Long haul travel exposes the pilot to increased risk of disease and illness not experienced by his colleagues confined to Europe. Indeed, aviation itself is partly responsible for the spread of disease and its constantly changing pattern around the world. It should be emphasised that this chapter merely touches on the risks, diseases and preventative measures available at the time of writing (1999). Up to date advice should always be sought from the airline's doctor or a travel clinic. Some travel immunisations are available on the NHS, some airlines provide or pay for others. Always carry adequate health insurance and a form E111 for reciprocal arrangements within the E.C.
The increased risk of illness is due to a number of factors, some of which cannot be prevented. Constant time-zone changes, consequent sleep disruption and inadequate time to adapt to climatic changes are dealt with in another chapter. Unaccustomed sunbathing can cause from sunburn to sunstroke. Malignant melanoma due to sun exposure is three times more common in pilots than in the general population. Exercise in the heat of the day can be unwise and dehydration can be avoided by six non-alcoholic pints a day in tropical climates. Too much alcohol can lead to unnecessary risks taken in the swimming pool, on the road, even in bed. Different food (especially shellfish) and standards of hygiene require caution. Bites from strange insects result in serious diseases, some fatal, which may be prevented by prophylactic drugs or inoculations prior to travel. The risks fall mainly into three main groups, borne by food, insects and people.
"Travel broadens the mind and loosens the bowels". Diarrhoea is the commonest cause of incapacitation in aircrew. Poor food hygiene and water polluted by inadequate sewage disposal are the main causes, although altered diet, excess alcohol and sunbathing may contribute. Food poisoning is therefore most prevalent in the tropics and sub-tropics.
Ingestion of bacteria is the usual cause affecting half of all travellers to the tropics, E. Coli responsible for half the cases. Shigella, Campylobacter, Salmonella (can cause typhoid) and Vibrio Cholerae are also common. Viruses from shellfish are now on the increase. "Keep it hot, keep it cold or throw it away". Cooked food should be just that, well cooked and served hot. Bacteria multiply at a prodigious rate in food left around at room temperature. The incubation period for toxic food poisoning can be less than 60 minutes and the ensuing incapacitation can have disastrous consequences. Do the crew still eat different meals? Avoid uncooked food except peeled fruit and vegetables. Shellfish, especially oysters, are particularly dangerous. Hotel tap water is not always safe, so boil it or disinfect it. Bottled mineral water should be a better bet.
Treatment: Most attacks are self limiting and clear up in a couple of days without specific treatment. Drink more fluid as soon as it starts - bottled water, flat Coke or 7-Up or weak tea - little and often, at least three litres a day. If it "runs" into the second day, six level teaspoons of sugar and one of salt to each litre of safe water will replace some of the good things that disappear down the pan. There is no need to starve and readily digestible food in moderate amounts is OK. Diarrhoea tablets such as Loperamide (Immodium or Arret) may be used if the diarrhoea persists, but the theory of 'let it all come out' still holds favour with many doctors.
If the diarrhoea persists for more than three days then medical advice should be sought. Clearly no-one should contemplate operating an aircraft if suffering discomfort from diarrhoea, or taking drugs to combat it.
Common Food-Borne Infections
Hepatitis A (Infective hepatitis): A viral infection of the liver, usually caught from swallowing contaminated water or food washed in it. Shellfish, especially oysters, thrive in such water and often contain it.
Incubation: 15-40 days.
Symptoms: Nausea, stomach pain, yellow jaundice of skin and whites of eye, dark urine, pale stools. Can seriously damage the liver.
Treatment: No active treatment, requires rest, so probably off flying for several months. No alcohol for at least six months; I said it was serious! As only infectious orally, it is safe to PAX home once the worst symptoms have subsided.
Immunisation: One injection a fortnight before travel lasts one year, a booster 6 - 12 months after the first jab increases cover for up to ten years. An alternative instant acting injection of immunoglobulin will only cover for 2 - 3 months.
Another gastro-intestinal infection from food and drink contaminated by bacteria and prevalent in countries with poor sanitation.
Incubation: 1 - 3 weeks.
Symptoms: Fever, eventually progressing to delirium, severe headaches, tiredness, internal haemorrhage, bowel perforation.
Treatment: Antibiotics, treat dehydration.
Immunisation: One injection, 80% effective after 12 days, but lasts only three years.
An acute intestinal infection spread by bacteria from same culprits as above; usually occurs in epidemics.
Incubation: A few hours - 5 days.
Symptoms: Profuse watery diarrhoea followed by vomiting and muscle cramps.
Treatment: Treat dehydration.
