Olga Lechky is a freelance writer living in North York, Ont.
Canadian Medical Association Journal 1995; 153: 996-998
[résumé]
With more Canadians travelling outside the country than ever before, there is greater risk of contracting exotic illnesses that few used to worry about. Low-risk Europe and the United States used to be the preferred destinations, but today many people travel to destinations far off the beaten tourist path.
Many of these travellers are turning to family physicians for advice on immunization and other health tips. Being asked for travel advice on Borneo or New Guinea may intimidate physicians whose geographic knowledge is fuzzy. However, a few guiding principles and good resources can help physicians ensure that their patients will be healthy when they return to Canada.
Dr. Mark Wise, a Toronto family physician and staff physician at the Travel Clinic in Thornhill, Ont., says most doctors can practise travel medicine without passing their patients on to another physician "if they're willing to keep up with new developments in the field in the same way they keep up with new developments in, say, hypertension."
He says basic questions that should be covered in a pre-travel consultation include:
Since sex tourism, where the focus is on visits to prostitutes, is widespread in Southeast Asia, Wise says all patients should be counselled on safe-sex practices and on the risk of HIV infection associated with tattoos and acupuncture.
Although travel in most tropical or developing countries invariably presents some degree of health risk, this may vary among different regions of the same country, says Wise. Large urban centres in tropical countries are generally free of malaria, although there are exceptions, especially in tropical Africa and the Indian subcontinent. High-altitude areas sitting more than 770 m (2500 feet) above sea level are also considered safe.
Well-developed resort areas pose few health risks. Cartagena, a popular package-tour destination in Colombia, appears at first glance to be a high-risk destination because it is in tropical South America. In fact, it is a cosmopolitan, historic city that thrives on tourism generated by the luxury hotels lining its beach strip. Apart from being careful about food and water, a person vacationing in Cartagena will not encounter health risks such as yellow fever and malaria that may threaten a traveller in rural Colombia.
"In a pretravel consultation, I assess the patient's risk [first]," says Wise, "then I go on to immunizations, malaria prophylaxis, diarrhea prevention and management, and then other odds and ends, depending on the destination and other factors."
The only vaccine a physician may not administer routinely is yellow fever vaccine, whose use is restricted to designated centres and physicians; information about designated yellow fever centres is available from local public-health departments. All other vaccines commonly used to protect travellers can be ordered from the manufacturers and administered in the physician's office.
Wise cites tropical Africa, both west and east, as high-traffic destinations for Canadians, and notes that a growing number of immigrants to Canada are natives of Ghana and Nigeria, who face health risks when they return for visits. The wildlife conservation parks of East African countries such as Kenya and Tanzania are also popular for safari holidays. Vaccination for yellow fever is recommended according to the length of stay and types of activities; many countries now require proof of yellow fever vaccination from travellers who have been in Africa or South America.
Meningococcal vaccine is highly recommended because there are endemic and epidemic areas in both the eastern and western parts of tropical Africa. Immunization for typhoid and hepatitis A is also recommended because travellers will likely be exposed to contaminated food and water; longer-term travellers to Africa are strongly advised to get vaccinated for hepatitis B because of the disease's high incidence.
But malaria still poses the main risk in tropical Africa. Malaria prophylaxis is mandatory, especially for patients who will be in rural areas. In Africa, malaria is generally resistant to chloroquine, so the appropriate antimalarial product - currently mefloquine - must be prescribed. Patients must be counselled on how to take the drug before, during and after their trip. Other precautions against malaria include insect repellent, the use of long-sleeved shirts and long pants and mosquito netting around the bed at night, and avoidance of the outdoors between sundown and dawn.
Prevention and treatment of traveller's diarrhea is also important for visitors to tropical Africa, says Wise. Doctors should advise travellers to drink water that is bottled, boiled or treated by water-purifying tablets. The maxim for eating fruits and vegetables is: "Cook it, peel it or forget it."
Despite precautions, many travellers will still develop diarrhea and they should carry antidiarrheal medication in a first-aid kit. For mild diarrhea an antiperistaltic product such as loperamide hydrochloride is recommended; for dysentery and fever that may have been caused by Salmonella or Shigella, a quinolone antibiotic for adults or a sulfa antibiotic for children will shorten the severity and duration of symptoms.
Wise also cautions that travellers to tropical Africa should be made aware of its very high incidence of HIV infection. Abstaining from sex or practising safe sex is a must in preventing infection; travellers should also carry their own sterile needles and syringes because African hospitals and clinics may use old or improperly sterilized syringes.
A popular holiday for the more adventurous is trekking in the mountains of Nepal. Apart from widespread poor sanitation - and thus the potential for diarrheal illnesses and hepatitis A infection - the major risk to trekkers is altitude sickness. Hypoxic stress can be manifested at elevations of 2000 m and higher. The symptoms include dizziness, nausea, vomiting, headache, fatigue and rapid heartbeat; this syndrome is unpleasant but rarely serious, says Wise. For a few days upon arriving at a high-altitude destination, travellers should rest, drink plenty of fluids and avoid exertion. At many hotels in high-altitude areas, oxygen bags are available for use during acute distress.
A more serious risk is the development of high-altitude pulmonary edema after rapid ascent above approximately 3000 m. Climbers and trekkers need a good guide who will allow time for acclimatization before ascending higher, and not climb too high on a given day. For people with a history of altitude sickness, acetazolamide can be prescribed as a prophylactic.
Sometimes travellers are exposed to risks en route to their destinations. Wise says most trekkers in Nepal also pass through malarial areas in India either before or after their trek. Closer to home, many travellers arrive in high-altitude Quito in Ecuador directly from North America without a chance to acclimatize. After spending a few days in Quito, many go on to Guayaquil, the port from which cruises leave for the Galapagos Islands, and an endemic area for malaria. A brief stay, or even a journey through such an area, can pose a high risk.
Wise says all travellers should be reminded to use sunscreen and to avoid walking barefoot. In tropical destinations, especially Africa, patients should be cautioned about the risk of contracting schistosomiasis, which is usually caused by wading, washing or swimming in fresh water.
Personal safety tips are important in pretravel counselling, Wise notes. "People don't tend to die as a result of infectious diseases except malaria when they're travelling," says Wise. "But they could die or be seriously injured as a result of violence or motor-vehicle accidents." Recent murders of tourists in the Dominican Republic and Antigua highlight the potential risk of robbery and random violence, and travellers should be cautioned to stay with groups of people and avoid deserted beaches and unlit alleyways at night.
In most developing countries, it's common to see packs of stray dogs roaming city streets and the countryside. Stray cats are also ubiquitous. Patients should be counselled to stay away from these animals and not try to befriend them - they are not the domestic pets of North America. Wise notes that rabies is endemic in many developing countries, and even if an animal is not rabid it can still inflict a bad bite if frightened or provoked.
Besides becoming familiar with a few good resources, the best way for doctors to become more knowledgeable about international travel is to attend hospital clinical days dealing with tropical medicine. "Physicians should also plan to take some time out for themselves," says Wise. "Go and travel and get off the beaten path - both for your own pleasure and education."