Last-minute holidays may be the ideal antidote to urban boredom, but without proper precautions you could find yourself facing a much greater malady. Ensure your trip is a healthy one. Disappearing into the wild blue yonder has never been easier. A reasonably pliable credit card combined with a travel agent piloting a smoking keyboard means waking thoughts of a stress-busting break can become cocktails on a distant beach by sundown. Smoothing your way from the Mid-Levels goldfish bowl to a snorkellers' playground are cheap, plentiful flights and hotel operators who compete like Siamese fighting fish for the scraps from a fickle market. But when break time is over, how many millions of new friends are you likely to be taking home with you? A quick trip may mean liberation from the irritating need to plan; but if you make no plans to inoculate yourself from the less desirable characteristics of a place then you could soon be making a follow-up trip ... to hospital. Dr Susan Jamieson (contactable via www.drjamieson.com ) has noted an increase in holiday-related illnesses with the advent of affordable, convenient travel. 'More people seem to be coming in sick with the usual food poisoning,' she says, 'but I've also seen cases of typhoid. It's a nasty disease, yet one simple vaccination lasts three years. 'From Hong Kong, it's easy to reach the Golden Triangle, for example, which has some of the worst malaria in the world. It's a worry, because travellers are not even taking malaria tablets or sleeping under mosquito nets. If someone comes to see me with what looks like flu, and they've just been on holiday, it's possible they've got malaria. 'It's easy to pop across to Cambodia, but people don't pay attention to the risks. They see their friends coming back healthy and see no reason not to go themselves; places are accessible, travel has become average. How could it be dangerous? At the very least they should be vaccinated against hepatitis A and B and typhoid. That's a good base for travel in this region.' Some places will always be more likely than others to send you home looking a funny colour, but even first-world countries, while not carrying a 'vaccination required' tag, may land you with a few unwanted souvenirs if you haven't had certain jabs. Give them a miss and that cheap holiday may turn into an expensive time-out from normal life, especially if you combine it with an absence of travel insurance. AFRICA Vaccinations recommended: typhoid, hepatitis A and B, rabies, polio, yellow fever, tuberculosis and tetanus. Africa has an impressive armoury of diseases and infections. Malaria is endemic, so use a robust repellent and sleep under a mosquito net. If you develop what seems like flu up to six months after returning home, assume it is malaria and seek treatment. For visitors on trekking holidays, rabies and hepatitis B immunisation are essential, as are vaccinations for tuberculosis and meningitis. Epidemics of the latter arrive with the end of the dry season in June and are transmitted in the same way as a cold. BALI Vaccinations recommended: typhoid, Japanese encephalitis and hepatitis A and B. The rumblings in Bali are not the sole preserve of religious fundamentalism: 30 to 50 per cent of visitors return home with diarrhoea. Hepatitis A is also widespread and travels in contaminated food and water. Avoid shellfish, ice, tap water and salads. BRITAIN Vaccinations required: none. Although Britain is thought of as a 'safe' destination as far as illness is concerned, cold, dank winter weather can provoke chest infections, coughs and colds, which are common across the country. To stop such conditions becoming more serious, some doctors recommend a flu shot for visits from November to March. CHINA Vaccinations recommended: polio, Japanese encephalitis, hepatitis A and B and typhoid. Give yourself a fighting chance of staying out of hospital by staying off mainland buses. Other than that, sleep under a mosquito net in summer to avoid flu-like Japanese encephalitis, which is fatal in one case in three, and watch out for dirty water and ill-kept or badly prepared food, especially outside cities. Typhoid and hepatitis A lurk within. FIJI Vaccinations recommended: hepatitis A. In addition to the usual suspects of ice, tap water's laboratory of microscopic gatecrashers, salads and shellfish, travellers to Fiji risk contracting dengue fever if they neglect to pack their mosquito net and insect repellent. Symptoms appear about a week after the mosquito has dined, and are typified by muscle pain, fever, headaches and a rash. INDIA Vaccinations recommended: hepatitis A and B, typhoid, polio and rabies. Hygiene can be an infrequent guest at Indian restaurants, even in the largest cities, making those hepatitis and typhoid jabs all the more important. Avoid contact with stray dogs anywhere in the country, take a course of anti-malarial Malarone pills and sleep under a mosquito net. SINGAPORE Vaccinations recommended: hepatitis A. Perhaps less sterile than it would like to think, the Lion City produces clams, oysters and mussels in estuaries subject to water pollution. Dense road traffic may also mean a holiday in hell for asthmatics. THAILAND Vaccinations recommended: hepatitis A, Japanese encephalitis and rabies. For Bangkok and other major cities, Dr Jamieson's basic immunisation package should suffice. Rural and remote areas may be home to Japanese encephalitis and rabies. The latter hitches a ride with bats, cats, monkeys and dogs, so avoid all contact. UNITED STATES Vaccinations required: none. Apart from maniacal Saudi Arabians playing Ernst Blofeld, and no-go zones in just about every metropolis, what could you have to worry about in 'the best damn country there's ever been on Earth', as P.J. O'Rourke called it. Lyme disease, that's what. Of particular interest to hikers and other fresh-air fiends, Lyme disease is transmitted to humans by the bite of infected blacklegged ticks. Symptoms include fatigue, fever, headaches and a rash. Left untreated, the infection can spread to joints, the heart and the nervous system. But you can avoid this by using plenty of insect repellent. See www.mdtravelhealth.com and www.travelhealth.co.uk for more information.