Mosquito activity to increase following heavy rain

Department of Health

Residents along the northern NT coast are reminded to protect themselves from mosquito bites, with salt marsh mosquito numbers expected to drastically increase from 16 October following heavy rainfall.

The Top End Health Service Director of Medical Entomology, Nina Kurucz, advised that heavy rainfall and high tides will trigger extensive mosquito breeding in coastal areas until the monsoonal rain floods their breeding sites.

The Medical Entomology team has conducted ground mosquito control around Darwin and Palmerston, with large areas of mosquito breeding sites being aerially treated in the Shoal Bay swamp system on 10 October 2020.

“Despite the control efforts, there will be an influx of mosquitoes from outside the control area, as these mosquitoes are capable of dispersing up to 50km,”Ms Kurucz said.

“We expect mosquito numbers to remain high for at least two weeks due to the high humidity, with further mosquito hatches triggered by additional rain or the next high tides in mid-October.”

Salt marsh mosquitoes can transmit the Ross River virus. While the high risk period for the virus is from December to March, the disease can be contracted all year round.

To minimise the chance of being bitten by mosquitoes people should:

  • Wear protective light-coloured clothing with long sleeves, long trousers, and ankle protection with socks, in areas where mosquito bites are likely.
  • Avoid outdoor exposure near wetlands and areas of dense vegetation as well as other areas of high mosquito activity.
  • Use a protective repellent containing 20% DEET, picaridin or PMD (extract of lemon eucalyptus) and other mosquito protection devices as a supplement to protective clothing when outdoors in areas of mosquito activity.
  • Ensure infants and children are adequately protected against mosquito bites.
  • Tip out water filled containers in backyards, including buckets, plant drip trays and tyres.
  • Consider bifenthrin insecticide barrier treatments by licensed pest control companies for use around residential grounds.
  • Ensure windows and doors have screens to prevent mosquitoes from entering houses.

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