Zika Virus Infection Produces a Reduction on Aedes aegypti Lifespan but No Effects on Mosquito Fecundity and Oviposition Success

Abstract

A Zika virus (ZIKV) pandemic started soon after the first autochthonous cases in Latin America. Although Aedes aegypti is pointed as the primary vector in Latin America, little is known about the fitness cost due to ZIKV infection. We investigated the effects of ZIKV infection on the life-history traits of Ae. aegypti females collected in three districts of Rio de Janeiro, Brazil (Barra, Deodoro, and Porto), equidistant ~25 km each other. Aedes aegypti mosquitoes were classified into infected (a single oral challenge with ZIKV) and superinfected (two ZIKV-infected blood meals spaced by 7 days each other). ZIKV infection reduced Ae. aegypti survival in two of the three populations tested, and superinfection produced a sharper increase in mortality in one of those populations. We hypothesized higher mortality with the presence of more ZIKV copies in Ae. aegypti females from Porto. The number of eggs laid per clutch was statistically similar between vector populations and infected and uninfected mosquitoes. Infection by ZIKV not affected female oviposition success. ZIKV infection impacted Ae. aegypti vectorial capacity by reducing its lifespan, although female fecundity remained unaltered. The outcome of these findings to disease transmission intensity still needs further evaluation.

Keywords: Aedes aegypti; Zika; disease transmission; fecundity; survival; vectorial capacity.

Figure 1

The viral load in the body and head of Aedes aegypti mosquitoes infected and superinfected with ZIKV from Deodoro and Porto field populations. Dpi: days postinfection; dpsi: days post superinfection. *p < 0.05; ** p < 0.001. Due to low-sample sizes, Barra population data were not included in the analysis.

Figure 2

Aedes aegypti survival curves according to treatment (control, infected, and superinfected). Data for (A) Barra, (B) Porto, and (C) Deodoro populations. CTR: control (noninfected mosquitoes); INF: infected mosquitoes; SINF: superinfected mosquitoes.