Immunisation: Less than 50% effective, so not recommended (or available) routinely. The World Health Organisation state it is no longer a legal requirement, though some African and South American countries may require evidence of vaccination or other persuasion before allowing entry.
Many tropical diseases are transmitted by mosquitoes. Avoid getting bitten. Most patrol from dusk till dawn, so wear long sleeves and trousers, preferably light coloured and sprayed with DEET repellent around cuffs and ankles and on exposed skin. Sleep in an air conditioned room (they don't like the cold) or if not, under a net impregnated with insecticide in a room with screens across openings. Burning insecticides may help.
Endemic in the tropics and subtropics. Kills more people worldwide than any other disease and is on the increase. The parasite is transmitted by the bite of the female anophyles mosquito. The local community may develop some immunity, but Europeans not compliant with bite avoidance or taking prophylactic medication are especially at risk.
Incubation: 12 - 30 days.
Symptoms: Several different strains, so symptoms vary from a recurring flu-like illness with high fever and shaking chills to coma and rapid death.
Treatment: Diagnosis only confirmed by examining a blood smear. Effective drug treatment is available if started in time.
Anti-malaria pills provide some protection as there is no suitable inoculation as yet. The emergence of resistant strains, new endemic areas, new medication make it essential to obtain up to date advice from your airline doctor. Side effects of some medications preclude their use by pilots, in conflict with other advice you might receive. Stick rigidly to the instructions, some pills must be taken a whole month after leaving the zone. Tell your doctor where you have been if you fall ill after overseas travel.
An acute viral infection spread by mosquitoes in sub-Sahara Africa and South America.
Incubation: 3 - 6 days.
Symptoms: Violent onset of high fever, backache, red eyes, dark blood in vomit, stools and urine before proceeding to the yellow discoloration of the skin. It may regress spontaneously without treatment after twelve days or worsen until death.
Immunisation: Very effective, one injection valid after ten days and lasting ten years. Make sure you obtain an International Certificate and carry it when travelling. Some countries, especially in Central Africa, will not allow entry without it, or may insist on several days quarantine and an injection on the spot.
A flu-like illness transmitted by urban mosquitoes during the day.
Incubation: 5 - 8 days.
Again - avoid getting bitten.
Close or intimate contact with other humans can be bad for your health! Exchanging bodily fluids through either homo or heterosexual encounters, even contact with droplets from mouth or throat, can be fatal! Condoms are not 100% reliable.
The Human Immuno-deficiency Virus (HIV) which causes Acquired Immuno-deficiency Syndrome (Aids) dwells in the blood, semen, vaginal secretions of an infected person of which there are millions worldwide. It is spread through sex, infected needle or blood transfusion.
Incubation: 6 months - 10 years! Symptoms are legion as the weakened immune system leaves the body defenceless against most infections.
There is as yet no inoculation against it although more effective treatments are appearing. Cabin staff sometimes fear they may catch it following assault from a passenger. They should be referred to the airline doctor for advice.
A viral illness transmitted in the same manner as HIV but one hundred times more infectious.
Incubation: 1 - 6 months.
Symptoms: Vary from loss of appetite, nausea and vomiting, to joint pains, rash, death.
Immunisations are usually reserved for health care workers and should not be necessary for pilots if the precautions are heeded.
An acute illness following invasion of the gut by a virus with high affinity for nervous tissue. Usually caught from contact with faeces or throat excretions.
Incubation: 3 - 21 days.
Symptoms: Range from mild fever to paralysis.
The UK population has been immunised with oral vaccine since 1956. A booster for travellers is suggested every 10 years.
A bacterial infection spread by droplets from throat which can become obstructed, together with muscle weakness.
Immunisation: routine for UK children for many years, however a special low-dose adult booster may be required for visiting high-risk countries, mainly the former USSR.
Bacterial infection of lining of the brain and spinal cord transmitted by cough or sneeze.
Incubation: up to 3 days.
Symptoms: Malaise and high temperature, headache, photophobia, rash. It can be fatal. An increasing number of strains are being isolated.
Immunisation is usually required if flying pilgrims to Mecca or the Hadj, and lasts three years.
Acute viral infection from bite of infected animal. Don't handle animals. If bitten, wash wound thoroughly with soap and water and seek medical advice quickly.
Acute bacterial infection from even a minor cut leading to agonising muscle spasm. UK population routinely protected since 1961. Booster lasts ten years. Seek medical advice if unprotected.
These are the most common diseases pilots will be exposed to in the course of their travels. There will always be new ones to challenge us; CoxSachie virus in Malaysia, Ebola virus in South Africa and St. Louis Encephalitis in Florida and New York are some I have been asked about recently. Your airline doctor should be able to advise as and when they occur.
Dr S A Goodwin
Airport Medical Services Limited