Fight the Bite
Written by Peter McClelland
Friday, 31 March 2017
Print E-mail

Public awareness programs are vitally important in combating mosquito-borne diseases. There’s a strong focus on local government and GPs have an important role to play as well, says Environmental Health Hazards Managing Scientist (WA) Dr Michael Lindsay.

201704-Lindsay-Michael-Dr-Feb 17Dr Michael Lindsay“An education program such as Fight the Bite is just one of a number of initiatives in mosquito management in WA. We’ve got a long-standing research history that goes right back to the 1950s and the development of the Ord River Scheme.”

“The latter was a major water-management undertaking and it was crucially important to assess its impact on a public health level.”

“We’re well aware that certain environments and environmental conditions are more likely to be associated with outbreaks of mosquito-borne disease and effective management programs will need to focus on everything from risk management and improved surveillance to monitoring the environment, as well as raising community awareness through programs like Fight the Bite.”

Blood tests for diagnosis

“It’s important for GPs to know that mosquito-borne infections in WA may present with similar symptoms to other communicable diseases. Therefore, it’s imperative to do confirmatory blood testing with specific serological or molecular assays in accredited laboratories. Definitive diagnosis generally requires testing of two (acute and convalescent) blood samples, although a presumptive diagnosis is possible based on one blood sample.”

 “GPs should also ask for a detailed travel history with specific dates and locations for up to a month prior to the onset of symptoms, but particularly from 3 days to 3 weeks prior to onset which is the average incubation period post-exposure to an infected mosquito.”

“The other critical aspect is that GPs notify the Department of Health of all confirmed cases because this information is really important in informing a broader public health response.”

There is a strong regional emphasis on both the nature and the incidence of these outbreaks, says Michael.

“It’s very much a ‘local’ approach, at times. For example, an emphasis on Murray Valley encephalitis during and just after the wet season in the Kimberley and a spring/summer targeted focus on Ross River virus in the South-West.”

“The Department of Health and Local Governments endeavour to provide clear and consistent messages at certain times of the year – and, indeed, sometimes in a particular year – when the risk of mosquito-borne pathogens is elevated.”

Local government needs help

“There are 139 Local Governments across the State and it is incumbent upon the Department of Health to support and build the capacity of their environmental health teams to manage mosquito-borne viruses to protect local communities.”

“The majority of bites are just a nuisance, but we would regard any mosquito-borne illness as a mosquito encounter that’s gone wrong.”

The world of microbiology and zoology is not without its humorous moments. If you’re ever invited to an entomologists’ knees-up make sure you lock it in your diary.

“It’s only the female mosquito that bites. They do that to obtain the protein in our blood, which enables them to lay a substantial quantity of eggs.”

“There’s a species in the Kimberley that breeds in the rot holes of the Boab tree. Females of this species are so focussed on the exhaled plume of carbon dioxide as you breathe, to lead them to a potential bloodmeal, that the only place you usually get bitten by them is on the tip of your nose. A well-known entomologist’s party-trick is to squash one of these mosquitoes as it lands on your nose and to announce, look…….it’s a Tripteroides punctolateralis!”

And that annoying buzz when the lights go out?

“Once a mosquito gets within a few feet of its intended victim a range of chemical cues come into play. Some people get bitten more than others and some individuals find themselves in the unenviable position of being more attractive to a particular species.”

“There are some mosquitoes that have adapted well to being indoors and finding a resting place when the light remains on. There’s actually one that used to be called Culex fatigans (now Culex quinquefaciatus), presumably due to the induced fatigue as it keeps you awake at night.”

Tips for your Patients

Fight the Bite: cover-up, repel, clean-up (Fight the bite website):

  • Wear long, loose-fitting, light coloured clothing, covering as much of the body as you can. Mosquitoes can bite through tight clothes like jeans. Make sure children are also appropriately covered up.
  • Use insect repellent containing DEET (diethyltoluamide) or picaridin and always follow instructions on the label.
  • Stop mosquitoes breeding in water pooling around your home or holiday accommodation by emptying water from containers.
  • Avoid exposure around dawn and dusk when many mosquito species are most active.
  • Ensure infants are protected using suitable clothing, bed nets and screens.
  • Ensure insect screening on houses and camping equipment is in good condition.