applicable to T. congolense and T. brucei in particular. In theory a VSG-based test may be more suited to the detection of T. vivax, but the problems with such tests for T. vivax would be much the same as those surrounding the RoTat 1.2-based test for T. b. evansi.…”

A targeted door-to-door strategy for sleeping sickness detection in low-prevalence settings in Côte d’Ivoire

“…In such a context, it is important to reinforce passive surveillance strategies integrating HAT control activities into the general healthcare system and focusing on patients self-presenting for consultation [7, 20, 23, 26]. However, integration of this strategy encounters political and technical challenges partly due to difficulties in diagnosing the disease as well as the capacity of health facilities to cover the population at risk, generally living in remote rural areas far from the main health structures [12, 20].…”

“…However, integration of this strategy encounters political and technical challenges partly due to difficulties in diagnosing the disease as well as the capacity of health facilities to cover the population at risk, generally living in remote rural areas far from the main health structures [12, 20]. Moreover, case detection in passive surveillance is first based on clinical symptoms leading to the detection essentially of late stage cases that were probably parasite reservoirs for years before diagnosis and treatment was made [15].…”