Researchers puzzled by Ross River Fever spike
A REGULAR two or three-year spike in Ross River Fever cases has combined with recent weather conditions to cause an alarming increase in the illness in Ipswich.
As reported by the QT last week, Ipswich has seen a spike in Ross River Fever cases, with 60 Ipswich residents diagnosed with the debilitating illness in the past month.
Jonathan Darbro, a research officer with the QIMR Berghofer Medical Research Institute, said the exact reasons for the Ross River spike were not known.
"Ross River spikes every two or three years and there are a high number of cases, but we are not exactly sure why," he said.
"There are a number of theories. Some have to do with the animal hosts that the virus lives in year-round, and that every few years you have a bunch of new animals that are immunologically naive. They all get infected, and the mosquitoes bite them and get infected and then they start biting people.
"All of the rain produced a lot of breeding sites for flood water mosquitoes which are important in Ross River transmission."
Mr Darbro said mosquitoes didn't breed in running water.
"But the breeding sites that are most important if it rains, and the rivers goes over its banks, are in temporary pools," he said.
"Mosquitoes don't breed in big numbers in ponds or wetlands because there are fish and other insects that eat them.
"But when you have a big puddle that forms after rain temporarily, and mosquitoes get there first, it is great for then because they have no competition."
Mr Darbro said council mosquito control was good in Ipswich and that spraying with larvicide would eradicate the mast majority of mozzies.
Ipswich people need to take precautions to ensure homes are not breeding sites.
"You can avoid being out at dusk and dawn which are the main biting times, make sure the windows and doors are well screened and if you have to go out at mosquito time, use a repellent," Mr Darbro said.