Online Medical Reference

Travel Medicine for the
Primary Care Physician

Steven D. Mawhorter

Published: August 2010

International tourism and business travel is a growing industry. The World Tourism Organization has estimated that there were 675 million international travelers in 1999, roughly a 50% increase compared with the prior decade.1 Although most international travel is in developed countries, more than 10 million persons from the United States and Canada travel to developing countries each year.1 Many destinations lack pure water systems and disease control programs. Travel to these countries requires specific preparation to avoid illness, and general health advice should be sought before international travel. Physicians are often called on to prepare their patients for travel and to treat them afterward. A primary care provider might serve this role, but the constantly changing and highly specialized information makes a dedicated travel medicine expert more likely to be able to handle the individual needs of varied travelers and their unique itineraries. A study by the Centers for Disease Control and Prevention2 has found that primary care physicians and even the embassy staff of foreign countries could not completely prepare their patients. Consulting an international travel medicine expert before travel reduces the risk of illness associated with travel sevenfold.

This chapter focuses on aiding the primary physician to partner with travel medicine experts. It emphasizes areas of travel medicine that are commonly encountered and therefore most practical for primary care physicians to address.

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Definition

A functional definition of the goals of travel medicine is to:

  • Counsel patients about how to avoid risky behavior and exposure to infectious agents or disease vectors (pretravel counseling).
  • Immunize against illness when it is difficult to limit exposure.
  • Use preventive or symptom-triggered medications when immunization vaccines are not available.

There are new consensus guidelines on travel-related health issues in the United States from the Infectious Diseases Society of America. In addition, the Canadian Health System (Health Canada) has published its own set of guidelines on topics related to travel medicine. It should be noted that, like any guidelines, these represent only a starting point for care, which must be individualized for each person coming for travel advice. Moreover, it must be realized that because medicine availability varies among countries, some recommendations may not fit with available resources in the reader’s home country. Specifically, there is no oral cholera vaccine available in the United States.

The Centers for Disease Control and Prevention (CDC) has revised its travel notice definitions and uses more common terminology. The four-tiered system is designed to help travelers and health care professionals assess risk in the ever-changing landscape of international travel. The CDC travel section (http://wwwn.cdc.gov/travel/) provides recognized expertise from a U.S. perspective, especially in the Yellow Book section.

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Prevalence

Fifty percent to 75% of travelers to the tropics and subtropics report minor medical complaints, many of which are preventable. This high incidence emphasizes the importance of pretravel counseling. Overall, up to 10% of travelers alter their planned activities because of illness, mostly traveler’s diarrhea, 5% become ill enough to require medical attention abroad, and 2% are too ill to be able to immediately return to work after their return.4

Fatal illness while traveling is extremely rare. Although 1 in 100,000 Swiss travelers to developing countries has died while traveling, compared with 0.3 in 100,000 travelers to North America, both mortality rates were lower than for those who did not travel.5 Such statistics reflect the general good health of most travelers.

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Pretravel Counseling for all Travelers

Pretravel counseling should be sought before international travel begins. The following health issues and priorities have been outlined.1,3 The traveler should first be advised about required immunizations based on international regulations. In addition, many other immunizations are recommended to reduce the impact of destination-specific health risks. Second, issues of malaria risk, prevention, and chemoprophylaxis should be reviewed. Third, general health advice should include the following:

  • Food and beverage precautions
  • Insect bite avoidance
  • Accident and injury prevention
  • Risk-behavior management—drug use, casual sex, personal safety, high-altitude adjustment

These reflect the most prominent health-related issues associated with international travel, especially travel to lesser developed countries. Tailoring the advice to the individual traveler is important and usually requires the expertise of the travel medicine specialist.

The importance of sunscreen and insect repellent should be stressed. It is good to reinforce food and water precautions, including brushing the teeth with purified or bottled water and avoiding ice in drinks.

Jet Lag

Jet lag is a common unavoidable condition, without any specific therapy. Over the years, many remedies have been sought, but no magic bullet has been found. Adequate hydration and avoidance of excess alcohol are two of the most useful tips.6 Melatonin is involved in the circadian cycles in many animals, leading to considerable interest in its potential role for treating jet lag. Studies of melatonin in travelers have shown small and inconsistent reductions in jet lag symptoms.7,8 The safety of melatonin has not been established, although it is widely available in health food stores. Some evidence supports exposure to outdoor sunlight at the travel destination, which may speed acclimatization.7,8 Important events and meetings are best scheduled at least 48 hours after arrival, if possible.

Electronic Resources

Patients with access to the Internet can review helpful information about medical preparation for foreign travel from several sources (see later, “Resources for Travelers: Electronic Resources”). One of the most notable is the CDC travel information section. The World Health Organization also posts information related to international travel health concerns. A particular advantage of these sources is that they allow the patient to review information related to specific travel plans, which will generate focused questions for review during pretravel counseling. For practical travel information, including passport and visa questions, as well as U.S. State Department travel advisory information, their website is an excellent resource.

Immunization

More than one dozen vaccines are available for diseases with a high prevalence in developing countries (Box 1). Some are the familiar vaccines recommended for all Americans and others are for diseases mostly found in the developing world or in specific travel destinations. The vaccines that a traveler needs depend on the itinerary and the patient’s current immunization status. Primary care physicians should make sure that travelers are up to date in their routine immunizations before going abroad; however, immunizations for rare and travel-related diseases are best left to experts in travel medicine.

