Travel health experts advise preparing for a trip four to six weeks before you travel, especially if you need vaccinations.
"Vaccination is just one element of protecting yourself from infectious disease," says Professor David Hill, director of the National Travel Health Network and Centre (NaTHNaC).
UK residents visiting their country of origin should also be vaccinated as any immunity they may have built up previously in their native country will have reduced over time.
Water and food safety abroad
Many infectious diseases are transmitted through contaminated food and water, and insect bites.
You can reduce your risk of these diseases by following some basic guidelines:
- Don't drink tap water or use it to brush your teeth in countries with poor sanitation. Use filtered or bottled water instead.
- Don't put ice in drinks. Bottled fizzy drinks with an intact seal are usually safe, and so are boiled water and hot drinks made with boiled water.
- Don't eat salads, uncooked fruits and vegetables unless you've washed and peeled them yourself.
- Don't eat food that has been kept at room temperature in warm environments or has been exposed to flies.
- Don't consume unpasteurised milk, cheese, ice cream and other dairy products, or raw or undercooked seafood.
"You should only eat freshly prepared food that is thoroughly cooked and served piping hot," says Professor Hill.
Avoiding insect bites
- Try not to go to areas that are highly infested with biting insects.
- Malaria mosquitoes bite between dusk and dawn, so being indoors during these hours can reduce the number of bites.
- Research shows products containing the chemical DEET are the most effective insect repellents and are safe when used correctly.
- Mosquitoes can bite through tight clothing, so wear loose-fitting long trousers and long sleeves in the evenings in malaria hotspots.
- Sleep under a mosquito net to avoid being bitten at night. Carry a small sewing kit so you can repair any holes that develop.
Travellers' diarrhoea (TD)
Travellers' diarrhoea is the most common illness in people travelling from the UK to developing countries. It is caused by eating or drinking contaminated food or water. Foods most likely to cause TD are those that have not been thoroughly heated or have been left out at room temperature.
You can reduce your risk of TD by following good food and water hygiene practices. If you develop TD, drink regularly to avoid dehydration. In most cases, TD will only last a few days, but you may want to pack medication.
Find out more about preventing diarrhoea.
Malaria is a serious and sometimes fatal disease that is common in tropical countries. It is spread by night-biting female mosquitoes carrying a parasite called plasmodium. About 1,750 people a year return to the UK with malaria. Most of them catch it because they didn't take any tablets or didn't take the right ones for the areas they visited.
See your GP or go to a travel clinic for specific advice and the correct tablets for the country you're visiting before you travel. Avoiding mosquito bites will also reduce your risk.
Traveller Alex Cheatle tells how he learned the hard way when he decided to stop taking his malaria tablets during a round-the-world trip. Read Alex's story.
Find out more about preventing malaria.
Dengue is a virus spread by an infected Aedes mosquito, which usually bites during the day. Dengue is a risk in areas such as southeast Asia, the Caribbean and South America. The best way to avoid infection is to avoid mosquito bites.
Symptoms include fever, headache, muscle and joint pain and, in some cases, a rash. The illness usually lasts a few days and serious complications are uncommon. There is no specific anti-viral treatment. Symptoms such as fever and headache can be treated individually.
Find out more about dengue.
HIV and STIs
Unsafe sexual behaviour can expose travellers to HIV and sexually transmitted infections (STIs), such as gonorrhoea, chlamydia or syphilis. Drinking too much alcohol may decrease your inhibitions and make you more likely to have unsafe sex.
Avoid sex with a new or unknown partner, and always use condoms. The condoms you can buy in developing countries may not be reliable, so buy them in the UK and take them with you.
Find out more about STIs.
Hepatitis A is caused by a virus. It is caught through food or water that has been contaminated by human faeces. Foods that grow close to the ground, such as strawberries and lettuce, are particularly risky. Crustaceans that feed on the seabed, such as oysters and clams, are also a risk.
Infected people can pass on the virus if they don't follow proper hygiene practices. Early symptoms include weakness, loss of appetite, nausea and fever, followed by the onset of jaundice. Highly effective hepatitis A vaccines are available and should be considered by most travellers.
Find out more about preventing Hepatitis A.
Hepatitis B is caused by one of the most common viruses worldwide. It is a major cause of chronic liver disease and liver cancer. Symptoms include flu-like complaints, loss of appetite, nausea, diarrhoea, abdominal pains and jaundice.
The virus is spread through sexual intercourse, blood transfusions, contaminated needles (including tattoo needles) and poorly sterilised medical and dental equipment. High-risk regions include sub-Saharan Africa, southeast Asia and the Pacific islands. A vaccine is available for those at risk of hepatitis B.
Find out more about hepatitis B.
Typhoid is a potentially fatal disease caused by the bacteria Salmonella typhi. It is acquired through contaminated food or water in areas with poor sanitation. The Indian subcontinent has the highest incidence of typhoid.
Symptoms include sudden fever, severe headache, nausea, abdominal pain, loss of appetite, constipation or diarrhoea. Vaccination is recommended for travellers visiting high-risk areas.
Find out more about preventing typhoid.
Yellow fever is a viral disease transmitted by infected mosquitoes in tropical regions of sub-Saharan Africa and South America. Early symptoms include aching, fever, headache, loss of appetite, nausea, and vomiting. In severe cases, this can lead to organ failure and death. The disease is preventable by vaccination and is rare in travellers. Some countries require you to be vaccinated against yellow fever as a condition for entry.
Find out more about preventing yellow fever.
Rabies is caused by a virus that attacks the central nervous system. When it reaches the brain, it causes swelling, inflammation and death. The virus is found in the saliva of infected animals, including dogs and bats, and is passed to humans by bites or scratches.
Africa, Asia and South America are rabies risk areas. Vaccination is advised before you travel to high-risk areas. If you get a bite or scratch from a potentially infected animal, wash the wound with soap and water and seek urgent medical care.
Find out more about preventing rabies.
Meningitis is the swelling of the lining around the brain and spinal cord, which is caused by different types of germs. Early symptoms include fever, headache, nausea, and vomiting, just like many mild illnesses. The germs, which are present in the nose and throat, can be passed from person to person by close and regular contact through coughing, sneezing and kissing.
Meningitis risk areas include sub-Saharan Africa, where there are annual outbreaks. Vaccines are available to travellers visiting high-risk zones, although the risk of meningitis for tourists is low. Vaccination against meningitis is a requirement for pilgrims attending the Hajj or Umrah in Saudi Arabia.
Find out more about preventing meningitis.
Article provided by NHS Choices