The risk of illness or injury increases with duration of travel, so special consideration should be given to travelers who are planning long-term visits (≥6 months is a common definition) to low- or middle-income countries, whether they are expatriates with definite plans or adventurers with open itineraries. Points to discuss in the pre-travel consultation include accessing care at the destination, vaccines, infectious diseases not prevented by vaccines, injury prevention, and psychological and cultural issues that long-term travelers may encounter.
ACCESSING CARE ABROAD
Before departure, all long-term travelers should undergo complete medical and dental examinations. It also may be beneficial to have a psychological evaluation, as early repatriation is often due to psychological issues that could be addressed prior to travel. Travelers should anticipate that they will need care at some point during their stay, and they should plan where they will get it and how they will pay for it. Those traveling for work or with an organization (such as a university or the Peace Corps) may have a predetermined source of care and some may access advice from the international expatriate community. In contrast, other travelers should identify a source in advance. Long-term travelers should also determine if they will need supplemental travel health insurance and evacuation insurance since health insurance can be a challenge to procure locally.
In some countries, travelers are likely to encounter poor-quality (substandard, falsified, counterfeit, or expired) medications. Because the pills and packaging may be nearly indistinguishable from their legitimate counterparts, travelers should bring a sufficient supply of their routine medications (antihypertensive or antihyperlipidemic drugs, for example) from the United States. There are different options to obtain sufficient medications: (1) request an override from the insurance company to dispense the entire quantity of medication, (2) pay out of pocket for the full amount of medication needed and then submit to insurance company for reimbursement, or (3) rely on friends or family members who visit to bring refilled medication supplies.
Routine vaccines, including influenza vaccine, should be updated. In addition, long-term travelers should be aware of any vaccine requirements at their destination for employment, schooling, or entry. A number of travel-related vaccines warrant consideration:
- Hepatitis A and typhoid vaccines are appropriate given the cumulative risk, although the traveler should be aware that the latter does not provide full protection.
- Travel-associated hepatitis B infections are rare, but the risk for travelers may be higher than for nontravelers, and the vaccine should be considered for all long-term travelers and expatriates.
- Meningococcal disease is more likely in travelers with prolonged exposure to local populations in endemic or epidemic areas; quadrivalent vaccine should be considered for those at risk.
- Japanese encephalitis is associated with longer stays in endemic areas, and the vaccine is recommended for travelers who plan to reside in endemic areas or travel for ≥1 month to endemic areas, or travelers anticipating outdoor activities in endemic areas after dusk.
- Rabies pre-exposure prophylaxis is an important consideration for people spending a prolonged time in endemic countries, especially in areas where rabies immune globulin is not available (which is true of many resource-limited countries). Vaccinating children who will be living in high-risk areas is a priority.
- Numerous unvaccinated Chinese expatriates have recently fallen ill from yellow fever while working in Angola, illustrating the importance of yellow fever vaccination for travelers who will be staying in an endemic area or a country with a vaccine requirement.
In addition to the intended destination, consider disease risk in surrounding areas, since long-term travelers may be likely to travel locally. For example, a short-term traveler to Seoul would not be considered at risk for Japanese encephalitis, but an expatriate living in Seoul may have opportunities to visit the Korean countryside or other areas in Asia where he or she could be exposed.
INFECTIOUS DISEASES NOT PREVENTED BY VACCINES
Data suggest that the incidence of malaria increases and the use of preventive measures decreases with the increasing length of stay. For instance, malaria incidence in British travelers returning from West Africa after a stay of 6–12 months was 80 times that of the incidence in travelers who had stayed only 1 week. Among expatriate corporate employees in Ghana, adherence to malaria prophylaxis deteriorated with increasing duration of stay, and all those who had been on the site for >1 year had abandoned prophylaxis. About half of the cohort used insect repellent only intermittently, and more than one-third never used repellent. Even though most British expatriates from the UK Foreign and Commonwealth Office had good knowledge about malaria and its prevention strategies, they adhered to malaria prophylaxis <25% of the time; only 25% reported rigorous compliance, and 13% reported having contracted malaria. Given the high relative risk of malaria for travelers in Africa, these data on long-term travelers and expatriates highlight worrisome risks and practices.
A traveler who will be residing in an area of continuous malaria transmission should continue to use malaria prophylaxis for the entire stay. It is important to reassure the traveler that the drugs are safe and effective. Doxycycline has been well-tolerated for long-term malaria prophylaxis in the military, and CDC has no recommended limits on its duration of use for malaria prophylaxis. Mefloquine has been used frequently during prolonged stays by Peace Corps volunteers, with a discontinuation rate of 0.9%. Mefloquine may be appropriate for long-term prophylaxis in chloroquine-resistant areas because of its convenient weekly dosing, but concern has increased regarding its neuropsychiatric side-effect profile, especially the recent Food and Drug Administration label indicating that neurologic side effects may persist. Atovaquone-proguanil has shown good long-term tolerability in post-marketing surveillance, with a discontinuation rate of only 1% because of diarrhea. Peace Corps Volunteers prescribed atovaquone-proguanil adhered to prophylaxis best when compared with those given doxycycline and mefloquine. If long-term use (>5 years) of chloroquine is planned, a baseline ophthalmic examination with biannual follow-up is recommended to screen for potential retinal toxicity.
