An outbreak of a mosquito-borne virus has been declared in a fourth north Queensland region, health authorities say.
Townsville is on alert after it was confirmed on Thursday night that a West End resident had contracted the virus - the first case in the city this wet season.
Three other outbreaks have been declared in Cairns and nearby Port Douglas and Innisfail.
In total, about 93 people have come down with dengue fever in north Queensland since late last year.
About three-quarters of those infected live in the northern suburbs of Cairns.
Townsville public health physician Dr Steven Donohue said although the outbreak appeared to be localised, she urged residents to take precautions to stop it spreading further.
"Our messages today are that people need to clean up their yards and surface spray their homes to prevent dengue mosquitoes breeding," he said.
Mosquitoes that carry the virus, Aedes aegypti, are normally found in tropical climates and only live and breed in urban areas.
They generally hide in dark areas and bite during the day, mainly mornings and evenings.
Dr Donohue encouraged residents in all affected areas to check their properties for any vessels containing water as this is where the insects typically bred.
Dengue can cause a sudden fever with severe headaches, muscle and joint pains and can lead to vomiting and diarrhoea or a rash.
Health authorities are asking anyone who experiences these symptoms to contact their doctor so they can be tested for dengue.
Between December 2012 and July 2013, about 184 dengue cases were reported in the Cairns region.
