Transcript of Mosquito Information - Dr. Stephen Doggett.
Dr Stephen L. Doggett, Senior Hospital Scientist, Department of Medical Entomology, ICPMR, Westmead Hospital: Why are we seeing more mosquitoes this year? Simply because of the rain. With more rain we get obviously more water, with more water we get more mosquitoes, more mosquitoes, we get more disease.
There are three main diseases transmitted by mosquitoes in New South Wales. There's Ross River virus disease, Barmah forest virus disease and Murray Valley encephilitis, which is potentially the most important because it can be fatal.
It's fortunate most people who get bitten by a mosquito carrying the virus will not actually develop any disease. It's estimated about one in a hundred people who were bitten by an infected mosquito will do so.
To avoid these mosquito-borne diseases we need to avoid getting bitten by mosquitoes, simply that. And there are four main strategies.
First of all, try to avoid areas where mosquitoes are prone, such as bush land habitat, wetlands, swamps, particularly if there's native animals because it's combination of the native animals and the mosquito which increases the risk of mosquito-borne viral diseases. Secondly, if you need to go into these areas, try to avoid the peak mosquito biting time, which is typically dawn and dusk. So if you need to go into these areas, wear loose-fitting clothing, particularly long sleeves and long pants, rather than shorts.
There's various repellents on the market and the two most effective are those that contain deet (DEET) or picaridin. There's also a range of other chemicals on the market sold to repel mosquitoes and other biting insects.
These are sometimes called natural products including tea tree oil or citronella. These are just not very effective at repelling mosquitoes and preventing biting. Some of these may only last for one or two minutes.
So how often do you need to apply these products? Well, you need to follow label instructions. Generally with the lower percentage of active ingredients, which is the DEET or the picaridin, they need to be applied on a more regular basis. As a good guide, if you start feeling mosquito bites it's time to reapply.
Most people think there's only one or two species of mosquitoes but in Australia there are actually about 300 different species. We take Sydney alone and there are around 60 to 70 different species. Fortunately only about ten of these actually cause problems. Either they cause nuisance biting or transmit diseases to us or even our pets.
So what can we do about mosquitoes around the home? Well we can think about what can be done outside the home, what can be done to the home, and what can be done within the home.
Outside the home we need to reduce containers that can hold water because that's where mosquitoes can breed. This can be from blocked gutters, from blocked drains to plants such as bromeliads, which will provide great habitat for mosquitoes to breed in. We can actually apply residential insecticide to the air of the home and to the vegetation around the home, which can be done by a professional pest manager.
To the home, it's important to fit fly screens to the windows and doors to avoid mosquitoes coming in. But if that's not possible, and it's not always possible with the construction of Australian homes, then what can we do inside the home to reduce mosquito bites?
First of all, sleeping at night we can sleep under bed nets and we can impregnate them with insecticide called permethrin. We can use vaporizing insecticide mats. These are plug in units that plug into the mains, heat up and produce a stream of or vapor of insecticide that are very effective at killing mosquitoes. Sleeping under fans make it very difficult for mosquitoes to come in, fly, land on you and bite you.
So there are various things that can be done around the home to reduce mosquito bites.