Poster Presentation 9th Australasian Virology Society Meeting 2017

‘Blood thirsty and ready to strike’ Mosquito and Arbovirus surveillance within a military training area (#143)

Christina Neuman 1 , Lisa M Rigby 1 , Weng K Chow 1 , Brady A McPherson 1 , Wenjun Liu 1
  1. Australian Army Malaria Institute, Enoggera

Arbovirus infection is one of the biggest health threats to the Australian Defence Force (ADF) with the potential to impede military capability. In both Mar 2016 and May 2017, there were laboratory confirmed RRV and BFV outbreaks in one of the military training area (TA) in Shoalwater bay, QLD with 60 and 25 personnel affected respectively. In order to reduce the future Arbovirus threat to military personnel, we conducted Arbovirus surveillance within a TA in Tully, northern QLD. Multiple approaches were applied for this surveillance namely two types of CO2 mosquito traps; honey-baited nucleic acid preservation cards to collect mosquito saliva and field RT-PCR using universal Alpha-, Flavivirus and RRV specific primers for the detection Arboviruses from mosquitoes and nucleic acid preservation cards. Total 15,734 mosquitoes were trapped over a nine day period. The most dominant species were Culex sitiens (23.5 %), and Verrallina spp (58.2%). The average number of mosquitoes per trap was 95 in the EVS traps and 888 in the FBTs, indicating a high density of mosquitoes in the Tully area at end of Mar 2017. However, we did not detected any Arboviruses in field RT-PCRs run from the 151 pools of mosquitoes and 32 nucleic acid preservation cards RNA extractions, even though our RT-PCRs can detected as low as 1pfu of RRV. The mosquitoes were transported back to AMI laboratory at Brisbane for virus isolation by mosquito homogenate inoculation into C6/36 cells and then subsequent transferral of the cell culture fluid to infect Vero cells. One BFV was isolated from Verrallina spp. caught in one of the FBTs. Sequence analysis revealed this new isolate has a 98.5% similarity to isolate ‘1996 BFV’, indicated the slow evolution of BFV in Australia. Taken together, we concluded that multiple surveillance approaches are needed to apply for further Arbovirus surveillance.