Mosquito plague has hit south eastern Australia partly due to floods

Melbourne University pest and environmental adaptation research group's professor Ary Hoffmann said mild weather and intermittent rainfall had created a perfect storm for fresh water 'mozzies' on the hunt for a bloody meal.

"The numbers are definitely up from what we'd normally see at this time of the year," he said.

"With consistent rainfall you have a situation where the breeding sites that mosquitos use are being continually topped up and effectively a female mosquito lays her eggs, then you have a rain event and it gets flooded, and the eggs hatch and then that starts the next cycle.

"That allows the larvae to develop quite quickly."

"Anything that breeds in fresh water, particularly small containers, is going to be doing wonderfully well at the moment," Dr Hoffmann said.

All mosquitoes require water to complete their lifecycle, with some species suited to breed in very small containers like old tyres, discarded plastic containers and tree holes. Other species preferred larger water bodies like water tanks or ponds.

Cleaning rubbish build ups and gutters and repairing fly screens is the best way to prevent mosquitos breeding in the home.

"Mosquitos will breed in areas where there's lots of rubbish around. Because those rubbish areas tend to fill up, that's where you have containers that fill with water," Dr Hoffman said.

"And it can be big or small, an old boat or a septic tank could fill up and become a breeding ground or it might be a pot plant base or an old bottle that's filled up sitting in the rubbish."

While mosquitos may seem bigger, they vary in size from very small to quite large, with more than 300 species in Australia.

"There's lots of native mosquitos in Australia that are part of the natural environment. Most mosquitos won't harm you, they're just a nuisance," Dr Hoffman said.

If you've ever wondered why you're a 'mozzie magnet' while no one else at the table is getting bitten, studies have recently confirmed that some people are naturally more attractive to mosquitos.

"It's partly genetics unfortunately. You cant do too much about it," Dr Hoffman said.

"You may have a combination of genes, you may sweat more, or you may give out a particular odour that is more attractive to mosquitos."

Highly targeted people have higher levels of carboxylic acids on their skin, he said.

"If you go to the gym and get sweaty, that makes you more attractive to 'mozzies'.

"Mosquitos will hone in on certain types of odours and CO2 that's coming off your body, so have a shower and put on clean clothes as soon as you can," Dr Hoffman said.

Experts recommend using mosquito repellant, wearing long shirts and pants, and being extra vigilant at dawn and dusk.

Some 'mozzies', like the common pest Aedes notoscriptus, will happily breed in very small amounts of water, so the drip trays under pot plants are a potential breeding site that should be cleaned.

This species can transmit viruses like Ross River Virus and is also the prime suspect for the transmission of the bacterium that causes Buruli ulcer.

Mosquito-spread Japanese Encephalitis Virus (JEV) has been in the spotlight this year since the illness was found in piggeries across Victoria, Queensland and NSW in February.

Last week a case of Japanese encephalitis was identified in a man from the Riverland region in South Australia where there is an ongoing flood emergency.

IN OTHER NEWS:

Climate change is triggering more variable conditions including more intense rain periods, suggesting that episodes when mosquitoes transmit disease and become problematic will increase in frequency.

In 2019 a modelling study looked at the impact of four climate change scenarios from an increase in average global temperatures under 2°Celsius to up to 5°Celsius on the transmission of mosquito borne viruses like dengue fever, Zika and yellow fever.

It argued that if the planet were to warm up to 5°Celsius almost one billion more people could be exposed to mosquito-borne diseases for the first time by 2080.