What are dengue, Zika, and chikungunya?
Dengue, Zika, and chikungunya are all diseases caused from being bitten by infected Aedes mosquitoes, which are present in many tropical countries, Asia, and the Pacific.
Dengue fever emerged as a worldwide problem in the 1950s, and is becoming more and more widespread. With more than one-third of the world's population now living in areas at risk of infection, dengue virus is a leading cause of illness in the tropics and subtropics. Up to 400 million people are infected worldwide every year.
Zika and chikungunya spread to Asia and the Pacific in 2013.
How do you catch dengue, Zika, and chikungunya?
You catch these illnesses by being bitten by mosquitoes that live in many popular tourist destinations, such as Southeast Asia and the Pacific Islands. You cannot catch dengue, zika, or chikungunya in New Zealand, and if you have returned to New Zealand with one of these illnesses, you cannot infect other household members.
What are the symptoms of dengue, Zika, and chikungunya?
Dengue fever usually begins with a sudden onset of a high fever and a severe headache. Those affected may also get a skin rash and muscle and joint pain. Nausea, vomiting, and loss of appetite are common. The illness usually lasts up to 10 days, but recovery may take some time, and people can feel tired and depressed for weeks.
Zika and chikungunya cause similar illnesses to dengue, but tend to be milder. However, they can still cause an unpleasant illness with painful joints and skin rashes and zika has recently been linked with severe abnormalities in unborn babies.
Image taken from UpToDate (2016)
How are dengue, Zika, and chikungunya diagnosed?
All are diagnosed by a combination of typical symptoms, and blood tests.
How are dengue, zika, and chikungunya treated?
There is no specific treatment for dengue, zika, and chikungunya, but it is important to take paracetamol rather than aspirin for the fever, headache and muscle pains with dengue, as aspirin can increase the risk of bleeding. People should also rest and drink plenty of fluids. Those who become more unwell may need hospital treatment with fluids into their veins and close monitoring, to make sure they don’t start to bleed or lose too much fluid from their bloodstream.
How can dengue, zika, and chikungunya be prevented?
There is no vaccine to protect against dengue, Zika, and chikungunya, and no drugs you can take to prevent them (like you can with malaria). The most effective way to protect against it is to avoid mosquito bites. Please note that these mosquitoes bite during all hours of the day, not just in the evenings:
- Apply insect repellent to skin. The most effective repellents are those containing DEET (diethyl toluamide) – at a concentration of between 30% to 50%, or picaridin - at a concentration of 20%. You can apply repellent over sunscreen.
- Wear clothing that covers the arms and legs
- Wear hats and shoes (rather than sandals)
- Apply permethrin insecticide to clothes
- Use mosquito nets impregnated with permethrin
- Use electric insect-repellent devices, or mosquito coils
- When possible, stay in accommodation that has screens on doors and windows, or is air-conditioned.
Can dengue, Zika, and chikungunya be fatal?
There is a severe form of dengue fever - known as dengue haemorrhagic fever - which can cause bleeding and collapse, and can be fatal. This is more common in people who get dengue fever more than once. Dengue haemorrhagic fever is fatal in about five percent of cases, mostly among children and young adults. This risk is important for Pacific peoples who may make a number of visits back to their home country over the years, and so risk repeat infections.
Zika and chikungunya are not thought to cause fatal illnesses in adults, though there is increasing concern that Zika causes severe illness and death in unborn babies.
What does the public health service do?
Auckland Regional Public Health Service (ARPHS) receives notifications of all cases of dengue, Zika and chikungunya in the Auckland region, and is responsible for investigating the country of origin of infection, and giving health advice to prevent further infection. ARPHS also works to make sure exotic mosquitoes do not become established in Auckland.
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