Avaliação da competência vetorial de populações de Aedes albopictus de Manaus, Amazonas ao Zika Vírus

Abstract

Zika virus (ZIKV) causes an arbovirose with widespread worldwide distribution transmitted to humans by the bite of females of infected mosquitoes. Ae. aegypti and Ae. albopictus are considered the main vectors, being widely distributed particularly in the tropical region where the virus is prevalent. Although Ae. albopictus is typical of wild environments, this species is also found adapted to the urban environment. In Manaus its occurrence has been recorded since 2002, however its role in the ZIKV transmission dynamics is unknown. To be considered a good vector the mosquito must have vector competence, which involves the susceptibility of the mosquito to become infected by a virus, to replicate it and to transmit it. Studies on the vectorial competence of the genus Aedes for the ZIKV are wide, but with divergent results. For Ae. albopictus in Brazil, only one study was carried out with a population of Rio de Janeiro, and there was no information on the vectorial competence of this species in the city of Manaus. This work aimed to evaluate the vectorial competence of a population of Aedes albopictus from the city of Manaus to the ZIKV. The work was carried out in the entomology laboratory of the Tropical Medicine Foundation. Females of Ae. albopictus were exposed to the virus through artificial feeding and, for comparison purposes, a population of Ae. aegypti was used as control group. Rates of virus infection and dissemination were analyzed through the body and head by RT-qPCR, after dissection on the 7th, 14th and 21st day post-infection. Transmission analysis to determine vector competence occurred on the 14th day post-infection from saliva collection and quantification by RTqPCR. The population of Ae. albopictus from Manaus was susceptible to infection with ZIKV, presenting values similar to that observed for the control group formed by a population of Ae. aegypti evaluated on the same days post infection. It presented infection rates of 65% in the 7th dpi and 70% in the 14th and 21st dpi. The rates of disseminated infection were 23% in the 7th dpi, 57% in the 14th and 14% in the 21dpi. Vector competence was 30% in the 7th dpi, 40% in the 14th and 10% in the 21st. Transmission of the virus was observed in 30% of the 10 Ae. albopictus analyzed. The results obtained in this study demonstrated that the Ae. albopictus from Manaus is susceptible to ZIKV, allowing replication over the post-infection days; infection rates were high and similar to that observed for Ae. aegypti, the main vector of the ZIKV in the world. In addition to being susceptible, Ae. albopictus also showed that the virus had spread to the salivary glands, demonstrating that the population of Ae. albopictus in the city of Manaus presents the vectorial competence as vector of the Zika virus. The great geographic distribution and the high adaptability of Ae. albopictus make their transmission potential an indication of attention as the outbreak of ZIKV continues.

Keywords: Arbovirose, susceptibility, viral replication, competence, vector.