Mozzies may be infected with Japanese encephalitis this summer. Here's what you need to know when spending time outdoors

Victorian men reportedly in critical condition He was hospitalized with Japanese encephalitis after being bitten by a mosquito.

This news comes after both victoria and New South Wales In recent weeks, it has issued public health alerts warning about the virus.

So, what is Japanese encephalitis? If you live, work or vacation in a mosquito-prone area this summer, how can you protect yourself and your family?

Australian mosquito-borne diseases

Compared to other parts of the world, Australia traditionally has a very low risk of potentially life-threatening mosquito-borne diseases.

There is no prevalence of dengue fever, yellow fever or malaria. However, many viruses still exist, Local mosquitoes may spread.

About 5,000 cases of mosquito-borne diseases It is reported every year in Australia. Most of these causes are ross river virus. The disease caused by this virus is not fatalhowever, it can cause severe debilitation.

diseases caused by two other pathogens; Japanese encephalitis virus and murray valley encephalitis Viruses are much rarer, but can be deadly.

The symptoms of human disease caused by these two viruses are similar.

most people are infected show no symptoms. In mild cases, symptoms such as fever, headache, and vomiting may occur. In more severe cases, neck stiffness, disorientation, drowsiness, and seizures may occur. In severe cases, neurological complications can be lifelong and, in some cases, life-threatening.

There is no specific treatment for either disease, but vaccines are available. Japanese encephalitis This may be suitable for certain high-risk people (more on that later).

Impact of weather patterns

Murray Valley Encephalitis Virus It has been known in Australia for decades. Since the outbreak of a major outbreak across the Murray-Darling Basin region in 1974, activity has generally decreased. Northern Australia only.

Outbreaks in south-eastern Australia are often accompanied by flooding caused by: La Niña weather pattern. Floods provide ideal conditions for mosquitoes. waterfowl Something that harbors a virus.

Japanese encephalitis virus Closely related to Murray Valley encephalitis virus. mosquito You can transmit both viruses by biting waterfowl.. However, the Japanese encephalitis virus has only recently become widespread in Australia.

After the heavy rains brought by La Niña in 2020, the following situation occurred. lasted for 3 years, Murray Valley Encephalitis Virus Come back and Japanese encephalitis virus I arrived for the first time.

Japanese encephalitis virus was first discovered in southeastern Australia. Summer 2021-2022,and Rapid increase in mosquitoes and waterfowl Floods at the time contributed to the spread.

It was around 80 diseases It has been caused by a combination of these two viruses over the past four years. This includes: 7 people die from Japanese encephalitis across Queensland, New South Wales, South Australia, Victoria.

Additional deaths from Murray Valley encephalitis have been reported in recent years, two each. western australia and Northern Territory.

In the summer of 2023-2024, Hot, dry summer weather is backthe number of mosquitoes decreases, Number of cases The proportion of illnesses caused by Japanese encephalitis virus and Murray Valley encephalitis has decreased.

now Both viruses appear to be making a comeback.. So what's going on?

What will be different this summer?

This summer, Japanese encephalitis virus was detected. Mosquitoes and stray pigs in New South Wales. Viruses were also detected from environmental monitoring I know at least one person in northern Victoria is affected There.

Meanwhile, Murray Valley encephalitis virus was detected in a flock of guard chickens. used by health authorities To test for increased risk of mosquito-borne diseases – New South Wales and in the Kimberley region western australia.

It is unusual to see activity of these viruses when conditions are relatively dry and mosquito numbers are relatively low.

Some areas of Australia may have experience floodHowever, many parts of the country continue to experience hot and dry conditions. This is bad news for mosquitoes.

There is no evidence that mosquito numbers are surging like they were during La Niña. Flooding into the Murray-Darling Basin.

There is also no evidence of increased waterfowl activity. in fact, The number has been decreasing in recent years.

So why do Japanese encephalitis virus and Murray Valley encephalitis virus become active again when the situation seems less favorable?

Despite the prediction that Return of rare midsummer La Niña phenomenonthere is still some speculation as to what this means Temperature and precipitation. Although you may not see flooding, there may still be enough water around for mosquitoes to live.

In the case of Japanese encephalitis virus, it is probably Stray pig It plays a more important role in its spread. we know numbers are increasing In even drier conditions, mosquitoes and feral pigs are likely to emerge. and other wild animalsthey congregate where they can find bodies of water.

After an unexpected arrival, the Japanese encephalitis virus now appears to be here to stay. However, further research is needed into how this virus interacts with local mosquitoes and wildlife under the influence of increasingly unpredictable climate conditions.

How can you reduce your risk this summer?

public health warning for victoria and New South Wales It is particularly focused on specific areas around Griffith and Narromine in northern Victoria and New South Wales, where the virus has been detected.

If you live or work in an area where there is a risk of Japanese encephalitis, seek advice from your local health authority to determine whether you have been infected with Japanese encephalitis. Eligible for vaccination. Residents of designated local government areas in affected areas in both states are now eligible to be vaccinated free of charge.

However, there are no vaccines available for Murray Valley encephalitis or Ross River virus.

No matter where you live, it's important to protect yourself from mosquito bites. apply insect repellent If you are outdoors, you can use it at any time of the day, especially at dawn and dusk when mosquitoes are most active, or if you are in scrubland or wetlands where mosquito numbers may be high.

You can be more protected by covering your body with long-sleeved shirts, long pants, and covered shoes.