Mosquito-borne illnesses

Please note that the following guidance has been developed by the Chief Medical Officer, Monash University.

A summary guide is provided here which may be printed and distributed to your travellers.

About mosquito-borne illnesses

Mosquito-borne illnesses are spread to people via mosquito bites. A mosquito bites an infected person or animal and transmits the virus to another person through a subsequent bite. Mosquito borne viruses include:

  • malaria;
  • dengue;
  • West Nile virus;
  • chikungunya;
  • yellow fever;
  • Japanese encephalitis;
  • Zika;
  • Ross river fever;
  • Murray Valley encephalitis; and
  • Barmah Forest virus.

Although there are mosquito borne illnesses in Australia, the risk of getting a disease from a mosquito bite is highest in tropical and subtropical areas in Africa, Asia, Pacific Islands and the Americas. The CDC classifies areas of risk of dengue and destination specific outbreak information is available via DFAT Smartraveller.

Preventing mosquito bites

The best way to prevent mosquito-borne illnesses is to protect yourself against mosquito bites. Follow these tips:

  • Ensure all areas of your skin are covered with insect repellent containing DEET (see Environmental Protection Agency (EPA) - for advice about selecting repellents);
  • Wear loose fitting long-sleeved shirts and pants (and cover your feet);
  • Spray your clothing and gear with permethrin spray (available for purchase at most chemists);
  • Protect your environment from mosquitoes indoors and outdoors by:
    • Using the fly screens on windows and doors;
    • Sleeping in accommodation with air conditioning and sealed windows and doors;
    • Sleeping under Permethrin-treated mosquito nets (for open accommodation)
    • Empty water-holding containers to prevent mosquitos from laying eggs in or near the water.

The World Mosquito Program (based at Monash University) undertakes critical work to protect the world from mosquito-borne illnesses. Check-out the Wolbachia method and how they have reduced the spread of dengue and other viruses across the globe.

Before you travel

As early as possible before you travel, you should make an appointment with University Health Services, your local GP or a travel clinic to receive the appropriate travel health advice, and any required immunisations or medicines. This is important to maximize your wellbeing and preventing infection while you are travelling. What you will need will depend on your individual needs and specific health circumstances, as well as where you are going, how long you are going for and the activities you will be undertaking. Recommended topics to discuss with your doctor are:

  • What vaccinations are recommended or required for your destination;
  • Whether malaria prevention medications are recommended;
  • The best ways to reduce your risk of water or food-borne infections;
  • How to best protect yourself from vector (e.g. mosquito, tick, fleas, lice, flies, snails) infections;
  • Any concerns relating to sexual health and sexually transmitted infections.

About dengue

According to the World Health Organisation, dengue fever is one of the top ten global health threats. It is also rapidly spreading, with a 30-fold increase in global incidence over the past 50 years. Dengue can occur anywhere the mosquito that spreads it is found (Aedes aegypti mosquitoes), with over 140 countries affected. The most significant dengue epidemics have occurred in Southeast Asia, the Americas and the Western Pacific. Viruses like dengue are most common in densely populated urban areas, where mosquitoes prefer to breed in containers and discarded items. There is no vaccine available in Australia for dengue fever.

Symptoms and treatment of dengue

Many people who get dengue will not have any, or only present mild symptoms. For those who do present symptoms, they usually occur 4-10 days after infection and last 2-7 days. The most common symptoms are:

  • headache
  • high fever
  • rash
  • sore muscles and joints (Dengue is also called “break-bone” fever)
  • nausea, vomiting

There is no specific medical treatment for dengue. After recovery, people may feel tired for several weeks. Some people develop severe dengue. Individuals who are infected for the second (or more) time are at greater risk of severe dengue. In severe cases, dengue can be fatal.

Severe dengue symptoms often come after the fever has gone away and include:

  • bleeding gums or nose
  • blood in vomit or stool
  • severe abdominal pain
  • persistent vomiting
  • rapid breathing
  • pale and cold skin
  • being very thirsty
  • feeling very weak and tired.

Monitoring for warning signs of severe disease and getting urgent medical care in these cases is important.

If you suspect you have dengue, please do the following:

  • take paracetamol;
  • drink fluids;
  • seek medical attention if your symptoms are severe;
  • contact Global24 (+61 2) 9312 5191 or assistance@global24.com.au for advice about hospitals or to escalate to Monash;
  • take extra care to avoid being bitten by mosquitos, as that is how dengue spreads to others.

Last reviewed: June 2025