The warning applies to people visiting or living in bush areas or near rivers in and around Sydney, as well as regional and rural areas.
Mosquito borne infections become more prevalent as we move into autumn and recent rain and flooding have led to increased mosquito breeding. Mosquito surveillance has found evidence in recent weeks of mosquitoes carrying Barmah Forest and Ross River viruses the Georges River suburbs of Alfords Point, Illawong, Lugarno and Bankstown in southern Sydney. Sentinel chicken surveillance has detected Kunjin virus in a few chickens near Griffith and Forbes.
People need to take steps to avoid mosquito bites - protect yourself with clothing and repellent; protect your home with screens and remove collections of water around the house where mosquitoes can breed.
NSW Director of Communicable Diseases, Dr Vicky Sheppeard, said the next few weeks will be ideal breeding conditions for mosquitoes which carry a range of human diseases like Ross River virus, Barmah Forest virus, Kunjin virus, and Murray Valley Encephalitis virus.
“These infections can cause symptoms including tiredness, rash, fever, and sore and swollen joints. The symptoms usually resolve after several days but some people may experience these symptoms for weeks or even months,” Dr Sheppeard said. “Infection with Kunjin or Murray Valley Encephalitis can also cause more severe effects such as encephalitis.”
“While the number of reported human cases of mosquito borne infections have not been very high so far this year, with 47 cases of Ross River virus and 28 cases of Barmah Forest virus notified in January and February 2014, case numbers usually rise in the autumn months,” Dr Sheppeard said.
Avoiding mosquito bites will be especially important now and until at least after Easter when many people may be enjoying outdoor activities such as camping or fishing in areas with high mosquito numbers.
Mosquitoes that carry these viruses are usually most active in the hours after sunset and around dawn but can bite throughout the day. Simple steps to avoid being bitten by mosquitoes include:
- Use an effective repellent on exposed skin areas. Re-apply repellent every few hours, according to the instructions, as protection wears off from perspiration, particularly on hot nights or during exercise.
- The best mosquito repellents contain diethyl toluamide (DEET) or picaridin. Botanical based products (e.g. eucalyptus, citronella etc) provide only limited periods of protection.
- Topical repellents are not recommended for use on children below the age of 3 months.
- Note that prolonged or excessive use of repellents can be dangerous, particularly on babies and young children. Avoid putting repellent near eyes and mouth, spread sparingly over the skin, and rinse off once you are indoors.
- Provide mosquito netting, where necessary,both indoors and outdoors.
- Cover up as much as possible with loose fitting clothing and sensible footwear. Avoid tight clothes.
- Cover your clothes with repellent as mosquitoes can bite through material but be careful as some repellents stain clothes.
- Use mosquito coils outdoors and vapourising mats indoors. Notethat devices that use light to attract and electrocute insects have not been proven to be effective in reducing mosquito numbers.
- When camping, use flyscreens on caravans and tents or sleep under mosquito nets.
Some types of mosquitoes like to breed around homes, even those in cities and towns, so people should also take steps to remove potential mosquito breeding sites around the home. This includes any container that holds water such as buckets, tyres, tarpaulins and black plastic, pot plant bases, aluminium cans and plastic containers.