Chikungunya Virus and Aedes Mosquitoes: Saliva Is Infectious as soon as Two Days after Oral Infection

Abstract

Background Aedes aegypti and Aedes albopictus are potential vectors of chikungunya virus (CHIKV). The recent CHIKV outbreaks were caused by a new variant characterized by a mutation in the E1 glycoprotein gene (E1-226V) which has favored a better transmissibility by Ae. albopictus. As Ae. albopictus tends to replace Ae. aegypti in many regions, one question remained: is Ae. albopictus as efficient as Ae. aegypti to transmit the variant E1-226V of CHIKV?Methodology and FindingsWe infected orally both species with the variant E1-226V and estimated the infection, the viral dissemination, and the transmission rate by real time RT-PCR. Additionally, we used an in vitro assay to determine the amount of virus delivered by mosquitoes in their saliva. We found that Ae. aegypti as well as Ae. albopictus ensured a high replication of the virus which underwent an efficient dissemination as detectable in the salivary glands at day 2 post-infection (pi). Infectious CHIKV particles were delivered by salivary glands from day 2 with a maximum at day 6 pi for Ae. albopictus (103.3 PFU) and day 7 pi for Ae. aegypti (102.5 PFU).Conclusions Ae. albopictus is slightly more efficient than Ae. aegypti to transmit the variant E1-226V of CHIKV. These results will help to design an efficient vector control to limit transmission as soon as the first human cases are diagnosed.

Vector Competence of Aedes aegypti and Aedes vittatus (Diptera: Culicidae) from Senegal and Cape Verde Archipelago for West African Lineages of Chikungunya Virus

“…This early dissemination, as well as early transmission potential, has been observed in previous studies. 36,37 The infection rates we observed were relatively low in all of the Ae. aegypti populations we tested compared with populations from other geographic regions.…”

A nonhuman primate model of chikungunya disease

“…The reported correlation between dose and disease severity (more severe at a higher dose) is interesting and may explain, at least in part, the range of symptoms observed in humans. The doses used by the authors are within ranges likely delivered by mosquitoes (24). It would have been interesting if some primates had been challenged by CHIKV-infected mosquitoes, given the increasing evidence that chikungunya fever has an immunological component.…”

Chikungunya Virus: A Novel and Potentially Serious Threat to New Zealand and the South Pacific Islands

“…27 Aedes albopictus mosquitoes can transmit CHIKV within two days of biting a viremic host, and once infected, the mosquito is able to transmit the arbovirus for life. 7 Because this species is an aggressive biter and can take four blood meals during its life span at 20°C, 27 conditions in Auckland would be ideal for a CHIKV outbreak. In addition, it has been previously established that this area of the country could be receptive to dengue.…”

“…albopictus mosquitoes resulting in improved viral replication and transmission efficiency. [7][8][9] It was shown that a single mutation can increase the range of vectors and hosts of this virus, resulting in greater geographic distribution and establishment in new areas. 9 In 2007, Italy registered the first CHIKV outbreak autochthonously transmitted in Europe.…”