Histoire du foyer de la trypanosomose humaine africaine de nola en republique centrafricaine, de 1971 à 2004

La trypanosomiase humaine africaine (THA) ou maladie du sommeil, affection redoutable qui fit jadis beaucoup de ravages au sein des populations dans différentes régions d’Afrique dont celle de Nola enRépublique Centrafricaine (RCA), reste un problème de santé publique en Afrique sub-saharienne. La cinquante sixième assemblée mondiale de la santé, tenue le 26/03/2003, reconnaissait que les douleurs,les souffrances et la mortalité dues à la trypanosomiase menacent quotidiennement plus de 60 millions d’habitants dans plus de 37 pays d’Afrique sub-saharienne dont 22 comptent parmi les moins avancés.Nous rapportons ici, l’histoire du foyer de THA de Nola en RCA, de 1971 à 2004. Sur le plan méthodologique, il s’agit d’une étude rétrospective couvrant la période de 1971 à 2004. Sur des fichesd’enquête établies, nous avons collecté des données à Nola à partir des registres des trypanosomés et à Bangui la capitale, à partir des rapports des missions de prospection de dépistage actif. L’analyse desdonnées a été faite à l’aide du logiciel EPI INFO 6 version 2000. De 1971 à 2004, 3348 patients ont été recensés parmi lesquels 1814 anciens malades et 1534 nouveaux cas. Les femmes étaient plus atteintes (54%) que les hommes avec un sex-ratio de 1,2. La tranche d’âge la plus touchée est celle de 20 à 29 ans (67,0%). L’indice de morbidité nouvelle (IMN) est passé de 0,01% en 1971 à 1,7% en 1991 et à 0,05% en 2004. L’indice de contamination totale (ICT) est passé de 0,05% en 1971 à 2,3% en 1989 et à 0,05% en 2004. Les cas de rechutes et de réinfections représentaient 54,2% entre 1992 et 2004. La majorité des malades dépistés étaient en 2ème phase (64%). La lutte anti-vectorielle avec pose de pièges coniques imprégnés d’insecticides a été primordiale dans la maîtrise de l’épidémie dans cette région

EFFECT OF THE AQUEOUS EXTRACT OF JUSTICIA INSULARIS T. ANDERS (ACANTHACEAE) ON OVARIAN FOLLICULOGENESIS AND FERTILITY OF FEMALE RATS

Justicia insularis T. Anders (Acanthaceae) is a medicinal plant whose leaves and those of three other plants are mixed for the preparation of a concoction used to improve fertility and to reduce labour pains in women of the Western Region of Cameroon. Previous studies have demonstrated the inducing potential on ovarian folliculogenesis and steroidogenesis of the aqueous extract of the leaf mixture (ADHJ) of four medicinal plants (Aloe buettneri, Dicliptera verticillata, Hibiscus macranthus and Justicia insularis) among which the later represented the highest proportion. This study was aimed at evaluating the ovarian inducing potential of J. insularis in immature female rats. Various doses of the aqueous extract of J. insularis were daily and orally given, for 20 days, to immature female rats distributed into four experimental groups of twenty animals each. At the end of the experimental period some biochemical and physiological parameters of ovarian function were assayed. The administration of the aqueous extract of Justicia insularis significantly induced an early vaginal opening in all treated groups (P < 0.001) as well as an increase (at doses of 50 or 100 mg/kg) in the number of hemorrhagic points, Corpus luteum, implantation sites, ovarian weight, uterine and ovarian proteins. Ovarian cholesterol level (P < 0.05) significantly decreased in animals treated with the lowest dose (12.5 mg/kg). The evaluation of the toxicological effects of the extract on pregnancy showed that it significantly increased pre- and post-implantation losses, resorption index and decreased the rate of nidation as well as litter’s weight. These results suggest that the aqueous extract of Justicia insularis induces ovarian folliculogenesis thus justifying its high proportion in the leaf mixture of ADHJ

The potential of podshaving in studies of the role of trichomes in Vigna resistance to the podbug Clavigralla tomentosicollis Stal (Hemiptera: Coreidae)

