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In the context of the human African trypanosomiasis elimination process, reliable and accurate diagnostic tools are crucial for exploring the role of a potential animal reservoir of Trypanosoma brucei gambiense. The immune trypanolysis test (TL) using the variant antigen types (VAT) LiTat 1.3 and LiTat 1.5, described as a specific serological method to detect people infected by T. b. gambiense, seems to be a promising tool. However, its specificity was recently questioned during field animal surveys. The present study evaluates the performance of TL during experimental T. b. brucei infection in pigs. Eight infected pigs and four uninfected pigs were followed up with blood and plasma collection. Blood was used for parasitological investigation. TL was performed on the plasma with the LiTat 1.3, LiTat 1.5 and LiTat 1.6 VATs. All control pigs remained negative to parasitological investigation and TL. Trypanosomes were detected in all the infected pigs and the first detection was between 10 and 14 days post infection (dpi). TL results showed that infected pigs developed antibodies against the three VATs. The first antibody detections by TL occurred between 14 and 21 dpi for antibodies directed against LiTat 1.6, 21 and 168 dpi for antibodies directed against LiTat 1.5 and 70, and 182 dpi for antibodies directed against LiTat 1.3. This study highlights for the first time that TL using LiTat 1.3 and LiTat 1.5 VATs is not specific to T. b. gambiense. Development of specific diagnostic tools for the detection of T. b. gambiense infections in animals, especially in pigs, is still needed.

The World Health Organisation has targeted the elimination of human African trypanosomiasis (HAT) as zero transmission by 2030. Continued surveillance needs to be in place for early detection of re-emergent cases. In this context, the performance of diagnostic tests and testing algorithms for detection of the re-emergence of Trypanosoma brucei gambiense HAT remains to be assessed. We carried out a door-to-door active medical survey for HAT in the historical focus of Batié, South–West Burkina Faso. Screening was done using three rapid diagnostic tests (RDTs). Two laboratory tests (ELISA/T. b. gambiense and immune trypanolysis) and parasitological examination were performed on RDT positives only. In total, 5883 participants were screened, among which 842 (14%) tested positive in at least one RDT. Blood from 519 RDT positives was examined microscopically but no trypanosomes were observed. The HAT Sero-K-Set test showed the lowest specificity of 89%, while the specificities of SD Bioline HAT and rHAT Sero-Strip were 92% and 99%, respectively. The specificity of ELISA/T. b. gambiense and trypanolysis was 99% (98–99%) and 100% (99–100%), respectively. Our results suggest that T. b. gambiense is no longer circulating in the study area and that zero transmission has probably been attained. While a least cost analysis is still required, our study showed that RDT preselection followed by trypanolysis may be a useful strategy for post-elimination surveillance in Burkina Faso.

The World Health Organization (WHO) has set the goal of gambiense-Human African trypanosomiasis (HAT) elimination as a public health problem for 2020 and interruption of transmission in humans for 2030. In this context, it is crucial to monitor progress towards these targets using accurate tools to assess the level of transmission in a given area. The aim of this study was to investigate the relevance of the immune trypanolysis test (TL) as a population-based bioassay to evaluate Trypanosoma brucei gambiense transmission in various epidemiological contexts. Significant correlations were observed between HAT endemicity levels and the percentage of TL-positive individuals in the population. TL therefore appears to be a suitable population-based biomarker of the intensity of transmission. In addition to being used as a tool to assess the HAT status at an individual level, assessing the proportion of TL positive individuals in the population appears as a promising and easy alternative to monitor the elimination of gambiense HAT in a given area.

Salmonella enterica serotype Typhimurium multilocus O sequence type (ST) 313 has been reported as an emerging cause of invasive salmonellosis in sub-Saharan Africa (1). ST313 is almost exclusively from sub-Saharan [...]

OBJECTIVE: To evaluate the performance of serological tests using dried blood on filter-papers (micro-card agglutination test for trypanosomiasis (micro-CATT)) performed under field and laboratory conditions and using whole blood ((CATT/T.b. gambiense) (wb-CATT) and latex agglutination (LATEX/T.b. gambiense) (wb-LATEX)) for the serodiagnosis and surveillance of human African trypanosomiasis in West and Central Africa. METHODS: We evaluated the micro-CATT, wb-CATT and wb-LATEX methods in Côte d'Ivoire and the Central African Republic by screening 940 people. Sensitivity and specificity were calculated for each serological test; only patients with the confirmed presence of trypanosomes in the blood or lymph aspirate were considered true positives. Positive and negative predictive values were also calculated. FINDINGS: Each of the tests showed a lower sensitivity in the Central African Republic than in Côte d'Ivoire. CONCLUSION: The results confirmed the efficiency of the classic wb-CATT to detect sleeping sickness patients. The micro-CATT method can be used for human African trypanosomiasis surveillance if the test is performed on the same day as the blood collection, or if samples are stored at 4 ºC. Otherwise, micro-CATT can be used when absolute sensitivity is not required. wb-LATEX should only be used for high-specificity screening.

