If your travel plans include ecotourism to a rain forest, adventure travel such as white-water rafting in Third World countries or backpacking in remote areas, extra health precautions are necessary.
There are vaccines for such typical diseases as cholera, diphtheria, tetanus, hepatitis, polio, rabies, typhoid fever and yellow fever. However, you can't take all the shots at one time; indeed, it's wise to space some weeks to a month apart.
And malaria prophylaxis is provided through medication taken before, during and after your journey.
It's best to get your injections from your own physician, county health clinic or tropical medicine specialist before leaving home. Factors such as age or an existing medical condition or medication program can alter the vaccination treatment. Pregnant or nursing women or women who plan to become pregnant should discuss this with their doctors.
Avoid getting injections in foreign lands: You could be trading the risk of one illness for that of AIDS or hepatitis.
Many of the diseases mentioned above are transmitted by contaminated food or water or through mosquito bites. Which disease you need to protect yourself from depends primarily on where you are going, how long you'll be staying and the time of year you are traveling.
The information here is for adults in good health:
Cholera _ Travelers to South and Central America need be particularly concerned with cholera; it reached epidemic proportions in 1991 and is still widespread. There's been an epidemic in Africa for 20 years.
This acute diarrheal infection is transmitted through contaminated food or water.
The primary series vaccine is given in two doses one week to one month apart. A booster can be given every six months. Since the vaccine is only 50 percent effective, some physicians believe it gives a false sense of security.
Diphtheria/Tetanus _ These two diseases are listed together because protection from them is usually administered in one shot. Typically in the United States, children are given immunization for diphtheria and tetanus as part of a routine program before entering school.
Diphtheria causes inflammation of the heart and nervous system and is transmitted through contaminated food or milk. Tetanus (also called lockjaw) is an acute infectious disease that enters the body through a wound or cut.
Hepatitis _ Hepatitis A, a viral disease, attacks the liver and interferes with its ability to cleanse the body. It is caused by contaminated water and food.
Immune globuli is given in a single dose, for travel of less than three months. For longer journeys, additional treatment is recommended.
Hepatitis B is acquired through blood contact or sexual activity. Protection is generally given to health-care workers and to those visiting endemic areas for more than six months.
Malaria _ Caused by the bite of an infected female Anopheles mosquito, malaria symptoms include sweating, fever, headache, malaise and shaking.
Appropriate chemoprophylaxis depends on the area to be visited . The first line of defense is chloroquine (brand name, Aralen). This is taken once a week, beginning one to two weeks before arrival in the area, continuing through each week in the affected area, and for four weeks after leaving.
However, in many regions of the world, the malaria parasite has developed resistance to chloroquine. For these areas, mefloquine (brand name, Lariam) is taken on the same schedule as chloroquine.
Mefloquine is not recommended for pregnant women, children under 30 pounds or someone with a history of epilepsy, psychotic disorders or adverse reaction to the drug.
Typhoid Fever _ Initial symptoms are flu-like, followed by a high fever, then diarrhea or constipation. It is caused by salmonella typhi, found in contaminated food and water.
An oral vaccine is given in four doses over seven days. The preferred plan for the injected vaccine is two doses four weeks apart; or it can be given in three doses seven days apart, but this treatment provides less protection.
Yellow Fever _ A yellow fever inoculation is the one most likely to be required for entry into other countries. This viral disease is caused by mosquito bites and is marked by fever, vomiting and jaundice.
The vaccine is one shot, renewed every 10 years. It must be administered by an approved Yellow Fever Vaccination Center. State and local health departments can identify regional centers. The center provides an International Certificate of Vaccination that must include the center's official stamp and be signed by the provider.
Even though you have received inoculations for these diseases, don't think you can disregard common sense measures to safeguard your health.
Most of these diseases are transmitted either through ingesting contaminated food or drink or through a mosquito bite. Protect yourself from mosquitoes by wearing long-sleeved tops tucked into long pants with snug cuffs. Permethrin (brand names Permanone and Nix) is available for spraying on clothes and will last through several washings.
DEET (N,N-diethylmethylbenzamide) in 30-percent solution is recommended for use on exposed skin. It should be washed off when indoors.
Patricia Stafford is a freelance writer living in Los Angeles.