Travel Advisories
Travel Advisories
Authors: Philip R. Fischer, MD, DTM&H, Associate Professor of Pediatrics, Department Pediatric & Adolescent Medicine, Mayo Clinic, Rochester, MN; and Abinash Virk, MD, Senior Associate Consultant, Director of the Travel and Geographic Medicine Clinic, Division of Infectious Diseases, Departments of Internal Medicine and Pediatrics, Mayo Clinic, Rochester, MN.
Peer Reviewers: John C. Christenson, MD, Professor of Pediatrics, Chief, Division of Infectious Diseases, Department of Pediatrics, University of Utah School of Medicine; and David Freedman, MD, Director, UAB Traveler’s Health Clinic, Division of Geographic Medicine, University of Alabama at Birmingham.
Editor’s Note—Millions of North Americans travel across international borders each year. Foreign trips provide a wealth of personal and professional experiences, but they also bring significant health risk. Primary care physicians (PCPs) can play a key role in ensuring that international travelers get appropriate pretravel guidance to prevent adverse health consequences and that they benefit from appropriate pretravel vaccinations and medical prescriptions. In addition, PCPs serve at the front-line of caring for symptomatic returned travelers.
The Opportunity
Most international travelers, even those going to developing regions in the Tropics, stay well during their travel. Nonetheless, many others become ill, and most of those illnesses could have been prevented. PCPs have the opportunity to prepare travelers for healthy trips and to provide care for those who return with symptomatic illness.
The Problems Morbidity
How common are physical complaints in travelers? Nearly half of Swiss travelers to developing countries reported that they had some health problem.1 Approximately 9% consulted a physician because of their problem. One of 200 required hospitalization, and one of 100,000 died overseas.
What health impairments occur in international travelers? Diarrhea is common and occurs in approximately one-third of travelers.2 Other travelers suffer from the usual sorts of things that might have affected them at the same time had they stayed at home, such as upper respiratory infections and heartburn. "Exotic" illnesses are much less common but can occur. Malaria occurs in about 2% of travelers to West Africa who do not take chemoprophylaxis.3 Hepatitis A affects about 0.3% of unvaccinated travelers to endemic areas. Approximately 4% of long-term U.S. missionaries in Africa become infected with hepatitis B with each year of service.4 About 0.2% of adult travelers pick up a sexually transmitted disease. Typhoid fever makes a few of each 10,000 travelers ill.
Mortality
In the decades around the beginning of the 20th century, long-distance travel was more dangerous, and anti-infective measures were less effective than today. Only a minority of the early missionaries with Africa Inland Mission survived their first years in east Africa. About 11% of Presbyterian missionaries between 1873 and 1929 died, mostly due to infection.3 Though much less common now as we prepare to enter the 21st century, death can happen during overseas trips. Now, with the ease of travel for more mature populations, approximately half of deaths related to international travel are due to cardiovascular disease.3 While changed schedules, diets, and levels of activity might contribute to some of these deaths, it is probably coincidental that some of these deaths just happened to occur during a trip. Injury is the next most common cause of death in international travelers and accounts for about 20% of deaths during travel.5 Approximately one-third of these deaths are due to motor vehicle accidents, and drowning accounts for another 15%. Violent crimes account for less than 10% of overseas deaths. Fatal infection is now much less common and accounts for only a couple percent of overseas death in travelers.
Inaccurate Advice
Realizing that diarrhea is extremely common in travelers, that tropical infections do sometimes occur, and that most overseas deaths are usually due to pre-existing risk or trauma, how well prepared are travelers to face these risks? Recent surveys suggest that the pretravel advice given by PCPs is often inaccurate. A phone survey of Canadian healthcare providers revealed that only one-fourth could give correct advice for malaria prevention,6 and another study showed that only 12% of U.S. PCPs who give pretravel advice gave proper advice about malaria.7
How can PCPs stay informed and current with the burgeoning field of travel medicine? First, PCPs must decide if they want to stay current. For the patients’ sake and in view of medico-legal concerns, many PCPs choose to refer all international travelers to specialized clinics for pre-travel care. A geographical listing of experienced travel clinicians in America is available at http://www.astmh.org/clinics/clinindex.html or http://www.istm.org. For PCPs who wish to remain current and to stay aware of appropriate pretravel guidance, several resources are available (see Table 1). The CDC website is especially useful for those seeking specific recommendations for individuals traveling to particular geographic areas.
| Table 1. Travel Health Information for the Medical Professional |
Texts
• Bia FJ, ed. Travel Medicine Advisor. 2nd ed. Atlanta, GA: American Health Consultants; 1993 (updated bimonthly, 800-688-2421).Commercial Site • Shoreland, Inc., P.O. Box 13795, Milwaukee, WI 53213-0795 U.S.A. (800) 433-5256Internet Sites (see also Freedman DO. Infect Dis Clin North Am 1998;12:543-547.) • American Society of Tropical Medicine and Hygiene http://www.astmh.org____________________________________________________________________________________ |
Poor Compliance
So, physicians must rise above the majority and be careful to provide accurate pretravel guidance. But, what of travelers? Do they comply with the pretravel advice that is given? The early chapters of the Bible suggest that humanity’s first geographical displacement resulted from noncompliance with food selection advice, and people have generally been noncompliant with pretravel advice since. In a large study of European travelers of whom more than 90% had received medical advice about malaria prophylaxis, only 55% were compliant with their chemoprophylactic regimen.8 A similar study of Americans yielded equally discouraging results of limited compliance.9 As to food and water hygiene, it has been shown that only 2% of travelers adhere to good food selection, and the median number of food choice "mistakes" was five during the first three days of travel; not surprisingly, the incidence of diarrhea correlated with the number of dietary "mistakes."10 Despite lay and professional counsel, studies show that casual and even unprotected sex is not uncommon in travelers.11
What can be done? PCPs have long-term relationships and credibility with their patients. Perhaps they are the best suited to give pretravel advice that will be implemented as specific disease-preventing and health-promoting behavior. They should also be able to tailor particular pretravel advice and prescriptions to the patient’s own health condition and travel plans.
Pretravel Advice
Safety
It has been suggested that "injuries are not accidents."12 Injuries often occur due to willful negligence and bad choices. Travelers should be advised and urged to be particularly careful with pedestrian and vehicular travel. "Look both ways" might be a lifesaving reminder for Americans going to British Commonwealth countries. Appropriate restraints (seatbelts for most, carseats for young children) and helmets (for bicycle and motorcycle rides) should be available, and travelers should consider using larger, newer vehicles. Night driving and helping apparently disabled vehicles along roadsides can be risky in some areas (such as East Africa). Taxis that aren’t pre-scheduled are risky in other places (such as Mexico). Alcohol should not be mixed with driving or water sports. Parents should check the "childproofing" of lodging when traveling with children and should pay particular attention to stairways, balconies, and electrical outlets.
