There are almost 100 species of mosquitoes in Western Australia. Many of these are serious pests and/or transmit disease-causing viruses or parasites. Mosquito management is only necessary if people and mosquitoes come into contact, either in residential or recreational areas that are within dispersal range of mosquito breeding habitats. The overall aim of mosquito management is to reduce the pest or vector (disease carrying) mosquitoes to a level where the impact on the adjacent human population is kept to an acceptable low level.
Mosquitoes lay and develop in standing water, in both natural and/or man-made water bodies such as: lakes, pools, swamps, ground pools, irrigation ditches, tree holes and leaf axils (crevice formed between stem of plant and leaf). In urban environments, especially in backyards, mosquitos breed in range of water-holding containers such as: pot plant drip trays, septic and water tanks, roof gutters, ponds, disused containers, poorly maintained swimming pools, dog water bowls and disused car tyres.
The removal or maintenance of these sites can permanently reduce mosquito numbers in backyard situations.
Mosquitoes can act as vectors (transmitters) of diseases because the adult female will seek out repeated blood meals to mature successive egg batches throughout her life. Female mosquitoes can pick up viruses and pathogens from one vertebrate animal (host) and pass them on to another host in subsequent blood feeds. These pathogens and viruses can replicate (multiply) in both host (including humans) and mosquitoes. Humans can only be infected from the bite of an infective female mosquito and cannot become infected by direct contact with another human or animal.
In WA, the mosquito-borne diseases of most public health concern are:
- Ross River virus (RRV) disease
- Barmah Forest virus (BFV) disease
- Murray Valley encephalitis (MVE)
- Kunjin disease (KUN).
In nature, RRV, BFV, MVE and KUN diseases are passed back and forth between wildlife and some species (types) of mosquitoes. Humans can only catch these diseases through the bite of an infected mosquito.
Other common diseases spread by mosquitoes are:
- Japanese encephalitis
- yellow fever.
Local transmission of dengue, malaria, chikungunya, Japanese encephalitis and yellow fever do not currently occur in WA. This is because the mosquitoes that transmit these diseases are not currently present in WA. However, these diseases may be contracted while travelling overseas. See Fight the Bite prevention campaign for more information about mosquito control while travelling.
You can manage mosquito populations in your home by the following measures:
- Physical control – such as source reduction by filling, draining or removing breeding sites.
- Biological control – such as the introduction of aquatic predators in ponds (eg fish) to reduce mosquito larvae.
- Chemical control – such as the application of insecticides (adulticides or larvicides).
- Cultural control – such as planning outdoor activities to avoid mosquito activity times and building screened outdoor living areas.
The Department of Health is responsible for monitoring insect-borne diseases and coordinating the management of insects of public health significance across WA. A key component of this statewide program is to provide support for local government mosquito management programs through the Contiguous Local Authorities Group (CLAG) funding scheme. The CLAG scheme is a mechanism to assist local governments with management, funding and advice on the technical aspects of health-driven mosquito control, in an effort to reduce the risk of mosquito-borne diseases throughout WA.
The scheme currently provides funding to local governments and covers:
- Fifty percent of their overall cost of mosquito larvicides.
- Fifty percent of costs associated with adulticides (in northern WA where treating large water bodies during and after the wet season is impossible).
- Funding towards minor earthworks to eradicate mosquito breeding sites.
- Funding towards community awareness campaigns.
- One hundred percent of helicopter aerial treatments in high-risk Ross River virus areas of the south-west of the state.
CLAG members also benefit as the Department of Health requires that members:
- have regular meetings
- work together to share knowledge, experience and logistics
- review current human disease statistics
- discuss mosquito management approaches for each region – allowing statewide integration of mosquito management approaches and the diseases they spread.
The Department of Health, in collaboration with local governments, conducts mosquito control programs in areas where mosquitoes are suspected of carrying disease. However, despite these programs, Ross River virus and Barmah Forest virus will always be a threat because they occur in natural cycles between mosquitoes and animals, and it is simply not possible to eliminate all mosquitoes. Therefore it is important for people to take personal measures to reduce the risk of contracting disease and to reduce the breeding of nuisance mosquitoes.
Talk with your neighbour/the owner of the property that is the source of the problem and request that they resolve the issue.
To report a mosquito issue, please call Customer Service on (08) 9311 8111 or email firstname.lastname@example.org with your contact details and address of the property of concern. Your request will be allocated to an Environmental Health Officer for follow-up.