Natural Infection of Aedes aegypti by Chikungunya and Dengue type 2 Virus in a Transition Area of North-Northeast Brazil

Abstract

Dengue fever, chikungunya, and Zika are diseases caused by viruses transmitted by Aedes aegypti and Aedes albopictus. In Brazil, the number of human infections is high, but few studies are performed in mosquito vectors. This study aimed to investigate the presence of Zika, Dengue and Chikungunya viruses in Ae. aegypti and Ae. albopictus from the municipalities of Alto Alegre, Caxias, Codó, and São Mateus do Maranhão, located in the state of Maranhão, Northeast Brazil. The mosquitoes were collected with a mechanical aspirator, identified, triturated, and then submitted to RNA extraction and RT-qPCR. The positive samples were confirmed by virus isolation and genome sequencing. Three hundred and forty-eight Ae. aegypti (176 males and 172 females) and 12 Ae. albopictus (eight males and four females) were collected and tested. Ae. aegypti was the only vector positive in two municipalities—Codó, with detection of Chikungunya virus (CHIKV) belonging to the East-Central-South African genotype, and in Caxias, with detection of Dengue virus (DENV)-2 belonging to the Asian/American genotype. The detection of CHIKV and DENV-2 is evidence that those viruses are maintained in arthropod vectors, and shows the epidemiological risk in the area for chikungunya cases and a possible increase of severe dengue cases, associated with the occurrence of dengue hemorrhagic fever.

Dengue infection modulates locomotion and host seeking in Aedes aegypti

“…To identify the potential molecular mechanism regulating the observed increase in sensitivity to human odor in 14 dpi females, the transcript abundance in the primary olfactory tissue, the antennae, was assessed in non-infected females and those infected with low and high levels of DENV-1. The high infection level used in this study is in accordance with virus titers detected naturally in mosquitoes [40]. A gene ontology analysis of molecular function associated with the antennal transcripts identified oxidoreductase and transferase activity, but not odorant binding, as affected 14 dpi with DENV-1, with higher transcript abundance in the antennae of infected females with natural levels of infection.…”

“…The four dengue serotypes [52,53], including one of the most infectious serotypes, DENV-1 [40], have similar extrinsic incubation periods [54], with a high viral titer in the midgut and abdomen by 7-11 dpi [24,31]. In contrast with the previous hypothesis that mosquito behavior post-infection is a response to any challenge to the immune system [9,55,56], locomotion has been shown to be affected in a pathogen-specific manner by several infectious agents.…”

“…RNA samples presenting a Cq higher than the median (Cq > 24.455) were considered as having a low level of infection, while samples with a lower Cq (Cq < 24.455) were considered as having a high level of infection (S4 Data). While this represents an arbitrary division of infection levels, the high level of infection encompasses the range found naturally [40].…”

Special Issue “Emerging Viruses: Surveillance, Prevention, Evolution, and Control”

“…Maia et al [12] present the discovery of novel viruses in mosquitoes from Brazilian wetlands, including viruses from nine different families: Iflaviridae, Phenuiviridae, Rhabdoviridae, Flaviviridae, Reoviridae, Chuviridae, Circoviridae, Partitiviridae,and Totiviridae. The natural coinfection of Aedes aegypti by chikungunya and dengue type 2 virus in Brazil is also reported by Aragão et al [13] The influence of the environment on chikungunya virus transmission in Senegal is revealed by Sow et al [14]. Barbosa Costa et al [15] describe a possible silent circulation of the Saint Louis encephalitis virus among humans and equids in Brazil.…”

Chikungunya virus Detection in Aedes aegypti and Culex quinquefasciatus during an Outbreak in the Amazon Region

“…Ae. aegypti mosquitoes are a worldwide recognized vector for CHIKV and, in Brazil, female mosquitoes of the same species have already been found naturally infected in the states of Sergipe [38] and Maranhão [39,40], both in the Northeast region of the country. A recent study in an urban park in Rio Grande do Norte, also in the Northeast, identified CHIKV in pools of Ae.…”