Tropical Medicine : While On Your Trip

While On Your Trip

If you are traveling to an area with malaria, be sure to take your antimalarial regularly. Failure to do so will lessen the protectiveness of the medication. See instructions in the Malaria section for what you should do if you forget to take a pill.

To prevent dengue fever and malaria, avoid mosquito bites. Use insect repellents during the day and especially between dusk and dawn. Sleep in well-screened or air conditioned accommodation or use bed nets, impregnated with an insecticide (see Before You Leave). Wear trousers and long sleeves at dusk wherever possible and avoid outdoor activity after sundown.

When traveling to warmer or tropical climates, use sunblock (SPF 15 or greater) regularly, especially if you are taking medications (such as tetracycline) which increase skin sensitivity to the sun. Remember, reflection from water or snow can intensify the sun’s radiation power and even a cloudy day can cause a serious burn.

Traveler's diarrhea or "tourista" is usually caused by impure water consumed while traveling. The water in some countries can contain organisms which will cause diarrhea in those not accustomed to them. Because Canada's municipal water supplies are treated to remove most waterborne organisms, travelers from Canada may experience diarrhea while traveling abroad if they consume local water, or food prepared with local water in less developed countries.

To prevent traveler's diarrhea

Drink boiled water (3 min) or commercially bottled water or beverages and pasteurized milk and dairy products. Hot drinks such as tea and coffee are also generally safe.
Avoid ice, salads, reheated foods, uncooked shellfish and food from street vendors.
Choose fruit that you can peel.

Traveler diarrhea attack rates of 20%-50% are commonly reported.

High-risk destinations include most of the developing countries of Latin America, Africa, the Middle East, Asia and Haiti.
Intermediate-risk destinations include most of the Southern European countries and a few Caribbean islands.
Low-risk destinations include Canada, Northern Europe, Australia, New Zealand, the United States, and a number of the Caribbean islands.

Tourista is slightly more common in young adults than in older people. The reasons for this difference is unclear, but may include a lack of acquired immunity, more adventurous travel styles, and different eating habits. Attack rates are similar in men and women. The onset of TD is usually within the first week, but may occur at any time during the visit and even after returning home.

These can be prevented by taking some precautions.

Swim in fresh water only if you know that it is free of biharzia (schistosomiasis), waterborne parasites found in the Caribbean, South America, Africa, the Middle East and Southeast Asia. These parasites penetrate unbroken skin and cause an infection of the bowel or the bladder. In certain areas, fatal primary amebic meningoencephalitis has occurred following swimming in warm dirty water. Swimmers should avoid beaches that might be contaminated with human sewage or with dog feces.
Avoid walking with bare feet because some intestinal parasites enter the body through skin contact with contaminated soil. Wear sandals or sneakers.
Use a condom if you intend to have sex with strangers while traveling. This will decrease (but not eliminate) your risk of sexually transmitted diseases such as gonorrhea, syphilis, hepatitis B and AIDS.
Do not share needles to inject intravenous drugs. Hepatitis B and AIDS vary in occurrence from country to country. Injection drug use is not only a risk to health, it may also land you in serious trouble with police authorities.

You should be safety and security conscious during travel. Economic conditions in lesser developed countries can cause increased crime rates and tourists are often targeted.

Do not walk alone in remote areas, back streets or beaches, where there may be risk of personal attack or bag snatching.
Valuables should be left at home or deposited in hotel safes.
Travelers cheques, cash, passports and tickets should not be carried in bags that can be snatched. Use a body belt for these essential travel items.

Injuries, especially those from motor vehicle crashes, pose the greatest risk of serious disability or loss of life to international travelers. The risk of motor vehicle-related death is generally many times higher in developing countries than in North america. Motor vehicle crashes result from a variety of factors, including inadequate roadway design, hazardous conditions, lack of appropriate vehicles and vehicle maintenance, unskilled or inexperienced drivers, inattention to pedestrians and cyclists, or impairment due to alcohol or drug use; all these factors are preventable or can be abated. Defensive driving is an important preventive measure.

When driving or riding, request a vehicle equipped with safety belts, and, where available, use them. Cars and trucks should be carefully inspected to assure that tires, windshield wipers, and brakes are in good condition and that all lights are in good working order. Where available, also request a vehicle equipped with air bags. As a high proportion of crashes occur at night when drivers are returning from “social events,” avoid nonessential night driving, alcohol, and riding with persons who are under the influence of alcohol or drugs.

This risk of death in a motor vehicle crash is greater for persons sitting in the front seat than for those in the rear seat. Where possible, travelers should ride in the rear seats of motor vehicles. Pedestrian, bicycle, and motorcycle travel are often dangerous, and helmet use is imperative for bicycle and motorcycle travel. In developing countries, helmets will likely not be available, so bring your own with you if you plan to ride bicycles or motorcycles. For travel with young children, you should bring your own child safety seat.

Fire injuries are also a significant cause of injuries and death. Do not smoke in bed, and inquire about whether hotels have smoke detectors and sprinkler systems. Travelers may wish to bring their own smoke detectors with them. Always look for a primary and alternate escape route from rooms in which you are meeting or staying. Look for improperly vented heating devices which may cause carbon monoxide poisoning. Remember to escape a fire by crawling low under smoke.

Jet Lag is the result of traveling over many time zones in a short amount of time; flying east produces the most severe effects. Jet lag leads to daytime sleepiness, insomnia, diminished appetite, and even headaches, irritability and poor concentration. The traveler can take several steps to diminish the effects of jet lag.

If possible, book a non-stop flight to reduce the chance of delays and cancellations that can extend your travel time immensely.
Try to schedule flights to arrive in the late afternoon or evening.
Start your trip well-rested. Get a good nights sleep the night before your departure.
While traveling, drink plenty of water to avoid dehydration and wear loose comfortable clothing.
Set your watch to the destination time when beginning your flight and try to adjust your activities to that time.
When you arrive, sleep and wake at local times. If you need to, take small naps no longer than a half an hour.
Allow yourself the first two to three days to compensate for lost time. This means holding off any strenuous plans until your body has readjusted to the local time. In the meantime, exposure to daylight will help your body reset its natural clock. Just remember the sunscreen!

Travellers at high altitude are prey to a constellation of ailments ranging in severity from mild discomfort to life-threatening illness. Altitude-related problems are as real a health hazard as any infectious disease, yet are too often neglected in travel preparations. Risks are mainly related to the decreased air pressure at high altitude, resulting in less oxygen in the blood. Three general principles
apply to all altitude-related health risks:

First, individuals differ tremendously in their vulnerability to the effects of high altitude. Thus, a rate of ascent suited to most members of a party may be hazardously too rapid for others. These differences in susceptibility are genetically determined and are independent of fitness or “will power”.

Second, altitude-related illness can almost always be entirely prevented with very simple precautions.

Finally, while the effects of elevation may be indistinguishable from those of hypothermia, hypoglycemia, or a host of other condition seen in travellers, any unwell person at high altitude should be assumed to have symptoms caused or exacerbated by altitude that can be relieved by immediate descent.

See Altitude Sickness in the disease section for detailed information

Source: CDC Yellow Book 1999 and LCDC http://www.hc-sc.gc.ca/pphb-dgspsp/tmp-pmv/travel/advice_e.html 1999-2000.