Food and Water Precautions
It has been said that "travel broadens the mind as it loosens the bowels."13 Travelers’ diarrhea is often caused by enterotoxigenic Escherichia coli, Campylobacter, Salmonella, Shigella, and other bacteria that come through food and water contamination.13 Similarly, typhoid-causing Salmonella, intestinal parasites, and gastrointestinal viruses also enter travelers in impure food and water. Despite the studies of limited compliance, travelers should be urged to carefully choose food and water. Particularly in developing countries, food should have been peeled (like bananas) or recently well-cooked (no raw fruits and vegetables or partly cooked meat; no food from street vendors). Beverages should usually be boiled (without adding other liquids after boiling, such as milk added to tea) or commercially prepared.14 In developing countries, tap water, even in the quantities used for tooth brushing or for making ice cubes, should be strictly avoided. Chemical treatment is possible, but pregnant women should be cautioned about the use of excessive amounts of iodine. Simple filters remove larger germs such as Cryptosporidium but also require the addition of a chemical resin to kill viruses. Appropriate purifiers can be obtained from camping stores for about $80 and might help some travelers avoid the hassle and cost of repeatedly buying bottled water.
"Simple" measures are also useful, and reminders to implement them might help travelers. Handwashing is the most effective way of limiting the transmission of many diseases. While alcohol-containing lotions have become popular for travelers, simple soap-and-water washing coupled with drying with a clean dry cloth or paper towel is still the most effective way of cleaning hands before eating.
Insect Avoidance
Certainly, any pretravel counsel must be personalized for an individual’s itinerary and planned activities. Doing indoor business in Beijing in the winter is much different than going on safari in the Serengeti during wet season. Insects are, at best, a nuisance to travelers but may also, at many times, be life-threatening to tourists. Mosquitoes biting inside or outside from dusk to dawn can carry malaria, while other mosquito species with different biting habits can carry yellow fever and dengue. Ticks can carry Rickettsia, and flies can serve as vectors for filarial germs and sleeping sickness. It is prudent to protect travelers from insects.
When going to areas where malaria is endemic, travelers should be advised to limit outdoor activities during evening and night-time hours. Screens can block the penetration of insects through windows and doors, and netting, especially when impregnated with an insecticide such as permethrin, can be used to block the access of insects to sleeping tourists. Tourists should choose air-conditioned rooms.15 For times when insects are active in places where insects carry disease-causing germs, travelers would be advised to cover as much of their skin as possible with long sleeves and long pants or skirts.
Chemical protection of the skin is also advised for travelers to places where insect-borne disease occurs.16 Despite some lay press bemoaning the risks of the repellent DEET (N,N-diethyl-meta-toluamide), it has been used in millions of individuals without complication. The reported complications have usually occurred with oral ingestion, contamination of the eyes, or heavy application. The duration of DEET’s effectiveness is related to its concentration. A solution of about 30% will give four or more hours of protection. Lower concentrations give less lasting protection. Toxicity in children has not clearly been linked to concentration, but many people shy away from using concentrations greater than 30% in children.17 DEET should be applied in a thin layer to exposed areas of skin with attention to avoid oral and ocular use.
Another chemical effective in decreasing insect bites is permethrin. This insecticide may be applied to clothes (or bed nets) to kill insects before they have a chance to reach an individual’s skin. Permethrin used to lightly moisten both sides of clothes will keep the clothes insecticide-laden and protective for several weeks, despite use and laundering.18 Other natural means and chemical products intended to prevent insect bites are significantly less effective than DEET and permethrin.
Body Fluid Exposures
While the HIV infection epidemic has heightened public awareness of risky behaviors, many adult travelers actually plan to have casual sexual activity as part of their travel, and not all practice "safe sex."11,19 During pretravel visits, PCPs can remind travelers of the dangers of casual sex and alert them to excellent (abstinence) as well as usually adequate (condoms) means of preventing the transmission of viruses.
Other travelers might be tempted to commemorate their trip with a special body piercing or tattoo. Clearly, making memories like this under less than aseptic conditions might shorten the lifetime during which to remember the trip. PCPs should remind travelers of the risks of HIV and hepatitis B virus contamination of body piercing.
Skin-penetrating injury and medical care can also be associated with disease transmission. Unfortunately, not even all medical personnel are aware of geographical risks of HIV, and many do not take appropriate precautions when they travel.20 Travelers can be reminded of sites offering good medical care near points of their itinerary (details available to members from International Association for Medical Assistance to Travelers at http://www.sentex.net/~iamat) and should be reminded to insist on the use of new, sterile materials should injections, dental care, or suturing become necessary. Obviously, blood transfusions would be reserved for cases of actual life-threatening necessity.
Jet Lag
Commercial jet travel makes it possible to cross almost a complete time zone for each hour of flight. A body can quickly become disoriented from its usual diurnal rhythm. Jet lag presents as malaise with an altered reaction time and decreased ability to concentrate along with daytime sleepiness and night-time awakening. Jet lag gets more bothersome as travelers age, and it is more common with eastward than westward travel.21,22 Travelers should be counseled to drink plenty of non-alcoholic fluids during their flight and the early days of their trip and to get some vigorous physical exercise, whether walking in the airplane or taking a brisk walk each day in the new destination. Beginning on the flight, travelers should try to adjust their sleeping times to the night periods at their destination. Many experts suggest breaking up trips between multiple continents with a day en route (a day or two in Europe for U.S. travelers headed to Africa, for instance). For those whose travel plans make it difficult to accept a few days of jet lag, the symptoms might be helped with the use of medications (noted below).
High Altitude22
High-altitude trekking is becoming more popular and more accessible to a large segment of the population. Tragedies on Mount Everest in recent years have demonstrated not only the accessibility of such sites to less than fully experienced travelers but also the risks of visiting high-altitude locations.
Approximately 20% of overnight visitors to altitudes above 9000 ft. experience acute mountain sickness. They note headache, gastrointestinal upset, and malaise. Preventive measures include slow ascent (no more than 1000 ft./d on trekking trips), ingestion of plenty of nonalcoholic fluids, and planning to sleep at lower than peak altitudes. The use of benzodiazepines and alcohol probably worsens altitude sickness. Acetazolamide (dosing details below) has some preventive efficacy as well. The mild symptoms of acute mountain sickness usually subside with time or resolve with descent.
