Distribution and relative densities of Aedes aegypti in Niger.

Its climate and environmental conditions put Niger at particularly high risk of the spread of Aedes mosquitoes, which can transmit arboviruses. In September 2016, the Republic of Niger reported its first outbreak of Rift Valley Fever (RVF) in the northern region of Tahoua, near the Mali border, particularly in the departments of Tchintabaraden, Tassara, and Abalak. The history of RVF has showed that epidemics and epizootics have a considerable socioeconomic impact in affected countries, such as Niger, whose populations are particularly concerned by livestock farming. Cross-sectional studies were conducted to investigate the abundance of Aedes aegypti and the risk of arbovirus transmission in 54 villages between 2002 and 2017. Sampling took place in 27 villages, with three methods used in each village: (a) capture of aggressive female mosquitoes landing on human adult volunteers from three households, both indoors and outdoors, during two consecutive nights ; (b) insecticide spray collections of resting mosquitoes early in the morning in five selected dwellings, different from those chosen for landing catches, and (c) capture by four Centers for Disease Control (CDC) light traps, both indoors and outdoors, for two nights. The remaining 27 villages were sampled only by insecticide spray collection of resting mosquitoes. The inventory, distribution, and abundance of mosquito species found at the sampled localities were evaluated. The mosquitoes (Culicidae) caught belonged to four genera, namely: Anopheles spp., Aedes spp., Culex spp. and Mansonia spp. Besides these Culicidae, other biting Diptera (Phlebotomes) were found during the capture. À total of 130,424 adult mosquitoes was caught during the study, 2.6% (3,444/130,423) of them Aedes spp. Aedes aegypti accounted for 96.6% of the Aedes spp. captured. Ae. Aegypti was collected in 41.0% (22/54) of the villages and was abundant (accounting for more than 15% of all mosquitoes captured) in 5 localities. The presence, geographical distribution, and abundance of Ae. aegypti near and in human habitations suggest a high risk of arbovirus transmission in Niger. The high abundance of arbovirus vectors encountered in this study should be a source of concern. Our observations highlight the importance of quantifying and monitoring the risk of arbovirus transmission in Niger. These results are of great importance for public health.

Risk factors associated with bovine tuberculosis and molecular characterization of Mycobacterium bovis strains in urban settings in Niger.

A retrospective and a longitudinal survey were carried out at the abattoir of Niamey. Results showed a highly significant difference in suspected tuberculosis (TB) gross lesions among different animal species (P < 0.0001). The proportion of carcasses with TB-like lesions was 0.19% among cattle, 0.11% among camels, 0.001% among sheep and 0.0006% among goats. In cattle, cows are significantly more affected than the other categories (P < 0.001). Also in cattle, TB-like lesions are mostly localized in the lungs (92.77%) followed by the lymph nodes (50.87%) and the liver (32.40%). The prevalence of gross lesions compatible with bovine TB (BTB) is strongly influenced by the season (P < 0.0001), is closely correlated with the origin of the animals (P < 0.001) and has a negative impact on the weight of affected animals (P < 0.0001). Sixty-two samples of suspected TB gross lesions were subject to microbiological analysis and molecular typing of strains. Mycobacterium bovis was identified in 18 animals showing five different spoligotypes, belonging to type 'African 1' previously identified in Central and West Africa. In addition, a profile (SB1982) not previously reported distinguished by the absence of spacers 3, 4, 9, 16, 22, 30 and 39-43 has been characterized in this study. To assess risk factors for BTB transmission, a questionnaire on animal husbandry practices, food habits, and clinical signs of TB in animals and humans was submitted to the heads of 1131 randomly selected households. The main risk factors identified are consumption of unpasteurized milk (91%) and lack of hygiene within households (32-74%). Clinical signs that could be attributed to TB were also reported both in humans and in animals of the households.

Confirmation of immunogenic consensus sequence HIV-1 T-cell epitopes in Bamako, Mali and Providence, Rhode Island.

The design of epitope-driven vaccines for HIV has been significantly hampered by concerns about conservation of vaccine epitopes across clades of HIV. In previous work, we have described a computer-driven method for a cross-clade HIV vaccine comprised of overlapping, highly conserved helper T-cell epitopes or "immunogenic consensus sequence epitopes" (ICS epitopes). Here, we evaluated and compared the immunogenicity of 20 ICS HIV epitopes in ELISpot assays performed using peripheral blood monocytes (PBMC) from HIV-infected donors in Providence, Rhode Island, USA and in Bamako, Mali, West Africa. Each core 9-mer HIV sequence contained in a given consensus peptide was conserved in at least 105 to as many as 2,250 individual HIV-1 strains. Nineteen of the 20 ICS epitopes (95%) were confirmed in ELISpot assays using PBMC obtained from 13 healthy, HIV-1 infected subjects in Providence, and thirteen of the epitopes (65%) were confirmed in ELISpot assays using PBMC derived from 42 discarded blood units obtained at the Central Blood Bank in Bamako. Twelve of the epitopes were confirmed in ELISpot assays performed both in Providence and Bamako. These data confirm the utility of bioinformatics tools to select and design novel vaccines containing "immunogenic consensus sequence" T-cell epitopes for a globally relevant vaccine against HIV; a similar approach may also be useful for any pathogen that exhibits high variability (influenza, HCV, or variola for example). An HIV vaccine containing these immunogenic consensus sequences is currently under development.

[Antimicrobial drugs in poultry nutrition: resistance levels in Escherichia coli]. / Drogas antimicrobianas em nutrição de aves: níveis de resistência em Escherichia coli.

In a battery experiment, a hundred of day old broiler chicks (Hubbard) divided into ten groups, were fed for eight weeks with 50, 75 or 100mg/Kg of ration of chloramphenicol and tetraciclyne; 40, 80 or 120mg/ 2 liters of drinking water of nitrofurazone. During three months defecated feces from each bird were sampled and analysed at intervals of 15 days for the isolation of Escherichia coli strains which were submitted to the determination of drug resistance. The results showed that utilization of antimicrobial drugs selected a resistant population of Escherichia coli at 300 microgram/ml of chloramphenicol tetraciclyne and 30 microgram/ml of nitrofurazone, during the dietary period. In addition the characterization of the R factor made by conjugation against apropriated recepient strains, demonstrated it's presence in some of the tested strains has only been noted the mobilization of the tetraciclyne marker.