City of Karratha

Mosquito control

The City of Karratha maintains a comprehensive mosquito monitoring and control program across its town sites. Increased mosquito activity after rainfall events including cyclones is common and inundation of tidal flats and mangroves is a contributing factor that increases mosquito breeding. The City's mosquito management program is in place due to the disease risk that mosquitos pose and detailed information about mosquito borne viruses is available on the Department of Health website.

What can I do to protect myself and stop mosquitoes breeding around my home?

  • Cover up by wearing light coloured long sleeve shirts and long pants that are loose fitting
  • Apply personal insect repellent containing DEET or Picaridin if possible
  • Reduce outdoor activities during periods when mosquitoes are more active (dawn and dusk)
  • Ensure fly screens to doors and windows are fitted and maintained
  • Some spatial repellents might also be useful (pyrethroid containing coils etc.)
  • Check your property for potential breeding sources
    - Empty pot plant bases weekly or fill the base with sand to absorb water
    - Plants that can hold water such as bromeliads should be washed out weekly
    - Ensure rainwater tank overflow pipes are screened and access covers are fitted securely
  • Keep swimming pools maintained
  • Ensure plumbing and vents to septic tanks are screened
  • Wash out birdbaths, ornamental pools and pet drinking bowls weekly

What does the City's Health Service do to manage mosquitos?

The City maintains a flock of sentinel chickens that are used to monitor Murray Valley Encephalitis and Kunjin prevalence in the area. The City receives notifications from the Department of Health on infectious diseases including mosquito borne viruses and patients are contacted to assist in the identification of mosquito breeding sites.

The City has a number of control options at its disposal. These will only control numbers of mosquitoes and not eliminate them. Eliminating harmful mosquitoes is not possible and eliminating mosquitoes entirely is not desirable as they have a role in plant pollination and as food for other animals. The controls include:

  • Cultural controls - Fight the Bite with its three key messages of cover up by wearing loose fitting, light coloured clothing, repel biting insects with insects repellents containing DEET or Picaridin and clean up sources of standing water around the home. This is the first line approach as mosquitoes are always present and more plentiful in the wet season
  • Chemical controls - These can target mosquito larvae and adults. For larvae the options include a growth inhibitor which dissolves in water and prevents larvae from maturing to adults; and a surface treatment which kills larvae attaching their breathing tube to the water surface preventing them from breathing. For adult treatments, surface sprays and fogging are the main approaches
  • Physical controls - These include modification of drainage systems or channelling in wetlands to improve drainage and alter water flow to interrupt the breeding cycle of mosquitoes

The City reviews prevailing weather conditions when choosing which control measure to adopt. Fogging as a treatment option will only occur during a disease outbreak and/or following a major climatic event where the risk to public health of the community as a whole outweighs the risk to the environment from application of the adulticide.

Mosquitoes vary with different species breeding in fresh, brackish or polluted water. Additionally, some species travel large distances (up to 50km) whereas other species do not move far from the neighbourhood in which they bred. Therefore identifying the mosquito species provides valuable information in the investigation of mosquito activity.

What does the City's Health Service do to manage biting midges?

Midges are smaller than mosquitoes and have a similar appearance. Their bites are commonly mistaken for mosquito bites. While the midge bite can be irritating and has the potential to become infected in susceptible individuals, midges are not known to spread disease and for this reason are not involved in the City's mosquito management program. Further information about biting midges is available on the Department of Health website.