Box 1 Immunizations for Travelers
Routine Vaccinations
Inactivated
Diphtheria-tetanus (Td vaccine for persons ≥7)*
Hepatitis A*
Influenza
Pneumococcal
Poliomyelitis (inactivated)*
Hepatitis B
Live Attenuated
Measles-mumps-rubella
Travel-Specific Vaccines
Inactivated
Anthrax
Japanese encephalitis
Meningococcus*
Plague
Rabies
Typhoid (Vi antigen)
Diphtheria-tetanus (Td vaccine for persons 7 years of age and older)*
Hepatitis A*
Influenza
Pneumococcus
Poliomyelitis (inactivated)*
Hepatitis B
Live Attenuated
Measles-mumps-rubella
Typhoid (Ty21a)
Yellow fever*

*Frequently recommended.

†Occasionally recommended.

‡Rarely recommended.

© 2002 The Cleveland Clinic Foundation.

Vaccines for Primary Care Administration

Adults who have not completed their primary vaccination series need to complete them for full protection.9 Updated general vaccine information, as recommended by the Advisory Committee on Immunization Practices (ACIP) can be found at the National Immunization home page on the CDC website (http://www.cdc.gov/vaccines/). Vaccine-based immunity to tetanus, diphtheria, pertussis, polio, and other entities wanes over time, and these diseases are more prevalent abroad; booster vaccination is recommended. Pregnant or immunocompromised travelers should seek specific advice from a travel medicine specialist. Some guidelines regarding vaccines for pregnant travelers can be found at http://www.cdc.gov/vaccines/pubs/preg-guide.htm.

Tetanus-Diphtheria. After the initial series, boosters should be given every 10 years. Many of the now-independent former Soviet states have experienced diphtheria outbreaks, which can be life-threatening but are vaccine preventable. A newer formulation of tetanus vaccine now includes both diphtheria and an acellular pertussis component (Tdap). This is the current recommendation of the ACIP when booster doses are needed.

Influenza Vaccine. Influenza vaccine should be given every fall to those older than 65 years or younger people with chronic disease. Of note, the peak influenza incidence in the Southern Hemisphere is during their winter season, June through August.

Pneumococcal Vaccine. Pneumococcal vaccine should be given to all persons older than 65 years.

Polio Vaccine. A single booster of inactivated poliovirus vaccine provides lifelong protection in adults who have received the primary series. The exceedingly rare reports of wild-type polio in the Western Hemisphere make the vaccine optional for travel there. Polio is a viral disease transmitted by oral contamination. Rare outbreaks in Africa and Asia are reinforcing the recommendation for adult travelers to receive a booster before travel to certain destinations.

Measles Vaccine. For travelers born after 1957, a second measles booster, if not previously given, should be considered, given the high prevalence of measles in the developing world. As recent as 2006, mumps outbreaks in the United States and measles (rubeola) in Germany indicate, even travel to developed countries may pose certain vaccine-preventable risks. Two doses of vaccine at least 28 days apart are considered protective for measles, mumps, and rubella (MMR).

Hepatitis A Vaccine. Hepatitis A vaccine is highly recommended for almost all international travelers. Hepatitis A is prevalent and is spread through contaminated food and water. This inactivated virus vaccine achieves 80% to 98% immunity within 15 days after one intramuscular dose.10 A booster dose at 6 months provides prolonged immunity for up to 10 years or longer. Minimal arm soreness at the site of injection and self-limited headaches are occasionally reported. Safety and efficacy have been shown in patients as young as 1 year of age. Good data support the efficacy of the vaccine, even when given immediately before travel, obviating the need for immune globulin.11 A combination hepatitis A and B vaccine (Twinrix) produces higher titers to each agent compared with univalent vaccine (see elsewhere in this text, “Hepatitis A”).

Hepatitis B Vaccine. Hepatitis B vaccine was recently added to the routine vaccine schedule for children. However, unvaccinated adults typically receive this vaccine only when they expect high-risk exposure to blood or body fluids. The schedule, three shots over 6 months, does not make this vaccine “travel friendly.” Travelers planning extended travel to developing countries, or traveling to adopt a child from an endemic area, may benefit from vaccination. Accelerated protocols to achieve protective immunity within four weeks exist using combination hepatitis A and B vaccine.12 A booster at twelve months was performed in the study participants.

Vaccinations by Travel Medicine Specialists. Some travelers to high-risk areas need vaccinations against meningococcus, yellow fever, and typhoid. These three are generally well-tolerated vaccines. Uncommon diseases such as anthrax, rabies, plague, and Japanese encephalitis are also preventable with immunizations. However, because of the rarity of these diseases and the fairly significant local side effects of their vaccines, these vaccines should only be used for travelers at especially high risk.9 Knowing when to give these vaccines requires the expertise of a travel health specialist.

Meningococcal vaccination is recommenced for the “meningitis belt” of sub-Saharan Africa and other focal areas, depending on disease prevalence. Physicians must review travel health advisories frequently to stay abreast of this critical information. Because of crowded conditions and extensive international mingling, this vaccine is required for all pilgrims on the Hajj and Umrah to Mecca.

Yellow fever occurs throughout most of urban and rural South America and Africa. The live attenuated vaccine is highly effective, but can only be given at a state-approved center. Although direct travel to a nonendemic area requires no vaccinations, some countries require proof of vaccination before entry if the traveler’s itinerary includes any areas of possible yellow fever exposure.9 Hence, most travelers to South America and Africa need to go to a travel clinic that can give yellow fever vaccine.

