Institute of Medical Research and Study of Medicinal Plants IMPM

Yaoundé, Cameroon

Institute of Medical Research and Study of Medicinal Plants IMPM

Yaoundé, Cameroon
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Pourrut X.,IRD Montpellier | Diffo J.L.D.,GVFI Cameroon | Somo R.M.,Institute of Medical Research and Study of Medicinal Plants IMPM | Bilong Bilong C.F.,University of Yaounde I | And 2 more authors.
Veterinary Parasitology | Year: 2011

To document the prevalence of gastrointestinal parasites in Cameroonian monkeys and to assess the risk of transmission to humans, we sampled 125 primates belonging to 15 species, of which 78 had been captured for bushmeat in the wild, and 47 were pets kept in urban areas. Seven nematode species, one trematode, one cestode and three protozoa were detected. Eight different parasite species were found in Cercopithecus nictitans and six in C. neglectus, C. pogonias and Cercocebus agilis. Helminths were found in 77% of monkeys, and protozoa in 36%. Trichuris sp. and Entamoeba coli were the most frequent parasites, being found in 54% and 36% of animals, respectively. Helminths were more frequent in adults than in juveniles, while the prevalence of protozoa was not age-related. No significant gender difference was found. Bushmeat monkeys had a significantly higher prevalence of helminth infection than pets (92% versus 51%), whereas there was no significant difference in the prevalence of protozoa (32% versus 43%). Among helminth species, Strongyloides fulleborni was more prevalent in bushmeat monkeys than in pets (55% versus 15%), as were Ancylostoma spp. (62% versus 9%). As these parasites are transmitted transcutaneously by infectious larva, they have a high potential for transmission to humans, during butchering. One pet monkey kept in an urban household in Yaoundé was infected by Schistosoma mansoni. The potential public health implications of these findings are discussed. © 2010.

PubMed | Institute of Medical Research and Study of Medicinal plants IMPM and University of Cape Town
Type: Journal Article | Journal: Evolution, medicine, and public health | Year: 2015

Cameroon is the country in which HIV-1 group M (HIV-1M) likely originated and is today a major hotspot of HIV-1M genetic diversity. It remains unclear, however, whether the highly divergent HIV-1M lineages found in this country arose during the earliest phases of the global HIV-1M epidemic, or whether they arose more recently as a result of recombination events between globally circulating HIV-1M lineages.To differentiate between these two possibilities, we performed phylogenetic analyses of the near full genome sequences of nine newly sequenced divergent HIV-1M isolates and 15 previously identified, apparently unique recombinant forms (URFs) from Cameroon.Although two of the new genome sequences were clearly classifiable within subtype G, the remaining seven were highly divergent and phylogenetically branched either outside of, or very near the bases of clades containing the well characterised globally circulating viral lineages that they were most closely related to. Recombination analyses further revealed that these divergent viruses were likely complex URFs. We show, however that substantial portions (>1 Kb) of three of the new genome sequences and 15 of the previously characterised Cameroonian URFs have apparently been derived from divergent parental viruses that branch phylogenetically near the bases of the major HIV-1M clades.Our analyses indicate the presence in Cameroon of contemporary descendants of numerous early-diverging HIV-1M lineages. Further efforts to sample and sequence viruses from such lineages could be crucial both for retracing the earliest evolutionary steps during the emergence of HIV-1M in humans, and accurately reconstructing the ancestral sequences of the major globally circulating HIV-1M lineages.

Tongo M.,International Center for Genetic Engineering and Biotechnology | Tongo M.,University of Cape Town | Tongo M.,Institute of Medical Research and Study of Medicinal plants IMPM | Essomba R.G.,International Center for Genetic Engineering and Biotechnology | And 14 more authors.
Infection, Genetics and Evolution | Year: 2015

HIV-1 subtype G has played an early and central role in the emergent complexity of the HIV-1 group M (HIV-1M) epidemic in central/west Africa. Here, we analysed new subtype G env sequences sampled from 8 individuals in Yaoundé, Cameroon during 2007-2010, together with all publically available subtype G-attributed full-length env sequences with known sampling dates and locations. We inferred that the most recent common ancestor (MRCA) of the analysed subtype G env sequences most likely occurred in ~1953 (95% Highest Posterior Density interval [HPD] 1939-1963): about 15. years earlier than previous estimates. We found that the subtype G env phylogeny has a complex structure including seven distinct lineages, each likely dating back to the late 1960s or early 1970s. Sequences from Angola, Gabon and the Democratic Republic of Congo failed to group consistently in these lineages, possibly because they are related to more ancient sequences that are poorly sampled. The circulating recombinant form (CRF), CRF06_cpx env sequences but not CRF25_cpx env sequences are phylogenetically nested within the subtype G clade. This confirms that the CRF06_cpx env plausibly was derived through recombination from a subtype G parent, and suggests that the CRF25_cpx env was likely derived from an HIV-1M lineage related to the MRCA of subtype G that has remained undiscovered and may be extinct. Overall, this fills important gaps in our knowledge of the early events in the spread of HIV-1M. © 2015 Elsevier B.V.

