Let’s Calmly Explain The Japanese Encephalitis Virus That’s On The Rise

Japanese Encephalitis, a brain-swelling pig flu, seems on paper to be the apocalyptic sequel to COVID-19, with New South Wales recording its first death from the virus last week. 

However, before you start freaking out and buying toilet paper, here’s what you should know about the virus.

What Is Japanese Encephalitis??

Japanese Encephalitis, or JEV, is a disease spread by mosquitoes that causes swelling of the brain, which in extreme cases can cause brain damage and death.

However, NSW Health notes the risk of experiencing symptoms is extremely low.

“Less than one percent of people infected with JEV will experience symptoms,” reads a statement on their website. “Some infected people experience an illness with fever and headache. People with a severe infection may experience neck stiffness, disorientation, tremors, coma and seizures.

“Among those who develop severe infection, some will go on to experience permanent neurological complications or possibly death. Symptoms, if they are to occur, usually develop five to 15 days after being bitten by infected mosquitoes.”

It’s important to note that JEV has actually existed in the far northern parts of Australia since the 1990s, and has been monitored and controlled by biosecurity agencies. 

How does it Spread?

Put simply, Japanese Encephalitis can only spread to a human host via a mosquito transferring the virus from an infected animal. 

This means that humans can’t catch the virus from each other — mosquitoes can’t transfer the virus from infected humans to non-infected ones. As the US Centre for Disease Control puts it: “Humans are incidental or dead-end hosts, because they usually do not develop high enough concentrations of JE virus in their bloodstreams to infect feeding mosquitoes”. 

Animals that can be infected by Japanese Encephalitis include pigs, horses and donkeys, cattle, sheep, goats, water buffalo, chickens, and even cats and dogs.  However, there are only a couple of animals who are capable of actually transmitting the virus via mosquito once sick! They are water birds, such as herons, and the humble pig.

Places with lots of pigs, such as piggeries, are therefore critical places for the transmission of the virus. Wild boar populations — numerous in the northern states of Australia — are also a concerning way the virus can spread. 

What’s The Deal With The Latest Outbreak?

JEV is making headlines due to outbreaks in Victoria and South Australia, the virus has previously never travelled further south than Cape York. 

Experts are warning that the east coast floods are proving to be the perfect condition for the virus’s transmission. University of Queensland virologist Dr Jody Peters told the ABC that this year’s La Nina event had created “excellent environmental conditions” for JAV. 

Dr Peters told the ABC that the flooding of waterbird habitats is of particular concern and could trigger migration events that led to further transmission of the virus. “Waterbirds in particular, they will become infected, they develop a lot of virus in their bloodstream and then they subsequently infect another mosquito and that drives this transmission cycle,” Dr Peters told the ABC. 

The current death toll of the virus is two people, one man from Northern Victoria and another from New South Wales. There are 15 confirmed human cases of JEV at the moment.

There’s Already A Vaccine For JEV

Fortunately, a vaccine already exists to combat JAV. The government announced today that it is purchasing 130,000 doses of the vaccine to ensure Australians are protected. 

You don’t have to get into arguments with your relatives about whether it works or not either, the efficacy of just a single dose of the vaccine has been recorded by the World Health Organisation to be 99.3 percent. 

Apart from that, people in mosquito prone areas are being told to wear long sleeve shirts and apply mosquito repellent, particularly in the evenings. You can check out the full NSW Health fact sheet for advice here.