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Travel Medicine

Almost 500 million people annually venturing across international borders. Of these, it is estimated that 40 million Americans travel or work abroad annually. Although most travelers complete their business or holiday without medical upset, many have special medical needs that require individualized attention before their departure or develop problems while abroad.

Family physicians are in an excellent position to provide valuable pretravel counseling for patients and attend to the needs of returning travelers. Although many physicians associate travel medicine with rare and exotic tropical illnesses, most morbidity that occurs during

The most critical encounter with a prospective traveler is the pretravel brief. During this session, it is essential to review the traveler's proposed itinerary, medical history, current medications and current immunization status. In many offices, patients are asked to complete a short questionnaire before the visit to help the staff efficiently target issues that need to be addressed (Appendix A).

The pretravel brief should focus on the following issues:

1. Immunization review and update.

2. Behavioral counseling (food and water precautions, protective measures against insect bites, safe sexual behavior, motor vehicle safety, etc.).

3. Prevention of malaria and other insect-borne diseases.

4. Management of traveler's diarrhea (recognition of symptoms, initiation of self-treatment).

5. Prevention of sexually transmitted diseases.

Immunizations

Immunizations are the cornerstone of preventive medicine for travelers. In general, there are three classes of immunizations to consider for travelers: routine immunizations (ie, not directlybe followed.

Routine Immunizations

Diphtheria, Tetanus, Pertussis and Haemophilus influenzae Type B. All adult travelers should be advised to have current (within 10 years) immunization against diphtheria and tetanus. Travelers to the former Soviet Union should be aware of recent diphtheria epidemics. For travelers requiring booster doses, the combination vaccine with tetanus and diphtheria toxoid (Td) should be used.

Measles, Mumps and Rubella. Measles (rubeola) remains endemic in many developing nations. For this reason, all travelers to developing countries should have current vaccination

Varicella. Vaccination against varicella zoster is now routinely offered as a part of the primary childhood immunization schedule. There are no special considerations for travelers.

Hepatitis B, Since the introduction of the recombinant DNA vaccine against hepatitis B, universal immunization during infancy has been widely endorsed, and hepatitis B vaccine is now considered a

CONDITIONAL ROUTINE IMMUNIZATIONS

Pneumococcal Pneumonia. Vaccination with the polyvalent pneumococcal preparation should be considered in all persons over age 65, asplenic persons and those with specific comorbid conditions, such as diabetes mellitus or chronic lung disease. Travel confers no added risk.

TRAVEL-SPECIFIC IMMUNIZATIONS

Hepatitis A. Hepatitis A is the most common vaccine-preventable illness acquired by travelers. It is critical that at-risk individuals receive vaccination against hepatitis A. Before 1995, individuals at risk were given prophylactic immune globulin. Travelers from the United States to areas outside of Canada, Japan, Australia, Scandinavia or Western Europe (Figure 1) should now receive the hepatitis A vaccine rather than immune globulin. Hepatitis A vaccine (Havrix®, Vaqta®) is

Yellow Fever. Yellow fever vaccine (YF-Vax) is the only remaining vaccination required for entry 1o some countries. It is a live virus preparation made from the 171) strain of the yellow fever virus. The World Health

Cholera. No countries officially require proof of immunization against cholera before entry. The parenteral vaccine is a killed bacterial preparation that confers incomplete immunity. Several promising oral vaccines against

Typhoid. Three preparations are available for immunization against typhoid fever. This vaccination should be

Plague. Plague vaccine is a killed bacterial preparation and is not recommended for the routine traveler. Candidates for the vaccine include persons with prolonged occupational exposures, such as anthropologists or

Typhus. Typhus vaccination is not recommended, and manufacturing of the vaccine has been discontinued in the United States.

Meningococcal Meningitis. Meningococcal vaccine (Menomune®) is indicated for pilgrims to Saudi Arabia during the Hajj season. Other potential recipients include travelers to epidemic areas, such as sub-Saharan Africa,

Rabies. Rabies-infected animals can be found around the globe. Preexposure prophylaxis with human diploid cell rabies vaccine (Imovax®) should be considered only in travelers at particularly high risk of acquiring a wild

Japanese Encephalitis. Japanese encephalitis vaccine 0E-VAX®) is a killed viral preparation and is recommended for travelers who anticipate a prolonged stay in endemic areas, such as rural Asia, where they

Tuberculosis. The bacille Calmette-Guerin (BCG) vaccine is not routinely recommended in areas with ongoing

Protective Measures Against Insect Bites

Another critical function of the pretravel brief is to provide the traveler with a thorough review of protective measures to prevent insect bites (Table 3). Although vaccinations are available against several of the more

ALTITUDE SICKNESS

Altitude sickness refers to a continuum of pathophysiologic processes that occur when a person is exposed to continuous ambient altitudes that are higher than normal for the individual. In areas of higher elevation, less

JET LAG

Jet lag refers to the physiologic and psychologic changes that occur when travelers rapidly cross multiple time zones. Symptoms are primarily due to an alteration of innate circadian cycles. Social and environmental cues

Food- and Waterborne Illnesses

After leaving the Caribbean Islands, the Joneses plan to travel to South America, heading to Brazil for Carnival. They will also visit Uruguay, Argentina and the Falkland Island&

Various diseases are transmitted through contaminated food or water. Travelers must comply with safe food and beverage precautions to minimize the risk of acquiring such diseases.

