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The prevalence of trypanosomiasis was studied in the Sudano-Guinean highlands of western Cameroon in 107 cattle through parasitological examination and serological analysis. Parasitological examination revealed the presence of trypanosomes in cattle with a prevalence of 16.82%, regardless of cattle breed. The highest prevalences were obtained from cross-breeds (23.33%) and Red Fulani (21.74%), followed by Gudali cattle (6.67%). Conversely, serological analysis highlighted antibodies against T.brucei in 42.17 % of cattle. The highest seroprevalences were identified in White Fulani (60.00%), followed in order by the Gudali (37.14%), the Red Fulani (48.15%) and the crossbreeds (21.05 %). Seroprevalence obtained were significantly higher than the parasitological prevalence. The dilutions performed on the positive sera have proven that regardless cattle breed, the level of antibodies produced was generally low. Infestations in trypanosomes have not significantly affected the neither haematocrit nor blood cell counts. Concerning babesiosis, parasitological search revealed 11.20% of cattle infected, with 6.67, 10.87, 6.67 and 20.00% respectively for the white Fulani, red Fulani, gudali and crossbreeds. Infections with Babesia sp did not affect significantly blood parameters studied. Concerning babesiosis, parasitological search revealed 11.20% of cattle infected, with 6.67, 10.87, 6.67 and 20.00% respectively for the white Fulani, red Fulani, gudali and crossbreeds. Infections with Babesia sp did not affect significantly blood parameters studied.Keywords: prevalence, trypanosomiasis, babesiosis, cattle

Background: Tsetse flies are vectors of human and animal African trypanosomiasis. In spite of many decades of chemotherapy and vector control, the disease has not been eradicated. Other methods like the transformation of tsetse fly symbionts to render the fly refractory to trypanosome infection are being evaluated. The aim of the present study was to evaluate the association between trypanosome infections and the presence of symbionts in these tsetse species. Tsetse flies were trapped in two villages of the "Faro and Deo" Division of the Adamawa region of Cameroon. In the field, tsetse fly species were identified and their infection by trypanosomes was checked by microscopy. In the laboratory, DNA was extracted from their midguts and the presence of symbionts (Sodalis glossinidius and Wolbachia sp.) and trypanosomes was checked by PCR. Symbionts/trypanosomes association tests were performed. Results: Three tsetse fly species including Glossina tachinoides (90.1%), Glossina morsitans submorsitans (9.4%) and Glossina fuscipes fuscipes (0.5%) were caught. In all the population we obtained an occurrence rate of 37.2% for Sodalis glossinidius and 67.6% for Wolbachia irrespective to tsetse flies species. S. glossinidius and Wolbachia sp. occurrence rates were respectively 37 and 68% for G. tachinoides and 28.6 and 59.5% for G. m. submorsitans. Between Golde Bourle and Mayo Dagoum significant differences were observed in the prevalence of symbionts. Prevalence of trypanosomes were 34.8% for Glossina tachinoides and 40.5% for Glossina morsitans submorsitans. In G. tachinoides, the trypanosome infection rates were 11, 2.6 and 13.7%, respectively, for T. brucei s.l., T. congolense forest type and T. congolense savannah type. In G. m. submorsitans, these infection rates were 16.7, 9.5 and, 2.4% respectively, for T. brucei s.l., T. congolense forest type and T. congolense savannah type. Conclusions: The rate of tsetse fly infection by trypanosomes was low compared to those obtained in HAT foci of south Cameroon, and this rate was not statistically linked to the rate of symbiont occurrence. This study allowed to show for the first time the presence of Wolbachia sp. in the tsetse fly sub-species Glossina morsitans submorsitans and Glossina tachinoides.

With the absence of effective prophylactic vaccines and drugs against African trypanosomosis, control of this group of zoonotic neglected tropical diseases depends the control of the tsetse fly vector. When applied in an area-wide insect pest management approach, the sterile insect technique (SIT) is effective in eliminating single tsetse species from isolated populations. The need to enhance the effectiveness of SIT led to the concept of investigating tsetse-trypanosome interactions by a consortium of researchers in a five-year (2013-2018) Coordinated Research Project (CRP) organized by the Joint Division of FAO/IAEA. The goal of this CRP was to elucidate tsetse-symbiome-pathogen molecular interactions to improve SIT and SIT-compatible interventions for trypanosomoses control by enhancing vector refractoriness. This would allow extension of SIT into areas with potential disease transmission. This paper highlights the CRP's major achievements and discusses the science-based perspectives for successful mitigation or eradication of African trypanosomosis.