The recommendation for typhoid vaccination is itinerary-specific. The original inactivated vaccine had a high incidence of bothersome reactions. Currently, an oral live attenuated typhoid vaccine (Salmonella typhi Ty21a) and an improved, inactivated, injectable typhoid vaccine (Vi antigen) are available. Special instructions are needed for the oral vaccine, including avoiding coadministration of antibiotics.

General Issues Related to Travel Vaccination

Coadministration. Multiple vaccinations are often recommended for travel to developing countries. This raises important practical issues about vaccine coadministration. Inactivated vaccines can be given on the same day without altering their immunogenicity,9 although local reactions such as arm soreness may be greater when this is done. Studies have revealed that diphtheria, pertussis, and tetanus, inactivated poliomyelitis vaccine (or oral poliovirus vaccine), Hemophilus influenzae type b, measles, mumps, and rubella, and hepatitis B vaccine may all be given on the same day, with consistent efficacy.

In theory, live virus vaccines may impair the immune responses of each other, and it is suggested that they be given more than 30 days apart. The live attenuated yellow fever and oral poliovirus vaccines are not affected by coadministration.

Immunoglobulin. If it is necessary to give immunoglobulin for passive antibody protection, inactivated vaccines may be given at the same time with no impact on their efficacy. MMR vaccine is best given at least 14 days after immunoglobulin, and 6 months after whole blood or red blood cell transfusion.

Adverse Reactions. The most typical adverse reaction is arm soreness. It is often helpful for the traveler to take acetaminophen regularly for 2 to 3 days after vaccine administration to diminish local arm soreness. The most common adverse allergic vaccine reaction is an egg protein allergy. Because influenza vaccine is developed in embryonic chicken eggs, as is the yellow fever vaccine (see later), caution must be exercised. Also, measles and mumps vaccines are developed in chicken embryo cell cultures. In general, if patients can eat eggs and egg products without reaction, they can receive the vaccines without reaction. Protocols exist to enable vaccination of patients with significant allergy.13

Rare patients are allergic to the vaccine antigen, animal proteins, antibiotics, preservatives, or stabilizers used in vaccine preparations. No currently recommended vaccines contain penicillin or penicillin derivatives. MMR vaccine contains trace amounts of neomycin. However, almost all those with neomycin “allergy” actually show a delayed-type hypersensitivity contact dermatitis rather than a systemic allergic response.9 This reaction is not a contraindication to receiving the vaccine.

Rare anaphylactic reactions to diphtheria and tetanus vaccines have been reported. Skin testing to tetanus toxoid is available to determine whether a patient truly has this sensitivity.

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Specific Conditions

The six leading health problems of travelers are listed in Box 2. Motor vehicle accidents are the leading cause of morbidity and mortality in travelers. Traveler’s diarrhea and hepatitis A are examples of common food- and water-borne illnesses. Malaria is a vector-borne illness, and gonorrhea is a sexually transmitted disease. Although routes of acquisition vary, most of these disorders are preventable.

Box 2 Leading Health Problems of International Travelers*
Motor vehicle accidents
Diarrhea
Malaria
Upper respiratory tract infection
Hepatitis A
Gonorrhea

*Listed in order of frequency.

© 2002 The Cleveland Clinic Foundation.

Motor Vehicle Accidents

Motor vehicle accidents remain the leading cause of accidents and mortality around the world for travelers. Hence, the most life-affecting advice we give is to buckle up and drive defensively. When renting a car overseas, travelers should specifically request one with seat belts; they are not standard equipment in all countries. Moreover, taking safety precautions while driving limits the risk of a significant accident with trauma that may require a blood transfusion in a setting in which the blood supply is not necessarily safe.

Traveler’s Diarrhea

Traveler’s diarrhea is a clinical entity defined as three or more loose or watery stools within 24 hours, associated with one or more additional constitutional symptoms, including crampy abdominal pain, nausea, or both.6 Most cases are acute, watery, and self limited, without dysenteric or chronic symptoms. Causes of watery diarrhea include bacteria (>80% of cases), viruses, and parasites. Enterotoxigenic Escherichia coli is the leading bacterial pathogen (Box 3). Other causes vary by geographic location and time of year. Chronic diarrhea is usually nonbloody, without fever, but extends over a few weeks (Box 4). Dysentery or bloody diarrhea accounts for up to 15% of cases of traveler’s diarrhea. Bloody stools indicate a more invasive process, referred to as dysentery, which has an overlapping but slightly different list of causative organisms. Fever more often accompanies dysentery.

Box 3 Pathogens Associated With Acute Diarrhea in Travelers
Watery Diarrhea
Enterotoxigenic Escherichia coli
Salmonella species
Shigella species
Campylobacter species
Vibrio spp., including V. cholera
Noroviruses
Dysentery
Shigella species
Salmonella species
Campylobacter species
E. coli O157:H7
Entamoeba histolytica

© 2002 The Cleveland Clinic Foundation.

Box 4 Causes of Chronic Diarrhea in Travelers
Pathogens
      Giardia lamblia
      Entamoeba histolytica
      Cryptosporidium
      Cyclospora
      Schistosoma mansoni
      Schistosoma japonicum
Malabsorption
Tropical sprue

© 2002 The Cleveland Clinic Foundation.

