Travel Advice: Insects, Malaria and Altitude




Insect Bites

Mosquitoes, certain types of flies, ticks and bugs can transmit many different diseases. e.g. malaria, dengue fever, yellow fever. Some bite at night, but some during daytime. The main way to avoid illness is to avoid being bitten, where possible:

  • If your room is not air conditioned, but screened, close shutters early evening and spray room with knockdown insecticide spray. In malarious regions, if camping, or sleeping in unprotected accommodation, always sleep under a mosquito net (impregnated with permethrin). Avoid camping near areas of stagnant water, these are common breeding areas for mosquitoes etc.
  • Electric insecticide vaporisers are very effective as long as there are no power failures! Electric buzzers, garlic and vitamin B are not effective.
  • Cover up skin as much as possible if going out at night, (mosquitoes that transmit malaria bite from dusk until dawn). Wear light coloured clothes, long sleeves, trousers or long skirts.
  • Use insect repellents on exposed skin. (Choose those containing DEET or eucalyptus oil base. A content of approximately 35% DEET is recommended for tropical destinations.) Clothes can be sprayed with repellents too. Impregnated wrist and ankle bands are also available. Check suitability for children on the individual products.
  • Report any unexplained illness with symptoms such as fever, headache, malaise, muscle aches and fatigue.


Malaria is probably the most common and most serious disease you will be exposed to when travelling.  Malaria is caused by a microscopic parasite transmitted by female mosquitoes when they take a blood meal at your expense.  There are four species of malaria parasite, of which Plasmodium falciparum is the most dangerous and can lead to cerebral malaria and death.

Malaria usually starts as a fever and you will feel very unwell.  Other symptoms may include diarrhoea, headache or a cough.  In a malarious area, all illnesses with fever should be considered to be malaria until proved otherwise.  Seek medical help as soon as you can if you become ill.

Check carefully the areas you plan to travel to and take anti-malarial tablets (prophylaxis) if advised by the travel-health nurse or doctor.  Some tablets can be bought over the counter in a chemist but others are only available on prescription.  Do not take over-the-counter tablets if prescription-only prophylaxis has been advised.

You can get malaria even when taking prophylaxis, but this happens more commonly in individuals who forget to take one or more tablets.  It is essential that you take the tablets you are prescribed regularly and on time and for the whole of the recommended time after leaving a malarious area (sometimes for 4 weeks after).

Mosquitoes that transmit malaria bite mainly at night, but this can be any time from dusk onwards and even just after dawn.  Use insect repellent containing at least 35% DEET, wear long, loose clothing when possible and consider taking a mosquito net impregnated with permethrin to sleep and rest under.  These can be bought in outdoor/camping shops which stock a full range of products.  Do not rely on insect repellent and mosquito nets alone if you have been advised to take prophylaxis as well; all forms of protection are important.

  • Take adequate supplies of the antimalarial agent suited to your area of travel and remember to take it. People die every year from malaria in the UK.
  • Even with the best prophylaxis you may still catch malaria so have a high index of suspicion.
  • Report any unexplained illness with symptoms such as fever, headache, malaise, muscle aches and fatigue.
  • Malaria can occur up to two years after being bitten by an infected mosquito.
  • If you become unwell with fever up to a year after returning from a malarious area, see your GP and tell them you have travelled abroad.

Travellers to High Altitude

Acute altitude sickness occurs when an individual who is accustomed to low altitudes rapidly climbs to high altitude (above 8,000 feet). Clinical features of mild altitude sickness are:

  • Headache
  • Loss of appetite
  • Nausea
  • Fatigue
  • Dizziness
  • Insomnia
  • Extremity oedema
  • Dyspnoea
  • Palpitations 

The treatment for acute altitude sickness ranges from rest and analgesia, to oxygen therapy and descent.

Extreme altitude sickness can be fatal. It is advised that climbers should acclimatise if climbing to high altitude:

  • If above 10,000 feet, no more than 1000 feet should be climbed per 24 hour period.
  • If a climber develops symptoms of mild altitude sickness then he/she should rest for 24 hours at that altitude.
  • If a climber has more severe symptoms then he/she must descend to the last altitude at which they felt well. This should occur whether or not they are using medication prescribed to help cope with high altitude.

The following preventative measures should be utilised:

  • Slow ascent e.g. once over 8000ft (2500m) avoid sleeping more than1000ft (300m) higher than previous day
  • Keep warm
  • Keep well hydrated and avoid alcohol
  • High carbohydrate diet
  • Modest exercise on acclimatising days