More serious altitude problems—pulmonary edema and cerebral edema—may be life-threatening. When individuals notice tachypnea unrelated to activity, severe cough, or severe headache with clouded thinking in themselves or their companions, the emergency treatment should begin with immediate descent to lower altitude. Along the way or on arrival, oxygen and medications (steroids, diuretics, nifedipine) might also be used.
Special Populations
PCPs can often comfortably deal with pretravel counsel for healthy adults. It might be more intimidating, however, to try to advise a less than average patient. A recent publication has reviewed the travel health of pediatric, pregnant, and compromised individuals.23-25
Pediatric Travelers. Parents should carefully consider whether the benefits of a particular foreign trip outweigh the inconvenience and health risks imposed on their children. If so, some precautionary counsel might be appropriate. On intercontinental flights, attention to seating choice can help the comfort of an infant (bulkhead for special cots), young child (near aisle for walks), or older child (good screen view for entertainment). Special games, toys, and books might be included in the carry-on luggage. Snacks should be available for unanticipated delays between flights. Sedatives are not usually counseled, but a test dose to rule out an excitatory reaction should be provided before the trip if antihistamines are to be used. Decongestants do not seem to decrease the risk of earache during descent, but chewing, drinking, and swallowing might help reopen eustachian tubes. On arrival at the destination, parents should be prepared for safe vehicle travel (carseat in a rear seat with seatbelts for children younger than 4 years, seatbelts for all children, rested driver who has not ingested alcohol). Each lodging should be "childproofed" on arrival. The risk of skin cancer is directly related to blistering sunburn in childhood, so sunscreen and protective hats and clothes should be part of the travel packing. Personal identification that is visible on clothes (names, towns, teams) might prompt "strangers" to act like "friends" with young children; such personalized clothing should be avoided. In addition, because of the concern over the abduction of children, single parents or parents with a last name different from that of the child should carry documentation that they have legal responsibility for the child.
Pregnant Travelers. Any pregnant woman might deliver prematurely. Before traveling during pregnancy, a woman should carefully consider her own comfort with an emergent delivery and medical care in her country of destination. Certainly, women with a history of premature delivery, with partial cervical dilation, or with twin gestations would be counseled to postpone any nonessential foreign travel. While exercise and activity are good for pregnant women, any significant change in activity level, such as often occurs during travel, might provoke a preterm delivery. Women who choose to travel during pregnancy should carry a copy of their medical histories (including prenatal screening test results and sterile medications that might be needed for intrapartum group B streptococcal prophylaxis, for instance) and a list of competent obstetricians in the area of their destination (available from http://www.sentex.net/~iamat). Because of the risks of infection in pregnancy, pregnant women should be compulsively compliant with food and water hygiene and with malaria prevention measures.
Medically Compromised Travelers. Medically compromised individuals might be particularly ready to enjoy a "once in a lifetime" trip, but they pose particular challenges to the physicians responsible for their care. Travelers regularly taking medication should carry a good supply of their medicine with enough accessible to continue taking it even if a carry-on bag or suitcase is delayed in travel. Individuals carrying syringes or narcotics might benefit from a note from their PCP documenting their need of these materials for appropriate medical purposes. Pretravel visits can provide a good opportunity to ensure that all travelers are current on usual vaccinations (second MMR vaccine for those born after 1956, pneumococcal and influenza vaccines for elderly and chronically ill). Guidelines have been published for the care of HIV-positive patients26 and for asplenic individuals.25 Diabetics will need to adjust the timing of their meals and insulin dosing during travel across time zones; details of how to do this are available.27 Patients with cardiac and/or lung disease need to be aware that commercial aircraft are pressurized to the equivalent of an altitude of 6000-8000 ft. and that the lower levels of inspired oxygen for the flight hours might compromise their health. Individuals with resting, preflight PaO2 of less than 70 would likely benefit from supplemental oxygen during flight.25 Frequent walks around the cabin during long flights and the use of loose-fitting clothing might be advised for individuals predisposed to venous stasis and thrombosis.
Pretravel Prescriptions
Many travelers seek help from a PCP before a trip because they think they "need shots" or malaria medicine. Clearly, such visits should be used to provide good pretravel counsel about health-enhancing behaviors. However, at the same time, travelers should receive appropriate prescriptions for useful medications and vaccinations.
Vaccination
Vaccination is important, but it does not obviate the need for other healthy habits. Not all insect-borne and food- and water-transmitted infections can be prevented by vaccination, so other preventive measures are also important. Vaccinations relevant to international travel have been reviewed recently28,29 and are summarized in Table 2.
| Table 2. Vaccination for International Travel | ||
| Vaccination | Usual Route* | Remarks |
| Routine
Tetanus Diphtheria Measles Polio Varicella Hepatitis B Pneumococcus Influenza |
IM IM IM or SC IM or PO IM IM IM IM |
Within 5-10 years of travel Especially for Russia two if born after 1956 No indigenous cases in Western Hemisphere If not known to be immune Series of three injections For elderly For chronically ill, elderly |
| Particular to Travelers
Yellow Fever Hepatitis A Typhoid Cholera
|
SC IM PO IM Not required; SC IM, ID SC |
Some parts of South America and Africa For almost all foreign travelers > 6 years of age; protection for 5 years > 2 years of age; protection for 2 years not usually used in U.S. For long stay in some parts of rural Asia For some professionals and children For some parts of Africa, Asia |
|
*IM = intramuscular, SC = subcutaneous, PO = oral, ID = intradermal ________________________________________________________________________ |
||
All travelers should be up-to-date on the usual vaccines. The pretravel visit provides a good reason to make sure there has been a recent tetanus immunization (with the diphtheria part being especially important for those traveling to the Russian republics), that the second MMR has been given to those born after 1956 (preschoolers can get the second any time that is at least a month after the first one; children going to measles-endemic areas should have this second immunization before traveling), and that varicella immunity is certain. As mentioned, elderly individuals and travelers with chronic medical conditions might be helped by pneumococcal and influenza vaccination. (Influenza was an important problem even for travelers to Alaska last year.)
Hepatitis B is particularly prevalent in Asia and Africa and can be transmitted through emergent medical care and, occasionally, through casual nonintimate contacts. Even travelers without particular risk behaviors such as sexual contact and intravenous drug injections could benefit from the full hepatitis B vaccine series.
Yellow fever vaccine is the only immunization that is officially required to cross some international borders. It is required for many African and South American countries and is advisable for some areas even for which it is not required. Current recommendations are available from the CDC and WHO websites (see Table 1). Each vaccine should be given at least 14 days prior to arrival in an area of risk and provides protection for 10 years.