Avoiding Foodborne and Water-borne Illnesses

Some precautions can make eating overseas much safer. Travelers should be counseled to adhere to the following recommendations:

  • Choose foods that are thoroughly and recently cooked, not reheated.
  • Wash all fruits and vegetable with clean water before slicing them, to avoid carrying bacteria into the otherwise clean inside layers. Raw fruits and vegetables peeled by travelers are usually safe.
  • When dining out, where one has less control over food preparation, avoid raw meat, fish, and vegetables, especially salads. Street vendor food is risky unless properly prepared in front of you. Caution must even be exercised regarding airline food prepared in lesser developed countries.
  • Avoid drinking tap water; even hotel tap water used for brushing teeth can be a source of infection. Ice should be considered contaminated, including ice cubes on flights that originate in developing countries. Commercially prepared bottled or canned beverages are usually safe alternatives to water.
  • Purify drinking water by boiling it, treating it with halogens (chlorine or iodine), or filtering it when reliably clean water is not available. Water brought just to a boil before cooling is generally as safe as water boiled for several minutes.6 Compared with boiling, halogen treatment is less likely to remove parasites. Because halogens are most effective in clear water, cloudy water should first be allowed to settle until clear. Filters are somewhat expensive, but effective. The combination of halogen treatment and filtering is almost as good as boiling.

In summary, regarding food and water precautions, the CDC has developed a simple rule of thumb: “Boil it, cook it, peel it, or forget it.”

Prophylaxis

Prophylactic antibiotic use is generally discouraged.14 Widespread medication use increases the likelihood of side effects, including photosensitivity, vaginal and superficial fungal infections, and severe drug reactions, such as Stevens-Johnson syndrome. It is a nuisance to take a medication every day for a condition that may not develop. Prophylactic medication use may also lead to a false sense of security, resulting in decreased compliance with the more important and effective general recommendations for food and water precautions. Finally, antibiotic resistance is a growing problem, with well-documented examples among diarrheal pathogens. Prophylactic antibiotic use is more likely to induce resistance than the occasional treatment regimens outlined below.

Diagnosis

The diagnosis is clinical. The categorization of routine traveler’s diarrhea versus dysentery versus chronic diarrhea has been noted earlier.

Treatment

Dehydration is the major health risk. Oral rehydration solutions containing both carbohydrates or sugar and salt are optimum as fluid replacement. Patients can prepare their own inexpensive solutions, using simple and available ingredients (Fig. 1). The cereal-based formula provides four times as many calories as the glucose-based recipe, and may help decrease the stool volume and duration of diarrhea.6 Ricelyte, a fully prepared cereal-based oral rehydration solution, can be purchased over the counter.

The principle behind oral rehydration is that glucose facilitates water absorption, and sodium absorption is coupled with glucose absorption. Too much sugar inhibits water absorption and can actually cause water loss via osmotic diarrhea. An ideal glucose concentration for water absorption is about 2.5%. Many drinks, such as apple juice, cola, sports drinks, and flavored gelatin contain about 6% glucose. These drinks can be diluted by adding approximately 1.5 volumes of water. It is important to dilute with clean (bottled, boiled, or chemically treated) or sterile water to avoid an increased infectious burden or secondary infection.

Untreated, traveler’s diarrhea (TD) usually remits spontaneously in 3 to 5 days. Antibiotics often diminish the symptoms of traveler’s diarrhea to approximately 1 day, and the addition of loperamide (Imodium) may further reduce the duration of symptoms to less than 1 day.14 However, loperamide therapy should be avoided if the diarrhea is bloody or fever is present (dysentery). These symptoms should also be used as indicators to seek local medical attention, because they may indicate a more serious medical condition. Symptom-initiated antibiotic treatment is usually effective when taken for 1 to 5 days.6

Several options for pharmacologic therapy include bismuth subsalicylate, ciprofloxacin, azithromycin, furazolidone (Furoxone), and rifaximin (Xifaxan). Although bismuth subsalicylate can be effective as prophylaxis and treatment, the large doses required make it impractical. It also binds to antibiotics and limits their effectiveness. The quinolones are rapidly effective for the common causes of traveler’s diarrhea. Furazolidone is not as rapidly effective as the quinolones, but can be given to children and has anti-Giardia activity (when given for 7-10 days) not seen with the other antibiotics. More recent data make azithromycin an attractive option for children and quinolone-allergic adults.15 Rifaximin is a newly approved nonabsorbable antibiotic. It is indicated for persons older than 12 years with TD caused by noninvasive strains of E. coli. The narrow spectrum of rifaximin and recent availability of generic ciprofloxacin continue to make quinolones my preference for episodic self treatment of TD in adults. Emergence of quinolone-resistant diarrheal pathogens, especially in South Asia, reinforces the need for updated expertise and itinerary-specific recommendations.

Recommendations

I currently recommend ciprofloxacin, twice daily for 3 days, as symptom-initiated treatment for traveler’s diarrhea in adults.6,14 Some newer quinolones such as levofloxacin (Levaquin) may induce more photosensitivity, making them less attractive for travelers. Azithromycin (Zithromax) is a current alternative for children or for those unable to tolerate quinolones, although not U.S. Food and Drug Administration (FDA)-approved for this indication (Table 1).

Table 1 Recommended Medications for Acute Traveler’s Diarrhea
Medication Age Group Dosage*
Ciprofloxacin (Cipro) Adults 500 mg twice daily
Ofloxacin (Floxin) Adults 400 mg twice daily
Azithromycin (Zithromax) Adults 500 mg once daily
Children >6 mo 10 mg/kg once daily (max 500 mg/day)
Furazolidone (Furoxone) Adults 100 mg four times daily
5-17 yr 25-50 mg four times daily
1-4 yr 15-25 mg four times daily
1 mo-1 yr 7-15 mg four times daily

Furazolidone duration is 7 to 10 days when treating Giardia lamblia.

