Simon Calder: The Man Who Stays At Home

Travel can seriously damage your health

By the middle of the day, the timetable became distinctly unappetizing: "11.55 - Sexual Health and the Traveller; 12.30 - Lunch; 14.00 - Schistosomiasis". Someone had mischievously scheduled a meal between news of the terrifying spread of HIV infection along major highways in southern Africa, and a talk on the spectacular results of the intravascular migration of schistosomes (lavishly illustrated with pictures of the worms that happily burrow through your body in pursuit of a slithery soul mate).

By the middle of the day, the timetable became distinctly unappetizing: "11.55 - Sexual Health and the Traveller; 12.30 - Lunch; 14.00 - Schistosomiasis". Someone had mischievously scheduled a meal between news of the terrifying spread of HIV infection along major highways in southern Africa, and a talk on the spectacular results of the intravascular migration of schistosomes (lavishly illustrated with pictures of the worms that happily burrow through your body in pursuit of a slithery soul mate).

Those of a timid disposition who attended Thursday's Travel Medicine Study Day in London may have concluded early on that it is unwise to venture any nearer Abroad than Kent. Indeed, even going that far may be risky; the event's compere, Peter Barrett, had travelled all the way from Leeds and picked up a nasty cough.

Dr Barrett is medical director for the travel health organisation Masta, which convened the event to bring health professionals and tour operators up-to-date on the threats to the 21st-century wanderer. Courage needs to be part of every traveller's kit, judging by the manifold menaces that await. Natural threats such as Thursday's earthquake on the Japanese island of Hokkaido have always existed, but are now augmented by new dangers such as terrorism.

John Simpson, deputy director of the Health Protection Agency's Emergency Response Division, was booked to talk about "Bioterrorism Risk and the Traveller", but strayed into advice about conventional terrorism: "If you hear a bang, don't run in the opposite direction," he urged. In the kind of attack that killed more than 200 people in Bali a year ago, a double bomb is used, where a small explosion creates panic and makes everyone run towards a larger bomb.

"The gentlemanly terrorism of the past seems to have gone," said Dr Simpson. Biological warfare began in the 14th century, when a besieging army in the Crimea catapulted dead bodies infected with plague over the battlements. (That sort of caper makes even a Club 18-30 holiday in Faliraki seem civilised.) Bioterrorism followed much later. Even in the twisted minds of its perpetrators, it cannot be counted a dazzling success. Dr Simpson cited the events in 1984 when followers of Bhagwan Shree Rajneesh in Oregon scattered cultured salmonella on salad buffets in fast-food restaurants. Eight hundred people fell ill, but no one died.

I think I was comforted by Dr Simpson's assurance that it is easy to spot an anthrax attack in a rural area, because "cows will fall over first", and by his view about the risk of villains trying deliberately to spread the disease that appeared earlier this year: "Sars would be no interest to a bioterrorist. It's far too slow and not deadly enough, not very infectious. The one thing you might use it for is to cause panic."

Don't panic, though, was Dr Simpson's conclusion: "The threat of bioterrorist attacks is very low. Mother Nature's bioterrorism is far more likely, and if you go to Colombia you're far more likely to be kidnapped or shot."

I WAS reminded of the magnificent escape of Matthew Scott from his Colombian kidnappers in the Sierra Nevada this week during the session on schistosomiasis, also known as bilharzia. The adventurous male parasites that cause this debilitating condition think nothing of swimming the wrong way up the human bloodstream, carrying their female partner, and breaking through layers of tissue to reach the gut or bladder. These jolly creatures were discovered by Theodore Maximillian Bilharz, perhaps appropriately at the University of Tübingen, in 1852. Sadly, a decade later he went off to East Africa with the Duke of Saxe-Coburg-Gotha, caught typhus, and died. But at least he is immortalised in medicine.

