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

Significant efforts to control human African trypanosomiasis (HAT) over the three past decades have resulted in drastic reductions of disease prevalence in Côte d’Ivoire. In this context, the costly and labor-intensive active mass screening strategy is no longer efficient. In addition to a more cost-effective passive surveillance system being implemented in this low-prevalence context, our aim was to develop an alternative targeted active screening strategy. In 2012, we carried out a targeted door-to-door (TDD) survey focused on the immediate vicinities of former HAT patients detected in the HAT focus of Bonon and compared the results to those obtained during classical active mass screening (AMS) surveys conducted from 2000 to 2012 in the same area. The TDD that provides a friendlier environment, inviting inhabitants to participate and gain awareness of the disease, detected significantly more HAT cases than the AMS. These results suggest that the TDD is an efficient and useful strategy in low-prevalence settings where very localized transmission cycles may persist and, in combination with passive surveillance, could help in eliminating HAT

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

Significant efforts to control human African trypanosomiasis (HAT) over the three past decades have resulted in drastic reductions of disease prevalence in Côte d’Ivoire. In this context, the costly and labor-intensive active mass screening strategy is no longer efficient. In addition to a more cost-effective passive surveillance system being implemented in this low-prevalence context, our aim was to develop an alternative targeted active screening strategy. In 2012, we carried out a targeted door-to-door (TDD) survey focused on the immediate vicinities of former HAT patients detected in the HAT focus of Bonon and compared the results to those obtained during classical active mass screening (AMS) surveys conducted from 2000 to 2012 in the same area. The TDD that provides a friendlier environment, inviting inhabitants to participate and gain awareness of the disease, detected significantly more HAT cases than the AMS. These results suggest that the TDD is an efficient and useful strategy in low-prevalence settings where very localized transmission cycles may persist and, in combination with passive surveillance, could help in eliminating HAT

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

Abstract -Significant efforts to control human African trypanosomiasis (HAT) over the three past decades have resulted in drastic reductions of disease prevalence in Côte d'Ivoire. In this context, the costly and labor-intensive active mass screening strategy is no longer efficient. In addition to a more cost-effective passive surveillance system being implemented in this low-prevalence context, our aim was to develop an alternative targeted active screening strategy. In 2012, we carried out a targeted door-to-door (TDD) survey focused on the immediate vicinities of former HAT patients detected in the HAT focus of Bonon and compared the results to those obtained during classical active mass screening (AMS) surveys conducted from 2000 to 2012 in the same area. The TDD that provides a friendlier environment, inviting inhabitants to participate and gain awareness of the disease, detected significantly more HAT cases than the AMS. These results suggest that the TDD is an efficient and useful strategy in low-prevalence settings where very localized transmission cycles may persist and, in combination with passive surveillance, could help in eliminating HAT. Résumé -Stratégie médicale ciblée en porte-à-porte pour la détection de la trypanosomiase humaine africaine dans des régions de faible prévalence en Côte d'Ivoire. D'importants efforts pour contrôler la trypanosomiase humaine africaine (THA) au cours des trois dernières décennies ont permis une réduction importante des prévalences en Côte d'Ivoire. Dans ce contexte, les prospections médicales classiques de masse ne sont plus adaptées en termes de coût-efficacité. En plus de développer un système de surveillance passive plus rentable dans ce contexte, notre but était de soutenir l'élimination de la THA en élaborant une stratégie active alternative basée sur une détection ciblée de cas. Dans le foyer de Bonon, nous avons mené en 2012 une surveillance médicale en porte-à-porte ciblée sur le voisinage immédiat d'anciens cas de THA et comparé les résultats à ceux des prospections médicales classiques de masse menées entre 2000 et 2012 dans la même zone. La stratégie ciblée en porte-à-porte, qui contribue à une meilleure sensibilisation des populations, a détecté significativement plus de cas de THA que la prospection médicale classique de masse. Ceci montre que la stratégie ciblée en porte-à-porte est une stratégie efficace dans les contextes de faibles prévalences où des cycles de transmission très localisés peuvent persister, qui est complémentaire à la surveillance passive pour atteindre l'objectif d'élimination de la trypanosomiase humaine africaine

The study of trypanosome species circulating in domestic animals in two human African trypanosomiasis foci of Côte d'Ivoire identifies pigs and cattle as potential reservoirs of Trypanosoma brucei gambiense.

