There are two mosquitoes of concern that can transmit dengue fever in Australia, the dengue mosquito and the Asian Tiger mosquito.
Dengue mosquito (Aedes aegypti )
Where is the dengue mosquito found in Australia?
How can I tell if it's a dengue mosquito?
Where does the dengue mosquito live and breed?
Where are the dengue mosquito breeding sites?
How do dengue mosquitoes transmit dengue?
Asian tiger mosquito (Aedes albopictus)
Where is the Asian tiger mosquito found in Australia?
How can I tell if it's a Asian tiger mosquito?
Where does the Asian tiger mosquito live and breed?
What is the lifecycle of the Asian tiger mosquito?
Where is the dengue mosquito found in Australia?
On the mainland of North Queensland, one mosquito transmits the dengue virus: Aedes aegytpi (dengue mosquito).
In Australia, this mosquito is currently only found in inland and coastal population centres of Queensland. There are no recent records to date of it being found in Queensland's southeast corner. There is a potential however for Aedes aegypti to re-establish in the Northern Territory, Western Australia, South-east Queensland and New South Wales.
How can I tell if it's a dengue mosquito?
The dengue mosquito looks like many other mosquitoes in north Queensland so it is difficult for the layperson to identify without the use of a microscope. As a rule of thumb, if you have mosquitoes biting you indoors during the day in north Queensland, it is likely that they are dengue mosquitoes.
The dengue mosquito (Aedes aegypti) can more readily be identified by its behaviour. Look for these signs:
- It likes to live indoors and bite people indoors
- It is hard to catch; it moves very quickly, darting back and forth
- It likes to hide under furniture and bite people around the feet and ankles
- Its bite is often relatively painless, so people may not notice they are being bitten or they may think they are being bitten by sandflies/biting midges.
The adult mosquito prefers to rest in dark areas inside and under houses and buildings. Favourite resting spots are under beds, tables and chairs; in wardrobes and closets; on piles of dirty laundry and shoes; inside open boxes; in dark and quiet rooms; and even on dark objects such as clothing or furniture.
The dengue mosquito prefers to bite humans during daylight. It is very cautious when biting, flying away quickly at the slightest disturbance. An effective way to kill the adult mosquito is to apply a residual insecticide (cockroach surface spray) onto the areas where they prefer to rest.
Where does the dengue mosquito live and breed?
The dengue mosquito is unusual in that it does not breed in swamps or drains, and does not often bite at night.
It is sometimes referred to as the ‘cockroach of mosquitoes’ because, unlike most mosquitoes that prefer swamps and bushland, the dengue mosquito is truly domesticated and prefers to live in and around people’s homes.
Where are the dengue mosquito breeding sites?
The dengue mosquito frequents backyards in search of containers holding water inside and outside the home, such as:
- cans
- buckets
- jars
- vases
- pot plant dishes
- birdbaths
- boats
- tyres – discarded with no rims
- roof gutters blocked by leaves
- striking containers (used to strike plants)
- tarpaulins and black plastic.
It can also breed in natural containers like:
- bromeliads
- fallen palm fronds.
In drier conditions it also breeds in water in subterranean sites such as:
- wells
- telecommunication pits
- sump pits
- gully traps.
The dengue mosquito does not fly very far, so if you get rid of mosquito breeding sites around your home, you will significantly reduce your risk of being bitten by dengue mosquitoes.
For more information view the Guide to the prevention of dengue mosquito breeding.
How do dengue mosquitoes transmit dengue?
Dengue mosquitoes are common in Queensland but often do not carry dengue. A female mosquito can only become infected with dengue after biting an infected human who is viraemic, ie. there are enough dengue virus particles in the person’s blood to infect a mosquito.
An infected person can transmit dengue to mosquitoes at home, at work or anywhere they visit. This can happen within 3-4 days of being bitten and can continue to do so up to 12 days. (Dengue is not spread directly from person to person.)
In 8-10 days the infected mosquito is able to transmit the virus to other people. Thus the cycle of transmission takes only 14 days. One dengue-infected female mosquito is capable of biting and infecting several people during one feeding session.
Where is the Asian tiger mosquito found in Australia?
In 2005, the Asian tiger mosquito was found in the Torres Strait islands on the northern tip of Australia. The Asian tiger mosquito is an introduced species that can transmit dengue. It is notorious for rapidly colonising new geographic areas, including colder climates. If this species becomes established on mainland Australia it would become a pest and dengue risk to a much larger part of Australia. The Australian Commonwealth Government and Queensland Health commenced an Aedes albopictus (Asian tiger mosquito) control program in 2005.
In the Torres Strait islands the dengue virus can transmitted by the dengue mosquito (Aedes aegypti ) as well as the Asian tiger mosquito.
How can I tell if it's an Asian tiger mosquito?
The Asian tiger mosquito (Aedes albopictus) is very similar to its cousin the dengue mosquito (Aedes aegypti ) but has a characteristic stripe down the middle of its back. Some characteristics associated with the Asian tiger mosquito include:
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It is a medium size mosquito (2-3mm), black in colour with white markings
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The mosquito appears to be wearing black and white striped socks on its legs
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It is active during the daytime and prefers to feed at dusk and dawn
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It is an aggressive biter
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It prefers to be outside in shady and sheltered bush environments
Where does the Asian tiger mosquito live and breed
The Asian tiger mosquito breeds in the same containers as the dengue mosquito. However, it differs from the dengue mosquito in its ability to breed in natural containers in the bush such as tree holes, cut bamboo, banana trees and coconut shells. Unlike its domestic relative the dengue mosquito, the Asian tiger mosquito likes to live in the bush. The female lays her eggs along the inside wall of the water-filled container at the waters edge. The eggs are designed to survive periods of being dry and will “activate” or hatch upon contact with water again. The mosquito does not like stagnant, dirty water nor does it like salt or brackish water.
For information view the Guide to the prevention of dengue mosquito breeding.
What is the lifecycle of the Asian tiger mosquito?
The mosquito egg hatches when in contact with water. After the egg hatches, small wrigglers can be seen in the water. The wrigglers require approximately 7-10 days before emerging as adults. The adult mosquito lives approximately 1-2 months. The survival and life cycle of the mosquito varies depending on food sources and climatic conditions. Typically, it is the older mosquito that transmits disease.
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