Tropical Diseases on Holiday

Going on holiday is an exciting opportunity to relax, explore new destinations, and experience different cultures. While many travellers focus on packing essentials and planning activities, staying healthy should be a top priority—especially when visiting regions where tropical diseases are prevalent.

Even the fittest traveller can be at risk of contracting mosquito-borne illnesses like dengue, Zika virus, and malaria, which can turn a dream holiday into a serious health challenge. This guide will explain these common diseases, their symptoms, and how to reduce your risk of infection.

Dengue, Zika Virus, and Malaria: What Are They?

Dengue, Zika virus, and malaria are illnesses spread by infected mosquitoes, primarily in tropical and subtropical regions. While dengue and Zika are viral infections, malaria is caused by a parasite that attacks red blood cells, often leading to severe complications if untreated.

There are currently no vaccines against dengue, Zika virus, or malaria.

How Are These Diseases Transmitted?

All three diseases are contracted through the bite of an infected mosquito. The mosquito first becomes a carrier by feeding on an infected person, then spreads the virus or parasite to others through subsequent bites.

While both dengue and Zika are caused by viruses that multiply in the bloodstream, malaria is different—it results from a parasite that invades and destroys red blood cells, leading to potentially life-threatening complications.

READ MORE: Bites and Stings

Symptoms of Common Tropical Diseases

Dengue Fever

Dengue, also known as "breakbone fever" due to its intense muscle and joint pain, typically begins with a sudden high fever lasting 2 to 7 days. Other symptoms include:

• Severe headaches and pain behind the eyes
• Nausea, vomiting, and extreme fatigue
• Skin rash appearing 2 to 5 days after fever onset.
• In severe cases (dengue haemorrhagic fever), bleeding from the gums, nose, or internal organs can occur, requiring urgent medical attention.

Zika Virus

Zika virus symptoms are usually mild and can include:

• Low-grade fever
• Rash and joint pain
• Conjunctivitis (red eyes)
• Muscle pain and headaches

Most cases resolve without medical treatment, but Zika can have serious complications, especially for pregnant women, as it has been linked to birth defects like microcephaly in newborns. It has also been associated with Guillain-Barré syndrome, a rare but serious neurological condition.

Where Are You at Risk?

The risk of contracting dengue, Zika virus, or malaria depends on your travel destination. These diseases are most common in tropical and subtropical regions where mosquitoes thrive.

Dengue

Dengue is primarily found in urban and semi-urban areas with warm, humid climates. You may be at risk in:

• Central and South America
• The Caribbean
• The Pacific Islands
• Parts of Africa and Asia
• Some southern U.S. states
• Southern Europe (spring, summer, and autumn), including France, Italy, Spain, Portugal, Madeira, and Croatia

Zika Virus

Zika is found in many of the same regions as dengue, including:

• Central and South America
• The Caribbean
• The Pacific Islands
• Parts of Africa and Asia

Malaria

There are several types of malaria, but falciparum malaria is the most dangerous, particularly in Africa. While Europe is currently malaria-free, rising global temperatures could change this in the future. You can catch malaria in:

• Much of Africa and Asia
• Central and South America
• Parts of the Middle East
• The Dominican Republic and Haiti
• Some Pacific Islands

Who is Most at Risk?

Anyone can contract dengue, Zika, or malaria, but certain groups face a higher risk of severe illness, including:

• Adults over 65
• Young children (especially under 1 year old)
• Individuals with weakened immune systems
• Pregnant women

Pregnancy, Malaria, and Zika

Both malaria and Zika pose serious risks during pregnancy:

• Malaria can infect the placenta, reducing the supply of oxygen and nutrients to the baby, potentially leading to complications.
• Zika virus has been linked to severe birth defects, including microcephaly, which affects brain development.

If you are pregnant or planning to conceive, you may want to avoid travelling to regions where dengue, Zika, or malaria is present.

Are there Medications or Vaccines I Can Take to Prevent Dengue, Zika or Malaria?

There is no vaccine or medication to prevent dengue or Zika virus, so mosquito bite prevention is essential. However, anti-malarial medication is available to reduce the risk of malaria in affected areas.

Depending on where you plan to visit, you may need to get vaccinations for other diseases common to your holiday destination.

READ MORE: What Vaccinations Do I Need for my Holiday?

How Can I Reduce My Risk?

Whether in a region affected by dengue, Zika, or malaria, the best way to stay protected is to prevent mosquito bites.

Key Prevention Tips

Cover Up: Wear long-sleeved shirts, trousers, and socks, especially in the evenings when mosquitoes are most active.

Use Insect Repellent: Apply a 50% DEET repellent to exposed skin and clothing. Remember to apply sunscreen first, then repellent.

Use Insect Sprays Indoors: If staying in a screened room, spray insecticide at dusk and close all doors and windows.

Plug-in Repellents: Use an electric plug-in device that releases pyrethroid-based insect repellent overnight.

Sleep Under a Mosquito Net: If staying in an unscreened room or sleeping outdoors, use a mosquito net treated with insecticide (e.g., pyrethroid). Ensure:

• No holes in the net
• It reaches the floor or is tucked under the mattress.

Taking these precautions—along with malaria medication where necessary—will greatly reduce your risk of infection.

What Should You Do If You Think You Have Dengue, Zika, or Malaria?

If you develop flu-like symptoms such as fever, muscle aches, headaches, or fatigue after travelling to a tropical region, it’s important to take your symptoms seriously.

When to Seek Medical Help

Seek urgent medical attention if you experience:

• Severe symptoms such as persistent high fever, severe headaches, breathing difficulties, confusion, or bleeding (from the nose, gums, vomit, or stool)—these could indicate severe dengue or malaria complications.
• Recurring fever, chills, and sweating in cycles—a sign of malaria.
• Symptoms during or after pregnancy. Zika and malaria can cause complications for both the mother and baby.

If you feel unwell after returning home, inform your doctor about your recent travels - some tropical diseases have an incubation period and may not cause symptoms immediately.

READ MORE: How to Find Medical Care Abroad

Managing Mild Symptoms

For mild cases of dengue or Zika, treatment mainly involves rest, hydration, and over-the-counter pain relief (such as paracetamol). Avoid ibuprofen or aspirin, as these can increase the risk of bleeding if you have dengue.

Malaria always requires medical treatment, so if there’s a risk you’ve been infected, don’t wait—get tested as soon as possible.

Why Travel Insurance Is Essential

Tropical diseases can require costly medical treatment, hospital stays, or even emergency evacuation. Comprehensive travel insurance that covers medical expenses, repatriation, and trip cancellations is crucial for peace of mind.

Planning ahead with the right insurance and medical precautions means you can travel with confidence, knowing you're protected if the unexpected happens.

READ MORE: Do I Need Travel Insurance?

Tropical diseases like dengue, Zika, and malaria can pose serious health risks, but with proper preparation and precautions, you can minimise your risk while travelling. Research the risks at your destination, consider anti-malarial medication if needed, and take mosquito bite prevention seriously by using repellent, wearing protective clothing, and sleeping under mosquito nets.

If you develop symptoms during or after your trip, seek medical attention promptly, especially if you experience severe fever, bleeding, or breathing difficulties. Early diagnosis and treatment can make a crucial difference, particularly with malaria.

Finally, investing in comprehensive travel insurance ensures you’re covered for unexpected medical expenses, giving you peace of mind throughout your journey. With the right precautions in place, you can focus on enjoying your adventure safely.