Flooding isn’t the only risk in La Nina’s wet weather as mosquitoes move in – and now we have the Japanese encephalitis virus to worry about.

Mosquitoes are a problem every summer, but the recent arrival of the mosquito-borne Japanese encephalitis virus in eastern Australia has raised more significant concerns.

There are hundreds of different mosquito species in Australia, but only a few pose a threat to public health. The activity of these mosquitoes varies from season to season with differences in rainfall and temperature.

A changing climate and extreme wet weather events can increase mosquito populations and bring additional hazards.

How can we reduce the risk of contracting mosquito-borne diseases, including Japanese encephalitis?

First, some mozzie basics

Mosquitoes need stagnant water to complete their life cycle. Immature mosquitoes hatch and complete their development under water until they pupate before emerging as adult mosquitoes.

Female mosquitoes need blood before they can lay eggs. They seek blood from different types of animals and can pick up the virus in addition to ingesting blood. This virus can then be passed to another animal or human when they need blood.

Mozzies make you sick by injecting a cocktail of saliva and viruses when they bite. “Mozzie spit” can leave you with a red itch as well as a dose of a potentially fatal disease.

What diseases can mosquitoes transmit?

Australia has always struggled with mosquito-borne diseases. Ross River virus infects thousands of people every year. Extreme weather events are increasing the number of events around our cities and growing coastal communities.

Murray Valley encephalitis virus is extremely rare but can be fatal. Significant outbreaks have been closely associated with flooding in the Murray-Darling Basin region.

Mosquito-borne diseases are more dangerous than humans. Horses can experience severe symptoms after being infected with Ross River virus or Kunjin virus.

There are also concerns about cattle ephedrine fever and bovine skin disease.

Even in our backyard, our dogs can be affected by parasites spread by mosquito bites.

Dogs can also get sick from mosquito bites.(ABC Ballarat: Rhiannon Stevens)

What about Japanese encephalitis virus?

The discovery of the mosquito-borne Japanese encephalitis virus last summer changed the landscape of mosquito-borne disease in Australia.

The disease can be mild, with common symptoms being fever, joint pain and rash. In severe cases, people also experience headaches, neck stiffness, confusion, seizures, and sometimes coma and death. Less than 1 percent of those infected will develop encephalitis, a severe brain infection that can be fatal.


Leave a Comment