"Although not a 'killer disease' in the usual sense, it gnaws insidiously at the general health of entire populations," is the view of Dr Bertel Squire, who told us that 200 million people are infected with the parasite, which thrives in fresh water in tropical areas. Breeding pairs can live happily inside you for up to 15 years. The more extreme consequences include a granulated tumour on the genitals, or epilepsy triggered by worms setting up home in the brain - events that would take the edge off the most exciting trip.

"TRAVELLERS HAVE more sex abroad!" yelled one of the slides in the sexual health session presented by Lynda Bramham. Mostly, travellers have sex with one another rather than locals. They meet new, exciting people in new, exciting places, often with alcohol involved - a factor in three out of five liaisons. They are away from those who might disapprove, "such as their partner", noted Ms Bramham.

One-third of travellers fail to practise safe sex, not always through ignorance: two out of five said they had received pre-travel advice on the risks of casual sex, but it made no difference to their conduct. "Most travellers still have no perceived personal risk," says Ms Bramham. Her tip for healthy holidays: take your partner.

Even if sexually transmitted infections left participants with little appetite for lunch, the midday banter was full of tasty nuggets. Some (male) executives sent to tricky parts of the world demand a double dose of dioralyte to be added to their medical kit - not to counter dehydration, but because the mix of sugar and salt apparently acts as a first-rate hangover cure.

A few microbes of good news for travellers were revealed. Research on a vaccine for West Nile Fever is proceeding, well, feverishly, which may have something to do with the fact that it affects rich Americans, not poor Africans. Progress is being made towards finding a jab that would protect against dengue fever, which is currently enjoying a rapid mosquito-borne spread around the world. This viral infection is occasionally fatal, but most of the time it will merely cause a bout of high fever, vomiting and severe headaches.

The mosquito is the tropical traveller's worst enemy. This week in Mozambique, Bill Gates gave £100m to research aimed at finding a cure for malaria, while in London the travel health guru Richard Dawood led a journey of exploration of the disease. A mosquito bites in order to get red blood cells to mature its eggs. If it feeds on an infected organism (such as a human being), it picks up the parasite, which is then passed on (after an incubation period in the mosquito of about 10 days) each time the mosquito bites again. Once the parasite gets into your liver, it infects your bloodstream, possibly fatally.

Malaria parasites behave like bioterrorists, spreading drug resistance around the world as rapidly as scientists dream up new treatments.

The first line of defence against this chain of events is not to get bitten: tougher than you might think, according to Paul Goldstein of Exodus Travel. "If you've got red hair, you're buggered," he said, though he added, "I've been to Africa 63 times and I still haven't caught it." The most voracious mosquitoes in the world, he believes, are well away from malarial areas, in the far north: "For getting absolutely nailed, Alaska is the worst."

To minimise the risks of a bite, cover up exposed skin, especially around dawn and dusk, use repellents containing the compound Deet (or lemon eucalyptus based repellents) and sleep under mosquito nets. And female tourists should ideally not conceive: "Pregnant women attract twice as many mosquitoes as other travellers," noted Dr Dawood.

In the unlikely event that you stay healthy abroad, you may feel psychologically out of sorts when you come home. According to Dipti Patel, who works in occupational health for the BBC, three-quarters of returning aid workers suffer from "reverse culture shock". Delegates were too polite to ask Dr Patel which of the Corporation's macho hacks were the biggest wimps when faced with the inoculation needle; I know of at least one prominent presenter who, after a hepatitis jab for a trip to India, had to go and lie down in a darkened room for the afternoon.

By the time the day had ended, I was ready for that darkened room - my head full of warnings about the next influenza pandemic, the effect of altitude on night vision even at the summit of Ben Nevis and the worrying interaction between fresh yak dung and hot beverages in Himalayan tea houses. The only safe conclusion: travel is bad for your health, and the trip of a lifetime may shorten your lifespan.

Dr Simpson, who began the day's proceedings, ended with a simple message. "One piece of travel advice not given enough is 'don't go'."

Masta: 09068 224 100, www.masta.org

Additional research by Daniel McAllister