Taxonomy and genetic structure of Meru oak populations, Vitex keniensis Turrill and Vitex fischeri Gürke, in East Africa

Vitex keniensis Turrill (Verbenaceae), the Meru oak, is a popular but threatened indigenous forest tree species in East Africa valued for high quality timber, fast growth, edible fruits, medicine, bee forage (honey). The tree has a high agroforestry potential. However, efforts to promote its propagation and conservation is hampered by lack of information on its biological and ecological characteristics. The taxonomic distinction between its populations in Mt. Kenya and Nyambene hills and those of V. fischeri in Lake Victoria and Mt. Elgon regions has been unclear. The research project investigated the taxonomy and compared the mating systems and genetic structure of the four populations of V. keniensis and V. fischeri .The Vitex populations showed similarity in their leaf, flower, seed and seedling morphology, phenological pattern, polyploidy (2n=96) and autotetraploidy, homogamy, partial self-incompatibility, bee-pollination, inter-population reproductive compatibility and low inter-population variation 3.5%. These observations differed from the expected pattern of their geographical distance, ecological gradient and the current taxonomic grouping. The low population divergence could be attributed to common ancestry and possibly lack of divergence. V. keniensis and V. fischeri should be considered conspecific. The name V. fischeri has priority, the well-known name, V. keniensis (Meru oak) therefore falls into synonymy, thus Vitex fischeri (= V. keniensis ).The bulk of genetic variation is within the populations (96.5%), therefore sampling from any of the four populations can capture a sufficiently large gene pool of the species for improvement breeding and conservation. It is a bee-pollinated, autotetraploid, therefore a minimum of a hundred dispersed mature trees at least 300 m apart can be preserved in-situ, and their propagules used for ex-situ conservation, breeding and propagation stock (living gene-bank).</p

Human Norovirus prevalence in Africa:a review of studies from 1990 to 2013

OBJECTIVES: To assess the contribution of Human Norovirus to diarrheal diseases in Africa.   METHODS: We conducted a systematic review of the PubMed and EMBASE databases for published articles of Human Norovirus in Africa between 1990 and 2013. Data were extracted from selected studies and analysed.   RESULTS: A total of 208 eligible studies were identified, of which 55 (from 19 countries) met the inclusion criteria. Many cases were of sporadic gastroenteritis (70.9%) in children (82%), 65.4% of which were seen in an outpatient setting. Over half (59.4%) of affected children were under 5 years of age. The pooled prevalence rate of Human NoV was 11% (95% CI 8-14%) and the meta-analysis indicated significant heterogeneity between the studies. However, the conditional negative binomial regression could not clearly find the factors affecting the Human NoV prevalence rates reported. A close relationship was found between Human Norovirus strains from environmental and clinical samples.   CONCLUSION: Unreported sporadic gastroenteritis cases of Human Norovirus are common in Africa. Most are community-associated infections. Possible environmental transmission routes have been documented. Combined environmental and clinical studies are required for targeted actions to control transmission of Human Norovirus in Africa. Systematic surveillance of Human Norovirus is needed to measure the burden of Norovirus-induced gastroenteritis in Africa and support any requirements for vaccine development. This article is protected by copyright. All rights reserved

Comparing genetic diversity in agroforestry systems with natural forest: a case study of the important timber tree Vitex fischeri in central Kenya. Agroforestry Systems 67

Abstract It is possible that current tree domestication practices undertaken by farmers reduce the genetic base of tree resources on farms, raising concerns regarding the productivity, sustainability and conservation value of agroforestry ecosystems. Here, we assessed possible changes in genetic variation during domestication in the important and heavily utilised timber species, Vitex fischeri Gu¨rke (syn. Vitex keniensis), by comparing geographically proximate forest and farm material in central Kenya. Employing RAPD analysis, a total of 104 polymorphic markers revealed by five arbitrary primers were scored in a total of 65 individuals, 32 from forest and 33 from farmland. Despite concerns of possible genetic erosion, forest and farm stands did not differ significantly in levels of genetic variation, with H values of 0.278 and 0.269, respectively. However, Mantel tests did reveal greater geographically related associative genetic structure among individuals in farm rather than forest material, with r M values of 0.217 and 0.114, respectively. A more detailed analysis of structure suggested this could be due to local variation in origin of some on-farm trees. Implications of data for the genetic management of V. fischeri stands during farmer-led tree domestication activities are discussed. At present, there appears little reason to reject on-farm V. fischeri as a source of germplasm for future on-farm planting or for conservation purposes, although this situation may change and will require monitoring

Development Of An Asthma Awareness Film In London Secondary Schools

National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care, North Thame

Seroprevalence of Infections with Dengue, Rift Valley Fever and Chikungunya Viruses in Kenya, 2007.

Arthropod-borne viruses are a major constituent of emerging infectious diseases worldwide, but limited data are available on the prevalence, distribution, and risk factors for transmission in Kenya and East Africa. In this study, we used 1,091 HIV-negative blood specimens from the 2007 Kenya AIDS Indicator Survey (KAIS 2007) to test for the presence of IgG antibodies to dengue virus (DENV), chikungunya virus (CHIKV) and Rift Valley fever virus (RVFV).The KAIS 2007 was a national population-based survey conducted by the Government of Kenya to provide comprehensive information needed to address the HIV/AIDS epidemic. Antibody testing for arboviruses was performed on stored blood specimens from KAIS 2007 through a two-step sandwich IgG ELISA using either commercially available kits or CDC-developed assays. Out of the 1,091 samples tested, 210 (19.2%) were positive for IgG antibodies against at least one of the three arboviruses. DENV was the most common of the three viruses tested (12.5% positive), followed by RVFV and CHIKV (4.5% and 0.97%, respectively). For DENV and RVFV, the participant's province of residence was significantly associated (P≤.01) with seropositivity. Seroprevalence of DENV and RVFV increased with age, while there was no correlation between province of residence/age and seropositivity for CHIKV. Females had twelve times higher odds of exposure to CHIK as opposed to DENV and RVFV where both males and females had the same odds of exposure. Lack of education was significantly associated with a higher odds of previous infection with either DENV or RVFV (p <0.01). These data show that a number of people are at risk of arbovirus infections depending on their geographic location in Kenya and transmission of these pathogens is greater than previously appreciated. This poses a public health risk, especially for DENV

Prevalence and factors associated with RVF virus among persons aged 15–64 years, Kenya, 2007.

<p>cut off point to include factors in multivariate is pvalue <0.1</p><p>p value is the global p value for the bivariate variable</p><p>M_OR_CI is the multivariate odds ratio</p><p>M_p_value is the category multivariate p value</p><p>Ref- reference</p><p>+—and above</p><p>N, n = number of persons</p><p>Prevalence and factors associated with RVF virus among persons aged 15–64 years, Kenya, 2007.</p

Prevalence and factors associated with chikungunya virus among persons aged 15–64 years, Kenya, 2007.

<p>cut off point to include factors in multivariate is pvalue <0.1</p><p>p value is the global p value for the bivariate variable</p><p>M_OR_CI is the multivariate odds ratio</p><p>M_p_value is the category multivariate p value</p><p>Ref- reference</p><p>+—and above</p><p>N, n = number of persons</p><p>Prevalence and factors associated with chikungunya virus among persons aged 15–64 years, Kenya, 2007.</p