Aedes albopictus(Diptera: Culicidae) as a Potential Vector of Endemic and Exotic Arboviruses in Australia

Abstract

In 2005, established populations of Aedes albopictus (Skuse) were discovered in the Torres Strait, the region that separates Papua New Guinea from northern Australia. This increased the potential for this species to be introduced to mainland Australia. Because it is an arbovirus vector elsewhere, we undertook laboratory-based infection and transmission experiments to determine the potential for Ae. albopictus from the Torres Strait to become infected with and transmit the four major Australian endemic arboviruses--Murray Valley encephalitis virus, West Nile virus Kunjin strain (WNV(KUN)), Ross River virus (RRV), and Barmah Forest virus--as well as the exotic Japanese encephalitis virus. Ae. albopictus is susceptible to infection with all viruses, with infection rates ranging between 8% for WNV(KUN) and 71% for RRV. Transmission rates of approximately 25% were observed for RRV and Barmah Forest virus, but these were < 17% for Murray Valley encephalitis virus, WNV(KUN), and Japanese encephalitis virus. Given its relative vector competence for alphaviruses, we also examined the replication kinetics and extrinsic incubation periods required for transmission of RRV and chikungunya virus. Despite lower body titers, more mosquitoes reared and maintained at 28 degrees C became infected with and transmitted the virus than those reared and maintained at 22 degrees C. The minimum time between Ae. albopictus consuming an infected bloodmeal and transmitting chikungunya virus was 2 d at 28 degrees C and 4 d at 22 degrees C, and for RRV, it was 4 d, irrespective of the temperature. Given its opportunistic feeding habits and aggressive biting behavior, the establishment of Ae. albopictus on the Australian mainland could have a considerable impact on alphavirus transmission.

Ten years of the Tiger: Aedes albopictus presence in Australia since its discovery in the Torres Strait in 2005

“…In addition, Ae. albopictus was able to transmit RRV and CHIKV after 4 and 2 days, respectively [21] , which concurs with previous studies on the extrinsic incubation period of these viruses [23] , [24] .…”

“…The vector competence of a Masig Island population of Ae. albopictus for a number of endemic and exotic viruses has recently been examined [11] , [21] , [22] . This population was a relatively competent vector of the alphaviruses, RRV, Barmah Forest virus and CHIKV, and DENV type 3, but less so for DENV type 2, Murray Valley encephalitis, West Nile (Kunjin subtype) and Japanese encephalitis viruses.…”

Chikungunya virus, risks and responses for Australia

“…Mosquito monitoring and control remain key planks in the armoury against arboviral diseases. Efforts are underway to prevent A. albopictus mosquitoes becoming established on the Australian mainland 29 . A. albopictus (the so‐called Asian tiger mosquito) is an efficient vector for CHIKV, has spread and is spreading globally, is an aggressive biter of humans (“the barbecue stopper” 30 ) and the mosquito largely responsible for CHIKV transmission in the Indian Ocean, West Africa, Europe and Papua New Guinea.…”

Notes on Zika virus – an emerging pathogen now present in the South Pacific

“…albopictus are also found in the Torres Strait, and there is concern that Ae. albopictus may become established in Australia's mainland 31 …”