Recent and potentially ongoing heavy rains across parts of Western Queensland could lead a surge in black fly and bush mosquito populations across the region, public health authorities have warned.
Central Queensland Public Health Unit Environmental Health Services Manager Angela Rea said black flies – more commonly known as sandflies in the Western Queensland region – were aggressive biters found in areas around streams and rivers.
“But heavy rains and flooding could also prompt a surge in bush mosquito populations across the region,’’ she said.
Ms Rea said while black flies (sandflies) did not transmit specific disease, allergic reactions and bacterial skin infections may occur from bites and scratching the bites.
Mosquito bites can result in a range of diseases, including Dengue virus, Ross River virus, Barmah Forest virus, Kunjin, Murray Valley Encephalitis virus and even Japanese Encephalitis Virus.
“The bites from both black flies (sandflies) and mosquitoes can itch and persist for several days and can become infected,’’ she said.
Ms Rea said black flies (sandflies) were active only during the day and did not bite at night.
Their peak activity period tends to occur from sunrise to mid-morning (10 am), and then late afternoon (4 pm) to sunset.
Bush mosquitoes, on the other hand are most active in the evenings, nights, and early mornings.
Ms Rea said the very best protection against mosquito-borne diseases and against black fly bites was to avoid being bitten in the first place.
Black fly (sandflies) and mosquito bites can be avoided by:
- Applying insect repellent,
- Using physical barriers, such as nets on prams and cots, to protect babies under three months old,
- If camping, sleep under a mosquito net,
- Avoiding outdoor activity when possible during the periods when black flies and mosquitoes are active,
- Keeping your shirt sleeves and front closely fastened (shirts with zippered fronts keep flies out better than buttoned shirts),
- Tucking trousers inside socks or high boots
- Ensuring insect screens on doors and windows are intact
- Using a knock-down insect spray in living areas.
Ms Rea said personal repellents containing DEET or picaridin tended to last longer than other repellents, depending on the concentration.
“Always use repellent in accordance with manufacturer’s instructions,’’ she said. To prevent skin infections from black fly (sandflies) or bush mosquito bites:
- Try to avoid scratching the bite.
- Apply calamine lotion or another anti-pruritic preparation to bite areas to prevent itching,
- Keep affected limbs elevated,
- Wash hands before and after touching open wounds,
- Watch skin sores for signs of infection.
If the bite areas become inflamed, clean with soap and water at least once a day, apply an antiseptic lotion and keep covered with a dry dressing.
Application of a cool compress (i.e. icepack wrapped in cloth) also can reduce inflammation. If skin sores become hot, red, swollen, or painful, see your doctor immediately.
Ms Rea said Central West residents also should take steps to eliminate mosquito breeding sites on their properties.
“Remove debris and vegetation from storm drains and ditches. Drain areas in and around yards and workplaces where water has temporarily accumulated,’’ she said.
“Empty all containers such as buckets, tyres, bird baths and plant pots and saucers weekly to reduce mosquito breeding.
“Mosquitoes also can breed in domestic water tanks, so checking the integrity of water tank screens and replacing damaged screens is a sound prevention measure.’’
She said anyone feeling unwell with high fever, headache, skin rash, neck stiffness, joint or muscle pain should see their doctor immediately.
- More information on black flies is available at: http://conditions.health.qld.gov.au/HealthCondition/condition/20/122/814/black-flies
- More information about mosquito-borne diseases is available at: http://www.qld.gov.au/health/conditions/all/prevention/mosquito-borne/index.html