Orally Co-Infected Aedes albopictus from La Reunion Island, Indian Ocean, Can Deliver Both Dengue and Chikungunya Infectious Viral Particles in Their Saliva

Abstract

BackgroundFirst described in humans in 1964, reports of co-infections with dengue (DENV) and chikungunya (CHIKV) viruses are increasing, particularly after the emergence of chikungunya (CHIK) in the Indian Ocean in 2005–2006 due to a new variant highly transmitted by Aedes albopictus. In this geographic area, a dengue (DEN) outbreak transmitted by Ae. albopictus took place shortly before the emergence of CHIK and co-infections were reported in patients. A co-infection in humans can occur following the bite of two mosquitoes infected with one virus or to the bite of a mosquito infected with two viruses. Co-infections in mosquitoes have never been demonstrated in the field or in the laboratory. Thus, we question about the ability of a mosquito to deliver infectious particles of two different viruses through the female saliva.Methodology/Principal FindingsWe orally exposed Ae. albopictus from La Reunion Island with DENV-1 and CHIKV isolated respectively during the 2004–2005 and the 2005–2006 outbreaks on this same island. We were able to show that Ae. albopictus could disseminate both viruses and deliver both infectious viral particles concomitantly in its saliva. We also succeeded in inducing a secondary infection with CHIKV in mosquitoes previously inoculated with DENV-1.Conclusions/SignificanceIn this study, we underline the ability of Ae. albopictus to be orally co-infected with two different arboviruses and furthermore, its capacity to deliver concomitantly infectious particles of CHIKV and DENV in saliva. This finding is of particular concern as Ae. albopictus is still expanding its geographical range in the tropical as well as in the temperate regions. Further studies are needed to try to elucidate the molecular/cellular basis of this phenomenon.

Differential replication of dengue virus serotypes 2 and 3 in coinfections of C6/36 cells and Aedes aegypti mosquitoes

“…Additionally, the presence of intra-host competition in the vector, which may favor the replication of some viral variants over others, has been reported for other infection models, either between two serotypes of the same virus [24] or between strains of the same serotype [25], thereby favoring the transmission of one of the variants. Similar behaviors have been reported for DENV and chikungunya virus coinfections, in which the percentages of infection spread were better for the Chikungunya virus [26].…”

WolbachiastrainwMel induces cytoplasmic incompatibility and blocks dengue transmission inAedes albopictus

“…Mosquito saliva contained numbers of viral particles in the expected range for Ae. albopictus infected with dengue virus (23) (Fig. 2), with an average of 67 ± 139 viral particles for the Uju.wAlbA/wAlbB strain and 29 ± 29 viral particles for the UjuT strain.…”

Entomological Coinfections of Arboviruses Dengue and Chikungunya Viruses along the Coastline of Kenya

“…This is because mosquitoes can feed multiple times on more than one human host and require multiple bites per each gonotrophic cycle (Harrington et al, 2014). Concomitant infections were reported in studies by Göertz et al (2017), Rückert et al (2017), Le Coupanec et al (2017) and Vazeille et al (2010). However, their reports are conflicting on the aspect of vector competence.…”

“…In Rabai area of coastal Kenya, flaviviruses and alpha viruses were isolated in Aedes aegypti only (Odhiambo, et al, 2014). The ability of a given Aedes species to carry multiple viral infections was demonstrated by Vazeille et al (2010). In their study, Aedes albopictus was orally infected with both Dengue and Chikungunya viruses with an ability to transmit them to their human host via its saliva.…”