Molecular detection of arboviruses in mosquitoes collected from Kyela district, Tanzania

Arboviruses belong to a group of viruses that are transmitted by arthropods, mainly mosquitoes and ticks causing clinical disease symptoms in humans and animals ranging from febrile illnesses to hemorrhagic fevers. The present study aimed at examining the circulation of Chikungunya, Dengue, Yellow fever and Rift valley fever viral genomes in Aedes mosquitoes from Kyela district in Tanzania. A systematic vector surveillance spanning two months and covering five sites in Kyela district was carried out in order to evaluate the potential role of Aedes spp. in arbovirus transmission in the study area. Mosquitoes were collected, identified to species level by using morphological keys, pooled in respect species and collection sites and screened for arboviruses by RT-PCR. Adult mosquitoes were collected from April to May, 2015 using CO2-baited CDC light traps, magnet traps as well as human landing collection (HLC). The study sites included Kyela town, Kajunjumele, Ipida, Matema and Njisi villages. A total of 480 blood-feed Aedes ssp. were collected, identified and grouped into 24 pools (120 mosquitoes per pool) according to species level and location. Out of the 480 Aedes spp. collected, Aedes aegyptir epresented the most abundant species totaling 338 (70.4%), followed by Aedes africanus 102 (21.2%) and Aedes natalensis being the minority, 40 (8.3%). Arboviruses were detected in nine pools (37.5%) including Alpha viruses (8 pools) and Flavi viruses (1 pool). No sample was positive for Bunya viruses.Chikungunya virus (CHIKV) was detected in 6 (75%) alpha virus positive pools that were collected mostly in the areas where rice cultivation was common. The findings of this study suggest that inhabitants in this region are highly likely to be exposed to arbovirus infections which may represent significant public health concerns.