JEV is a viral infection that is usually spread between waterbirds and pigs through the Culex species of mosquitoes, but it has also shown to infect humans and may cause severe disease including inflammation of the brain.
This virus began to spread in the summer of 2021 through areas near the Murray River in northern and north-west Victoria and Southern Riverina. It is believed that the virus will continue to emerge each summer during the time that mosquitoes become active.
Last summer, JEV was detected at piggeries and in humans across Victoria, New South Wales, Queensland and South Australia.
As of August 10, there have been 40 human cases of recorded JEV across the nation with nine in Victoria and 13 in New South Wales.
Alongside seven other LGAs, the Moira LGA has been identified as a high-risk area for the virus, according to Goulburn Valley Local Public Health Unit (PHU) clinical director, Dr William Cross.
“We did see a lot of cases around Moira and it's a combination of the fact that it's wet and it's flat and that creates lots of places where mosquitoes love to breed,” Dr Cross said.
“Last season was, according to our entomologist (mosquito researcher), the biggest season they've ever seen for mosquitoes.
“It also seems to be related to the Murray Darling River systems, which makes sense because mosquitoes need water to breed and waterbirds need water to breed as well.”
To prevent further outbreaks of the virus, the PHU needs to identify the type of people who are at higher risk so it can provide vaccines. Currently, the unit hasn’t been able to determine the true number of infections, as most people don’t display symptoms.
This is where the PHU’s serosurvey comes in. A serosurvey is the collection and testing of blood from a group of specimens over a period of time to determine the prevalence of antibodies. Antibodies are markers in the blood that show if someone has been infected with or vaccinated against a certain kind of disease.
The serosurvey will identify how many people in the Moira Shire had unrecorded JEV infections by testing for antibodies in their blood as Dr Cross explains.
“What this study is trying to do is to identify all the people that were infected with JEV but only had a mild form of the illness which was not noticed by the individual or detected by a doctor,” Dr Cross said.
“It will help us to understand which groups of people are at the highest risk of JEV infection and help to inform our planning for who gets vaccinated. As we have a limited supply of vaccines against Japanese encephalitis, we want to make sure that we are protecting those people at highest risk of getting infected and developing severe disease.”
The PHU is looking for participants who haven’t been vaccinated against JEV or haven’t been diagnosed with JEV yet.
People born in Bangladesh, Brunei, Cambodia, China, Guam, India, Indonesia, Japan, Laos, Malaysia, Nepal, North Korea, Pakistan, Papua New Guinea, Philippines, Russia, Saipan, Singapore, South Korea, Sri Lanka, Taiwan, Thailand, Timor-Leste or Vietnam are also unable to participate due to the high probability that they were exposed to JEV at a young age and would have already developed those antibodies.
People from all walks of life are encouraged to participate. Testing will take place over the following months at Dorevitch Pathology in both Yarrawonga and Cobram with Yarrawonga testing open from Monday to Friday and Monday to Thursday in Cobram. Bookings are not required and times may vary.
For more information on JEV visit the Better Health website.