Dengue fever

Incidence

It is estimated that up to 50-100 million cases of dengue occur each year worldwide and Travelvax has information on current outbreaks around the world. The geographical distribution of the disease has greatly increased in recent years and importation has also resulted in transmission in northern Australia and islands to its north, including those in the Torres Strait. The risk to travellers is generally low (about 1 per 1,000 per month) unless an epidemic is in progress.

Symptoms

The disease is characterised by fever, headache, pain behind the eyes and severe aching of muscles and bones, giving it its other name 'Breakbone Fever'. A rash may appear 3-4 days after the onset of fever. In uncomplicated cases, symptoms resolve in 7-10 days but fatigue may linger for 2-4 weeks.

Dengue is diagnosed by a blood test. It is sometimes difficult to differentiate dengue from other febrile diseases such as malaria and typhoid, so tests may be needed to exclude these.

It is important to note that a severe form of dengue, known as dengue haemorrhagic fever (DHF), may also be a risk wherever the disease occurs. DHF is rare in tourists and is usually associated with second or subsequent infections.

Prevention

While a dengue fever vaccine has been developed, its use is restricted to residents of countries which are endemic for dengue. As such, for tourists, at present the only way to prevent infection is to avoid mosquito bites.

Aedes mosquitoes tend to live in urban areas, are often present indoors, bite during daylight hours and breed in small collections of water around households. Prevent bites by -

• Wearing protective clothing
• Applying insect repellent containing DEET, Picaridin or Citriodiol (PMD) to exposed skin
• Using aerosol insecticides indoors
• Sleeping under a mosquito net if not in well-screened accommodation
• Using permethrin to impregnate nets and clothing
• Eliminating any standing water around the dwelling