Tropical Diseases on Holiday

Dengue (previously called dengue fever), Zika virus and malaria are all infections passed on by infected mosquitoes in certain parts of the world. Dengue and Zika are caused by viruses; malaria is caused by a microscopic parasite that is neither a virus nor a bacterium.

How Do You Catch Dengue, Zika Virus and Malaria?

All three diseases are caused by being bitten by an infected mosquito. The mosquito becomes infected by biting and drinking blood from an infected person. The virus or malaria parasite multiplies in their bloodstream, and they can then pass it on to another person when they bite them.

Where Am I at Risk?

The infection you’re at risk of depends on the part of the world you’re travelling to.

Dengue is mostly found in urban and semi-urban areas, largely in tropical and subtropical climates. You may be at risk in:

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

Zika is found in:

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

There are different types of malaria. They are all potentially very serious, but falciparum malaria is the most serious form. Falciparum malaria is found especially in Africa. Europe is currently regarded as malaria-free because of its climate, but if global temperatures rise this may change. You can catch malaria in:

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

Who Is at Risk?

Anyone can catch the Zika virus, dengue, or malaria. However, your risk of serious illness is higher if you:

• Are over 65.
• Are under 5 years old (especially under 1).
• Have a medical condition that could weaken your immune system.
• Are pregnant.

Pregnancy, malaria, and Zika

If you are pregnant and contract malaria, there is a risk that your placenta, or your baby, will become infected. Placental infection is more common and can stop your baby from getting enough nutrients and oxygen.

Zika can cause severe deformities to your baby if you catch it while you are pregnant.

If you are pregnant or trying for a baby, you may want to avoid travelling to any area where there is a risk of dengue, Zika, or malaria.

Can I Take Medication to Prevent It?

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

There are medications that can greatly reduce the risk of you contracting malaria – however, it’s important to take steps to avoid getting bitten by mosquitoes when you’re travelling to a malarious area, even if you’re taking this medicine.

Well before you travel, visit the fitfortravel website to see if there’s a risk of malaria in the country you’re going to. If there is, contact your pharmacist – malaria medications aren’t available on the NHS, but your pharmacist can advise you and sell you the correct medication for any destination.

This medication needs to be started before you go and taken the whole time you’re in a malaria-affected area and for up to a few weeks after you return. The timing of the course will depend on where you’re going and what anti-malarial you take – your pharmacist can give you full advice.

Remember that stopping a course of anti-malarial medication early, even if you’ve left the area affected by malaria, increases the risk of developing malaria.

How Can I Reduce My Risk?

As well as taking malaria-prevention medication, everyone should take steps to avoid getting bitten by mosquitoes in areas where dengue, Zika, and malaria are a risk.

Sensible steps include:

• Wearing long-sleeved shirts, long trousers, and socks, especially in the evenings when mosquitoes are most active.
  
  
• Use an effective insect repellent on any exposed skin (and sometimes on your clothing). The most effective is DEET repellent – 50% DEET lasts longer than lower concentrations. Apply DEET after your sunscreen.
  
  
• Use a knock-down insect spray at dusk if you’re in a screened room. Close all the doors and windows after this.
  
  
• If you have electricity in your room, use a plug-in device that releases an insect repellent called pyrethroid overnight.
  
  
• Use a mosquito net if you’re outdoors or in an unscreened room. Make sure it doesn’t have holes and reaches the floor. You should tuck it under your mattress. The mosquito net should be impregnated with an insecticide, such as pyrethroid.