Queensland Health is investigating two cases of locally acquired malaria as the state's total number of infections this year rises to 71.
In its latest notifiable conditions report, Queensland Health said a second locally acquired malaria case was recently identified in the Torres Strait Islands local government area.
Malaria is a life-threatening disease spread to humans by some types of mosquitoes and is mostly found in tropical countries.
Queensland Health said 97 per cent of the cases recorded to date this year had come from overseas, predominantly Papua New Guinea and the Solomon Islands.
The disease, which is preventable and curable, does not spread from person to person but rather through the bites of some infected female Anopheles mosquitoes.
Mater Health infectious diseases director Paul Griffin said mosquitoes that carry malaria are found in Australia, which can result in an imported case being a source of transmission to other people.
"We don't have mosquitoes capable of passing malaria on all throughout the country, but certainly in the more tropical parts of our country, the Northern Territory and northern parts of Queensland," he said.
"That's why in those areas we need to give people that advice to make sure we reduce the chance of local transmission."
Professor Griffin said while locally acquired cases were extremely rare, Queensland's public health system is equipped to deal with them.
"With more significant types of malaria, the severe consequences can be involvement of the brain, so cerebral malaria and even death," he said.
"It is something that we do need to take seriously and make sure we take steps to limit how much it is able to be passed on in our country."
The annual mean number of cases recorded in Queensland in the same period from 2020 to 2024 was 33, compared to 71 to date this year.
The Queensland Health websites states limited transmission occasionally happens in the Torres Strait Islands, following importation from PNG.
It states that in the past, locally acquired malaria has occurred on the outer islands of the Torres Strait including Saibai, Boigu, Erub and Badu Islands.
The last cases acquired on mainland Australia were during an outbreak in north Queensland in 2002, according to Queensland Health.
"Malaria used to be something that we had transmitted within Australia, but due to a host of different interventions locally acquired malaria has not been something that we have really dealt with for some 40 odd years," Professor Griffin said.
According to the World Health Organization, the most common early symptoms of malaria are fever, headache and chills, which typically start within 10 to 15 days of getting bitten by an infected mosquito.
