What is the issue
Of the 75 cases notified, a majority reported recent travel to Indonesia (particularly Bali) or Thailand. Three cases of chikungunya have been notified this year, two of which reported recent travel to Indonesia, and one case reported travel to India.
Both dengue and chikungunya are considered endemic in many countries in the Asia-pacific region, including popular travel destinations such as Indonesia and Thailand. Infection with these conditions therefore presents a real risk to Victorians travelling to these countries.
Chikungunya shares some clinical signs with dengue, and can therefore be misdiagnosed as such.
Who is at risk
Victorians travelling to Indonesia (particularly Bali) or Thailand.
Symptoms and transmission
Transmission for both conditions occurs through the bite of an infected mosquito, and cannot be transmitted from person to person. The incubation period for dengue is usually four to seven days (range three to 14). For chikungunya, the incubation period is usually between four and eight days (range two to 12).
Patients with dengue may present with symptoms of fever, headache, arthralgia, myalgia, rash, nausea, and vomiting. Typically a self-limiting illness, infection with dengue virus can occasionally develop into a potentially life-threatening complication called severe dengue (formerly Dengue Haemorrhagic Fever or Dengue Shock Syndrome).
Chikungunya presents similarly. The arthralgia caused by chikungunya is often very debilitating, usually lasting a few days to weeks.
The mosquitoes which transmit dengue and chikungunya are day-biting mosquitoes and therefore protective measures are focused on minimising opportunities for biting during the day. There is no vaccine against either infection, so prevention rests primarily on personal protective measures including:
- Avoidance of mosquito-prone areas
- Ensuring accommodation is mosquito-proof. Use mosquito nets, flying insect spray, mosquito coils or plug-in insecticide mats in rooms
- Using personal repellents containing diethyl toluamide (DEET) or picaridin
- Wearing long, loose-fitting, light-coloured protective clothing
Both dengue and chikungunya can be diagnosed early (within 5 days of illness onset) through PCR testing and later (5 days or more after illness onset) through IgM detection. Additionally NS1 antigen testing can be done from illness onset up to 9 days post-onset for dengue fever.
Under the Public Health and Wellbeing Regulations 2009, dengue is a Group B notifiable condition and is required to be notified to the Department of Health by medical practitioners within five days of initial diagnosis. Chikungunya is a Group A notifiable condition and requires immediate notification by telephone on 1300 651 160 or after hours on 1300 790 733. Written notifications can be made:
Communicable Disease Prevention and Control Unit on 1300 651 160 or email: email@example.com