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Dengue cases hit a 20-year high

January 17, 2017
Public Health and Wellbeing

6761864-3x2-340x227Dengue fever cases in Australia reached a 20-year high last year, driven by travellers being infected in tropical areas such as Bali and bringing the virus back with them.

More than 2000 cases of the mosquito-borne disease were confirmed in Australia last year, federal Health Department data shows.

University of Sydney mosquito expert Cameron Webb said dengue fever cases were increasing globally, and travellers were bringing the disease back to Australia. But, he said, if a person brought dengue fever back as an unwanted souvenir, they were unlikely to pass it on because most local mosquito species could not transmit the disease.

Microbiology professor Cameron Simmons, of the Peter Doherty Institute , said dengue fever was endemic (constantly being transmitted) throughout much of south-east Asia and the western Pacific , which were popular destinations for Australian travellers.

‘‘ Dengue has been a problem globally for 20 years, and in the last 10 years we have seen epidemic spread of the virus through many countries in our neighbourhood,’’ he said. ‘‘ The chance of travellers being infected may well be increasing.’’

But the increased number of cases in Australia could also be because more doctors were running tests that determined if returned travellers were infected with the disease.

The disease takes between three and 10 days to incubate, and causes flu-like symptoms that last for about a week. ‘‘ It can be a pretty miserable week of your life, and it sometimes takes a few weeks to fully recover,’’ Dr Simmons said.

An estimated 390 million people worldwide are infected with the dengue virus each year.

Dengue fever does not recur after the initial bout of the disease. However, if someone is infected a second time from another mosquito bite, the risk of potentially deadly complications such as internal bleeding or hemorrhaging from the nose and gums greatly increases, Dr Simmons said.

Dengue fever cases hit a 20-year high in Victoria and NSW last year, with the states recording 461 and 450 cases respectively. Younger people were over-represented in the figures for dengue infections last year. Those aged 25 to 34 accounted for about one in four of the 2129 cases, despite making up just 15 per cent of the Australian population.

There was a roughly even split of men and women contracting the disease .

Queensland has had by far the most dengue cases of any state over the past two decades, experiencing sudden rises in cases in 1993, 1998, 2003 and 2009 (when more than 1000 were confirmed ).

Dr Simmons said that was because far north Queensland was one of the few parts of Australia with mosquitoes capable of spreading the virus, and local outbreaks had occurred after infected travellers brought the disease back with them from overseas.

However, infection numbers in Queensland have been down in recent years, in part because of the Eliminate Dengue program, which effectively immunised the local mosquito population in tropical areas against the dengue virus.

The mosquito that spreads dengue, Aedes aegypti, is also capable of transmitting the Zika virus, which led to warnings of similar outbreaks in far north Queensland if an infected traveller brought the disease into the country.

There were 59 confirmed Zika cases in Australia last year, all of which were from travellers who were infected overseas.

Published by: AGE – Sunday, 15 Jan 2017 – Page 3