*All medications are recommended for 3 days for this indication (range 1 to 5 days).

© 2002 The Cleveland Clinic Foundation.

Chronic Diarrhea

Rarely, travelers experience chronic diarrhea, often with weight loss and malabsorption.16 Because the pathogens responsible are often not self limited and not sensitive to quinolone antibiotics (see Box 4), further medical care is necessary. These patients typically present to their primary care physician after returning home. Physicians should identify the causative agent and give pathogen-specific therapy in this situation. Dysentery is a serious medical condition. Again, it is important to make a specific diagnosis. Dysentery should be managed under the direct supervision of a physician.

Malaria

This review of travel medicine will not review classic malaria disease issues, but rather will focus on its prevention in international travelers. Each year, more than 7 million Americans travel to countries in which malaria is common.6 There are 1000 to 1500 reported cases (underreporting is common) of malaria each year, with the greatest number (≤83%) coming after travel to East Africa.6 Most mosquitoes that transmit malaria are found in rural areas, in contrast to those that transmit yellow fever. Therefore, travel to major urban areas usually does not pose a risk for malaria, but even short trips to rural areas may place travelers at risk.

Avoiding mosquitoes is the first objective. Travelers should use insect repellents and mosquito nets and consider staying indoors in the evening, which is the peak biting time for malaria-carrying mosquitoes. Soaking bed netting and clothing in permethrin can significantly reduce mosquito bites. Permethrin is colorless and odorless and remains active even after laundering. Diethyltoluamide (DEET) is one of the most widely recommended repellents. The product should contain 30% to 50% diethyltoluamide. Products with higher concentrations (≤100% diethyltoluamide) are not necessary and could, rarely, cause serious side effects, especially in young children. Microencapsulated preparations are still effective with the least systemic absorption. A new repellent, picaridin, has efficacy similar to diethyltoluamide when compared on a percentage active ingredient basis. Note that dark clothing, cologne, and perfume attract mosquitoes. Early enthusiasm for Skin-So-Soft, a moisturizing bath oil, has not been borne out as an effective insect repellent.

Given the potential severity of malaria, additional measures are prudent, including prophylaxis.

Prophylactic Drugs

No effective vaccines against malaria are currently available, but prophylactic medications dramatically reduce the risk. To select these medications, physicians need current data on the resistance patterns and relative risk of malaria in the country of destination, and knowledge of side effects and contraindications. The complexity of these considerations mandates referral to a traveler’s clinic. Drug resistance and specific travel plans are major reasons to choose one medication over another.

Chloroquine (Aralen) is the oldest, safest, and best tolerated of the available medications. It is safe throughout pregnancy (although pregnant women should avoid malaria-infested areas, if at all possible). Unfortunately, chloroquine-resistant strains of malaria are increasing, nearly all of them in Plasmodium falciparum, the most deadly of the parasites that cause malaria. Consequently, the areas of the world where chloroquine is still useful are continually shrinking and now include only Central America, the Caribbean, and limited parts of the Middle East and China.

Mefloquine (Lariam) is an alternative drug in areas of chloroquine resistance. Mefloquine can have unpleasant side effects of dizziness, anxiety, insomnia, and nightmares, which have been much publicized in recent travel literature.17 However, a similar incidence of central nervous system reactions was noted among Peace Corps volunteers who took chloroquine.18 Mefloquine reactions are more common in young adults than in older adults and children, and are potentiated by alcohol. The drug should be avoided in patients with a history of seizures or psychiatric disorders. Fairly extensive worldwide use has documented relatively safe use in the second and third trimesters of pregnancy. Because mefloquine works against the blood stage of malaria, which may take up to 4 weeks to appear after a bite, mefloquine must be continued for 4 weeks after leaving a malarial area.

Doxycycline (Vibramycin) is an alternative for patients traveling to areas with chloroquine resistance who are unable or unwilling to take mefloquine.6,9 However, it must be taken every day, compared with once a week for mefloquine, making it less convenient. Like mefloquine, doxycycline must be taken for 4 weeks after travel. In addition, doxycycline causes a higher incidence of photosensitization reactions, which can be particularly troublesome in sunny tropical countries. It also causes a slightly higher incidence of vaginal yeast infections. On the other hand, it may prevent traveler’s diarrhea. Of note, doxycycline is contraindicated throughout pregnancy and for children younger than 8 years.

Combined atovaquone-proguanil (Malarone) is the newest antimalarial drug on the market and is an alternative to mefloquine and doxycycline. It is active against chloroquine-resistant malarial organisms. Daily dosing ensures that a therapeutic level is reached quickly. If an extended trip has a very short segment with malaria exposure, it enables focused preventive treatment starting 1 or 2 days before entering the area. Because it works in the liver, it needs to be taken for only 1 week after leaving a malarial area. It should not be used as prophylaxis during pregnancy or in patients with renal failure.

To ensure the best effect, and because this drug can cause gastrointestinal upset, it should be taken with food or a milk-type drink or dairy product (e.g., milk, milkshake, yogurt), according to the package insert. It is crucial to recall that all such dairy products need to be pasteurized to be safe.