Hepatitis A vaccines are effective, safe, and easily tolerated. A single dose protects for at least a year, and a "booster" dose 6-12 months after the first extends protection to at least 10 years. This vaccine has largely supplanted the use of immune globulin for travelers. While not yet proven, there is some evidence that the vaccine may even be effective when given after exposure to hepatitis A virus.
Two relatively new typhoid vaccines are well tolerated and protect the majority of recipients. An oral vaccine requires four doses (a single capsule on alternate days for a 7-day course of administration) and protects for five years. The oral vaccine might be less effective when given concurrently with antimalarials or antibiotics. An injectable typhoid vaccine protects for two years when given as a single dose.
Cholera vaccine is no longer required for international travel. In fact, the older vaccines are of such low effectiveness that they are rarely used. Newer, oral vaccines hold promise but are not yet available in the United States.
Japanese encephalitis is transmitted by mosquitoes in several parts of Asia. It is mostly a problem in rural areas. Vaccine is recommended for people spending more than a month in rural parts of endemic regions during the September-November transmission season. Three vaccines are usually given (days 0, 7, and 30, with the last dose perhaps being given as early as 14 days after the first for individuals traveling imminently), and allergic reactions to the vaccine make it wise to watch recipients for 30 minutes after the injection. Protection is best when the series has been completed at least 10 days before travel.
Rabies vaccination is recommended for travelers at particular risk of contact with rabid animals (veterinarians, wildlife workers, children going to highly endemic cities). Vaccination requires three doses and is effective, but subsequently exposed individuals will still need some postexposure prophylaxis.
Meningococcal vaccine can be useful for travelers to Mecca and for individuals going to north-central Africa. Good protection is afforded against some strains of N. meningitidis.
Research continues. For now, however, E. coli and malaria vaccines are not clinically available.
Medical Kit
PCPs can advise international travelers to prepare a medical kit to take along on their trip. This kit would include some identifying information, first aid supplies, regularly used medications, medicines for symptomatic treatment of conditions that might develop, and prescription medicines (see Table 3).
| Table 3. Medical Kit for International Travel |
| Identification
• Photocopy of passport cover page and visa pages • Medical information Name, birthdate, weight Known medical allergies Chronic health conditions Routine medications and doses Blood type General Healthcare Items
First Aid Supplies
Routine Medications
Medicines Specific to Travel Situation
|
Diarrhea Medicines
Travelers’ diarrhea is very common,30 and most travelers’ diarrhea is bacterial in origin, with enterotoxigenic E. coli, Campylobacter, Salmonella, and Shigella accounting for the majority of cases.13 Illness with these organisms usually responds to standard antibiotic therapy. In some settings, however, organisms with less susceptibility to standard medications are more important causes of diarrhea. During winter, Campylobacter is relatively more common. In eastern Europe and Russia, parasitic causes such as Giardia are seen, and Cyclospora is noted in Nepal. Usually, however, presumptive treatment is directed against the usual bacterial causes.
Diarrhea prevention focuses on food and water hygiene. In addition, however, a nonspecific agent, bismuth subsalicylate, is partially effective in both preventing and treating travelers’ diarrhea. Through antimicrobial as well as anti-inflammatory and antisecretory properties, this compound can prevent up to 65% of cases of travelers’ diarrhea. Doses should be taken with each meal. This medication should be avoided in aspirin-sensitive individuals and in those on anticoagulants. Black discoloration of the tongue and stool is noted. However, bismuth subsalicylate is less effective and less convenient to use than antibiotics.
Antibiotics can also be effective in preventing travelers’ diarrhea. Ciprofloxacin prevents up to 90% of cases, and cotrimoxazole is a bit less effective. Experts, however, do not usually recommend medical prophylaxis for travelers’ diarrhea since this condition is self-limited and rarely life-threatening. Undesirable consequences of antibiotic prophylaxis of travelers’ diarrhea have been well described.31 The medical profession’s "do no harm" approach to the use of prescription medications and the consensus that the risk of adverse events is greater than the benefit result in chemoprophylaxis of travelers’ diarrhea rarely being offered. Only in rare cases of short foreign trips with a tight and inviolable schedule might antibiotics be preventively given. Consider prophylactic antibiotics for an immunocompromised host such as a transplant patient, patients on high-dose steroids, chemotherapy, or with a history of prior inflammatory bowel disorder. Cotrimoxazole and doxycycline have each been used for this purpose, but with resistance being increasingly reported, ciprofloxacin is usually the antibiotic of choice.
Treatment of affected individuals centers on oral hydration. Nonetheless, physicians can provide medications for travelers to carry for presumptive use in the event that diarrhea develops. Medication for self treatment usually includes an antibiotic and, for adults, an antiperistaltic agent. Ciprofloxacin is effective in shortening the course of travelers’ diarrhea. A single dose of 500 mg has been shown to be effective,32 but longer courses (such as 500 mg orally twice daily for 3-5 days) are also commonly used. Cotrimoxazole has been used for years and also covers Cyclospora infection,33 but bacterial resistance to cotrimoxazole is becoming increasingly prevalent.
The addition of an antiperistaltic agent improves the resolution of travelers’ diarrhea. Loperamide is effective in this regard and has little risk of adverse side effects. Nonetheless, it is not usually recommended for use in young children. The combination of loperamide and an antibiotic is rapidly curative of symptomatic diarrhea in travelers.34,35
Malaria Medicines
Antimalarial medications may be life-saving in both the prevention and treatment of malaria. The ease of prescription, however, should not distract physicians from stressing the importance of personal protective measures to prevent mosquito bites. Travelers to malaria-endemic areas of the world should be reminded about the importance of restricting outdoor evening activities, using protective bed nets, and applying DEET to exposed skin and permethrin to clothes.
Malaria chemoprophylaxis should be offered to all travelers to areas in which malaria is transmitted. Despite widespread resistance in most of the world, chloroquine is still effective against malaria found in Central America and some parts of the Middle East. Chloroquine is given in weekly, oral doses beginning one week before arrival in the endemic area and continuing through four weeks following return from the endemic area. The dose is 300 mg of chloroquine base for most adults, with a dose of 5 mg/kg/dose being used for younger or smaller individuals. Chloroquine tastes bitter but is generally tolerated. Some people report nausea and headache with chloroquine use, and a few (usually those with darker-pigmented skin) report itch. Reversible hair loss is rarely reported.
