Chikungunya virus

Chikungunya is a viral illness transmitted by infected mosquitoes that causes fever and severe joint pain. Chikungunya shares some clinical signs with dengue and can be misdiagnosed in areas where dengue is common. Chikungunya has been identified in nearly 40 countries in Asia, Africa, Europe and the Americas. It has circulated in the Pacific Region since 2011.

The mosquitoes that are able to spread chikungunya virus are not normally found in Aotearoa New Zealand, so chikungunya should only be considered in people who have recently travelled overseas. These are mainly the Aedes albopictus and Aedes aegypti species of mosquitos. Both species hide in and around the house and bite during the day. Any area within the range of these mosquitoes should be considered a potential risk area for mosquito-borne (‘arboviral’) diseases such as chikungunya. More than half the world’s population lives within the range of Aedes aegypti.

While Australia has had no cases (as of June 2020), mosquitoes capable of spreading the virus are present in some areas of Queensland.

There is no vaccine and no cure for the disease. Prevention is through avoiding mosquito bites. Treatment is focused on relieving the symptoms, to help with fever and joint pain. Once infected, it is likely that you will develop immunity. This means that you are unlikely to get it twice.

People most at risk

Those people most at risk for severe disease include newborns exposed during delivery, older adults (those over the age of 65 years), and people with certain medical conditions, such as high blood pressure, heart disease and diabetes.

Chikungunya infection is notifiable in Aotearoa New Zealand as an arboviral disease. This means that cases are notified to health officials so that steps can be taken to minimise risk and determine whether others are at risk of infection.

The majority of people infected with chikungunya virus become symptomatic. The incubation period is typically from 3 to 7 days (the range is 1 to 12 days). There is no specific therapy for chikungunya virus infection and acute symptoms typically resolve within 7 to 10 days. Chikungunya may also cause long term symptoms.

• acute onset of fever (typically >39°C)
• acute onset of polyarthralgia (aching joint pain), usually bilateral and symmetric, and can be severe and debilitating
• headache
• myalgia (muscle pain)
• arthritis
• conjunctivitis (eye infection, causing swelling and redness)
• nausea/vomiting
• maculopapular rash (causing red bumpy spots on the skin).

Chikungunya virus infection should be considered in patients with acute onset of fever and polyarthralgia, especially travelers who have recently returned from areas with known virus transmission.

As chikungunya infection may cause a rash that could be confused with other diseases such as dengue and measles, these other diseases do need to be ruled out. Diagnosis of chikungunya will first and foremost be by exclusion of other diseases such as dengue and measles, based on symptoms and travel history.

There is no specific treatment for chikungunya virus infection. If you're experiencing symptoms of chikungunya virus infection, see a doctor immediately.

Treatment to relieve symptoms includes:

• drinking plenty of fluids, to prevent dehydration
• get plenty of bed rest
• taking pain relief such as paracetamol at recommended doses.
• if you are taking medication for another medical condition, talk to your healthcare provider before taking additional medication
• don't take aspirin and other non-steroidal anti-inflammatory drugs (NSAIDS) until dengue can be ruled out
• during the acute stage of the disease, steroids are not usually indicated because of the potential for adverse effects

The main method of prevention is to avoid mosquito bites. The virus can be spread from an infected person to mosquitoes, leading to further infections in other people.

Visit Avoiding bug bites while travelling page for more information.