About 60% of emerging infectious diseases in humans are of zoonotic origin. Their increasing number requires the development of new methods for early detection and monitoring of infectious agents in wildlife. Here, we investigated whether blood meals from hematophagous flies could be used to identify the infectious agents circulating in wild vertebrates. To this aim, 1230 blood-engorged flies were caught in the forests of Gabon. Identified blood meals (30%) were from 20 vertebrate species including mammals, birds and reptiles. Among them, 9% were infected by different extant malaria parasites among which some belonged to known parasite species, others to new parasite species or to parasite lineages for which only the vector was known. This study demonstrates that using hematophagous flies as 'flying syringes' constitutes an interesting approach to investigate blood-borne pathogen diversity in wild vertebrates and could be used as an early detection tool of zoonotic pathogens.

Knowledge on faunal diversification in African rainforests remains scarce. We used phylogeography to assess (i) the role of Pleistocene climatic oscillations in the diversification of the African common pangolin (Manis tricuspis) and (ii) the utility of our multilocus approach for taxonomic delineation and trade tracing of this heavily poached species. We sequenced 101 individuals for two mitochondrial DNA (mtDNA), two nuclear DNA and one Y-borne gene fragments (totalizing 2602 bp). We used a time-calibrated, Bayesian inference phylogenetic framework and conducted character-based, genetic and phylogenetic delineation of species hypotheses within African common pangolins. We identified six geographic lineages partitioned into western Africa, Ghana, the Dahomey Gap, western central Africa, Gabon and central Africa, all diverging during the Middle to Late Pleistocene. MtDNA (cytochrome b + control region) was the sole locus to provide diagnostic characters for each of the six lineages. Tree-based Bayesian delimitation methods using single-and multilocus approaches gave high support for 'species' level recognition of the six African common pangolin lineages. Although the diversification of African common pangolins occurred during Pleistocene cyclical glaciations, causative correlation with traditional rainforest refugia and riverine barriers in Africa was not straightforward. We conclude on the existence of six cryptic lineages within African common pangolins, which might be of major relevance for future conservation strategies. The high discriminative power of the mtDNA markers used in this study should allow an efficient molecular tracing of the regional origin of African common pangolin seizures.

To understand the circulation and the spread of Torpanosoma congolense genotypes in animals of Fontem in the southwest region of Cameroon, T. congolense forest and T. congolense savannah were investigated in 397 domestic animals in eight villages. Out of the 397 domestic animals, 86 (21.7%) were found infected by trypanosomes, using the capillary tube centrifugation test. The PCR with specific primers identified 163 (41.1%) and 81(20.4%) animals infected by T. congolense forest and T. congolense savannah, respectively; showing for the first time the circulation of T. congolense savannah in the Fontem region. No infection with T. congolense savannah was found in pigs whereas goats and sheep were infected by T. congolense forest and/or T. congolense savannah. The prevalence of trypanosomes varied significantly amongst villages and animal species. The genotyping of T. congolense forest positive samples using microsatellites markers showed that multiple genotypes occurred in 27.2% (44/163) of animals sampled, whereas single genotypes were found in 73.8% (119/163) of samples. Some alleles were found in all animal species as well as in all villages and were responsible for major genotypes, whereas others (rare alleles) were identified only in some animals of few villages. These rare alleles were characteristic of specific genotypes, assimilated to minor genotypes which can be spread in the region through tsetse flies. The microsatellite markers show a low genetic variability and an absence of sub-structuration within T. congolense forest. The analysis of the microsatellite data revealed a predominant clonal reproduction within T. congolense forest. Pigs were the animal species with the highest number of different genotypes of T. congolense forest. They seem to play an important epidemiological role in the propagation and spread of different genotypes of T. congolense.

The control of onchocerciasis or river blindness by mass treatment of the population with ivermectin (IVM) has been a great success until now, so that in certain foci its elimination has become feasible. However, after more than 20 years of repeated IVM mass treatment, the disease still persists in many endemic countries. Sub-optimal responses and genetic changes have been reported in Onchocerca volvulus populations under high IVM pressure but more work is needed to determine whether resistance is developing. The situation needs to be urgently clarified to preserve the achievements of onchocerciasis control programs. In this study, O. volvulus adult worms were collected from the same individuals, before IVM exposure and following three years of annual or three-monthly treatments at 150 mu g/kg or 800 mu g/kg. Four single nucleotide polymorphisms (SNPs) occurring in the beta-tubulin gene of these parasites were investigated. We found changes in genotype frequencies in O. volvulus beta-tubulin gene associated with IVM treatments. The SNP at position 1545 (A/G) showed a significant increase in frequency of the less common nucleotide in the female worms following treatment. After 13 three-monthly treatments, female worm homozygotes with the less common genotype, prior to treatment, increased in frequency. The selected homozygotes, as well as heterozygotes, appeared to be less fertile (without or with very few embryonic stages in their uteri) than the wild-type homozygotes. These results provide additional evidence for genetic selection and strengthen the warning that selection for IVM resistance may be occurring in some O. volvulus populations.

