Febre Chikungunya

What is chikungunya?

Chikungunya (or chikungunya fever) is an illness caused by a virus. The virus gets into your system when you are bitten by a particular type of mosquito. The type of mosquito which transmits the chikungunya virus is called an Aedes mosquito. These mosquitoes tend to bite in the daytime rather than at night.

The mosquito carries the virus after biting another person or animal who has the chikungunya infection. The virus multiplies in your bloodstream, causing you to become unwell usually 4-8 days after the mosquito bite. The virus causes you to develop a temperature and joint pains. There may be other symptoms.

What causes chikungunya?

Anyone bitten by a mosquito infected with the chikungunya virus, can get the illness. It only occurs in certain parts of the world. It only occurs in countries where it is warm enough for the mosquito to survive.

It is not warm enough for this type of mosquito in the UK, so you cannot get the infection in the UK. However, if you travel to a country where there is an outbreak of chikungunya fever, you may become infected if you are bitten by an infected mosquito.

Up until 2013, chikungunya fever was mainly a risk only in certain parts of Africa and Asia. In 2013, however, cases were reported in the Caribbean and in North and South America. Since then there have been outbreaks across the Caribbean and the Americas, with many thousands of people catching the virus.

Who gets chikungunya?

Anybody at any age can get chikungunya fever. However, it tends to be more severe in certain groups of people. This includes:

• Newborn babies and very young children.

• People aged over 65 years.

• People with other medical conditions.

Is chikungunya contagious?

Chikungunya is not contagious; that is, you cannot catch chikungunya fever from another person. It is only passed on if you are bitten by a mosquito which has bitten another person or animal infected with the virus.

The exception to this is that newborn babies have been known to develop chikungunya fever shortly after birth if their mother has the infection. Infection with chikungunya fever during pregnancy may also result in infection and problems for the developing baby.

How common is chikungunya?

How common chikungunya is varies because it tends to occur in outbreaks. Since being first reported in the Caribbean and the Americas, there have been more than 1.2 million cases in these regions.

In the UK it is very rare. There were 295 cases reported in 2014 in England, Wales and Northern Ireland. All these illnesses happened in people who had travelled abroad. Most of them had been to the Caribbean or South America.

In 2016 the countries reporting most cases were Brazil (265,000 suspected cases), Bolivia and Colombia (19,000 suspected cases, respectively). In the African region, Kenya reported an outbreak of chikungunya resulting in more than 1,700 suspected cases. In 2017, Pakistan continued to respond to an outbreak which started in 2016.

What are chikungunya symptoms?

The symptoms of the illness usually start four to eight days after the person has been bitten by the infected mosquito. It starts with a high temperature (fever) and joint pains. The joint pains may be very severe.

The word 'chikungunya' comes from an African word which means 'that which bends up'. This is because people with the illness may be bent over in pain. Any joint can be affected but most commonly the joints of the hands, wrists and ankles are painful.

Outros sintomas que podem estar presentes incluem:

• Sentindo-se cansado.

• Sentindo-se mal.

• A rash.

• Dores musculares.

• Uma dor de cabeça.

Chikungunya rash

Chikungunya fever rash

© By Nsaa (Own work) via Wikimedia Commons

Usually the symptoms last one or two weeks, and then completely settle. In a few people, however, the joint pains can carry on for weeks or months after the infection has gone.

Very rarely more serious symptoms occur. These are more likely in more vulnerable people. For example, young babies, the elderly or people with other medical conditions may be more prone to the more serious symptoms. These more unusual complications include:

• Pains in the eye or loss of vision.

• Fits (convulsões).

• Sonolência.

• Infections in parts of the brain (meningite ou encefalite).

• Watery stools (diarreia).

• Problemas respiratórios.

• Problemas cardíacos.

• Kidney problems.

• Liver infection.

Are there any tests for chikungunya fever?

A blood test can be taken to confirm chikungunya. In the UK it has to be sent to a special laboratory for rare imported diseases. The blood sample can be checked to see if the virus can be found. It may also be checked for antibodies which are produced by your immune system to fight the virus.

What is the treatment for chikungunya?

There is no specific medication which tackles the virus itself. Normally you will be advised to take medicines such as paracetamol ou ibuprofeno to help with the joint pains and high temperature (fever). You will be advised to drink plenty of fluid. People who become very unwell may need to have extra care in hospital.

What is the usual outcome?

Most people make a full recovery within one to two weeks. Some people may be left with joint pains which can go on for weeks or months.

A very few people have complications (see the 'symptoms' section above). It is rare to die from chikungunya fever but it can happen occasionally.

How to prevent chikungunya fever - Advice for UK travellers

If travelling to an area where chikungunya fever occurs, take all possible precautions to avoid being bitten by a mosquito. For example:

• Use insect repellent. Those containing a chemical called N, N-diethylmetatoluamide (DEET) are known to be the most effective. Apply insect repellent regularly and re-apply after swimming. If also using sunscreen, apply the insect repellent after the sunscreen.

• Sleep in rooms with mosquito screens and/or mosquito nets.

• The use of mosquito coils may be helpful outside.

• Wear clothing that protects you from bites - ie long sleeves and long trousers. For areas affected by chikungunya fever, you need this type of clothing even in the daytime. This is because the Aedes mosquitoes tend to bite in the daytime, unlike other types which usually bite in the evenings. There are some insecticides available which can be sprayed on to clothing.

There is no vaccine available to prevent chikungunya infection.

If you develop a high temperature or joint pains while abroad, or shortly after you return, seek medical advice.