Distribution and diversity of mosquitoes and the role of Aedes in the transmission of arboviruses in selected districts of Tanzania

Author(s): Prof. Mark Rweyemamu , Dr. Leonard Mboera , Dr. Christopher Kasanga

Arboviruses belong to various families of viruses that are transmitted by arthropods, mainly mosquitoes and often cause diseases in humans. The objective of this study was to determine mosquito diversity and transmission of arboviruses by Aedes in selected ecosystems in Tanzania. Adult mosquitoes were collected from rural and urban settings using carbon dioxide-baited CDC light traps, Biogent sentinel traps, and the Mosquito Magnet traps. Reverse Transcription-Polymerase Chain Reaction assay was performed on pooled adult Aedes mosquitoes to detect the presence of Chikungunya, Dengue, Rift Valley fever (RVF) and Yellow fever (YF) viruses. A total of 42, 77 mosquitoes belonging to five genera (Aedes, Anopheles, Culex, Mansonia and Mimomyia) and 18 species were collected. Culex accounted for the largest (62.7%; n= 2,682) proportion of the mosquitoes while Anopheles for the lowest proportion (5.7%; n=245). Of the total mosquitoes collected, Culex quinquefasciatus accounted for more than a half (53.4%; n=2692), followed by Aedes aegypti 12.1% (n=520). Of the 34 adult Ae. aegypti pools tested, arboviruses were detected in 33(97%) pools. Dengue virus was detected in 47.6% (10/ 21) pools which tested positive for Flaviruses. Chikungunya virus was detected in 30% (3/ 10) pools which were positive for Alphavirus genera. Of 2 pools tested positive for Bunyavirus genus, Rift Valley fever virus was detected in 1 pool (50%). The presence of various mosquito vectors and detection of arboviruses in aedes mosquitoes leave the population of Tanzania at great risk of transmission of different pathogens and highlight a need for vector control measures in the country.

 

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