Epidemiological surveys were conducted in two historical human African trypanosomiasis foci in South Cameroon, Bipindi and Campo. In each focus, three sampling areas were defined. In Bipindi, only Glossina palpalis was identified, whereas four species were identified in Campo, G. palpalis being highly predominant (93%). For further analyses, 75 flies were randomly chosen among the flies trapped in each of the six villages. Large and statistically significant differences were recorded between both (I) the prevalence of Sodalis glossinidius (tsetse symbiont) and the prevalence of trypanosome infection of the major fly species G. p. palpalis and (2) the respective prevalence of symbiont and infection between the two foci. Despite these differences, the rate of infected flies harbouring the symbiont was very similar (75%) in both foci, suggesting that symbionts favour fly infection by trypanosomes. This hypothesis was statistically tested and assessed, showing that S. glossinidius is potentially an efficient target for controlling tsetse fly vectorial competence and consequently sleeping sickness.

Host and vector distribution of Trypanosoma brucei gambiense was studied in relation to habitat types and seasons. Six (19.35%) of the 31 mammal species recorded in Bipindi were reservoir hosts. Cercopithecus nictitans was confined to the undisturbed forest and the low intensive shifting cultivation zones, while Cephalophus monticola, Cephalophus dorsalis. Cricetomys gambianus, Atherurus africanus and Nandinia binotata occurred in all the habitat types. As for vectors of human African trypanosomiasis (HAT), Glossina palpalis palpalis, was the most abundant (99.13%) among tsetse fly species. It occurs in all biotopes with its highest density recorded in the village-adjacent forest. The village-adjacent forest is therefore the most risky transmission zone for HAT mainly during the short rainy season when G. palpalis palpails density is highest (2.91); while, the high and low intensive shifting cultivation zones are the most important contact zones between humans, G. palpalis palpalis and wild mammals in all seasons.

Despite the impact of some trypanosome species on human and livestock health, the full diversity of trypanosomes in Africa is poorly understood. A recent study examined the prevalence of trypanosomes among a wide variety of wild vertebrates in Cameroon using species-specific PCR tests, but six trypanosome isolates remained Unidentified. Here they have been re-examined using fluorescent fragment length barcoding (FFLB) and phylogenetic analysis of glycosomal glyceraldehyde phosphate dehydrogenase gGAPDH and 18S ribosomal RNA (rDNA) genes. Isolates from a monkey (Cercopithecus nictitans) and a palm civet (Nandinia binotata) belonged to the Tryponosoma cruzi clade, known previously only from New World and Australian terrestrial mammals, and bats from Africa, Europe and South America. Of the Four other isolates, three from antelope were identified as Tryponosoma theileri, and one from a crocodile as T grayi. This is the first report of trypanosomes of the T cruzi clade in African terrestrial mammals and expands the clade's known global distribution in terrestrial mammals. Previously it has been hypothesized that African and New World trypanosomes diverged after continental separation, dating the divergence to around 100 million years ago. The new evidence instead suggests that intercontinental transfer occurred well after this, possibly via bats or rodents, allowing these trypanosomes to establish and evolve in African terrestrial mammals, and questioning the validity of calibrating trypanosome molecular trees using continental separation. Crown Copyright (c) 2008 Published by Elsevier Ltd. All rights reserved.

Pour la première fois, une équipe de prospection médicale a effectué une campagne de dépistage dans le foyer de trypanosomiase humaine de Bipindi au Cameroun, plus connu sous le nom de "foyer de Lolodorf". Si l'histoire nous apporte des éléments qui pourraient expliquer l'installation de la trypanosomiase humaine dans la région depuis la fin du siècle dernier, au travers de plusieurs vagues de migrations, elle nous apprend aussi que ce foyer n'a jamais connu de flambée épidémique. La découverte de 44 malades lors de deux prospections médicales réalisées fin 1998 et début 1999, pose le problème du maintien à bas bruit de l'endémie et des conditions de son émergence. (Résumé d'auteur)

