Lassa Virus Circulation in Small Mammal Populations in Bo District, Sierra Leone.

Lassa fever is a viral hemorrhagic fever caused by the Lassa virus LASV, which was first isolated in the rodent Mastomys natalensis in 1974 in Kenema, Sierra Leone. As little is known about the abundance and the presence of LASV in rodents living in the Bo area, we carried out a small mammal longitudinal population survey. A standardized trapping session was performed in various habitats and seasons in six villages over two years (2014-2016) and samples collected were tested for arenavirus IgG and LASV. A Bayesian phylogenetic analysis was performed on sequences identified by PCR. A total of 1490 small mammals were collected, and 16 rodent species were identified, with M. natalensis (355, 24%) found to be the most prevalent species. Forty-one (2.8%) samples were IgG positive, and 31 of these were trapped in homes and 10 in surrounding vegetation. Twenty-nine of 41 seropositive rodents were M. natalensis. We detected four LASV by PCR in two villages, all found in M. natalensis. Phylogenetic analysis showed that the sequences were distributed within the Sierra Leonean clade within lineage IV, distinguishing a Bo sub-clade older than a Kenema sub-clade. Compared to other settings, we found a low abundance of M. natalensis and a low circulation of LASV in rodents in villages around Bo district

IMPACT OF PHYSICO-CHEMICAL CHARACTERISTICS ON AQUATIC BIODIVERSITY OF FIVE PROSPECTED WETLANDS FROM KIPUSHI MINING SITE IN HAUT-KATANGA PROVINCE IN THE DEMOCRATIC REPUBLIC OF THE CONGO

The development of mining industrialization are factors that have favored the pollution of aquatic ecosystems. The main purpose of this study was to assess the influence of physico-chemical parameters of surface waters on the abundance of hydrophytes in 5 wetlands in Kipushi city, Haut-Katanga Province in DRC. Samples were collected from four rivers, of which: Kanyameshi, Kafubu, Kipushi, Kamarenge and Lake Kamarenge. The study used the presses for the preparation of herbariums as well as multifunction probe for physico-chemical analyses in situ and a spectrophotometer (415 nm) for some parameters. For environmental observations, the analysis of sediments allows to assess the pollution level by metallic trace elements, which breaks the ecological balance of this aquatic ecosystem. The abundance indices of plant species in each waterbody were subjected to a Factorial Component Analysis in order to identify the distribution of the elements of the dominant plant associations. Data analysis was performed using PAST software. The findings showed 29 species distributed in 26 genera, 13 families and 11 orders. The Confirmatory Factor Analysis showed the distribution of plant groupings following a gradient of mineralization of the zones as well as that of abundance-dominance. Physico-chemical parameters influence the distribution of hydrophytes in wetlands. They constitute indicators of toxicity having an adverse consequence on the aquatic ecosystem for these metallic elements are not biodegradable. The more there is accumulation of dissolved metals in water, the more they create an environmental hazard

Utilization, Phytochemistry and Biological Activity of Hua gabonii Pierre ex De Wild.

Although few studies are reported, Hua gabonii remains scientifically unknown due to the lack of studies. However, this aromatic plant is used in developing countries as a condiment or in traditional medicine to treat various ailments. The literature reported that this species is rich in proteins, essential amino acids, and vitamins C and E. Its fruits would present an appreciable antioxidant power. Therefore, given its numerous uses in tropical countries, H. gabonii is a good candidate for further studies

No measurable adverse effects of Lassa, Morogoro and Gairo arenaviruses on their rodent reservoir host in natural conditions

Abstract Background In order to optimize net transmission success, parasites are hypothesized to evolve towards causing minimal damage to their reservoir host while obtaining high shedding rates. For many parasite species however this paradigm has not been tested, and conflicting results have been found regarding the effect of arenaviruses on their rodent host species. The rodent Mastomys natalensis is the natural reservoir host of several arenaviruses, including Lassa virus that is known to cause Lassa haemorrhagic fever in humans. Here, we examined the effect of three arenaviruses (Gairo, Morogoro and Lassa virus) on four parameters of wild-caught Mastomys natalensis: body mass, head-body length, sexual maturity and fertility. After correcting for the effect of age, we compared these parameters between arenavirus-positive (arenavirus RNA or antibody) and negative animals using data from different field studies in Guinea (Lassa virus) and Tanzania (Morogoro and Gairo viruses). Results Although the sample sizes of our studies (1297, 749 and 259 animals respectively) were large enough to statistically detect small differences in body conditions, we did not observe any adverse effects of these viruses on Mastomys natalensis. We did find that sexual maturity was significantly positively related with Lassa virus antibody presence until a certain age, and with Gairo virus antibody presence in general. Gairo virus antibody-positive animals were also significantly heavier and larger than antibody-free animals. Conclusion Together, these results suggest that the pathogenicity of arenaviruses is not severe in M. natalensis, which is likely to be an adaptation of these viruses to optimize transmission success. They also suggest that sexual behaviour might increase the probability of M. natalensis to become infected with arenaviruses