Discovery of mating in the major African livestock pathogen Trypanosoma congolense

The protozoan parasite, Trypanosoma congolense, is one of the most economically important pathogens of livestock in Africa and, through its impact on cattle health and productivity, has a significant effect on human health and well being. Despite the importance of this parasite our knowledge of some of the fundamental biological processes is limited. For example, it is unknown whether mating takes place. In this paper we have taken a population genetics based approach to address this question. The availability of genome sequence of the parasite allowed us to identify polymorphic microsatellite markers, which were used to genotype T. congolense isolates from livestock in a discrete geographical area of The Gambia. The data showed a high level of diversity with a large number of distinct genotypes, but a deficit in heterozygotes. Further analysis identified cryptic genetic subdivision into four sub-populations. In one of these, parasite genotypic diversity could only be explained by the occurrence of frequent mating in T. congolense. These data are completely inconsistent with previous suggestions that the parasite expands asexually in the absence of mating. The discovery of mating in this species of trypanosome has significant consequences for the spread of critical traits, such as drug resistance, as well as for fundamental aspects of the biology and epidemiology of this neglected but economically important pathogen

Phylogeography and Taxonomy of Trypanosoma brucei

Trypanosoma brucei, the parasite causing human African trypanosomiasis (sleeping sickness) across sub-Saharan Africa is traditionally split into three subspecies: T. b. gambiense (Tbg), causing a chronic form of human disease in West and Central Africa; T. b. rhodesiense (Tbr), causing an acute form of human disease in East and Southern Africa; and T. b. brucei (Tbb), which is restricted to animals. Tbg is further split into Tbg group 1 and Tbg group 2. Better understanding the evolutionary relationships between these groups may help to shed light on the epidemiology of sleeping sickness. Here, we used three different types of genetic markers to investigate the phylogeographic relationships among the four groups across a large portion of their range. Our results confirm the distinctiveness of Tbg group 1 while highlighting the extremely close relationships among the other three taxa. In particular, Tbg group 2 was closely related to Tbb, while Tbr appeared to be a variant of Tbb, differing only in its phenotype of human infectivity. The wide geographic distribution of the gene conferring human infectivity (SRA) and the fact that it is readily exchanged among lineages of T. brucei in eastern Africa suggests that human-infective trypanosomes have access to an extensive gene pool with which to respond to selective pressures such as drugs

Sex, Subdivision, and Domestic Dispersal of Trypanosoma cruzi Lineage I in Southern Ecuador

Trypanosoma cruzi is transmitted by blood sucking insects known as triatomines. This protozoan parasite commonly infects wild and domestic mammals in South and Central America. However, triatomines also transmit the parasite to people, and human infection with T. cruzi is known as Chagas disease, a major public health concern in Latin America. Understanding the complex dynamics of parasite spread between wild and domestic environments is essential to design effective control measures to prevent the spread of Chagas disease. Here we describe T. cruzi genetic diversity and population dynamics in southern Ecuador. Our findings indicate that the parasite circulates in two largely independent cycles: one corresponding to the sylvatic environment and one related to the domestic/peridomestic environment. Furthermore, our data indicate that human activity might promote parasite dispersal among communties. This information is the key for the design of control programmes in Southern Ecuador. Finally, we have encountered evidence of a sexual reproductive mode in the domestic T. cruzi population, which constitutes a new and intriguing finding with regards to the biology of this parasite

Profils épidémiologiques et cliniques des enfants handicapés mentaux des centres de l’Institut « ENVOL » du Togo

But : Dégager les aspects épidémiologiques et cliniques du handicap mental, en déterminer les étiologies afin d’envisager une approche de prise en charge appropriée des différents cas. Patients et Méthodes : Il s’est agi d’une étude descriptive portant sur 212 élèves de l’Institut Médico- Psycho-Pédagogique « ENVOL » du Togo, du 1er au 24 mars 2004. Résultats : Sur les 212 élèves examinés, 65 % étaient des garçons et 35 % des filles, avec un sex-ratio de 1,86. Ils étaient âgés de 16 ans en moyenne. A leur naissance, leurs mères avaient entre 20 et 29 ans (46,4%) et leurs pères entre 30 et 39 ans (45,4 %). La dysmorphie sans la morphologie de Trisomie 21 (84 %), le phénotype de Trisomie 21 (21,7 %) et l’infirmité motrice cérébrale (IMC) (10,8 %) étaient les principaux motifs d’admission aux centres « ENVOL ». Dans les antécédents, 93 % des élèves étaient nés par voie basse normale, 95,3 % étaient nés à terme, 31 % étaient associés à une anoxie périnatale, 12,3 % étaient épileptiques. Les tableaux cliniques étaient sous forme de syndrome dysmorphique (74,2 %) ou de dysmorphie isolée (25,8 %). Les anomalies prénatales (43 %) dont 71,4 % d’origine génétique, et les anomalies périnatals (21,7 %) dominées par l’anoxie périnatale (78,3 %) étaient les principales causes de retard mental. Conclusion : Cette étude nous a permis de nous rendre compte de la diversité étiologique et de la complexité de l’approche diagnostique du retard mental. Mots clés : Profils épidémiologiques et cliniques, enfants handicapés mentaux, Togo. Aim: To release the epidemiologic and clinical aspects of mental handicap, to determine the etiologies of them in the order to consider an approach of appropriated management of different cases. Patients and Methods: It was a descriptive study carrying on 212 pupils of Medico-Psycho-Educational institute “ENVOL” of Togo, from 1st to 24 march 2004. Results: On the 212 examined pupils, 65% were boys, 35% the girls, with a sex-ratio of 1.86. They were 16 years old on average. At their birth, their mothers had between 20 and 29 years (46.4%) and their fathers between 30 and 39 years (45.4%). Dysmorphy without the morphology of Trisomy 21 (84%), phenotype of Trisomy 21 (21.7%) and cerebral driving infirmity (10.8%) were the principal reasons for admission in the “ENVOL” institute’s centers. In the past medical history, 93% of the pupils had been born by normal vaginal delivery, 95.3 % were full-term infants, 31% were associated a perinatal anoxia, 12.3% were epileptics. The clinical pictures were in the form of dysmorphic syndrome (74.2%) or of isolated dysmorphy (25.8%). Anomalies prenatals (43%) including 71.4% of genetic origin, and anomalies perinatals (21.7%) dominated by perinatal anoxia (78.3%) were the principal causes of mental retardation. Conclusion: This study showed the etiologic diversity and the complexity of diagnostic approach of mental retardation.Key words: Epidemiologic and clinical profiles, mentally handicapped children, Togo

Efficacite de la strategie pcime (prise en charge integree des maladies de l’enfant) dans le diagnostic et le traitement de la toux et/ou des difficultes respiratoires chez les enfants de moins de 5ans vus en unites de soins peripheriques a Lome (Togo).

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