With well-publicised epidemics of dengue fever currently affecting far North Queensland, the NT Department of Health and Families (DHF) has reassured the public that there is no risk of dengue being acquired in the NT.
"Transmission of the dengue virus from mosquitoes to humans has not occurred in the NT since the late 1950s," explained DHF Acting Chief Health Officer Dr Steven Skov.
"This is largely due to meticulous surveillance and mosquito control programs being run by the Entomology Unit in the Department".
The dengue mosquito, Aedes aegypti, which is responsible for the Queensland outbreak, disappeared from the NT in the late 1950s and any subsequent incursions have been eradicated.
DHF's Entomology Unit has in place several surveillance systems to detect the mosquito should it return. Mosquito trapping is conducted weekly for the purpose of species identification.
In addition, egg detection traps, which reveal receptacle-breeding mosquitoes (that include the dengue mosquito) are checked every fortnight in major centres and port areas. Regular water- filled container surveys are also carried out in at-risk towns each year to ensure these towns are free of the dengue mosquito.
There have been two recent occasions when the dengue mosquito was detected in the NT - on Groote Eylandt in 2006 and in Tennant Creek in 2004.
"In both cases the mosquito was eradicated thanks to the extra hard work by the Entomology Unit," Dr Skov added.
"The only way dengue could be re-established in the NT is under very specific circumstances.
There are two main vectors of dengue fever: the dengue mosquito and the Asian Tiger mosquito (Aedes albopictus).
"Although neither exists in the Territory, both are potential threats as they could be introduced from either Queensland or from overseas. In Australia the dengue mosquito is confined to Queensland (see map attached). The Asian tiger mosquito is currently restricted to certain Torres Strait islands, but there is an imminent risk of it spreading to the mainland."
"In order for the virus to be transmitted in the NT, we would firstly have to see one of these mosquito species become established here. Then a person who already has the dengue virus in their system would have to be in the Territory and get bitten by that species of mosquito. That mosquito would have to survive for the 8-12 days it takes for the virus to replicate in its system. Only then could the virus be transmitted to another human."
The Australian Quarantine and Inspection Service (AQIS) also has surveillance programs which regularly detect these mosquitoes in water-holding containers on foreign vessels. The Service's vigilance is crucial in keeping the NT dengue-free. The public can also help maintain the NT dengue-free by eliminating all water-holding receptacles that would enable dengue mosquitoes to gain a foothold.
Dr Skov emphasised that the Territory does have the mosquito vectors of other diseases, such as Ross River virus disease and Murray Valley encephalitis.
"There's no doubt that covering up against mosquitoes is still important. Territorians should take precautions against mosquito bites by using insect repellant containing 20% DEET or Picaridin; wearing protective clothing; and avoiding areas near coastal swamps and mangrove areas - especially around dusk," Dr Skov said.
Media Contact: Cameron Jackson, DHF Media Liaison Officer 0401 116 144
Release date: 4 February 2009
