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Dengue Fever

Dengue fever is a potentially fatal illness caused by any one of four related viruses transmitted by Aedes mosquitoes, that bite during the day. Dengue is endemic in at least 100 countries in Africa, the Americas, the Eastern Mediterranean, South East Asia and the Western Pacific[67]. There can be sudden outbreaks of cases (epidemics) where thousands of people can become infected in a short space of time.

How do you get it?
Dengue is spread by a day biting mosquito and it only takes a single mosquito bite. Your chance of being bitten is highest a couple of hours after sunrise and just before sunset – the times when these mosquitoes feed most intensely. Anyone can develop dengue but spending long periods of time in tropical countries where dengue fever is common, especially during the transmission season, increases risk although even short-stay visitors can be affected. 

Signs and symptoms
As many as 80% of people infected with dengue virus are asymptomatic or only have mild symptoms [68]. Symptoms usually appear five to eight days after being bitten by an infected mosquito and typically include: a severe flu-like illness, with fever, headache, muscle ache and a rash. Most people will recover within one to two weeks. 

Others have more severe illness (usually less than 5% ), and in a small proportion it is life-threatening. In these cases the disease develops into dengue haemorrhagic fever (DHF), or into dengue shock syndrome (DSS), which are both potentially fatal [68]. It mainly occurs in young children growing up in risk areas and is rare in travellers. Warning signs for the rare dengue haemorrhagic fever include: spots or patches of blood under the skin, bleeding from the gums or nose, persistent vomiting and severe abdominal pain, vomiting blood or black, tarry stools. Patients can go into shock (a sudden drop in blood pressure), bleeding and organ damage. In dengue shock syndrome, the blood pressure drops to dangerously low levels which can result in organ failure and death. If you have any of these symptoms, you must seek immediate medical assistance. 

Most people will recover within one to two weeks. However dengue haemorrhagic fever is a potentially fatal complication. Dengue shock syndrome and dengue hemorrhagic fever occur in less than 5% of all cases of dengue, and is more common in children and young adults.

There is no specific treatment for dengue. In most people symptoms can be managed by taking paracetamol (it is important that travellers avoid aspirin, ibuprofen or other similar non-steroidal anti-inflammatory drugs as they can trigger internal bleeding in people with dengue), drinking plenty of fluids and resting. Infected people will feel tired and unwell for a couple of weeks, although it can sometimes take up to six weeks to recover completely.

Recommendations for Travellers
There is no vaccine against dengue, so avoiding mosquito bites is the only way to prevent infection.

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Dengue Fever. Here’s the point...

Dengue fever is a growing problem with a 30 fold increase in the last 50 years [69]. This increase is believed to be due to a combination of urbanisation, population growth, increased international travel, and global warming. With a risk of death and no specific treatment available, mosquito bite avoidance is the only way to protect against the disease.