Objective To report the findings of a second external quality assessment of Giemsa-stained blood film microscopy in the Democratic Republic of the Congo, performed one year after the first. Methods A panel of four slides was delivered to diagnostic laboratories in all provinces of the country. The slides contained: (i) Plasmodium falciparum gametocytes; (ii) P. falciparum trophozoites (reference density: 113 530 per µl); (iii) Trypanosoma brucei subspecies; and (iv) no parasites. Findings Of 356 laboratories contacted, 277 (77.8%) responded. Overall, 35.0% of the laboratories reported all four slides correctly but 14.1% reported correct results for 1 or 0 slides. Major errors included not diagnosing trypanosomiasis (50.4%), not recognizing P. falciparum gametocytes (17.5%) and diagnosing malaria from the slide with no parasites (19.0%). The frequency of serious errors in assessing parasite density and in reporting false-positive results was lower than in the previous external quality assessment: 17.2% and 52.3%, respectively, (P < 0.001) for parasite density and 19.0% and 33.3%, respectively, (P < 0.001) for false-positive results. Laboratories that participated in the previous quality assessment performed better than first-time participants and laboratories in provinces with a high number of sleeping sickness cases recognized trypanosomes more frequently (57.0% versus 31.2%, P < 0.001). Malaria rapid diagnostic tests were used by 44.3% of laboratories, almost double the proportion observed in the previous quality assessment. Conclusion The overall quality of blood film microscopy was poor but was improved by participation in external quality assessments. The failure to recognize trypanosomes in a country where sleeping sickness is endemic is a concern. Objectif Presenter les resultats d'une deuxieme evaluation externe de la qualite de la microscopie de frottis sanguins colores au Giemsa en Republique democratique du Congo, realisee un an apres la premiere. Methodes Un ensemble de quatre lames a ete livre aux laboratoires de diagnostic dans toutes les provinces du pays. Les lames contenaient: (i) des gametocytes de Plasmodium falciparum, (il) des trophozoites de P. falciparum (densite reference: 113 530 par µl), (iii) la sous-espece Trypanosoma brucei, et (iv) aucun parasite. Resultats Sur les 356 laboratoires contactes, 277 (77,8%) ont repondu. Dans l'ensemble, 35,0% des laboratoires ont correctement etudie les quatre lames mais 14, 1% d'entre eux ont obtenu les bons resultats pour 1 ou 0 lame. Parmi les erreurs majeures figuraient le non-diagnostic de la trypanosomiase (50,4%), la non-reconnaissance des gametocytes de R falciparum (17,5%) et le diagnostic du paludisme sur la lame depourvue de parasite (19,0%). La frequence de ces erreurs graves dans Ievaluation de la densite parasitaire et de l'obtention de resultats faussement positifs est inferieure a celle de la precedente evaluation externe: 17,2% et 52,3%, respectivement, (P < 0,001) pour la densite parasitaire et 19% et 33,3%, respectivement, (P < 0,001) pour les resultats faussement positifs. Les laboratoires ayant participe a la precedente evaluation de la qualite ont obtenu de meilleurs resultats que les nouveaux participants, et les laboratoires situes dans les provinces presentant un nombre eleve de cas de maladie du sommeil ont mieux reconnu les trypanosomes (57,0% contre 31,2%, P < 0,001). Les tests de diagnostic rapide du paludisme ont ete utilises par 44,3% des laboratoires, presque le double de la proportion observee dans la precedente evaluation de la qualite. Conclusion La qualite globale de la microscopie de frottis sanguin etait faible, mais a ete amelioree par la participation a l'evaluation externe de la qualite. L'incapacite a reconnaitre les trypanosomes dans un pays ou la maladie du sommeil est endemique est une preoccupation majeure. Objetivo Informar de los resultados de una segunda evaluacion de calidad externa de la microscopia en frotis de sangre con tincion de Giemsa en la Republica Democratica del Congo, llevada a cabo un ano despues de la primera. Metodos Se entrego un panel de cuatro muestras a laboratorios de diagnostico de todas las provincias del pais. Las muestras contenian: (i) gametocitos Plasmodium falciparum; (ii) trofozoitos R falciparum (densidad de referencia: 113 530 por µl); (iii) subespecies d'e Trypanosoma brucei y (iv) ningun parasito. Resultados De los 356 laboratorios contactados, respondieron 277 (77,8%). En total, el 35,0% de los laboratorios informo de las cuatro muestras correctamente, pero el 14,1% informo de resultados correctos en una o ninguna de las muestras. Los principales errores consistieron en no diagnosticar la tripanosomiasis (50,4%), no reconocer los gametocitos P. falciparum (17,5%) y diagnosticar malaria en la muestra sin parasitos (19,0%). La frecuencia de errores graves en la evaluacion de la densidad de los parasitos y en informar de resultados con falsos positivos fue menor que en la evaluacion de calidad externa anterior. El 17,2% y el 52,3%, respectiva mente (P < 0,001 ), en el caso de la densidad de los parasitos y el 19,0% y el 33,3%, respectivamente (P< 0,001), en lo que atane a los resultados con falsos positivos. Los laboratorios que participaron en la evaluacion de calidad anterior tuvieron mejores resultados que los laboratorios noveles, y los laboratorios de provincias con un numero alto de casos de la enfermedad del sueno reconocieron los tripanosomas con mayor frecuencia (el 57,0% frente al 31,2%, P Conclusion La calidad general de la microscopia en frotis de sangre se revelo escasa, pero experimento mejoras gracias a la participacion en evaluaciones de calidad externas. La incapacidad para reconocer los tripanosomas en un pais en que la enfermedad del sueno es endemica es un problema., Introduction With 97% of its population living in areas of stable malaria transmission, the Democratic Republic of the Congo is among the countries with the highest malaria burden in Africa. [...]