Dynamic of Mayaro virus transmission betweenAedes aegyptiandCulex quinquefasciatusmosquitoes and a mice model

Abstract

Mayaro virus (MAYV) is transmitted by Haemagogus spp. mosquitoes and has been circulating in Amazon areas in the North and Central West regions of Brazil since the 1980s, with an increase in human case notifications in the last 10 years. MAYV introduction in urban areas is a public health concern once the infection can cause severe symptoms similar to other Alphaviruses. Regarding to urban transmission, studies with Aedes aegypti demonstrate the potential vector competence of the species and the detection of MAYV in urban populations of mosquitoes. Considering the two most abundant urban mosquito species in Brazil, we investigated the dynamics of MAYV transmission by Ae. aegypti and Culex quinquefasciatus in a mice model. Mosquito colonies were artificially fed with blood containing MAYV and infection (IR) and dissemination rates (DR) were evaluated. On the 7th post-infection day (dpi), IFNAR BL/6 mice were made available as a blood source to both mosquito's species. After the appearance of clinical signs of infection, a second blood feeding was performed with a new group of non-infected mosquitoes. RT-q PCR and plaque assay were carried out with animal and mosquito's tissues. We found for Ae. aegypti a IR of 97,5-100% and a DR of 100% in both 7th and 14th dpi. Regarding Cx. quinquefasciatus, the IR found was 13.1-14.81% and DR ranged from 60% to 80%. To evaluate the mosquito-mice transmission rate, 18 mice were evaluated (Test=12 and Control=6) for Ae. aegypti and 12 animals (Test=8 and Control=4) for Cx. quinquefasciatus. All mice bitten by infected Ae. aegypti showed clinical signs of infection while all mice exposed to infected Cx. quinquefasciatus mosquitoes remained healthy. Viremia found in those animals ranged from 2.5 x 108 to 5 x 109 PFU/ml. Ae. aegypti from the second blood feeding showed a 50% infection rate. Our study showed the applicability of an efficient model to complete arbovirus transmission cycle studies and suggests that the Ae. aegypti population evaluated is a competent vector for MAYV highlighting the risk of establishment of MAYV urban cycle. The mice model employed here can be used more extensively for arthropod-vector transmission studies, with laboratory and field mosquito populations, as well as with other arboviruses.

Assessment of Mayaro virus vector competence of the mosquito Aedes aegypti (Linnaeus, 1762) populations in Argentine using dose–response assays

“…Previous studies have shown that Ae. aegypti is a competent vector of MAYV (Alomar & Alto, 2022; Alto et al, 2020; Brustolin et al, 2018; Diop et al, 2019; Krokovsky et al, 2023; Pereira et al, 2020; Sucupira et al, 2020; Long et al, 2011; Wiggins et al, 2018). However, conventional vector competence studies involve limited viral doses, and researchers often employ higher viral doses to enhance the likelihood of detecting infected mosquitoes.…”

Mouse Models of Mayaro Virus

“…IFNAR mice naturally infected with MAYV through the bite of the Aedes aegypti showed clinical signs of infection, while all mice exposed to Culex quinquefasciatus mosquitoes remained healthy. Clean Aedes aegypti mosquitoes were also able to become infected and maintain a 50% infection rate seven days after blood feeding in mice infected with MAYV, demonstrating a complete model of transmission (mosquito–host–mosquito) [ 26 ]. Eight-week-old IFNα/β/γR −/− (AG129) immunodeficient mice (type II interferon knockouts) have also proved to be an efficient model in vector competence studies.…”