Dengue, Malaria: Qld set for pre-pandemic levels of mozzie-borne diseases

Queensland is bracing for a return to pre-pandemic levels of diseases as travellers bring in potentially deadly infections from overseas.

Queensland is bracing for a return to pre-pandemic levels of mosquito-borne disease as travellers bring in potentially deadly dengue and malaria from overseas.

Since the beginning of the year, 30 cases of dengue and 17 of malaria have been reported – a massive spike on the last two years when there were no cases of dengue and only six of malaria during the same period.

The sharp increase in dengue, reported by Queensland Health for January 1 to March 19, suggests the annual total will far exceed the 58 cases in 2022 and the one case in 2021.

Malaria figures are also likely to surpass the 58 and 16 cases in 2022 and 2021 respectively.

Incidences of both diseases were highest in Brisbane’s south, with 10 dengue and four malaria.

Queensland has experienced 30 cases of dengue and 17 of malaria since the start of the year.

Scott Lyons, senior medical entomologist with Townsville Public Health Unit, said international students, workers, backpackers and Queenslanders returning from disease-hot spots – countries closest to the equator including Singapore, Indonesia, Thailand, Cambodia, Philippines, Kenya, Brazil, Colombia – were responsible for the surge in cases.

Mr Lyons said the World Mosquito Program at Monash University had all-but stopped the local spread of dengue by infecting the aedes aegypti mosquito – the primary type that hosts the disease – with a bacteria that stops the virus replicating in the insect.

“More than 90 per cent of these mosquitoes, which are found from Charters Towers up to Port Douglas, now have the wolbachia bacteria, so if they bite someone with dengue then bite another person, they won’t pass it on,” he said.

Mr Lyons said there had been no local transmission of malaria for decades.

A Queensland Health spokesperson said while some mosquito-borne diseases could be locally acquired – the most common being Ross River and Barmah Forest viruses – all 30 dengue and 17 malaria cases this year were acquired overseas.

“Dengue is mostly imported by overseas travellers, mainly from Indonesia,” the spokesperson said.

“Given the closure of international borders during the pandemic, there was a marked decline in some mosquito borne diseases, particularly malaria.

“It is expected that cases of typically imported mosquito borne diseases such as malaria and dengue will return to pre-pandemic levels.

“Prior to the pandemic in 2019, there were 112 cases of malaria recorded in Queensland, and 313 cases of dengue notified that year.”