All three patients are residents of Cairns and became ill in mid February 2003. One of them also had a connection with Mareeba (approximately 40 km west of Cairns) during the infectious period (1). The primary case has not yet been identified, and there is a possibility that more people may be infected in Cairns or Mareeba. The Dengue Action Response Team (DART) is carrying out extensive mosquito surveillance and eradication in line with the protocols established in the Dengue Fever Management Plan for North Queensland 2000-2005 (2).

Dengue is not endemic in Queensland but the mosquito vector Aedes aegypti, is common in north Queensland. Sporadic outbreaks occur when the virus is introduced via international travellers or residents returning from endemic countries, most typically, Asia and the south Pacific. There have been three large outbreaks of dengue in north Queensland since 1992, all originating from imported cases; one in Townsville (1992-3), involving 900 cases, one in the Torres Strait and Cairns (1996-7), involving 208 cases, and the third in Cairns, Mossman, and Port Douglas (2000), involving 498 cases (2).

Prevention of dengue focuses around avoidance of mosquito bites. Advice to European travellers to Queensland would include the use of an appropriate insect repellent (containing Diethyltoluamide (DEET)) and to wear long sleeved shirts and long trousers to limit skin available for bites. Aedes aegypti mosquitoes bite during the day (particularly around dawn and dusk) and may be found both outdoors and indoors. Spraying rooms with a knockdown insecticide and using an electrical pyrethroid vaporiser will help to control mosquitoes indoors. Air conditioning also tends to make mosquitoes less active. Sleeping under an impregnated mosquito net will minimise mosquito bites from dawn onwards.

All travellers to Australia should take measures to prevent bites to protect themselves against other mosquito-borne diseases such as Ross River virus, Barmah Forest virus, Kunjin virus, and Murray Valley Encephalitis.