Nkouawa A.,Asahikawa Medical College | Nkouawa A.,Institute of Medical Research and Study of Medicinal Plants IMPM | Sako Y.,Asahikawa Medical College | Li T.,Centers for Disease Control and Prevention | And 8 more authors.
Journal of Clinical Microbiology | Year: 2010

We compared the performance of loop-mediated isothermal amplification (LAMP) with that of a multiplex PCR method for differential detection of human Taenia parasites in fecal specimens from taeniasis patients. The LAMP method, with no false positives, showed a higher sensitivity (88.4%) than the multiplex PCR (37.2%). Thus, it is expected that the LAMP method has a high value for molecular diagnosis of taeniasis. Copyright © 2010, American Society for Microbiology. All Rights Reserved.

Tongo M.,University of Cape Town | Tongo M.,Institute of Medical Research and Study of Medicinal Plants IMPM | Burgers W.A.,University of Cape Town
Viruses | Year: 2014

The extraordinary variability of HIV-1 poses a major obstacle to vaccine development. The effectiveness of a vaccine is likely to vary dramatically in different populations infected with different HIV-1 subtypes, unless innovative vaccine immunogens are developed to protect against the range of HIV-1 diversity. Immunogen design for stimulating neutralizing antibody responses focuses on “breadth”-the targeting of a handful of highly conserved neutralizing determinants on the HIV-1 Envelope protein that can recognize the majority of viruses across all HIV-1 subtypes. An effective vaccine will likely require the generation of both broadly cross-neutralizing antibodies and non-neutralizing antibodies, as well as broadly cross-reactive T cells. Several approaches have been taken to design such broadly-reactive and cross-protective T cell immunogens. Artificial sequences have been designed that reduce the genetic distance between a vaccine strain and contemporary circulating viruses; “mosaic” immunogens extend this concept to contain multiple potential T cell epitope (PTE) variants; and further efforts attempt to focus T cell immunity on highly conserved regions of the HIV-1 genome. Thus far, a number of pre-clinical and early clinical studies have been performed assessing these new immunogens. In this review, the potential use of these new immunogens is explored. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Kwon J.C.,Sejong University | Leopold E.N.,University of Ngaoundéré | Jung M.C.,Sejong University | Emmanuel E.G.,University of Yaounde I | And 4 more authors.
Geosciences Journal | Year: 2012

The objectives of this study are to evaluate the extent of heavy metal pollution in water at the Municipal Lake of Yaounde, and to find out their variability and origin. Water from fifteen selected sites of the lake and River Mingoa, Cameroon was sampled in August 16 th of 2005 and 2006 and in 30 th August 2007 during the minor dry season; and subjected to the analyses of physicochemical parameters and various elements. In addition, multivariate data analysis techniques including principal component analysis (PCA) were utilized to determine the variations in heavy metal content in the Municipal Lake water and their natural or anthropogenic sources. The chemical results indicated that concentrations of Al, Fe, Mn, Cd and Pb in the study area exceeded the drinking water quality and they would pose health risk for users of these waters. This is evidence that River Mingoa, the main tributary to the Municipal Lake is the main collector of pollutants from activities in the sloping side of the Municipal Lake. Based on the multivariate statistical analysis, very high positive correlations were observed between elements, and five factors computed from PCA explained 86. 6% of total variance. These factor loadings are mainly controlled by anthropogenic inputs, lithogenic processes during weathering progress of natural parent materials and local geology. © 2012 The Association of Korean Geoscience Societies and Springer-Verlag Berlin Heidelberg.

Bigoga J.D.,University of Yaounde I | Nanfack F.M.,University of Yaounde I | Awono-Ambene P.H.,Organization de Coordination Pour la Lutte Contre les Endemies en Afrique Centrale OCEAC | Patchoke S.,Ministry of Public Health | And 6 more authors.
Parasites and Vectors | Year: 2012

Background: Development of large scale agro-industries are subject to serious environmental modifications. In malaria endemic areas this would greatly impact on the transmission paradigm. Two cross-sectional entomological surveys to characterize the Anopheles fauna and their entomological inoculation rates were conducted during May 2010 (peak rainy season) and December 2010 (peak dry season) in the intense rubber cultivated area of Niete in southern forested Cameroon. Methods: Mosquitoes were sampled by night collections on human volunteers, identified morphologically and members of the Anopheles gambiae complex further identified to species and molecular form. Parity status was determined following the dissection of the ovaries. Plasmodium falciparum circumsporozoite antigen indices were estimated after the identification of CS antigen by ELISA and the average entomological inoculation rates determined. Results: A total of 1187 Anopheles was collected, 419 (35.3%) in the rainy season and 768 (64.7%) in the dry season. Species found were the M molecular form of An. gambiae s.s (66.8%), An. ziemanni (28.3%), An. paludis (4.7%), An. smithii (0.2%). An. gambiae M-form was the principal species in the dry (56.2%) and wet (86.2%) seasons. Average overall entomological inoculation rate for the malaria vectors varied between the dry season (1.09 ib/p/n) and the rainy season (2.30 ib/p/n). Conclusions: Malaria transmission in Niete occurs both in the dry and rainy season with the intensities peaking in the dry season. This is unlike previous studies in other areas of southern forested Cameroon where transmission generally peaks in the rainy season. Environmental modifications due to agro-industrial activities might have influenced vector distribution and the dynamics of malaria transmission in this area. This necessitates the possible implementation of control strategies that are related to the eco-geography of the area. © 2012 Bigoga et al.; licensee BioMed Central Ltd.

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