Biological Sciences Collection

Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/76

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Browsing Biological Sciences Collection by Subject "Tanzania"

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    Assessing the genetic diversity of five Tanzanian chicken ecotypes using molecular tools
    (South African Society for Animal Science, 2013-12-21) Lyimo, Charles Moses; Weigend, Annett; Janßen-Tapken, Ulrike; Msoffe, Peter Lawrence; Simianer, Henner; Weigend, Steffen
    The study aimed to evaluate the genetic diversity of Tanzanian chicken populations through phylogenetic relationship, and to trace the history of Tanzanian indigenous chickens. Five ecotypes of Tanzanian local chickens (Ching'wekwe, Kuchi, Morogoro-medium, Pemba and Unguja) from eight regions were studied. Diversity was assessed based on morphological measurements and 29 microsatellite markers recommended by ISAG/FAO advisory group on animal genetic diversity. A principal component analysis (PCA) of morphological measures distinguished individuals most by body sizes and body weight. Morogoro Medium, Pemba and Unguja were grouped together, while Ching'wekwe stood out because of their disproportionate short shanks and ulna bones. Kuchi formed an independent group owing to their comparably long body sizes. Microsatellite analysis revealed three clusters of Tanzanian chicken populations. These clusters encompassed i) Morogoro-medium and Ching'wekwe from Eastern and Central Zones ii) Unguja and Pemba from Zanzibar Islands and iii) Kuchi from Lake Zone regions, which formed an independent cluster. Sequence polymorphism of D-loop region was analysed to disclose the likely maternal origin of Tanzanian chickens. According to reference mtDNA haplotypes, the Tanzanian chickens that were sampled encompass two haplogroups of different genealogical origin. From haplotype network analysis, Tanzanian chickens probably originated on the Indian subcontinent and in Southeast Asia. The majority of Kuchi chickens clustered in a single haplogroup, which was previously found in Shamo game birds sampled from Shikoku Island of Japan in the Kochi Prefecture. Analysis of phenotypic and molecular data, as well as the linguistic similarity of the breed names, suggests a recent introduction of the Kuchi breed to Tanzania.
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    Mosquito diversity and virus infection in Kilombero valley in South-eastern Tanzania
    (Sokoine University of Agriculture, 2015) Shayo, John Mariana
    Mosquito-borne viruses are an important cause of human and domestic diseases worldwide. As crucially important emerging pathogens, they have caused multiple, notable and unnoticed epidemics of human disease over recent decades. All mosquito-borne viruses circulate within sylvatic cycles among wildlife and forest mosquitoes and may cause diseases in rural and urban populations after spillover transmission to human and domestic animals. The aim of this study was to determine mosquito diversity and transmission of Rift Valley fever virus (RVFV), dengue virus (DENV) and Chikungunya virus (CHIKV) in South-eastern Tanzania. In the present cross-sectional study, a total of 1320 adult mosquitoes were collected using Biogent (BG) sentinel traps and battery-powered aspirators. In addition, a total of 31 larvae were collected using a dipping technique and allowed to hatch into adults. Morphological identification of mosquitoes showed the presence of 12 different species which were unevenly distributed among different ecological zones within the two districts. Culex mosquitoes were found to be dominant at all mosquito collection sites and represented 89.1% followed by 10.1% Aedes and 0.8% Mansonia. Aedes mosquitoes were pooled into groups of 20 mosquitoes resulting into a total of 12 pools. No mosquito pool was positive for DENV or CHIKV when Aedes mosquito pools were screened for these viruses. However, RVFV was found in two pools of mosquitoes including one of Aedes aegypti and another of Aedes pembaensis. Furthermore, when Aedes mosquito pools were screened, eight pools were positive for Flavivirus and six pools were positive for Alphavirus respectively. The positivity to Flavivirus and Alphavirus with concurrent absence of DENV and CHIKV in these mosquitoes indicates the presence of viruses other than DENV and CHIKV. Results obtained from this study show that mosquitoes in Kilombero Valley carry viruses of iii serious public health importance. It is recommended that mosquito-borne viruses be screened in febrile patients presenting at points of care in order to improve prognosis.