Fight the Bite represents the Department of Health's first attempt to actively raise awareness and improve prevention practices related to mosquitoes in Western Australia (WA). The multi-faceted campaign model involved a range of stakeholders and delivery methods over a 2 year period, achieving a recall rate of 8.2% among 2,500 survey participants. Significant regional differences were noted in campaign exposure, reflecting the variation in mosquito management issues throughout the State, and subsequent engagement by local government. Of those individuals with campaign recall, 43.8% reported an increase in awareness and 27.4% reported a change in behavior, which equated to a 1.7 and 1.2% change across the total survey population, respectively. The results of this study demonstrate that Fight the Bite has significantly improved awareness and prevention practices among those individuals who were exposed to the campaign. This was particularly promising, given the modest budget, resources, and time period over which the campaign was run prior to evaluation. This outcome means that Fight the Bite can be confidently adopted as a proven and standardized but regionally adaptable campaign approach to raising awareness about mosquito avoidance and mosquito-borne diseases by the Department of Health and its stakeholders. Future campaign aims include increasing reach through heightened and sustained promotion of Fight the Bite by both the Department and local government, as well as expanded collaboration with a range of stakeholders within the community.

Background: Culex tritaeniorhynchus has long been considered the primary vector of Japanese encephalitis virus (JEV), but until recently, it was considered exotic to Australia. When the species was detected in the country’s Northern Territory (NT) for the first time, the Western Australia (WA) Department of Health was cognisant of the risk it posed to the State because of the shared border and continuous mosquito habitat adjoining the two jurisdictions. The aim of this study was to undertake intensive mosquito surveillance in the Kimberley region to ascertain whether Cx. tritaeniorhynchus was present in WA, define the extent of its distribution and undertake phylogenetic analysis of select specimens to support hypothesized routes of entry into the state. Methods: Carbon dioxide (CO₂)-baited encephalitis virus surveillance (EVS) mosquito traps were deployed at various sites throughout the Kimberley region by surveillance officers within the Medical Entomology unit of the Western Australia (WA) Department of Health. Mosquitoes were then morphologically identified, and a subset of four specimens were confirmed as Cx. tritaeniorhynchus by molecular identification using Cytochrome Oxidase I (COI) DNA data and phylogenetic analysis. Results: From 31 March 2021 to 30 May 2024, a total of 211 female Cx. tritaeniorhynchus specimens were collected from 21 unique trap sites in the Kimberley’s Shire of Wyndham-East Kimberley (SWEK). Four COI DNA barcode regions were amplified and successfully sequenced for analysis. These sequences fell within a clade recognised as Cx. tritaeniorhynchus and specifically all sequences were in a clade with other specimens from the NT and Timor-Leste. Conclusions: This study represents the first detection of Cx. tritaeniorhynchus in WA. Given the widespread nature of trap sites that yielded the species and consecutive seasons over which it was observed, the authors surmise that Cx. tritaeniorhynchus is now established within the northeast Kimberley region. The findings are significant given the detection of the species coincides with the first significant outbreak of JEV activity on mainland Australia involving an estimated 45 human cases of Japanese encephalitis, 80 impacted commercial piggeries and widespread feral pig activity. Although the role that Cx. tritaeniorhynchus may play in JEV transmission into the future is not yet understood, it presents a potential risk to public health in the region. Graphical

Japanese encephalitis virus (JEV) emerged across mainland Australia in 2022, causing substantial impacts on public health and the pig industry. Its emergence raised concerns regarding potential spread into Western Australia (WA). This study aimed to determine JEV activity in WA with a focus on the Kimberley region between 2022 and 2024. It also examined potential pathways of JEV introduction into the state and the challenges associated with flavivirus serology. An integrated surveillance program comprising targeted feral pig surveillance and sentinel chicken monitoring was implemented across northern WA. Sera were screened using flavivirus ELISAs and confirmatory plaque reduction neutralisation tests (PRNT), while feral pig tonsils were tested by RT-qPCR. Evidence of JEV activity was detected in WA between 2022 and 2024. Serological findings from two feral pigs sampled in October 2022 provided the earliest indication of JEV transmission in the Kimberley region. Sentinel chicken surveillance subsequently identified JEV activity in Kununurra, Wyndham, Halls Creek and Newman during 2023 and Derby in 2024. These results provide the first published evidence of JEV activity in WA and highlight the importance of ongoing surveillance, vaccination, mosquito control and preparedness activities in northern Australia.