Dengue Fever: Symptoms, Prevention and Travel Safety for UK Travellers

Dengue fever is a viral infection transmitted to humans through the bite of infected Aedes aegypti and Aedes albopictus mosquitoes. While not endemic to the United Kingdom, it is one of the most common causes of fever in British travellers returning from tropical climates. According to the NHS and the UK Health Security Agency (UKHSA), cases are frequently reported in people returning from Asia, Africa, and the Americas.

Unlike the mosquitoes that carry malaria, which primarily bite at night, the mosquitoes that spread Dengue are most active during the day, particularly around sunrise and sunset. This makes daytime bite prevention a critical aspect of travel safety. While many cases are mild, a small percentage can develop into severe Dengue, formerly known as Dengue haemorrhagic fever, which requires urgent hospital care.

Common Symptoms

Symptoms usually begin 4 to 10 days after being bitten. The hallmarks of Dengue fever include:

• High temperature: A sudden fever reaching 40°C or higher.
• Severe Headache: Often described as a 'behind-the-eyes' pain.
• Muscle and Joint Pain: This can be so intense that the condition is nicknamed 'breakbone fever'.
• Nausea and Vomiting: Loss of appetite and general stomach upset.
• Skin Rash: A flat, red rash appearing 2 to 5 days after the fever starts.

Most symptoms self-resolve within a week, though the fatigue and low mood associated with the illness can linger for several weeks during recovery.

The risk of contracting Dengue fever is highest in urban and semi-urban areas where standing water allows mosquitoes to breed. According to NICE clinical knowledge summaries, travellers should be particularly cautious when visiting:

• South East Asia: Countries like Thailand, Vietnam, and Indonesia.
• The Caribbean: Popular holiday spots including Barbados and Jamaica.
• Central and South America: Particularly Brazil and Mexico.
• Sub-Saharan Africa: Risk levels vary by region but are present in many urban centres.

If you are planning a trip to these regions, consulting an online doctor in the UK for a pre-travel risk assessment can help you understand the current local outbreaks and the necessary precautions.

Bite Prevention Strategies

Avoidance is the best policy. Travellers are advised to:

• Use insect repellent containing at least 50% DEET on exposed skin.
• Wear long-sleeved shirts and long trousers, ideally treated with permethrin.
• Use air conditioning or window screens where possible to keep mosquitoes out of living spaces.
• Empty standing water from flowerpots or buckets near your accommodation.

Vaccination in the UK

A vaccine called Qdenga is now licensed in the UK for individuals aged 4 and older. It is particularly recommended for those who have previously had Dengue fever, as a second infection with a different strain of the virus carries a higher risk of severe complications. You can discuss your eligibility for the vaccine during a travel health consultation with a GP online.

Diagnostic Tests

If you return to the UK with symptoms, a GP will typically order blood tests to look for the virus or antibodies. Because symptoms overlap with malaria and typhoid, it is vital to disclose your full travel history.

Management at Home

There is no specific medication to cure Dengue. Management involves:

• Paracetamol: To manage fever and pain. Important: Avoid ibuprofen or aspirin, as these can increase the risk of bleeding in Dengue patients.
• Hydration: Drinking plenty of fluids (water and oral rehydration salts) to prevent dehydration.
• Rest: Allowing the body time to recover.

You should speak to a GP or use a private online doctor service if you are planning a trip to a high-risk area and need a personalised health plan. An online consultation is also appropriate if you have recently returned from abroad and feel unwell, but do not yet require emergency care.

An online GP can provide evidence-based advice on:

• Whether the Dengue vaccine is appropriate for your destination.
• Appropriate first-aid kits for tropical travel.
• Managing post-viral fatigue if you are recovering from a confirmed case of Dengue.
• Issuing sick notes if the illness is preventing you from returning to work after your holiday.

Severe Dengue is a medical emergency. It usually occurs 24-48 hours after the fever starts to drop. In these cases, the blood vessels become leaky, and the number of clot-forming cells (platelets) in the bloodstream drops. This can lead to shock, internal bleeding, and organ failure. If you or a travel companion notice persistent vomiting or bleeding from the gums, seek immediate hospital treatment in the country you are visiting or via A&E if you have returned to the UK.