Dataset Information

Evaluating the vector competence of Aedes simpsoni sl from Kenyan coast for Ngari and Bunyamwera viruses.

ABSTRACT:

Background

Bunyamwera(BUNV) and Ngari (NGIV) viruses are arboviruses of medical importance globally, the viruses are endemic in Africa, Aedes(Ae) aegypti and Anopheles(An) gambiae mosquitoes are currently competent vectors for BUNV and NGIV respectively. Both viruses have been isolated from humans and mosquitoes in various ecologies of Kenya. Understanding the risk patterns and spread of the viruses necessitate studies of vector competence in local vector population of Ae. simpsoni sl which is abundant in the coastal region. This study sought to assess the ability of Ae. Simpsoni sl mosquitoes abundant at the Coast of Kenya to transmit these viruses in experimental laboratory experiments.

Methods

Field collected larvae/pupae of Ae. Simpsoni sl mosquitoes from Rabai, Kilifi County, were reared to adults, the first filial generation (F0) females' mosquitoes were orally exposed to infectious blood meal with isolates of the viruses using the hemotek membrane feeder. The exposed mosquitoes were incubated under insectary conditions and sampled on day 7, 14 and 21days post infection to determine susceptibility to the virus infection using plaque assay.

Results

A total of 379 (Bunyamwera virus 255 and Ngari virus 124) Ae. simpsoni sl were orally exposed to infectious blood meal. Overall, the infection rate (IR) for BUNV and NGIV were 2.7 and 0.9% respectively. Dissemination occurred in 5 out 7 mosquitoes with mid-gut infection for Bunyamwera virus and 1 out of 2 mosquitoes with mid-gut infection for Ngari virus. Further, the transmission was observed in 1 out of 5 mosquitoes that had disseminated infection and no transmission was observed for Ngari virus in all days post infection (dpi).

Conclusion

Our study shows that Ae. simpsoni sl. is a laboratory competent vector for Bunyamwera virus since it was able to transmit the virus through capillary feeding while NGIV infection was restricted to midgut infection and disseminated infection, these finding adds information on the epidemiology of the viruses and vector control plan.

SUBMITTER: Mutisya J

PROVIDER: S-EPMC8248722 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Newly emerging or re-emerging arthropod-borne viruses (arboviruses) are important causes of human morbidity and mortality worldwide. Arboviruses such as Dengue (DENV), Zika (ZIKV), Chikungunya (CHIKV), and West Nile virus (WNV) have undergone extensive geographic expansion in the tropical and sub-tropical regions of the world. In the Americas the main vectors of DENV, ZIKV, and CHIKV are mosquito species adapted to urban environments, namely Aedes aegypti and Aedes albopictus, whereas the main vector of WNV is Culex quinquefasciatus. Given the widespread distribution in the Americas and high permissiveness to arbovirus infection, these mosquito species may play a key role in the epidemiology of other arboviruses normally associated with sylvatic vectors. Here, we test this hypothesis by determining the vector competence of Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus to Mayaro (MAYV) virus, a sylvatic arbovirus transmitted mainly by Haemagogus janthinomys that has been causing an increasing number of outbreaks in South America, namely in Brazil. Using field mosquitoes from Brazil, female mosquitoes were experimentally infected, and their competence for infection and transmission rates of MAYV was evaluated. We found consistent infection rate for MAYV in Ae. aegypti (57.5%) and Ae. albopictus (61.6%), whereas very low rates were obtained for Cx. quinquefasciatus (2.5%). Concordantly, we observed high potential transmission ability in Ae. aegypti and Ae. albopictus (69.5% and 71.1% respectively), in contrast to Cx. quinquefasciatus, which could not transmit the MAYV. Notably, we found that very low quantities of virus present in the saliva (undetectable by RT-qPCR) were sufficiently virulent to guarantee transmission. Although Ae. aegypti and Ae. albopictus mosquitoes are not the main vectors for MAYV, our studies suggest that these mosquitoes could play a significant role in the transmission of this arbovirus, since both species showed significant vector competence for MAYV (Genotype D), under laboratory conditions.