Dengue (pronounced DENgee) is a painful, debilitating mosquito-transmitted disease caused by any one of four different strains of the dengue virus. These viruses are related to the viruses that cause West Nile virus infection and yellow fever.
Each year, an estimated 100 million cases of dengue fever occur worldwide. Most of these are in tropical areas of the world with the greatest risk occurring in:
- The Indian subcontinent
- South-east Asia
- Southern China
- The Pacific Islands
- The Caribbean (except Cuba and the Cayman Islands)
- Central and South America (except Chile, Paraguay and Argentina)
Most cases in Westernised countries occur in people who contracted the infection while travelling abroad.
In Autumn 2012, an outbreak of dengue fever was reported in Madeira, Portugal. This was the first time that dengue fever had been reported in Madeira.
Dengue is transmitted by the bite of an Aedes aegypti mosquito infected with a dengue virus. The mosquito becomes infected when it bites a person with dengue virus in their blood. It can’t be spread directly from one person to another person.
Around 400 cases of dengue fever are reported in England, Wales and Northern Ireland each year, mostly in people returning from India and Thailand.
Symptoms of dengue
Symptoms, which usually begin four to six days after infection and last for up to 10 days, may include:
- A sudden, high fever
- Severe headaches
- Pain behind the eyes
- Severe joint and muscle pain
- Skin rash, which appears two to five days after the onset of fever.
Sometimes symptoms are mild and can be mistaken for those of the flu or another viral infection. Younger children and people who have never had the infection before tend to have milder cases than older children and adults. However, serious problems can also develop. These include dengue haemorrhagic fever, a rare complication characterised by high fever, damage to lymph and blood vessels, bleeding from the nose and gums, enlargement of the liver, and failure of the circulatory system. The symptoms may progress to massive bleeding, shock and death. This is called dengue shock syndrome (DSS).
People with weakened immune systems, as well as those with a second or subsequent dengue infection, are believed to be at greater risk of developing dengue haemorrhagic fever.
Diagnosing dengue fever
Doctors can diagnose dengue infection with a blood test to check for the virus itself or antibodies to it. If you become sick after travelling to a tropical area, let your doctor know. This will allow your doctor to evaluate the possibility that your symptoms were caused by a dengue infection.
Treatment for dengue fever
There is no specific medicine to treat dengue infection. If you think you may have dengue fever, you should use paracetamol but avoid medicines with aspirin or ibuprofen, which could worsen bleeding. You should also rest, drink plenty of fluids and seek medical advice. If you start to feel worse in the first 24 hours after your fever goes down, you should get to a hospital immediately to be checked for complications.