Dengue in Queensland on the decline at last - or is it?

Apr 13 2009

During the current Dengue epidemic in the tropical north of Queensland, health authorities found more than 50,000 potential mosquito breeding sites in Cairns alone.

Figures released this month revealed that in the four months after the Cairns outbreak was first declared, Queensland Health mosquito control teams inspected more than 14,000 properties in the Cairns region and the number of confirmed cases in the Far North soared to 860 in that time.

The outbreak surpassed the 725 Queensland cases recorded on the National Notifiable Disease Register in 2003 and the 654 cases in 1993 with cases confirmed in Cairns, Townsville, Port Douglas, Yarrabah, Injinoo and Innisfail - the latest outbreak occurring in Mareeba early in March.

Though the outbreak does now appear to be receding, with many suburbs being removed from the list of actively affected areas, health authorities continue to urge residents to remain vigilant as active transmission can re-emerge.

Cooler weather and less rainfall in the last month or so has given health authorities a chance to tighten their control of the epidemic but Queensland's Health Public Health Medical Officer Dr. Margaret Young says the battle against the spread of the disease is by no means over.

Dr. Young says though some suburbs have been removed from the list of locations where active transmission has occurred, that does not mean those suburbs will not re-emerge.

Dr. Young says the drier, cooler weather means the region is less conducive to the spread of the disease, but it is important that local residents ensure their yards do not become breeding grounds for mosquitoes over the Easter break.

Young says the return of the rain does increase the likelihood that opportunities for breeding will reappear in people's gardens and only a few days are needed for mosquitoes to breed in water.

Containers such as old tyres, pot plants, buckets and toys are among the main culprits cultivating dengue mosquito breeding grounds in the home, and must be removed or emptied out every two or three days.

Queensland Health says research into the outbreak has shown people who were around the home during the day have been more at risk of contracting the disease.

The type of water-holding items that have been most likely to be breeding dengue mosquitoes included: rimless tyres, buckets, tarps/plastic, bird baths, pot plant bases, boats, bromeliads and palm fronds.

Queensland Health Senior Medical Entomologist Brian Montgomery say by checking your yard once a week, and removing these items, you will significantly reduce the risk of catching dengue.

Mr Montgomery says while there is a definite slowdown in the rate of confirmed dengue cases, now is not the time for Cairns residents to be complacent.

The Cairns epidemic has been notorious for the speed of the outbreak - in 2003-04, it took 69 weeks to cause 536 cases, while it took just 14 weeks to cause the same figure during the current epidemic.