In South America, Asia, and Africa, chloroquine resistance is common. Mefloquine is the usual chemoprophylactic drug of choice. It is given in single oral weekly doses beginning 1-2 weeks prior to travel and, like chloroquine, continuing for four weeks after departure from the malarious area. It is dosed at 250 mg (or 228 mg depending on the source of the pills) per dose in adults and 5 mg/kg/dose for smaller travelers. It may be used at any age. There have been statistical hints of increased miscarriage rates in pregnant women using mefloquine, but mefloquine seems to be generally safe in pregnancy.36 Despite its great effectiveness and life-sparing potential, mefloquine is, however, associated with some side effects in about 25-40% of those who receive it.37 Nausea, vomiting, lightheadedness, and sleep changes (insomnia or vivid dreams) are commonly reported. These symptoms resolve with discontinuation of the medication, and most people choose to tolerate mefloquine’s side effects rather than to switch to a less effective preventive agent. In 1-2% of people on mefloquine, side effects are so severe that the medicine is discontinued. Seizures, cardiac rhythm disturbances, and psychiatric problems have all been reported. In most cases, however, individuals already had a known predisposition toward these problems, and mefloquine merely "unmasked" their underlying problem. Nonetheless, mefloquine should not be given to individuals with significant history of psychiatric trouble, seizures, or dysrhythmia. When these problems or intolerable gastrointestinal disturbance occur on mefloquine, the medication should be stopped, and an alternative antimalarial should be used. Adverse reactions are generally reversible with discontinuation of mefloquine.
Along rural areas of the Thai borders with Myanmar and Kampuchea, mefloquine resistance is reported. In these areas, doxycycline is the chemoprophylactic of choice. Doxycycline is also used for individuals who cannot take or tolerate mefloquine. Doxycycline is given in a daily oral dose of 100 mg (1.5 mg/kg/dose if less than 50 kg, not used before 8 years of age due to dental staining) beginning the day before arrival in a malarial area and continuing for four full weeks after departure from the endemic area. Photosensitivity reactions are well known with doxycycline, so sunscreen (that blocks both ultraviolet A and B rays) should be advised. Women prone to candidal vaginitis should be prepared to self-treat this problem if it occurs on doxycycline.
When someone is traveling to an area of chloroquine resistant malaria and cannot take or tolerate mefloquine or doxycycline, another option is to prescribe the combination of weekly oral chloroquine and daily oral proguanil (3 mg/kg/dose up to 200 mg/dose). Proguanil is not available in the United States but may be purchased in airport pharmacies in England or in pharmacies in malaria-endemic countries. Proguanil is generally well tolerated.
What if prophylaxis breaks down? No mosquito avoidance scheme is perfect, and no chemoprophylactic regimen is perfectly sure to work. Fevers developing more than a week after arrival in an endemic area should prompt immediate medical attention. If immediate medical evaluation is not possible, self-treatment may be considered as a temporizing measure while en route to emergent medical care. Self-treatment should not be used as a reason to delay appropriate medical care. The combination of sulfadoxine and pyrimethamine (Fansidar) has been used in the past for self-treatment, but resistance has increased in many parts of the world. Mefloquine and quinine might be given, but the best approach is to get to medical care as quickly as possible before "blindly" beginning antimalarial treatment.
Jet Lag Medicines
Some travelers, particularly those who have packed lots of activity into the early days of a brief trip, want medical help to deal with jet lag. Benzodiazepines provide sedation to facilitate sleep and are relatively safe (but are best not combined with alcohol). For adult travelers, zolpidem (Ambien) is often used in a dose of 5-10 mg per dose at the time of desired sleep during travel and at bedtime for the first few nights in the new setting.
Melatonin38 has been touted to prevent cancer and aging and to promote lots of other health benefits. Behind all the hype, however, it actually does seem to facilitate the adjustment to a new time zone. This natural hormone guides the diurnal cycles but has not been fully studied. Limited trials, however, suggest that a dose of 3-6 mg given at the destination’s bedtime (beginning en route and continuing for 4-5 nights) decreases symptoms of jet lag in some travelers.39 There are no known detrimental effects in concurrently using melatonin and zolpidem.
Motion Sickness Treatment
Persons known to be subject to motion sickness should consider taking helpful medications with them as they travel. Dimenhydrinate is a usual treatment, and meclizine also seems to be effective. Patches for transcutaneous administration are no longer readily available. The same treatment choices would apply for motion sickness in travelers as in domestic patients.
Altitude Sickness Medicines
For the 20% of travelers who experience mountain sickness, acetazolamide is the cornerstone of pharmacologic therapy to prevent altitude-related symptoms. It is prescribed for individuals who have had previous problems at altitude and for those who plan rapid ascent and are concerned that they might develop mountain sickness. Acetazolamide causes the excretion of bicarbonate via the kidneys with subsequent increases in respiratory ventilation and oxygen saturation. Thus, it rapidly mimics the adaptation that the body generally undergoes with gradual ascent to high altitude. The usual dose is 125-250 mg by mouth twice daily beginning a day before ascent and continuing during ascent and for the first two days at altitude.22 Sulfa-sensitive patients should not use acetazolamide. It is postulated to work in children, but no pediatric studies have been reported.
Corticosteroid therapy is effective in the treatment of severe altitude problems, such as pulmonary edema and, particularly, cerebral edema. Nifedipine is also effective in the treatment of high-altitude pulmonary edema. Each of these agents shows some preventive efficacy, but the potential side effects currently outweigh the risks of prophylactic use of these medications. As "standby" therapy for those having symptoms at altitude, dexamethasone and nifedipine might be useful. Nonetheless, they might also give medically naïve travelers a false sense of security that might delay a necessary descent. Thus, dexamethasone and nifedipine are not usually prescribed for non-physicians going to altitude.
After-Travel Consultation
Screening
Most returned travelers need no special post-travel healthcare. Some, however, could benefit from a visit after they return from their international excursion. Others come asking if they might have "picked up something." What screening is appropriate for returned travelers?
Following short-term tourism or business trips, screening is rarely necessary. After longer trips or after particular exposures, however, some asymptomatic individuals should be screened.40 Patients returning after more than three months in a developing country or after medical work in another country could be candidates for tuberculosis screening with a PPD. Waiting until three months after return would avoid missing some infected individuals who are still in the process of converting to PPD positivity during the early weeks after their return. Stool screening for parasites might be useful (to prevent the asymptomatic person from contaminating others in our nonendemic area) if the traveler ingested impure food or beverage, went barefoot in areas with hookworm infections, or coupled a nail-biting habit with lots of hands-on contact overseas. A serologic test for schistosomiasis a few months after return would also be appropriate after freshwater contact in an area where schistosomiasis occurs. Screening for malaria and eosinophilia in asymptomatic returned travelers is probably not indicated. HIV screening might be appropriate if there is a history of high-risk behavior.
