Trypanosomiasis prevalence in the cotton basin in the Sudanese zone of Côte d'Ivoire

La prévalence trypanosomienne a été évaluée dans les cheptels du bassin cotonnier en zone soudanaise de Côte d’Ivoire. Les prélèvements de sang ont été effectués du 22 avril au 21 mai 2016, sur 582 bovins dont 374 mâles et 195 femelles, appartenant aux phénotypes Méré, Zébu et Ndama. Les espèces de trypanosomes ont été d’abord identifiées sur le terrain à partir de frottis sanguins, puis caractérisées au laboratoire au moyen de la PCR (Polymerase Chain Reaction). Les trois espèces diagnostiquées sont, dans l’ordre décroissant de leur taux de prévalence, Trypanosoma congolense groupe savane, Trypanosoma vivax et Trypanosoma brucei brucei. Le plus grand nombre de bovins infectés provient de Korhogo, suivi de M’Bengué, puis de Ferkessédougou. Le taux d’infection est plus faible et du même ordre à Katiola, Koumbala, Diawara et Niellé. Les Méré sont les plus infectés par rapport aux Zébu et aux Ndama. Ces derniers sont les plus faiblement infectés. Chez les Ndama, la trypanotolérance apparaît encore plus efficiente chez les animaux de moins de 8 ans. Les Méré montrent une forte parasitémie due à Trypanosoma congolense ou à Trypanosoma vivax, sans toutefois faire la maladie. Mots clés : TAA, Prévalence, Zone soudanaise, Côte d’IvoireTrypanosomiais prevalence was evaluated in the flocks of the cotton basin in the Sudanese zone of Côte d'Ivoire. The blood samples were taken from April 22 to May 21, 2016, on 582 cattle including 374 males and 195 females, belonging to the phenotypes Méré, Zébu and Ndama. Trypanosome species were first identified in the field from blood smears and then characterized in the laboratory using PCR (Polymerase Chain Reaction). The three species diagnosed are, in decreasing order of their prevalence rate, Trypanosoma congolense savannah group, Trypanosoma vivax and Trypanosoma brucei brucei. Most of the infected cattle come from Korhogo, followed by M'Bengué and then Ferkessédougou. The infection rate is lower and of the same order in Katiola, Koumbala, Diawara and Niellé. Méré are the most infected compared to Zebu and Ndama. The latter are the most weakly infected. For the Ndama, trypanotolerance appears to be even more efficient in animals less than 8 years old. The Méré show a strong parasitaemia due to Trypanosoma congolense or Trypanosoma vivax, without however being sick. Keywords : AAT, Prevalence, Sudanese zone, Côte d’Ivoir

ETUDE DU COMPORTEMENT AU REPOS ET DES PREFERENCES TROPHIQUES DE ANOPHELES GAMBIAE DANS LA VILLE D’ADZOPE, COTE D’IVOIRE

An entomological follow up, carried out by house resting collection and outdoor resting collections was achieved from June 2006 to September 2008 in Adzope, a town located in South-west Côte d’Ivoire, in the forest zone. This study aimed at identifying the origin of the An. gambiae females bloodmeals. In total, 539 mosquitoes were collected, 390 house resting mosquitoes and 149 outdoor resting ones. The mosquitoes collected in the two environments belong to 3 genera: Anopheles (92.5 %), Culex (7.2 %) and Mansonia(0.2 %). An. gambiae was the only anopheles species collected. The study of its resting behavior reveals the existence in Adzope of two populations: endophilic and exophilic. The origin of 60 bloodmeals of this species was identified by the PCR-heteroduplex. In houses, the bloodmeals were collected on humans (97%) and goats (3%). In outdoor shelters, the collection was made on humans (87.5%), birds (3%) and cows (1.5%). The bloodmeals from unknown origins were 1.5%. Actually, the poultry was the host preference for animal-feeding females. An. gambiae presents a high anthropophilic rate and therefore a threat for Adzope population

Tsetse fly ecology and risk of transmission of African trypanosomes related to a protected forest area at a military base in the city of Abidjan, Côte d’Ivoire

African trypanosomoses, whose pathogens are transmitted by tsetse flies, are a threat to animal and human health. Tsetse flies observed at the military base of the French Forces in Côte d’Ivoire (FFCI base) were probably involved in the infection and death of military working dogs. Entomological and parasitological surveys were carried out during the rainy and dry seasons using “Vavoua” traps to identify tsetse fly species, their distribution, favorable biotopes and food sources, as well as the trypanosomes they harbor. A total of 1185 Glossina palpalis palpalis tsetse flies were caught, corresponding to a high average apparent density of 2.26 tsetse/trap/day. The results showed a heterogeneous distribution of tsetse at the FFCI base, linked to more or less favorable biotopes. No significant variation in tsetse densities was observed according to the season. The overall trypanosomes infection rate according to microscopic observation was 13.5%. Polymerase chain reaction (PCR) analyses confirmed the presence of Trypanosoma vivax and T. congolense forest type, responsible for African animal trypanosomosis. Our findings suggest that there is a risk of introduction and transmission of T. brucei gambiense, responsible for human African trypanosomiasis, on the study site. This risk of transmission of African trypanosomes concerns not only the FFCI base, but also inhabited peripheral areas. Our study confirmed the need for vector control adapted to the eco-epidemiological context of the FFCI base

Number of positive test results by type of study participant.

<p>Number of positive test results by type of study participant.</p

Consensus intensity and intensity scores given by 3 readers to the test lines in HAT Sero-<i>K</i>-Set and SD Bioline HAT (line 1 and 2).

<p>In case of a negative (N) consensus intensity the test line intensity was considered negative, the test line was interpreted positive if the consensus test line intensity was faint or stronger. N: negative, F: faint, W: weak, M: Medium, S: strong.</p><p>Consensus intensity and intensity scores given by 3 readers to the test lines in HAT Sero-<i>K</i>-Set and SD Bioline HAT (line 1 and 2).</p

Number of positive test results combining RDTs with trypanolysis, by type of study participant.

<p>Number of positive test results combining RDTs with trypanolysis, by type of study participant.</p

Tsetse fly ecology and risk of transmission of African trypanosomes related to a protected forest area at a military base in the city of Abidjan, Côte d’Ivoire

African trypanosomoses, whose pathogens are transmitted by tsetse flies, are a threat to animal and human health. Tsetse flies observed at the military base of the French Forces in Côte d’Ivoire (FFCI base) were probably involved in the infection and death of military working dogs. Entomological and parasitological surveys were carried out during the rainy and dry seasons using “Vavoua” traps to identify tsetse fly species, their distribution, favorable biotopes and food sources, as well as the trypanosomes they harbor. A total of 1185 Glossina palpalis palpalis tsetse flies were caught, corresponding to a high average apparent density of 2.26 tsetse/trap/day. The results showed a heterogeneous distribution of tsetse at the FFCI base, linked to more or less favorable biotopes. No significant variation in tsetse densities was observed according to the season. The overall trypanosomes infection rate according to microscopic observation was 13.5%. Polymerase chain reaction (PCR) analyses confirmed the presence of Trypanosoma vivax and T. congolense forest type, responsible for African animal trypanosomosis. Our findings suggest that there is a risk of introduction and transmission of T. brucei gambiense, responsible for human African trypanosomiasis, on the study site. This risk of transmission of African trypanosomes concerns not only the FFCI base, but also inhabited peripheral areas. Our study confirmed the need for vector control adapted to the eco-epidemiological context of the FFCI base