Hi John,
Our very own wavelandscott holds a senior position in a division of a large multinational
chemical company which manufactures products to help combat the global health
problems caused by mosquitoes.
At the latitude of Sydney, they are currently little more than a nuisance but at latitudes
of Brisbane and further north in Australia, they can pose a serious health risk
and one should take steps to avoid being bitten.
As an adjunct to the advice on repellents, one of the best pieces of advice
is to walk around your property and ensure there are no sources of free-standing
water in which they are breeding. Typical sources in the garden can be buckets
left outdoors, empty flower pots, bird baths, ponds, uncovered water tanks, blocked
roof guttering and so on.
Without the water, they can't breed and something as simple as emptying an old
used paint tin that has been sitting outside and has filled with rain water acts as
what WHO refers to as a source reduction vector control.
Further advice is published by NSW Health here -
http://www.health.nsw.gov.au/factshe.../mosquito.html
For organizations such as the company that Scott works for, mosquito control
is literally a matter of life and death for millions of people.
See here for information about a mosquito net product that is helping save lives
in places such as sub-Saharan Africa -
http://www.olyset.net/