Not for nothing, microplastics can (potentially) reduce the risk of mosquito-to-human transmission of arboviruses

Abstract

The impact of microplastic pollution has emerged as a significant global ecological concern. Various organisms have exhibited alterations in behavior or metabolic activities following exposure to microplastics (MPs). Mosquitoes, as crucial disease vectors, are particularly susceptible MPs exposure in the environment. Recent studies have demonstrated that MPs ingested by mosquitoes can be detected in vivo, potentially being transmitted during their different life cycles. However, it remains unclear whether MPs in vivo could affect mosquito infection with arboviruses. In this study, we identified that the physical adsorption effect of MPs is also effective against arboviruses, enabling the adsorption of Zika virus particles onto their surfaces. We established an exposure model by feeding adult Aedes albopictus (Skuse, 1895) (Diptera: Culicidae) with 1 μm MPs at concentrations of 5 and 50 μg/mL in 8% sucrose solution. The transmission rate of ZIKV and population transmission rate in the laboratorial Ae. albopictus exposure model began to decrease from day 7, showing statistically significant differences compared to the control group on days 10 and 14 (**, p < 0.01), significantly affecting their vector efficiency. This phenomenon is not solely dependent on the physical adsorption of MPs to arboviruses. Transcriptome analysis indicated that exposure to MPs influenced the expression levels of genes associated with mosquito virus infection, altering the function of relevant pathways, which consequently reduces their capability to transmit arbovirus. These findings suggest that exposure to MPs significantly affects the vector efficiency of mosquitoes, providing novel perspectives for the ecological risk assessment of MPs.