After a lengthy visit to another country, a medical evaluation visit is also useful to update routine healthcare measures. Vaccine schedules frequently change, and a review of status for children and for the elderly might identify additional vaccines that would be useful in the home setting. A review of normal growth (in children) and current diet recommendations (for adults) might also be useful as the traveler reintegrates into U.S. routines. Reviewing current recommendations for cancer screening (particularly for prostate cancer, colon cancer, and endometrial neoplasia) would also be valuable to someone returning after a long stay away from routine U.S. healthcare.
Fever
Despite every preventive effort prior to travel, travelers still come back with a fever—be it a common disease such as respiratory tract infection or something more exotic like a viral hemorrhagic disease. The most critical question that can accurately lead to a diagnosis of a travel-related disease is to ask about the recent travel history. If the patient is well educated prior to departure, that information may be offered spontaneously. If that does not occur, it is the responsibility of the physician to elucidate a detailed travel history. A detailed travel history includes destinations or locales visited, duration of visit (and potential exposure), type of travel such as guided tour, stay at hotels or resort vs. a backpacking trip, any illness during travel, and activities undertaken during travel (see Table 4). It is important to find out about antimalarial or anti-diarrheal if any taken, specifics of antibiotics, or other medications taken for any illnesses during the trip.
| Table 4. Components of a Detailed Travel History in a Returning Traveler with Fever |
| Destination(s)—recent and remote
• All areas visited chronologically • Duration at each site Activities undertaken (details) • Beaches • Swimming (sea or freshwater) • Camping • Hiking Type of travel • Guided or escorted tour • Low-budget travel Accommodations • Hotel • Private home • Camping • Rural homes Special exposures • Animal exposure • Insect bites or other arthropod exposure • Food experiences • Exposure to ill persons • Sexual exposures Pretravel immunizations Chemoprophylaxis and adherence to schedule Medications and drugs taken while traveling Illness while traveling ________________________________________________________________________________ |
So, what diseases should we be thinking of in a febrile returning traveler? The most common cause of fever in travelers returning from the Tropics is malaria, followed by self-limited febrile illnesses of unknown etiology as demonstrated in two retrospective studies.41 Malaria can occur up to one year after return and must be considered as the top diagnosis in the differential diagnosis. Most malaria in returning travelers occurs due to inappropriate chemoprophylaxis or patient’s nonadherence to the medications. In the United States, approximately 1000 cases of imported malaria occur annually. Plasmodium vivax (43-52%) and Plasmodium falciparum (33-39%) are the most frequently isolated species. P. falciparum acquisition is associated with travel to Africa whereas P. vivax is mostly acquired in Asia. The case-fatality ratio from falciparum malaria is 0.6-3.8%.37 This increases dramatically with delays in seeking care, diagnosis, and possible physician unfamiliarity with or unavailability of parenteral treatment of falciparum malaria. Fever occurs in 96% of patients with malaria, often accompanied by headache, malaise, chills, and nausea. Leukopenia and thrombocytopenia are common in malaria.
With appropriate exposure settings, rare "exotic" tropical diseases such as leishmaniasis, brucellosis, listeriosis, leptospirosis, or filarial diseases must be considered. However, commonplace infections such as upper respiratory tract or urinary tract infections occur more frequently and should be considered in the evaluation a febrile returned traveler. Sexual exposure occurs in approximately 20% of the travelers. In that context, it is important to consider STDs including HIV as a cause of presenting symptoms. Similarly in long-term travelers, hepatitis B may be a contributing factor. Overall, hepatitis A is common among travelers, particularly in the nonimmunized. Among patients returning from high Salmonella typhi or Salmonella paratyphi endemic areas such as the Indian subcontinent or Central or Latin American countries, one must consider typhoid or paratyphoid despite pretravel immunization history. Of viral diseases acquired in the Tropics, dengue or dengue hemorrhagic fever presents with fever with or without rash. Dengue hemorrhagic fever presents soon after return, with fever, rash, severe arthralgias, myalgias, and headache. Thrombocytopenia, capillary leak syndrome leading to hemoconcentration, and effusions are cardinal signs of imminent circulatory collapse. Supportive care is life saving. This syndrome usually occurs in the setting of prior dengue fever in the last 1-5 years. In the United States, 400 imported cases of dengue fever occurred between 1977-1992. In 1996, there were 43 confirmed cases of imported dengue in the United States. These cases were acquired in the Caribbean islands, Asia, the Pacific islands, Africa, and Central and South America.
Investigation of fever in a returning traveler is a matter of some urgency. Work-up should initially be directed to diseases with highest mortality in travelers. Malaria must be ruled out in all febrile returning travelers irrespective of chemoprophylactic use. The initial evaluation must include thick and thin malaria smears repeated thrice, blood cultures, routine laboratory such as complete blood counts, urinalysis, and chest radiograph. Specific exposure history, symptomatology or physical findings such as diarrhea, dysuria, hematuria, rash, meningismus, arthritis, hepatosplenomegaly, or lymphadenopathy should direct further tests.
Mildly ill patients with a nondiagnostic initial work-up can be observed with follow-up malaria smears in 4-6 weeks. Empiric therapy for malaria is not advised for smear-negative patients. For smear-positive patients but where species identification is pending and the patient is not acutely ill, the patient should not be allowed to go home until the diagnosis is confirmed and the treatment plan is initiated, whether inpatient or outpatient. It must be remembered that the diagnosis of malaria is only as good as the laboratory reading the slides. In highclinical suspicion for malaria and severely ill patient with signs of cerebral malaria or respiratory distress, empiric therapy for falciparum malaria should be started even in the absence of a positive smear. Acutely ill patients should be hospitalized for immediate care. Within this evaluation, it is also extremely important to consult with infectious disease specialists, especially if diagnosis is not apparent or if the diagnosis is known but the PCP is not familiar with the management. Mild (low parasitemia < 5%) falciparum malaria in a patient who was not on mefloquine can be treated with oral mefloquine 750 mg first day followed by 500 mg 24 hours later. Patients developing falciparum malaria on mefloquine prophylaxis should be hospitalized for treatment with parenteral quinidine gluconate and doxycycline. Treatment of P. vivax malaria is mainly a 3-day course of chloroquine (25 mg [base]/kg) followed by primaquine for 14 days.41 Failure of clearing of P. vivax with this regimen may require a higher dose of primaquine (30 mg [base] per day for 14 days) instead. After treatment is commenced, repeat malaria smears should be done on days 3, 7, and 28 to identify any early or late treatment failures resulting from chloroquine resistance among P. vivax. Chloroquine-resistant P. vivax is reported from New Guinea and Irian Jaya.41 A diagnosis of malaria is safely ruled out only once an alternative diagnosis and response to alternative therapy has been demonstrated.
