Host species and site of collection shape the microbiota of Rift Valley fever vectors in Kenya

Authors: TCHOUASSI, DAVID - International Centre Of Insect Physiology And Ecology; Muturi, Ephantus; ARUM, SAMWEL - International Centre Of Insect Physiology And Ecology; KIM, CHANG-HYUN - University Of Illinois; FIELDS, CHRISTOPHER - University Of Illinois; TORTO, BALDWYN - International Centre Of Insect Physiology And Ecology

Submitted to: PLOS Neglected Tropical Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2019
Publication Date: 6/7/2019
Citation: Tchouassi, D.P., Muturi, E.J., Arum, S.O., Kim, C., Fields, C., Torto, B. 2019. Host species and site of collection shape the microbiota of Rift Valley fever vectors in Kenya. PLOS Neglected Tropical Diseases. 13(6):e0007361. https://doi.org/10.1371/journal.pntd.0007361.
DOI: https://doi.org/10.1371/journal.pntd.0007361

Interpretive Summary: Rift Valley Fever (RVF) is a mosquito-borne disease that affects both humans and livestock causing abortion storm in pregnant ruminants and sudden death in newborns. RVF virus is also considered a potential bioterrorism agent due to its devastating effects, significant potential for international spread and lack of safe and efficient vaccines for medical and veterinary use. Motivated by the growing awareness that microbial communities associated with mosquitoes can be harnessed for mosquito control, we characterized for the first time the bacterial communities associated with the primary vectors of RVF virus in Kenya (Aedes mcintoshi and Ae. ochraceus). Our results show that two mosquito species harbor distinct bacterial communities that vary markedly by the site of collection. These differences may partly explain the observed variation in RVF virus infection rates between the two mosquito species and further studies are needed to identify which of the identified bacterial taxa could be utilized as novel tools for controlling this devastative viral disease.

Technical Abstract: The composition and structure of microbial communities associated with mosquitoes remain poorly understood despite their important role in host biology and potential to be harnessed as novel strategies for mosquito-borne disease control. We employed MiSeq sequencing of the 16S rRNA gene amplicons to characterize the bacterial flora of field-collected populations of Aedes mcintoshi and Aedes ochraceus, the primary vectors of Rift Valley fever (RVF) virus in Kenya. Proteobacteria (53.5%), Firmicutes (22.0%) and Actinobacteria (10.0%) were the most abundant bacterial phyla accounting for 85.5% of the total sequences. NMDS plots based on Bray-Curtis dissimilarities revealed a clear grouping of the samples by mosquito species, indicating that these two mosquito species harbored distinct microbial communities. Microbial diversity, richness and composition was strongly influenced by the site of mosquito collection and overall, Ae. ochraceus had significantly higher microbial diversity and richness than Ae. mcintoshi. Our findings suggest that host species and site of collection are important determinants of bacterial community composition and diversity in RVFV vectors and these differences likely contribute to the spatio-temporal transmission dynamics of RVF virus. Further studies are needed to determine the influence of identified microbial communities on host biology including susceptibility to RVF virus and their potential application in symbiotic control of RVF virus.