BACKGROUND:Important control efforts have led to a significant reduction of the prevalence of human African trypanosomiasis (HAT) in Côte d'Ivoire, but the disease is still present in several foci. The existence of an animal reservoir of Trypanosoma brucei gambiense may explain disease persistence in these foci where animal breeding is an important source of income but where the prevalence of animal African trypanosomiasis (AAT) is unknown. The aim of this study was to identify the trypanosome species circulating in domestic animals in both Bonon and Sinfra HAT endemic foci. METHODOLOGY/PRINCIPAL FINDINGS:552 domestic animals (goats, pigs, cattle and sheep) were included. Blood samples were tested for trypanosomes by microscopic observation, species-specific PCR for T. brucei sl, T. congolense, T. vivax and subspecies-specific PCR for T. b. gambiense and T. b. gambiense immune trypanolysis (TL). Infection rates varied significantly between animal species and were by far the highest in pigs (30%). T. brucei s.l was the most prevalent trypanosome species (13.7%) followed by T. congolense. No T. b. gambiense was identified by PCR while high TL positivity rates were observed using T. b. gambiense specific variants (up to 27.6% for pigs in the Bonon focus). CONCLUSION:This study shows that domestic animals are highly infected by trypanosomes in the studied foci. This was particularly true for pigs, possibly due to a higher exposure of these animals to tsetse flies. Whereas T. brucei s.l. was the most prevalent species, discordant results were obtained between PCR and TL regarding T. b. gambiense identification. It is therefore crucial to develop better tools to study the epidemiological role of potential animal reservoir for T. b. gambiense. Our study illustrates the importance of "one health" approaches to reach HAT elimination and contribute to AAT control in the studied foci

The complex health seeking pathway of a human African trypanosomiasis patient in Côte d'Ivoire underlines the need of setting up passive surveillance systems.

BackgroundSignificant efforts to control human African trypanosomiasis (HAT) over the two past decades have resulted in drastic decrease of its prevalence in Côte d'Ivoire. In this context, passive surveillance, integrated in the national health system and based on clinical suspicion, was reinforced. We describe here the health-seeking pathway of a girl who was the first HAT patient diagnosed through this strategy in August 2017.MethodsAfter definitive diagnosis of this patient, epidemiological investigations were carried out into the clinical evolution and the health and therapeutic itinerary of the patient before diagnosis.ResultsAt the time of diagnosis, the patient was positive in both serological and molecular tests and trypanosomes were detected in blood and cerebrospinal fluid. She suffered from important neurological disorders. The first disease symptoms had appeared three years earlier, and the patient had visited several public and private peripheral health care centres and hospitals in different cities. The failure to diagnose HAT for such a long time caused significant health deterioration and was an important financial burden for the family.ConclusionThis description illustrates the complexity of detecting the last HAT cases due to complex diagnosis and the progressive disinterest and unawareness by both health professionals and the population. It confirms the need of implementing passive surveillance in combination with continued sensitization and health staff training

Reactivity to the Litat 1.3, 1.5 and 1.6 VAT according to the different PCR profiles.

<p>PCR profiles are given as follow: PCR TBR result/PCR TCF result/PCR TVW result. n = number of animals with the corresponding profile. Numbers on the top are the numbers of animal positives with Litat 1.3 and/or 1.5 TL or with LiTat 1.6 only.</p

Number of domestic animals sampled by species and foci.

<p>Number of domestic animals sampled by species and foci.</p

Immune trypanolysis (TL) results.

<p>Proportion of the LiTat 1.6 (4A), LiTat 1.3 (4B) and LiTat 1.5 (4C) TL positive results on the total sample collection for each host in the two foci. A significant difference between Bonon and Sinfra is indicated with a star.</p