Signs and Symptoms

The onset of malaria can resemble a viral infection, with a fever persisting for several days and possibly weeks. The classic picture consists of shaking chills, with a very high fever and profuse sweating. The patient may also experience joint pain, nausea, vomiting, loss of energy, and headaches. After the acute malarial attack has passed, the disease may become chronic with occasional relapses if the infection is caused by a form with a relapsing liver stage (Plasmodium vivax or P. malariae, but not P. falciparum). An attack is sometimes difficult to recognize in infants and small children with no symptoms other than loss of appetite, extreme fatigue, and agitation. If a parent believes that he or she or their child is suffering an attack of malaria, expert medical assistance should be sought.

It is also important to note that the initial symptoms of malaria may occur up to 1 year after exposure. with or without preventive measures. Thus, it is necessary to emphasize the importance of patients reminding their doctor that they have traveled to an area with malaria when they are evaluated for a fever.

Upper Respiratory Tract Infections

Upper respiratory infections (URIs) are common throughout the world. Traveling brings a large number of people in contact with each other, probably accounting for the perception of increased respiratory illness when traveling. Although air is recirculated on commercial airliners, it is highly filtered, making it unlikely for a traveler to acquire a respiratory infection from another passenger. The few documented cases of severe respiratory infection acquired on airplanes are from people sitting in close proximity to the index patient on long flights.19 It is often wise to bring a favorite over-the-counter URI medication because selection and availability are unpredictable when traveling.

Severe acute respiratory syndrome (SARS) is an emerging infectious disease caused by a variant of coronavirus, a common cold virus.20 Its clinical manifestations are highly consistent with those of upper respiratory viral infections, including fever, cough, shortness of breath, and a short incubation period, typically less then 10 days. Unfortunately, SARS appears to have a much higher mortality rate, making it especially concerning. Proper attention to routine public health measures, such as hand washing and general hygiene can significantly minimize risk of infection. The additional use of face masks, especially National Institute for Occupational Safety and Health (NIOSH)-certified N95 fitted masks, can further reduce exposure when contact with a potentially infectious person is more likely. Regular surgical masks may provide some measure of protection, but the exact amount is uncertain. The 2004 SARS epidemic has abated, but it had a chilling affect on international travel during that time. In many ways, this changing nature of human health and its impact on our global world only reinforce the benefit of consultation with specialized international traveler’s health clinics before trips abroad. Itinerary review and updates on the latest information help maximize the likelihood of a healthy, productive, and enjoyable travel experience.

Influenza has been an occasional problem at some travel destinations, or rarely on some cruise lines. The issue is usually seasonal, but international travel can alter the usual timing of its occurrence. Older and immunocompromised travelers might consider adding prescription, oral, anti-influenza medication to take in case of exposure, which can be discussed with their travel health advisor. The recent concern regarding avian influenza, or “bird flu,” deserves mention. It is a rare disease contracted by those living in close contact with birds, chickens, and ducks. Average international travelers are at limited risk of disease. Precautions to take include avoiding close contact with live birds, eating only fully cooked poultry products, and paying attention to hand hygiene. Helpful information can be found at www.travel.state.gov/travel/tips/health/health_1181.html. Avian influenza pandemic concerns have prompted global efforts to institute pandemic preparedness measures. Information on the U.S. government’s overall response is available at www.pandemicflu.gov.

Sexually Transmitted Diseases

With gonorrhea among the top five diseases of international travelers and with HIV infection on the rise,21 physicians should counsel their patients about the risks and available prophylactic measures for sexually transmitted diseases. However, not all patients will follow this advice. A survey of more than 3000 Swiss travelers to developing counties found that 87% complied with recommended malaria chemoprophylaxis but, remarkably, 50% of the same travelers engaged in casual sex abroad, usually with a partner from the host country.22 Of the sexual encounters, 38% were unprotected, even though the travelers shared similar knowledge about the risks of HIV virus and other sexually transmitted diseases compared with malaria. Of note, those who engaged in high-risk sexual practices were not the same group who were noncompliant with malaria protective measures.

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Patients with Medical Conditions

If a patient with a preexisting medical condition is planning an international trip, the physician should ask about the destination and type of trip to decide whether special considerations are necessary. Examples include high-altitude destinations and adventure travel. In addition, some patients, such as those with diabetes, need special diets.6 Travelers with disabilities have special needs, and more resources are now available to facilitate enjoyable travel. (See later, “Resources for Travelers,” which includes helpful references for travelers with disabilities and special medical needs, including the location of dialysis centers.) I strongly encourage independent research to ensure that patients with disabilities plan ahead for their unique needs.

In general, patients with medical conditions should:

  • Keep their medications in their original containers to avoid customs delays.
  • Take along an epinephrine injection kit if they have severe allergies to foods or insect stings, unless this is otherwise contraindicated.
  • Consider taking a copy of their electrocardiogram, a recent medical summary, and the telephone number of their primary care physician in case a treating physician abroad needs to contact them. A list of English-speaking physicians around the world is available from the International Association for Medical Assistance to Travelers, 417 Center Street, Lewiston, NY 14092, 716-754-4883).
  • Investigate exactly what their insurance policies cover during travel overseas:
    • Medicare, for example, does not cover medical expenses outside the United States.
    • Supplemental insurance is usually available and is wise to consider.
    • Most pretravel medical evaluations and vaccinations are not covered by medical insurance plans. However, updating patients on routine immunizations, which further protect them overseas, may be covered.