Two shaving methods, one by using a sharp razor blade and the other a small pair of dissecting scissors, were tested on pods of Vigna vexillata accessions to investigate the effect of trichomes on feeding and development of the pod-bug Clavigralla tomentosicollis Stål (Hemiptera: Coreidae). Electron micrographs of unshaved (control) pods showed that all trichome types (glandular, long non-glandular and short non-glandular) were present on the pod surface. Shaving with a pair of scissors shortened long non-glandular trichomes, with little or no damage to the glandular types. Percentages of seed damage and nymphs surviving to the adult stage were similar (P>0.05) between unshaved and scissors-shaved pods. These pods showed significantly lower (P<0.05) percent seed damage than razor-shaved and solvent-washed pods, whose glandular trichomes were all completely scraped or washed off. The opposite trend was observed for the insect's growth index, indicating that glandular trichomes had a greater influence than non-glandular trichomes on feeding and development of C. tomentosicollis. The present study suggests that the scissor-shaving method would be more appropriate if the effect of trichome length is being investigated, and the more abrasive razor-shaving method if the effect of glandular trichomes is of interest

Inferences on pod wall and seed defenses against the brown cowpea coreid bug, Clavigralla tometosicollis Stal ( Hempptera Coreidae) in wild and cultivated Vigna species

Published online: 21 Dec 2001Studies were conducted in the laboratory to investigate the different components of the resistance of Vigna vexillata A. Richards, TVnu 72, and several cultivars of cultivated Vigna spp. to infestation and damage by the brown cowpea coreid, Clavigralla tomentosicollis Stäl. The main objective was to determine the different roles of the pod wall and seeds, and the relationship between seed size, number, and damage by this insect. Results showed that both the pod wall and seed clearly contribute different components to the resistance of TVnu 72 to C. tomentosicollis. Analysis of the results suggests that the seed defences and the pod wall pericarp may be more important than are trichomes in this resistance. Seed number was found to influence the extent of damage in a more predictable manner than seed size. However, because both of these traits are generally inversely related and mutually exclusive, their individual effects cannot be completely separated. The implications of these traits in a breeding programme targeted at a specific consumer group are discussed

Infestation and damage by Clavigralla tomentosicollis and Anoplocnemis curvipes (Hemiptera: Coreidae) in cowpea plants with modified leaf structure and pods in different positions relative to the canopy

Potted cowpea, Vigna unguiculata (L.) Walp., plants were used to determine the effects of defoliation and pod position relative to the leaf canopy on infestation and damage by the coreid pod-bugs Clavigralla tomentosicollis Stål and Anoplocnemis curvipes (F.). Temperature measurements were taken within and outside the canopy to determine whether there was a correlation to seed damage. Seed damage decreased significantly with increasing defoliation in plants infested with C. tomentosicollis; an inverse trend was observed with A. curvipes. Temperatures within the canopy increased as the number of leaves decreased. As observed in the defoliation experiment, C. tomentosicollis and A. curvipes reacted differently in a free-choice situation between pods located outside or within the canopy. Significantly higher numbers of C. tomentosicollis concealed themselves within the canopy, where they caused more severe damage to seeds, in comparison with numbers and damage outside the canopy. These trends were reversed for A. curvipes. There was a significant negative correlation between percentage of seed damage and temperature with C. tomentosicollis, and a significant positive correlation with A. curvipes, both in defoliated plants and those with pods distributed outside and within the canopy. Overall, plants with less dense canopy, and long peduncles holding pods outside the canopy showed some resistance to C. tomentosicollis, which is the most damaging pod bug on cowpea. Because such cowpea plants harbor fewer C. tomentosicollis, they are likely to suffer less overall damage from infestation by the complex of pod bugs that occur concurrently in cowpea fields

Assessment of chemical resistance of wild and cultivated Vigna species to the brown pod-bug Clavigralla tomentosicollis Stal (Hem., Coreidae)

The effects of secondary metabolites in different Vigna species on the development of Clavigralla tomentosicollis were investigated in an artificial seed system using different fractions of crude pod extracts, while the orientation response of this pod-bug to volatile extracts was studied using a dual-choice olfactometer. Feeding on the neutral fraction extracts, in contrast to the basic and acidic fractions, resulted in significantly higher mortalities, longer total developmental time, and lower growth index of the insects in comparison with controls. All volatile extracts elicited an avoidance reaction by C. tomentosicollis, except the volatile from the susceptible genotype IT84S-2246 which generally attracted as many insects as controls. Extracts from wild Vigna species showed higher activity than those from their cultivated relatives. The present study which has established that most secondary metabolites in cowpea pods were localized in the neutral fraction of the crude extract, could facilitate experiments on the separation and characterization of the toxic factors involve