Skin Problems
Skin lesions can be a manifestation of a systemic disease, local infestation, insect bites, or reactions. A prospective study of 269 patients with travel-related dermatoses noted that the majority (61%) of the skin problems occurred while traveling. Among patients presenting to the clinic for evaluation of skin lesions, the common diagnoses included cutaneous larva migrans (25%), pyodermas (18%), arthropod-reactive dermatitis, myiasis, tungiasis, urticaria, fever, and rash and cutaneous leishmaniasis.42 Travel to sub-Saharan Africa was most associated with skin problems. Additionally, the spectrum of skin lesions varied with the country or type of area visited.42 Visit to beaches was associated with cutaneous larva migrans and sunburns, while skin infections occurred during travel to mountainous regions. Similar to travel history for fever, a detailed travel and exposure history might lead to an accurate diagnosis of the skin lesion. The evolutionary history of the lesion(s) might shed light on the diagnosis. It is helpful to differentiate the lesions into papules, nodules (fixed or migratory), ulcers, linear, by pigmentation, and petechial or hemorrhagic (see Table 5).43 The presence of fever and a petechial or hemorrhagic rash should warrant an urgent evaluation since it may represent a viral hemorrhagic infection, meningococcemia, or rickettsial infection.42 Evaluation has to be in the context of the exposure history. The evaluation may require biopsies with special stains or procedures. For instance, diagnosis of an Onchocercarial rash requires multiple bloodless skin snips taken with special biopsy forceps and viewed in a microtiter plate after a few hours.
| Table 5. Skin Lesions Among Returned Travelers | |
| Papules
• Cercarial dermatitis • Furunculosis • Insect bites • Onchocercarial dermatitis (Onchocerca volvulus) • Sea bather’s eruption (Cnidaria dermatitis) Nodules • Bartonellosis (verruga peruana) • Gnathostomiasis • Leishmaniasis • Loa loa • Mycobacterium marinum • Myiasis (Bot fly, Tumbu fly) • Tungiasis (Tunga penetrans) Migrating nodules • Cutaneous larva migrans • Fascioliasis • Gnathostomiasis • Loa loa (Calabar swellings) • Paragonimiasis • Sparganosis |
Ulcers
• Anthrax • Buruli ulcer (Mycobacterium ulcerans) • Cutaneous leishmaniasis • Spider bite • Syphilis or other STDs • Tick eschar (Rickettsia connori, Rickettsia africae) • Tropical ulcer Linear • Cutaneous larva migrans • Insect reactions (Paederus irritans) • Phytophotodermatitis (lime juice) Hypopigmented lesion • Leprosy (long-term expatriates) • Pityriasis versicolor (Malassezia furfur) Aquatic • Cnidaria dermatitis (Portuguese man-of-war) • Sea urchin spines • Vibrio vulnificus cellulitis Petechial or hemorrhagic • Dengue • Leptospirosis (Leptospira species) • Meningococcemia • Rickettsial (RMSF, tick, or scrub typhus) • Viral hemorrhagic fevers |
| _________________________________________________________________________ | |
Diarrhea
Travelers’ diarrhea (TD) occurs when persons from a developed country go to developing countries. The incidence of TD depends on geographic area visited, food habits, host characteristics, and duration of stay. Approximately 30% of travelers to tropical countries for more than two weeks will develop TD.44 This relative risk of TD when visiting eastern Europe, Israel, Japan, South Africa, and the Caribbean islands is 20%.44 Travel to other industrialized countries is associated with minimally increased risk of TD. Original TD studies demonstrate TD to be a short-lived, noninvasive illness. Usually, symptoms occur 5-10 days after entry into the risk area. Enterotoxigenic E. coli (ETEC) is the most common cause of TD worldwide. However, other bacteria such as Salmonella, Shigella, Campylobacter, and enteroinvasive E. coli; viruses such as Rotavirus, Norwalk, and occasionally parasites are the etiologic agents for TD.13 No pathogen is identified in at least one-third of the patients. Shigella diarrhea tends to occur as people stay longer, while ETEC is mostly early during the stay. Seasonality influences TD caused by certain pathogens. Rotavirus, Campylobacter, and Salmonella are more often isolated in TD acquired in the winter. Host factors that predispose to TD include underlying immunosuppression including AIDS, hypochlorhydria, primary gastrointestinal pathology such as history of Crohns’ disease, chronic ulcerative colitis, and young (< 30 years) age. Although there is direct correlation with dietary indiscretion such as eating from street vendors, other evidence points lack of protection even in persons who are extremely careful about their diet. Consumption of certain foods is associated with an increased risk of specific diarrheal diseases. Consumption of unpasteurized milk/milk products increases the likelihood of acquiring Brucella, Salmonella, Campylobacter jejuni, Listeria, and, rarely in travelers, Mycobacterium tuberculosis or M. bovis. Eating of raw shellfish is associated with Norwalk virus, hepatitis A, E. coli, and Vibrio parahaemolyticus or V. vulnificus infection. Amebiasis can present with diarrhea with or without blood. The differential diagnosis of prolonged diarrhea (> 10 days) also includes parasitic or protozoan etiology.
Diarrhea assessment in a returned traveler should include detailed travel and food/water exposure history, medication history, and notation of the duration and severity of diarrhea. Initial work-up should include stool leukocytes, stool bacterial cultures, examination for stool ova and parasites, and C. difficile toxin, especially if the patient was on antibiotics. Specific examination such as an antigen detection test for Giardia or Cryptosporidium or a modified acid-fast stain for Cyclospora or Isospora may be helpful in evaluating protracted diarrhea. Eosinophilia with diarrhea suggests helminthic infections. Stool can be negative for any evidence of a helminthic infection since the life cycle may not have completed and, hence, absence of egg shedding (prepatent period). In such situations, repeat stool ova and parasite examination in 4-6 weeks may be helpful. Bloody diarrhea should prompt an evaluation of E. coli O157:H7, Shigella, typhoid, and amebiasis.
