Mosquito-borne diseases

Australia has seen an increase in mosquito numbers and bites this summer as heavy rain and flooding brought on by La Niña continues to wreak havoc, resulting in an increased risk of mosquito-borne diseases.

While mosquitos are a problem every summer, the recent arrival of the Japanese encephalitis virus in eastern Australia heightens concerns.

That’s why it’s important to be wary and take extra steps to protect yourself this wet season, both in the workplace and at home.

But before we get into that, let’s revisit some mozzie basics.

Some quick facts about mosquitoes

Mosquitoes need two key ingredients to complete their life cycle: water and warmth. Immature mosquitoes hatch from eggs and develop underwater before emerging as adult mosquitoes. 

Female mosquitoes need blood before they lay eggs. When looking for blood, they’ll most likely seek it from an animal, which is how viruses come into the mix. The animal – such as a pig or wild water bird – could be carrying a virus and pass it onto the mosquito when bitten. That virus can then be passed on to another animal, or person, when they need another hit of blood.

Australia has always had mosquito-borne diseases but the most common are the Ross River virus, which infects thousands of people each year, and the Barmah Forest virus. We’ve also seen cases of Murray Valley encephalitis (incredibly rare but fatal), Dengue fever and, most recently, the Japanese encephalitis virus.

What is Japanese Encephalitis?

Japanese encephalitis is caused by the Japanese encephalitis virus (JEV). Most people infected with the virus will experience either no symptoms or mild fever and headaches, but in some rare cases (about one in 100 people) it can cause brain swelling, which can be fatal.

People who work and live in areas close to pig populations (the number one carrier of the virus) and increased mosquito activity are the most at risk of infection. However, there are a variety of steps you can take to minimise the risk of mosquito-borne diseases. But first, you need to be able to know when you have it.

Symptoms to look out for

As we briefly mentioned, the most common mosquito-borne diseases in Australia are the Barmah Forest virus and the Ross River virus.

In terms of signs to look out for, people infected with either virus will experience similar symptoms, including:

• Fever
• Chills
• Headache
• Tiredness/fatigue
• Joint pain (more common with Ross River)
• Swollen joints
• Muscle tenderness
• Rashes
• Swollen lymph glands or nodes

However, some people (particularly children) may show no symptoms at all.

Most people will make a full recovery in a few weeks, but some may experience symptoms such as joint pain, tiredness and muscle tenderness for six months or more.

More information on these viruses and more can be found via Health Direct.

Mosquitoes in the workplace

Like any risk in the workplace, it is the primary responsibility of the employer or Person Conducting a Business or Undertaking (PCBU) to do what they can to ensure the health and safety of workers while they’re at work. They also have a duty of care to any who visits the workplace e.g. customers.

These are the steps an employer or PCBU can take to minimise the risks of workers being infected:

• Avoid being outdoors if possible, especially in the evening when mosquitoes are most active.
• Remove potential breeding grounds for mosquitoes i.e. standing water
• Ensure workers avoid contact with bodily fluids and tissues of potentially infected animals, or, if this isn’t possible, ensure they have appropriate training and equipment to protect themselves
• Install insect screens on doors, vents windows and other entrances, as well as any accommodation provided (e.g. tents)
• Use insecticide sprays, vapour dispensing units (indoors) and mosquito coils (outdoors) to clear rooms or repel mosquitoes from an area
• Ensure workers wear light-coloured, long, loose fitting clothing when outside or in mosquito-prone areas.

While there are no vaccines for the Barmah Forest, Ross River, Dengue or other common viruses in Australia, workers can be vaccinated for JEV. In this case, employers can encourage workers to get vaccinated to protect themselves.

If you have any other questions about protecting yourself at work, call Australian Unions on 1300 486 466.

Additional resources

Here are a few helpful links for more information. 

• Japanese encephalitis virus warning, WorkSafe QLD
• Japanese encephalitis fact sheet, Safe Work Australia
• Dengue fever fact sheet, Health Direct Australia
• Mosquito-borne diseases fact sheets, Health Direct Australia

Cover photo credit: Wolfgang Hasselmann on Unsplash