20 October 2010
Biting midges are set to reach their yearly peak over the next eight days, coinciding with October's full moon, according to DHF Director of Medical Entomology, Peter Whelan.
"Peak biting midge activity will occur in the period four days before and four days after the next full moon on 23 October, when they emerge from their mangrove mud breeding areas," he said.
"Biting midge activity is reliant on neap tides, which are linked to the later full moons. Female biting midges emerge around the neap tide but don't disperse out of the mangroves until around the full moon, after they have laid their first batch of eggs in their breeding places.
"Female mangrove midges need a blood meal for their second batch of eggs to mature."
In the Top End, the greatest numbers of midges are experienced during the late dry season and build up from August to November.
"Predicted La Nina weather conditions of heavy rainfall earlier than normal this year is expected to result in the peak of midge activity occurring in October, with the expected earlier heavy rains in November to December disrupting their main breeding areas on the banks of small mangrove creeks," Mr Whelan said.
DHF is reminding Top Enders to take precautions to protect themselves against being bitten.
The saliva midges inject into their human hosts contains chemicals that cause pain and swelling, particularly for newcomers to the NT.
"The bite area can be extremely itchy. People should avoid scratching bites because it can break the skin, introducing bacterial infections which can lead to unsightly sores."
Soothing lotions may provide relief. Ice packs can be applied to the site of stronger bite reactions, but a severe reaction may require medical attention.
"The best approach is to avoid areas where midges breed, especially during the hour on either side of sunrise and sunset. Midges are most prevalent in wide areas of mangrove that contain many small mangrove creek lines," Mr Whelan said.
"If you experience bites or are in a risk area, cover up with long-sleeved shirts, long trousers, socks and shoes and apply DEET or picaridin-based repellents. Insecticide coils, lanterns and barrier applications are also helpful."
Biting midges, or Culicoides ornatus, are expected throughout the NT coast within 1.5 km of extensive areas of coastal mangroves.
Mangrove creek areas and areas in Darwin and Palmerston that will see increased midge activity include:
Moderate:
· Ludmilla Creek | · Rapid Creek |
Moderate to High:
· Rapid Creek | · Durack |
· Alawa | · Driver |
· Stuart Park | · Moulden |
· Winnellie | · Archer |
· Coonawarra | · Bellamack |
High to Very High:
· Palmerston rural residential areas within 1 km of harbour-fronting mangroves.
Very High:
· Sadgroves Creek | · Reichardt Creek |
· Hudson Creek | · Lee Point |
· Mouth of Buffalo Creek | · Elizabeth River near Palmerston |
A 2010 calendar detailing expected biting midge periods is available at:
Media contact: Bridget Wild 89 992 751 or 0401 116 144