Special Considerations for Coronary Artery Bypass Surgery Patients

Of note, a growing number of international travelers have previously undergone coronary artery bypass grafting (CABG). A survey of 10,000 post-CABG patients has found that 40% had traveled recently to a domestic or foreign location.23 There was a very low incidence of myocardial infarction or hospitalization during the trip. The only identified health concern was that older post-CABG patients had slightly more shortness of breath when they traveled to Mexico and South America compared with other destinations, probably because of the higher altitudes of many destinations in Central and South America.22

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Conclusion

The goal of travel medicine is to allow the patient to enjoy a long-awaited vacation or work productively when on an important business trip. The needs of travelers to developing countries are unique. To ensure a safe and enjoyable trip, special pretravel counseling and immunizations are usually necessary. Primary care physicians are often the first to be contacted about plans for international travel. Therefore, they can initiate care and select those needing referral to a travel medicine clinic. Understanding the background issues related to the international traveler will facilitate patient care and the referral process. Bon voyage!

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Summary

  • Basic precautions with food and drinking water are necessary in developing countries. Most cases of traveler’s diarrhea respond to a short course of quinolone antibiotics and oral fluid replacement.
  • Travelers to countries where malaria is endemic should work to avoid contact with mosquitoes and should take chloroquine, mefloquine, chloroguanide (Malarone), or doxycycline prophylactically. Unfortunately, chloroquine resistance is increasing.
  • With gonorrhea among the top five diseases in international travelers and with HIV infection on the rise, physicians should counsel their patients about the risks and prophylactic measures available for sexually transmitted diseases.
  • Primary care physicians should make sure that travelers are up to date in their routine immunizations before going abroad; however, immunizations for rare and travel-related diseases are best left to experts in travel medicine. Almost all travelers should be vaccinated against hepatitis A.
  • The single most important health advice to travelers is to wear seat belts. When renting a car, travelers should specifically request one with seat belts, not standard equipment in all countries.

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Suggested Readings

  • Centers for Disease Control and Prevention: Travel Notice Definitions, 2004. Available at http://wwwn.cdc.gov/travel/notices.aspx#TravelNoticeDefinitions (accessed March 9, 2009).
  • Centers for Disease Control and Prevention. Health Information for International Travel, 2008 (The Yellow Book). Philadelphia, Elsevier, 2007.
  • DuPont HL, Capsuto EG: Persistent diarrhea in travelers. Clin Infect Dis 1996;22: 124-128.
  • Franco E, Giambi C, Ialacci R, Maurici M: Prevention of hepatitis A by vaccination. Expert Opin Biol Ther 2003;3:965-974.
  • Hill DR, Ericsson CD, Pearson RD, et al: The Practice of Travel Medicine: Guidelines by the Infectious Diseases Society of America. Clin Infec Dis 2006; 43:1499-1539. Available at www.journals.uchicago.edu/doi/pdf/10.1086/508782 (accessed March 9, 2009).
  • Keystone JS, Dismukes R, Sawyer L, Kozarsky PE: Inadequacies in health recommendations provided for international travelers by North American travel health advisors. J Travel Med 1994;1:72-78.
  • Mardh PA: What is travel medicine? Content, current position, tools, and tasks. J Travel Med 2002;9:34-47.
  • Paulson E: Travel statement on jet lag. Can Med Assoc J 1996;155:61-66.
  • Peiris JS, Yuen KY, Osterhaus AD, Stöhr K: Current concepts: The severe acute respiratory syndrome. N Engl J Med 2003;349:2431-2441.
  • Pickering L (ed): 2000 Redbook: Report of the Committee on Infectious Diseases. American Academy of Pediatrics, 2000.
  • Public Health Agency of Canada: Travel health: Know before you go! Available at www.phac-aspc.gc.ca/tmp-pmv/index-eng.php (accessed March 9, 2009).
  • Steffen R: The epidemiologic basis for the practice of travel medicine. In Lobel HO, Steffen R, Kozarsky PE (eds): Travel Medicine 2. Proceedings of the Second Conference on International Travel Medicine. Atlanta, International Society of Travel Medicine, 1992, pp 11-14.
  • Yates J: Traveler’s diarrhea. Am Fam Physician 2005;71:2095-2100.

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Resources for Travelers

Books About Travel Medicine and Personal Safety

  • Centers for Disease Control and Prevention: Health Information for International Travel, 2008 (The Yellow Book). Philadelphia, Elsevier, 2007.
  • Dawood R (ed): Travelers' Health: How to Stay Healthy Abroad. New York, Random House, 2002.
  • Jong EC, McMullen R (eds): The Travel and Tropical Medicine Manual, 3rd ed. Philadelphia, WB Saunders, 2003.
  • Keystone JS, Kozarsky PE, Freedman DO, et al (eds): Travel Medicine. New York, Mosby, 2004.
  • Rose SR, Keystone JS: 2006 International Travel Health Guide, 13th ed. New York, Mosby, 2006.
  • Savage PV: The Safe Travel Book. New York, Lexington Books, 1993.
  • Scotti AJ: Executive Safety and International Terrorism: A Guide for Travellers. Englewood Cliffs, NJ, Prentice-Hall, 1986.
  • Worring RW, Hibbard WS, Schroeder S: Travel Safely at Home and Abroad: Don't Be a Target! Helena, Mont, Uniquest Publications, 1996.

Electronic Resources

  • Centers for Disease Control and Prevention: Travel definitions. Available at http://wwwn.cdc.gov/travel (accessed March 9, 2009); 877-FYI-TRIP; Fax, 888-232-3299.
  • U.S. Department of State: http://www.travel.state.gov; Overseas Citizens Services, 888-407-4747; from overseas, 202 501 4444.
  • World Health Organization: http://www.who.int/topics/travel/en.