Presence of fecal WBC often differentiates invasive from noninvasive diarrhea. Symptomatic therapy is usually adequate for patients with noninvasive diarrhea where no fecal leukocytes are present in the stool. Treat specific bacterial or parasitic pathogen isolated especially when fecal WBC is present. If invasive diarrhea persists in a patient that has had a nondiagnostic initial work-up then a sigmoidoscopy or colonoscopy with random biopsies may be considered. Occasionally, duodenal aspirate will reveal a parasitic etiology such as Giardia or Strongyloides. If all investigations are unrevealing, then an empiric antibiotic course may be helpful. Choice of empiric antibiotic includes either a fluoroquinolone or azithromycin—an attempt to treat enteric gram-negative bacteria. If a patient was previously treated with a fluoroquinolone, then a trial of azithromycin for quinolone-resistant Campylobacter may be an option. Other antimicrobial options include metronidazole, trimethoprim/sulfamethoxazole, and quinacrine. Hepatitis A, B, or E is a consideration in nonimmune patients presenting with diarrhea and jaundice. Gonococci, Giardia, viruses (cytomegalovirus, herpes simplex virus, and rotavirus), other bacteria, and Strongyloides are some of the diarrheal agents among immunocompromised hosts including HIV/AIDS. Overall, the cause of diarrhea is frequently not identified. The recovery may be slow, and occasionally, the investigations will reveal an alternative underlying pathology such an inflammatory bowel disease. For persistent diarrhea, other causes such as lactase deficiency, collagenous colitis, fat malabsorption, laxative abuse, irritable bowel syndrome, bacterial overgrowth syndrome, and malignancy should be evaluated. Further tests such as lactose tolerance test, stool fat, thyroid function tests, HIV serology, and 5-indole acetic acid may provide the diagnosis.
In addition to the treatment of the etiologic agent, it is important to rehydrate patients with oral or parenteral fluids depending on the severity of the disease. This is particularly relevant for infants, the elderly, and patients with other co-morbidities. It is important to educate patients in the use of oral rehydration solutions when diarrhea occurs—while traveling or on return.45
Summary
PCPs are well positioned to provide pretravel advice and intervention to prevent travel-related health problems. Providers must, however, stay current on geographical risks, and they must customize their care to each traveler’s itinerary (see Table 6).
| Table 6. Topics and Treatments to Consider Covering in a Pretravel Consultation | |
| Advice
• Safety • Food and water precautions • Management of symptomatic diarrhea • Insect avoidance • Body fluid exposure risk • Jet lag prevention • High-altitude sickness prevention and management • Special concerns (children, pregnancy, chronic illness) • Preparing a medical kit |
Immunization
• Routine immunizations for all patients • Particular vaccines related to travel itinerary and activity Prescription • Diarrhea medication • Malaria medication • Jet lag preventive treatment • High-altitude sickness prophylactic |
| _________________________________________________________________________________ | |
PCPs are also well placed to care for returned travelers. They can judiciously screen asymptomatic individuals, and they can also initiate the evaluation and care of sick individuals. As our patients venture off to experience a world of opportunities, may we effectively help them minimize the health risks and maximize the personal benefits of their travel.
References
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2. Bruni M, Steffen R. J Travel Med 1997;4:61-64.
3. Reid D, Keystone JS. Health risks abroad: General considerations. In: DuPont HL, Steffen R, eds. Textbook of Travel Medicine and Health. Hamilton, Ontario: BC Decker; 1997:4-9.
4. Lange WR, Frame JD. Am J Trop Med Hyg 1990;43:527-533.
5. Hargarten SW, et al. Ann Emerg Med 1991;20:622-626.
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11. Keystone JS, Reid D. Compliance with travel health recommendations. In: DuPont HL, Steffen R, eds. Textbook of Travel Medicine and Health. Hamilton, Ontario: BC Decker; 1997:282-286.
12. Hargarten SW, Gursu KG. Accidents, bites, and stings. In: DuPont HL, Steffen R, eds. Textbook of Travel Medicine and Health. Hamilton, Ontario: BC Decker; 1997:258-261.
13. Peltola H, Gorbach SL. Travelers’ diarrhea: Epidemiology and Clinical aspects. In: In DuPont HL and Steffen R, eds. Textbook of Travel Medicine and Health. Hamilton, Ontario: BC Decker; 1997:78-86.
14. Ericsson CD, Rey M. Prevention of travelers’ diarrhea: risk avoidance and chemoprophylaxis. In: DuPont HL, Steffen R, eds. Textbook of Travel Medicine and Health. Hamilton, Ontario: BC Decker; 1997:86-91.
15. Schoepke A, et al. J Travel Med 1998;5:188-192.
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17. Fischer PR, Christenson JC. Contemp Pediatr 1998;15:15,28,204.
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20. Gamester CF, et al. BMJ 1999;318:158-160.
21. Waterhouse T, et al. Lancet 1997;350:1611-1616.
22. Kozarsky PE. Infect Dis Clin North Am 1998;12:305-324.
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26. Van Gompel A, et al. J Travel Med 1997;4:136-143.
27. Benson EA. Management of diabetes during international travel. In: Bia FJ, ed. Travel Medicine Advisor. 2nd ed. Atlanta, GA: American Health Consultants; 1993;15:1-5.
28. Jong EC. Infect Dis Clin North Am 1998;12:249-266.
29. Thompson RF, et al. Infect Dis Clin North Am 1999;13:149-167.
30. Angst F, Steffan R. J Travel Med 1997;4:118-120.
31. Ericsson CD. Infect Dis Clin North Am 1998;12:285-303.
32. Salam I, et al. Lancet 1994;344:1537-1539.
33. Hoge CW, et al. Lancet 1995;345:691-693.
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35. Ericsson CD, et al. J Travel Med 1997;4:3-7.
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Suggested Readings
1. Blair DC. Clin Microbiol Rev 1997;10:650-673.
2. Hilton E. Am J Managed Care 1997;10:1587-1592.
3. Schaffner W. Patient Care 1998(Sept 15):112-140.
4. Wolfe MS. Clin Infect Dis 1997;25:177-186.
Physician CME Questions
The most common cause of diarrhea among travelers is:
a. Enteroinvasive E. coli.
b. Shigella species.
c. Enterotoxigenic E. coli.
d. Salmonella species.
Approximately what percentage of patients are not compliant with their malaria prophylaxis?
a. 10%
b. 23%
c. 33%
d. 55%
Which of the following statements is false?
a. A solution of 30% DEET will provide protection for four or more hours.
b. Permethrin is an effective insecticide when applied to the clothes.
c. Oral ingestion of DEET is safe.
d. Patients should be advised to use DEET during the day as well as in the evenings.
Preventive antibiotics for travelers diarrhea are not recommended for which of the following patients going to Bangladesh for two weeks?
a. 45-year-old female patient with a liver transplant
b. 58-year-old healthy male
c. 22-year-old male with chronic ulcerative colitis
d. 67-year-old male with Rheumatoid arthritis on high-dose prednisone and methotrexate
e. 33-year-old female with rhabdomyosarcoma who has just completed her course of chemotherapy six weeks ago.
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