TRAVELER'S DIARRHEA

Traveler's diarrhea is the most frequently encountered pathogenic state associated with international travel. Between 20 and 40 percent of short-term travelers mad 70 percent of long-term travelers experience one or more episodes of diarrheal illness while abroad, representing approximately 300 million cases of traveler's diarrhea per year. Studies have shown that despite adequate counseling and knowledge regarding proper food and water

Causes of traveler's diarrhea are listed in Table 9. Enterotoxigenic strains of Escherich-ia colt account for 33 percent of all cases,so Illness is due to the production of an entero-toxin that creates a secretory state within the bowel lumen. Salmonella, Shigella and Campylobacter species are other bacterial causes of traveler's diarrhea. Vibrio para-haemoI.ticus has also been associated with acute diarrheal illness, and infection usually results from consuming raw or inadequately cooked seafood. Viral causes are presumed to be common. Parasitic (e.g., Giardia) and pro-tozoal (e.g., Cryptosporidium) infections are unusual causes (Table 9).

HEPATITIS A

As previously mentioned, hepatitis A is the most frequent vaccine-preventable infection in travelers. It is primarily acquired via the fecal-oral route and usually results from contaminated food, water or ice. Person-to-per-son

TYPHOID FEVER

Typhoid fever (enteric fever) is a systemic bacterial illness caused by Salmonella typhi or Salmonella paratyphi. The disease is transmitted by consumption of food or water that is contaminated by the feces of infected

MALARIA

Malaria is the most common infectious disease in the world. Over 300 million people are affected annually, with an estimated 1.5 million deaths. Malaria is most common in South and Central America, sub-Saharan Africa, the Middle East, the Indian subcontinent, Southeast Asia and the Pacific Islands (Figure 4). Malaria is not

Malaria is caused by a blood-borne parasite that is transmitted by the bite of an infected female Anopheles

Four species of Plasmodium can cause malaria: Plasmodium falciparum, Plasmodium vivar, Plasmodium ovale and Plasmodium malariae. P. falciparum is responsible for the majority of cases of malaria and accounts for 95 percent of malaria-related deaths. P. falciparum is

DENGUE FEVER

Dengue fever (breakbone fever) is an acute febrile illness caused by four types of fiavivirus. It is the most geographically widespread of all of the arthropod-borne illnesses. It is estimated that 10 million to 40 million cases of dengue fever occur annually worldwide. Epidemics have been reported and are primarily concentrated

YELLOW FEVER

Yellow fever is another acute viral infectious disease caused by a flavivirus primarily transmitted by the A. aegypti mosquito. The disease has two distinct transmission patterns: a sylvatic or jungle form, which occurs in the tropical forests of Africa and South America, and an urban form, which is most common in West Africa. In

JAPANESE ENCEPHALITIS

Japanese encephalitis is another arthro-pod-borne illness caused by a flavivirus. The disease is common in rural areas of Korea, Japan and China. It is spread by species of Culex and Anopheles mosquitoes that commonly

LEISHMANIASIS

Leishmaniasis is a protean disease of skin and mucous membranes (with potential visceral involvement) caused by protozoa of the genus Leishmania. The disease is transmitted by the bite of

AMERICAN TRYPANOSOMIASIS

American trypanosomiasis, or Chagas' disease, is a zoonotic infection caused by the protozoan Trypanosoma cruzi. It is transmitted by bites from an infected reduviid bug (kissing bug) when the insect's fecal material

AFRICAN TRYPANOSOMIASIS

African trypanosomiasis, or African sleeping sickness, is an illness caused by the protozoan Trypanosoma gambiense. It is transmitted by the bite of an infected tsetse fly. Symptoms include fever, headache, painless

PLAGUE

Plague is a bacterial infection caused by Yersinia pestis and is spread through the bites of infected fleas. Although historically significant pandemics of plague have been due to epizootic outbreaks in rat species that

TYPHUS

Scrub and tick typhus (not to be confused with typhoid fever) are rickettsial diseases spread by mites and ticks, respectively. Patients present with fever, myalgia, headache and a maculopapular rash. Eschar is often present

SCHISTOSOMIASIS

Schistosomiasis is an infectious disease caused by blood flukes (trematodes) acquired by swimming in contaminated bodies of fresh water. Three main species of Schistosoma pathogenic to man exist, and each has