Protect yourself from mosquito-borne illnesses

Mosquitoes spread several very nasty diseases which can affect travellers. Some of these mosquito-borne illnesses can be lethal, others may leave you with neurological damage. So it is in your best interests to protect yourself against the viruses and parasites that mosquitoes carry by getting vaccinated, taking malaria prophylaxis and practising mosquito bite avoidance.

What are the main mosquito-borne diseases of concern to travellers?

The main mosquito-borne diseases that affect travellers are:

  • malaria
  • Japanese encephalitis
  • yellow fever
  • Dengue fever
  • zika
How does malaria affect travellers?

Malaria is contracted from the bite of a mosquito infected with single-celled parasites. Malaria is widespread around the world in subtropical and tropical areas. Some cases can be very serious or fatal.

The symptoms of malaria appear 10 to 15 days after the mosquito bite. They include fever with shivering and sweating, headaches and muscle pains – exactly the sort of illness that can ruin your trip. Malaria can make you ill enough to need extended time off work or studying, and may make it hard for you to carry out caring duties and normal activities. The symptoms of malaria can also emerge up to a year later, after you get home.

Malaria prophylaxis is available at NX Travel Health Clinics. Ask which malaria med is best for you as some people tolerate different regimes better than others. And the right choice of drug may depend on where you are going.

Are travellers exposed to Japanese encephalitis?

Japanese encephalitis (JE) is a mosquito-borne virus that can leave the patient with permanent neurological damage. Most cases of JE are mild, but one in 250 cases progresses to a severe clinical case; and about 30 per cent of these patients will die. The World Health Organisation records 68,000 clinical cases of JE every year.

Five to fifteen days after being bitten by a mosquito infected with Japanese encephalitis the patient suffers a flu-like illness. If it progresses to encephalitis (swelling of the brain) convulsions, headaches, paralysis and neck stiffness can accompany a high fever.

Japanese encephalitis occurs in South East Asia and in the Indian subcontinent and is contracted from the bite of an infected mosquito. The relevant species of mosquito breeds in rice paddies. There is a vaccine available for Japanese encephalitis.

Are travellers at risk of yellow fever?

Yellow fever is a serious, sometimes fatal, viral illness that is spread by the mosquito species Aedes aegypti. Fatality rates can be as high as 60 per cent. Following a short incubation period – three to six days – the patient will experience yellow fever symptoms including sudden fever, muscle pain, nausea and vomiting and jaundice. Patients who recover from yellow fever have lifelong immunity.

Yellow fever is most common during the rainy season. You can catch yellow fever in tropical parts of Central and South America and Sub-Saharan Africa.

Do I need a yellow fever certificate?

Many affected countries will require proof of vaccination (an International Certificate of Vaccination) before you are allowed to enter. Border officials in some countries will ask to see a certificate if you are travelling from a place where yellow fever is present. If you cannot produce proof of immunity, you may be quarantined, immunised or refused entry. For detailed information see the yellow fever maps on NHS Fit for Travel.

The vaccine Stamaril protects against yellow fever and can provide lifelong immunity. Ask your healthcare adviser at NX Travel Health Clinics for the latest information and see our travel health article about yellow fever.

What is Dengue fever?

Dengue fever, also known as breakbone fever because of the muscular, joint and bone pains, mainly occurs in urban areas. Other symptoms include fever, rash and headache and during recovery many patients experience weeks of fatigue. Dengue is carried by the Aedes type of mosquito. A female mosquito feeds on a person with Dengue fever and though the mozzie suffers no ill-effect, it becomes infected for life. It will then infect any person it bites.

There is no vaccine for Dengue fever and if you catch it a second time the risk of serious complications increases.

Is Zika a risk at my destination?

Zika has been linked to birth defects if a pregnant person becomes infected. Mosquitoes spread this viral disease, but zika symptoms are very mild. They include rash, itch, mild fever, headache, red eyes, muscle and joint pains.

Strict measures against mosquito bites are recommended for all travellers, particularly people who are pregnant or likely to become so. Application to the skin of the mosquito repellent 50% DEET is recommended, and this is safe during pregnancy. For more information about zika, see NHS Fit for Travel. There is no vaccine against zika available to travellers.

How to avoid mosquito bites

As you can see it is a very good idea to avoid mosquito bites because not all mosquito-borne diseases can be vaccinated against. Wear loose neutral-coloured clothing with good limb coverage and use a reliable insect repellent or insecticide such as permethrin or DEET. Sleep in rooms equipped with air con and mosquito nets. Use sleeping nets wherever possible. And if a vaccine or malaria prophylaxis is available, make use of it.