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Environment

Australia Is Facing an Intense Mosquito Season

Erratic weather patterns in Australia have caused a boom in mosquito populations, and that means a rise in bloodsucker-borne diseases.
February 8, 2015, 10:00pm

Image via Flickr user John Tann

Erratic weather patterns in Australia have caused a boom in mosquito populations, and it's a problem that extends past just being frustrating at barbecues. The increase has driven a rise in bloodsucker-borne diseases, some of which are pretty terrible.

New South Wales has already experienced a dramatic spike in Ross River disease, a virus spread by mosquitoes that causes skin rashes, prolonged joint swelling, fatigue, and muscle ache. Meanwhile, Brisbane recently took on its biggest mosquito reduction measure in 15 years, proof that officials are taking the threat seriously.

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Stephen Doggett is the manager at Sydney's Westmead Hospital mosquito monitoring program. He told VICE that normal numbers rose two-to-three times in NSW coastal areas at the beginning of the current mosquito season. "That's always worrying because when we get more mosquitoes, we get more diseases," Stephen said. "As of January 25 this year, there have been 85 notifications of Ross River virus in NSW—the equivalent period in the last two years was only 35 and 52."

Ross River, along with Barmah Forest (another virus that causes similar symptoms) are carried by mosquitoes most commonly found near wetlands, salt marshes, and mud flats – so if you're planning on trekking anywhere remotely picturesque this season, the experts' advice is to load up on the Aerogard. Suburban backyards aren't entirely safe either. Container-breeding mosquitoes, those that hang around open containers of water such as rainwater tanks, can also carry the Ross River and Barmah Forest virus.

A warmer than average spring in NSW last year is believed to be the main factor behind the rise. The mosquito monitoring program reported an earlier start to the mosquito season in 2014, finding sizeable populations in October, a month earlier than usual. While not all mosquitoes carry disease, the longer the season is, the higher the chance of mosquitoes picking them up.

Last week, Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) and Bureau of Meteorology released a report basically stating that Australia would be hardest hit by climate change by the end of the 21st century. Along with the usual predictions for devastating weather events and temperature rises, scientists believe prolonged mosquito seasons will make these kinds of viruses even more prevalent. However, climate change effects on mosquitoes are about as predictable as tropical cyclones. Stephen explains the overall conditions could be drier, which may have a reverse effect. "The drier conditions may reduce mosquito numbers in certain areas," he said. "But funny enough, the Saltmarsh mosquito prefers drier conditions so we may see an increase in those. All we can say is that we expect to see change."

In Queensland, Brisbane residents are experiencing an intense mosquito season. Since major storms and heavy rainfall in November last year, the city council has sprayed 4400 hectares of public land in an effort to reduce virus-carrying saltmarsh mosquitoes. Mike Muller, medical entomologist for Brisbane City Council told VICE that numbers are exceptionally high at the moment. "In early November we had the first really big tide of the season and that was enough to hatch dormant eggs in marshes that could have been there for months," he said. "They're the worst pests because they're so mobile. They can travel up to five kilometres."

There are around 6000 cases of Ross River and Barmah Forest across Australia per year. While neither virus is deadly, there are currently no treatments or cures for either. Patients usually recover within a few weeks but some cases can drag on for months. Fortunately, outbreaks of the deadly dengue and malaria are rare within Australia, with cases usually isolated to northernmost regions of the country. Enjoy the rest of your increasingly diseased summer, Australia.

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