ABSTRACT
An arbovirus surveillance military exercise was conducted to assess the risk of Ross River virus (RRV) and Barmah Forest virus (BFV) in the Australian Defence Force (ADF) Wide Bay training area (WBTA), northeastern Australia, in April 2018. Of the 5,540 female mosquitoes collected, 3,702 were screened for RRV and BFV by quantitative reverse transcription-polymerase chain reaction in a field laboratory. One pool of Verrallina funerea was positive for RRV and 8 pools (7 pools of Aedes vigilax and 1 pool of Culex annulirostris) were positive for BFV. Phylogenetic analysis of the complete nucleotide sequence of the E2 protein subgrouped both RRV and BFV with viruses previously isolated from human infections, indicating the potential risk of RRV and BFV infection to ADF personnel while training in WBTA. This is the 1st time that both RRV and BFV have been detected in a military training area.
Subject(s)
Alphavirus/isolation & purification , Culicidae/virology , Ross River virus/isolation & purification , Alphavirus/genetics , Animals , Female , Military Personnel , Population Surveillance , Queensland , Ross River virus/geneticsABSTRACT
Two outbreaks of epidemic polyarthritis occurred among Australian Defence Force personnel during and following short military exercises in the Shoalwater Bay Training Area, northeastern Australia, in 2016 and 2017. Ross River virus (RRV) IgM was detected in acute-phase serum samples from most patients (28/28 in 2016 and 25/31 in 2017), and RRV was recovered from 4/38 serum samples assayed (1/21 in 2016 and 3/17 in 2017). Phylogenetic analyses of RRV envelope glycoprotein E2 and nonstructural protein nsP3 nucleotide sequences segregated the RRV isolates obtained in 2016 and 2017 outbreaks into 2 distinct sublineages, suggesting that each outbreak was caused by a different strain of RRV. The spatiotemporal characteristics of the 2016 outbreak suggested that some of the infections involved human-mosquito-human transmission without any intermediate host. These outbreaks highlight the importance of personal protective measures in preventing vectorborne diseases for which no vaccine or specific prophylaxis exists.
Subject(s)
Alphavirus Infections/epidemiology , Arthritis/epidemiology , Epidemics , Military Personnel , Ross River virus , Adult , Alphavirus Infections/virology , Arthritis/virology , Epidemics/statistics & numerical data , Female , Humans , Male , Middle Aged , Military Personnel/statistics & numerical data , Phylogeny , Queensland/epidemiology , Ross River virus/genetics , Young AdultABSTRACT
The complete genome sequences of three Ross River virus (RRV) isolates from infected Australian Defence Force (ADF) personnel and from mosquitoes collected in ADF training areas were determined. Phylogenetic analysis in comparison with all available complete RRV nucleotide sequences from GenBank split these three RRV isolates into two distinct sublineages.
