Mosquito expert Dr Cameron Webb

Setting a trap to keep track ... Dr Cameron Webb caught 10,000 mosquitoes in a small net one night. Photo: Ben Rushton

ASK NSW's mosquito expert Dr Cameron Webb if he has a favourite species, and he quips, ''Doesn't everyone?''

His is the Hexham Grey, the ''Jaws of the mosquito world.''

''I like it because as well as being beautiful, the Hexham Grey in its mature stages eats the larvae of other mosquito species.''

Many of us will spend the summer season trying to avoid mosquitoes, particularly the brown house mosquito whose infuriating buzz has kept generations of holidaymakers awake.

But Dr Webb, a clinical lecturer in medical entomology at Westmead Hospital and Sydney University, will be spending his time trapping and examining his catch to identify the species and the diseases they carry.

One night he caught 10,000 mosquitoes in the small mesh net (about the size of a kilo bag of sugar) he uses. There were so many he could hear them buzzing from a long way off.

The dry weather this year means the catch will be smaller, and the risk of mosquito-borne illnesses in metropolitan areas will be less, he said.

But the king tides in coastal regions and wetlands may see mosquito numbers boom just as people hit the coast for their beach holidays. The NSW Health Director of Health Protection, Dr Jeremy McAnulty, warned on Thursday that people should take steps to avoid exposure to mosquitoes, particularly those planning to holiday in bush, coastal and country areas.

"Mosquito activity increases in the warmer months and increases the danger of diseases such as Barmah Forest virus and Ross River virus which occurs particularly in rural, coastal and bush areas," Dr McAnulty said.

These viruses cause unpleasant symptoms including rash, fever, sore and swollen joints, which usually only last a few days.

"There is no specific treatment for these viruses. The best way to avoid infection is to avoid being bitten."

Dr Webb is also impatient with endless discussions about who gets bitten and why, although he concedes people do have different responses. ''Somebody with fewer bites may have a worse reaction than someone who was bitten more,'' he said. ''I often find it frustrating - as someone who wants to reduce the incidence of mosquito-borne disease - that people are more interested in why mosquitoes bite them and their friends, instead of going out and just using a repellent which we know will prevent bites.''

He said people often wanted to pursue natural alternatives to Diethyl Toluamide (DEET) or Picaridin, but these offered limited protection.

''So if you really want to prevent mosquito bites, particularly in areas with endemic disease risks, I recommend they avoid that [the natural alternatives] and they go for DEET or Picaridin which have been proven to be effective for a long period of time.''

Dr Webb said DEET had never been shown to be dangerous to humans, except in rare cases where it had been abused or ingested.

Although health authorities recommend DEET's use for children older than three months, he said if parents were worried about using repellent they should protect the child's cot or bed with mosquito netting.