Dans le but d'optimiser l'utilisation de la méthode d'isolement "in vitro" des trypanosomes sanguicoles par le "kit for in vitro isolation" (KIVI), une étude a été réalisée sur 14 KIVI positifs obtenus à partir de malades du foyer de Campo au Cameroun. Une estimation de la densité parasitaire par comptage régulier a été effectuée du jour où les KIVI ont été déclarés positifs à celui où les trypanosomes ont complètement disparu du milieu. Après application des analyses statistiques, nous avons pu observer que les trypanosomes se multiplient activement dans le KIVI et atteignent leur pic optimal de croissance après 26 jours plus or minus 1 (risque 5%) en moyenne. Il existe une corrélation linéaire significative (p=0.03) entre la quantité de parasites présents dans le KIVI le jour de son ensemencement et le jour où les parasites dans ce KIVI atteignent leur pic optimal de croissance. Ainsi, le nombre maximal de jours mis par les trypanosomes pour atteinde le pic optimal de croissance est significativement d'autant plus bas que la densité parasitaire de départ est élevée. Après ensemencement, un KIVI a besoin d'être surveillé pendant 40 jours avant d'être déclaré négatif. La durée pendant laquelle un KIVI positif conserve les trypanosomes dépasse 50 jours mais elle est variable selon les souches. La recherhce nécessite de grandes quantités de trypanosomes que le KIVI ne peut fournir. Il faut donc passer par une culture de masse sur le milieu de Cunnigham. Les repiquages effectués sur ce milieu avant J22 aboutissent à des densités élevées de trypanosomes (1200 x 10(exp 6) parasites/ml). Tous les repiquages effectués après J34 donnent des densités parasitaires faibles (200x10exp6 parasites/ml), insuffisantes pour la recherche. Il ressort de cette étude que le KIVI est un outil très utile pour l'isolement des trypanosomes sur le terrain... (D'après résumé d'auteur)

Pour la première fois depuis 13 ans, le foyer de trypanosomose humaine de Campo, à cheval sur la frontière entre Cameroun et Guinée équatoriales, a été prospecté. Le depistage s'est fait en juin 1998, simultanément des deux côtés de la frontière. L'étude de ce foyer connu depuis près d'un siècle, toujours actif, est particulièrement intéressante car il n'a jamais fait l'objet de flambée épidémique : le trypanosome y persiste à bas bruit. Selon les dépistages passifs signalés, la prévalence estimée se situe entre 0,2 et 0,5%. Dans la partie camerounaise du foyer, 5255 personnes ont été examinées (90,6% de la population rencensée) et 405 en Guinée équatoriale (71,3% de la population recensée). Le dépistage sérologique a été effectué avec le CATT 1.3 qui est le CATT classiquement utilisé lors des prospections, et avec le CATT latex. La recherche de trypanosomes a été faite par examen du suc ganglionnaire en cas de présence d'adénopathies, et, dans le sang, par Quantitative Buffy Coat (QBC) par la mini colonne échangeuse d'anions (mAEC), ainsi que par la mise en culture in vitro du sang des suspects sériologiques. Alors que 16 malades ont été dépistés au Cameroun, aucun ne l'a été en Guinée équatoriale. Les résultats obtenus montrent que le foyer de Campo est un foyer strictement camerounais, centré sur le village d'Ipono avec une faible prévalence (0,3%). La persistance de l'endémie est liée à la présence à Ipono d'un réservoir porcin de #Trypanosoma brucei gambiense$ qui a été mise en évidence lors de cette étude. Les données épidémiologiques recueillies permettent d'envisager une action concertée, médicale et entomologique, limitée au seul village d'Ipono, afin d'éradiquer l'affection. Lors de cette prospection, le CATT latex s'est avéré plus intéressant que le CATT 1.3 puisqu'à résultat égal, il diminue d'au moins 8 fois la charge de travail pour un coût moindre. Ce point reste à confirmer dans un foyer hyperendémique. (Résumé d'auteur)

Pour la première fois depuis 13 ans, le foyer de trypanosomiase humaine de Campo, à cheval sur la frontière entre Cameroun et Guinée Equatoriale, a été prospecté. Le dépistage s'est fait conjointement des 2 côtés de la frontière. Nous avons profité de cette occasion pour comparer le Card Agglutination Test for Trypanosomiasis (CATT) de type antigénique LiTat 1.3 classiquement utilisé dans les prospections, au CATT Latex, qui consiste en une suspension lyophilisée de latex couvert d'antigènes de surface variables de formes sanguicoles de #Trypanosoma brucei gambiense$ de types antigéniques LiTat 1.3, 1.5, 1.6. Nous avons également recherché l'existence de réactions sérologiques croisées entre trypanosomes, d'une part, et #plasmodium$ et microfilaires, d'autre part. Les résultats obtenus montrent que le foyer de Campo est un foyer Camerounais centré sur le village d'Ipono et de faible prévalence (0,3%). La persistance de l'endémie pourrait être liée à la présence d'un réservoir porcin à Ipono. Le CATT Latex a présenté, à la dilution de 1/4, une spécificité nettement supérieure (76,5%) à celle du CATT 1.3 au seuil de 1+ (42,8%). Au seuil de 1/8ème la spécificité du CATT Latex était de 93,8%. Pour les 2 CATT la sensibilité était de 100%. L'utilisation du CATT Latex en place du CATT 1.3 diminuerait, au seuil de 1/8ème, la charge de travail de près de 8 fois et le coût de 3 fois. Il n'y avait pas de réaction croisée avec les $plasmodium$ et les microfilaires. Il reste à le confirmer et à valider le seuil de détection dans un foyer de forte prévalence. (Résumé d'auteur)