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 "Mosquito diversity"

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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.
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    Mosquito diversity and virus infectivity in Kinshasa, Democratic Republic of Congo
    (Sokoine university of agriculture, 2015) Mbanzulu, Kennedy, M
    Mosquito species distribution patterns and their ecology is gaining importance, because global climate changes are thought to lead to the emergence of mosquito-borne diseases; which are of considerable medical and veterinary importance because of their high morbidity and mortality. This study was conducted in five municipalities of Kinshasa to determine mosquito diversity, and arboviruses infection within. Mosquitoes were collected using BG-Sentinel traps, battery-powered aspirator for adult and a dipping technique for larvae. One part (adults and larvae-hatched adults) served for species identification, using morphological keys and Ae. aegypti were further identified by PCR using primers targeting the guanylate cyclase (GUA) and phosphoglycerate kinase (PGK) genes. Another part (adults only) was pooled into groups according to mosquitoes’ genus and sampling sites. Each group was preserved in RNA later and screened for bunyaviruses, alphaviruses and flaviviruses. Positive groups were then tested for the presence of specific viruses using reverse transcriptase polymerase chain reaction (RT-PCR) assays. In total, 5714 mosquitoes were collected. Of these, 2814 adults and larvae-hatched adults were identified and belonged to 4 genera (Culex, Aedes, Anopheles and Mansonia), representing 12 mosquito species. Culex quiquenfiasciatus was the most predominant species, followed by Ae. aegypti, while Ae. luteocephalus seems to be reported for the first time in Kinshasa. 2900 mosquitoes were pooled in 29 groups of 100 mosquitoes and 12 pools were positive either for alphavirus or flavivirus or bunyavirus including mixed infection. Chikungunya, O’nyong’nyong and Rift valley fever viruses were mainly found in Aedes groups. A high frequency of arboviruses was found in agricultural areas around Ndjili River. The present study shows that mosquitoes in Kinshasa carry several arboviruses that may have serious public health implications. Such study in the human population of Kinshasa is needed.