    Newsletters and Periodicals

  • Consumer Reports Travel Letter, Consumers Union, 101 Truman Ave, Yonkers, NY 10703; 914-378-2000 or 800-234-1645.
  • Diabetic Traveler Newsletter, Box 8223 RW, Stamford, Conn 06905; 203-327-5832.

Kidney Dialysis Abroad

  • International Directory of Dialysis Centers. Creative Age Publications, 7628 Densmore Avenue, Van Nuys, Calif 91406; 800-442-5667 or 818-782-7328.
  • Dialysis Centers Around the World: http://www.globaldialysis.com.

Disability Travel Sites

  • General access information for the disabled: http://www.access-able.com.
  • Travel for hearing-impaired people: www.sath.org.
  • United Kingdom-based broad listing of information for disabled travelers: http://www.direct.gov.uk/DisabledPeople/fs/en.
  • U.S. Government Architectural and Transportation Barriers Compliance Board (Access-Board) produces and distributes a variety of publications for travelers with disabilities: http://www.access-board.gov (information can also be obtained via telephone, 800-872-2253 [voice] or 800-993-2822 [TTY]).
  • Wheelchair travel-oriented website: http://www.disabilitytravel.com.

Wilderness Medicine

  • Auerbach PS (ed): Wilderness Medicine, 5th ed. St. Louis, Mosby, 2007.
  • Auerbach PS, Donner H, Weiss E (eds): Field Guide to Wilderness Medicine, 2nd ed. St. Louis, Mosby, 2003.
  • Houston CS: Going Higher: The Story of Man and Altitude. Boston, Little, Brown, 1987.
  • Kennedy B: Caring for Children in the Outdoors. Oakland, Calif, Adventure Medical Kits, 1994.

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References

  1. Mardh PA: What is travel medicine? Content, current position, tools, and tasks. J Travel Med 2002;9:34-47.
  2. Keystone JS. Dismukes R. Sawyer L. Kozarsky PE: Inadequacies in health recommendations provided for international travelers by North American travel health advisors. J Travel Med 1994;1:72-78.
  3. North American Charter for Travel Health: A consensus statement on providing travel health advice, October 22, 1996. Available at http://www.travelhealth.net/travelagent.html (accessed March 9, 2009).
  4. Steffen R: The epidemiologic basis for the practice of travel medicine. In Lobel HO, Steffen R, Kozarsky PE (eds): Travel Medicine 2. Proceedings of the Second Conference on International Travel Medicine. Atlanta, International Society of Travel Medicine, 1992, pp 11-14.
  5. Lustenberger I: Todesfalle von Schweizern in Ausland (thesis). Zurich, Switzerland, University of Zurich, 1991.
  6. Rose SR, Keystone JS: 2006 International Travel Health Guide, 13th ed. New York, Mosby, 2006.
  7. Paulson E: Travel statement on jet lag. Can Med Assoc J 1996;155:61-66.
  8. Lamberg L: Melatonin potentially useful but safety, efficacy remain uncertain. JAMA 1996:276:1011-1014.
  9. Centers for Disease Control and Prevention: Health Information for International Travel, 2008. Washington, DC, U.S. Department of Health and Human Services, U.S. Government Printing Office, 2007.
  10. Innis BL, Snitbhan R, Kunasol P, et al: Protection against hepatitis A by an inactivated vaccine. JAMA 1994:271:1328-1334.
  11. Franco E, Giambi C, Ialacci R, Maurici M: Prevention of hepatitis A by vaccination. Expert Opin Biol Ther 2003;3:965-974.
  12. Connor BA, Blatter MM, Beran J, et al: Rapid and sustained immune response against hepatitis A and B achieved with combined vaccine using an accelerated administration schedule. J Travel Med 2007;14:9-15.
  13. Pickering L (ed): 2000 Redbook: Report of the Committee on Infectious Diseases. Elk Grove Village, Ill: American Academy of Pediatrics, 2000.
  14. Yates J: Traveler’s diarrhea. Am Fam Physician 2005;71:2095-2100.
  15. Taylor DN, Sanchez JL, Candler W, et al: Treatment of travelers’ diarrhea: Ciprofloxacin plus loperamide compared with ciprofloxacin alone. A placebo-controlled, randomized trial. Ann Intern Med 1991;114:731-734.
  16. DuPont HL, Capsuto EG: Persistent diarrhea in travelers. Clin Infect Dis 1996;22:124-128.
  17. Dawood R: Are these pills safe? Condé Nast Traveler 1996;31:37-41.
  18. Lobel Ho, Bernard KW, Williams SL, et al: Effectiveness and tolernace of long-term malaria prophylaxis with mefloquine. JAMA 1991;265:361-364.
  19. Olsen SJ, Chang H-L, Cheung TY-Y, et al: Transmission of the severe acute respiratory syndrome on aircraft. N Engl J Med 2003;349:2416-2422
  20. Peiris JS, Yuen KY, Osterhaus AD, Stöhr K: Current concepts: The severe acute respiratory syndrome. N Engl J Med 2003;349:2431-2441.
  21. Bonneux L, Van der Stuyft P, Taelman H, et al: Risk factors for infections with human immunodeficiency virus among European expatriates in Africa. BMJ 1988;297:581-584.
  22. Gagneux P, Blochlinger CU, Tanner M, Hatz CF: Malaria and casual sex: What travelers know and how they behave. J Travel Med 1996;3:14-21.
  23. Hargarten SW, Anderson AJ, Walker J, Barboriak JJ: Travel of U.S. citizens after coronary artery bypass surgery. J Travel Med 1996;3:7-10.