University of Antananarivo

About: University of Antananarivo is a education organization based out in Antananarivo, Madagascar. It is known for research contribution in the topics: Population & Lemur. The organization has 1561 authors who have published 1703 publications receiving 30922 citations. The organization is also known as: Tananarive University & Antananarivo University.

Small-scale land-use variability affects Anopheles spp. distribution and concomitant Plasmodium infection in humans and mosquito vectors in southeastern Madagascar.

Abstract: Deforestation and land-use change have the potential to alter human exposure to malaria. A large percentage of Madagascar’s original forest cover has been lost to slash-and-burn agriculture, and malaria is one of the top causes of mortality on the island. In this study, the influence of land-use on the distribution of Plasmodium vectors and concomitant Plasmodium infection in humans and mosquito vectors was examined in the southeastern rainforests of Madagascar. From June to August 2013, health assessments were conducted on individuals living in sixty randomly selected households in six villages bordering Ranomafana National Park. Humans were screened for malaria using species-specific rapid diagnostic tests (RDTs), and surveyed about insecticide-treated bed net (ITN) usage. Concurrently, mosquitoes were captured in villages and associated forest and agricultural sites. All captured female Anopheline mosquitoes were screened for Plasmodium spp. using a circumsporozoite enzyme-linked immunosorbent assay (csELISA). Anopheles spp. dominated the mosquito communities of agricultural and village land-use sites, accounting for 41.4 and 31.4 % of mosquitoes captured respectively, whereas Anopheles spp. accounted for only 1.6 % of mosquitoes captured from forest sites. Interestingly, most Anopheles spp. (67.7 %) were captured in agricultural sites in close proximity to animal pens, and 90.8 % of Anopheles mosquitoes captured in agricultural sites were known vectors of malaria. Three Anopheline mosquitoes (0.7 %) were positive for malaria (Plasmodium vivax-210) and all positive mosquitoes were collected from agricultural or village land-use sites. Ten humans (3.7 %) tested were positive for P. falciparum, and 23.3 % of those surveyed reported never sleeping under ITNs. This study presents the first report of malaria surveillance in humans and the environment in southeastern Madagascar. These findings suggest that even during the winter, malaria species are present in both humans and mosquitoes; with P. falciparum found in humans, and evidence of P. vivax-210 in mosquito vectors. The presence of P. vivax in resident vectors, but not humans may relate to the high incidence of humans lacking the Duffy protein. The majority of mosquito vectors were found in agricultural land-use sites, in particular near livestock pens. These findings have the potential to inform and improve targeted malaria control and prevention strategies in the region.

Taxonomic revision of Phyllanthus (Phyllanthaceae) in Madagascar and the Comoro Islands I: synopsis and subgenera Isocladus , Betsileani , Kirganelia and Tenellanthus

Abstract: In this first part of a taxonomic revision of Phyllanthus L. in Madagascar and the Comoro Islands, a synopsis of the 55 species and a key to the nine subgenera (three of which are new) and two sections are given. The taxonomic treatment in this paper includes the 11 species, four subspecies and two varieties of subgenera Isocladus G. L. Webster, Betsileani (Jean F. Brunel) Ralim. & Petra Hoffm. stat. nov., Kirganelia (A. Juss.) G. L. Webster and Tenellanthus Jean F. Brunel. Distribution maps and IUCN conservation assessments are provided for each taxon. The three Madagascan endemic species without phyllanthoid branching are placed in the new subgen. Betsileani separate from subgen. Isocladus. Revised circumscription of species within Kirganelia s.s. reduces the number of species in this group from nine to four. Section Pentandra G. L. Webster is separated as subgen. Tenellanthus as suggested by Brunel (1987).

Isolation and structural elucidation of cytotoxic compounds from the root bark of Diospyros quercina (Baill.) endemic to Madagascar.

Abstract: Objective To isolate and characterize the cytotoxic compounds from Diospyros quercina (Baill.) G.E. Schatz & Lowry (Ebenaceae). Methods An ethno-botanical survey was conducted in the south of Madagascar from July to August 2010. Bio-guided fractionation assay was carried out on the root bark of Diospyros quercina, using cytotoxicity bioassay on murine P388 leukemia cell lines as model. The structures of the cytotoxic compounds were elucidated by 1D and 2D NMR spectroscopy and mass spectrometry. Results Biological experiments resulted in the isolation of three bioactive pure compounds (named TR-21, TR-22, and TR-23) which exhibited very good in vitro cytotoxic activities with the IC50 values of (0.0175±0.0060) μg/mL, (0.089±0.005) μg/mL and (1.027±0.070) μg/mL respectively. Thus, they support the claims of traditional healers and suggest the possible correlation between the chemical composition of this plant and its wide use in Malagasy folk medicine to treat cancer. Conclusions The ability of isolated compounds in this study to inhibit cell growth may represent a rational explanation for the use of Diospyros quercina root bark in treating cancer by Malagasy traditional healers. Further studies are, therefore, necessary to evaluate the in vivo anti-neoplastic activity of these cytotoxic compounds as effective anticancer drugs.

Geographical distribution and relative risk of Anjozorobe virus (Thailand orthohantavirus) infection in black rats (Rattus rattus) in Madagascar.

Abstract: Hantavirus infection is a zoonotic disease that is associated with hemorrhagic fever with renal syndrome and cardiopulmonary syndrome in human. Anjozorobe virus, a representative virus of Thailand orthohantavirus (THAIV), was recently discovered from rodents in Anjozorobe-Angavo forest in Madagascar. To assess the circulation of hantavirus at the national level, we carried out a survey of small terrestrial mammals from representative regions of the island and identified environmental factors associated with hantavirus infection. As we were ultimately interested in the potential for human exposure, we focused our research in the peridomestic area. Sampling was achieved in twenty districts of Madagascar, with a rural and urban zone in each district. Animals were trapped from a range of habitats and examined for hantavirus RNA by nested RT-PCR. We also investigated the relationship between hantavirus infection probability in rats and possible risk factors by using Generalized Linear Mixed Models. Overall, 1242 specimens from seven species were collected (Rattus rattus, Rattus norvegicus, Mus musculus, Suncus murinus, Setifer setosus, Tenrec ecaudatus, Hemicentetes semispinosus). Overall, 12.4% (111/897) of Rattus rattus and 1.6% (2/125) of Mus musculus were tested positive for THAIV. Rats captured within houses were less likely to be infected than rats captured in other habitats, whilst rats from sites characterized by high precipitation and relatively low seasonality were more likely to be infected than those from other areas. Older animals were more likely to be infected, with infection probability showing a strong increase with weight. We report widespread distribution of THAIV in the peridomestic rats of Madagascar, with highest prevalence for those living in humid areas. Although the potential risk of infection to human may also be widespread, our results provide a first indication of specific zone with high transmission. Gathered data will be helpful to implement policies for control and prevention of human risk infection.