The possibility of pregnancy requires careful consideration for long-term female travelers to malarious areas. Malaria infection during pregnancy can result in severe complications to both mother and fetus. When pregnancy is anticipated, prophylaxis options may need to be adjusted. Ideally, this possibility should be explored before travel with all female long-term travelers of childbearing age. For women who are pregnant or plan to become pregnant during long-term travel, mefloquine is considered safe in all trimesters. Data from published studies in pregnant women have shown no increase in the risk of teratogenic effects or adverse pregnancy outcomes after mefloquine prophylaxis during pregnancy. Chloroquine has also been used long-term without ill effect on pregnancy. If a woman traveling long-term is taking atovaquone-proguanil, doxycycline, or primaquine, she should discontinue her medication and begin weekly mefloquine (or chloroquine in those areas where it remains efficacious) and wait at least 3–4 weeks to conceive so that a therapeutic blood level of mefloquine can build up.
Women who become pregnant while taking antimalarial drugs do not need a therapeutic abortion but should be advised during the pre-travel consultation of potential risks. The effect of atovaquone-proguanil on the fetus is unknown, but doxycycline is associated with fetal toxicity in animals and is contraindicated in pregnant women. Primaquine may harm a G6PD-deficient fetus, so it should not be used in pregnancy.
French service members deployed to the Central African Republic for 4 months in 2013 experienced malaria at a rate of 150 cases/1,000 person-years; a survey found that prophylaxis compliance correlated with other prophylactic measures against malaria (bed net use, insecticide on clothing, taking prophylaxis at the same time every day), correct perception of malaria risk, positive perception of prophylaxis effectiveness, and peer-to-peer reinforcement. For long-term travelers, the need for adjuncts to prophylaxis should also be stressed, such as personal protection measures to avoid mosquito bites (sleeping under a bed net, using screens, and applying repellents). Travelers should bring a sufficient supply of antimalarial drugs from the United States, since drugs purchased at the destination may be of poor quality. Even with urging to adhere to personal protective measures and reassurance that long-term prophylaxis is safe and effective, adherence is likely to decline over time. Consequently, the pre-travel consultation for a long-term traveler to a malarious area should stress the severity of malaria, its signs and symptoms, and the need to seek care immediately if they develop. Travelers could consider bringing a reliable supply of drugs to treat malaria if they are diagnosed with malaria.
Because diarrhea and gastrointestinal diseases are common in long-term travelers, they should be educated about the management of acute diarrhea including rehydration, the use of antimotility agents, empiric antimicrobial therapy, and when to seek care.
Tuberculosis risk may rise to the level of the local population if the traveler or expatriate has a longer stay and intimate contact with the local population. A baseline tuberculin test or interferon-γ release assay, followed by the same test after travel, should be considered, especially for health care workers or those who may be working in hospitals, refugee camps, or prisons.
Likewise, dengue seroconversion occurred at a rate of 3.4/1,000 people per month of stay in endemic areas among development aid workers. Other mosquito-borne viral illnesses are also a risk, so long-term travelers and expatriates should be advised to protect themselves from the mosquito vectors.
Risk for HIV and sexually transmitted infections are increased in travelers and expatriates, and the consistent use of condoms in expatriates is low (approximately 20%). Long-term travelers should be educated about the risk of HIV and sexually transmitted diseases in their destination, as well as preventive measures. The potential for occupational exposure to HIV is important to consider in health care workers; postexposure prophylaxis with antiretroviral therapy and risk avoidance should be included in the pretravel consultation.
Transfusion is a potential source of hepatitis C infection in expatriates. The risk of hepatitis E, spread by the fecal-oral route, is highest in Asia, although it has been transmitted in many different tropical locations. Pregnant women are at the highest risk of fulminant disease.
Other infections vary with location and include giardiasis, amebiasis, strongyloidiasis, schistosomiasis, cutaneous leishmaniasis, and filariasis. Strongyloides stercoralis infections can be prevented by not walking barefoot through the soil, and schistosomiasis may be prevented by not swimming or wading in fresh water. This latter risk is difficult to communicate to long-term travelers who, for example, may be living in sub-Saharan Africa and who look forward to river rafting or vacationing at a lake. The risks of strongyloidiasis and schistosomiasis increase with long-term travel, so screening on return (and also during long-term expatriate assignments for those with access to health care) should also be discussed. Cutaneous leishmaniasis and filariasis should be reviewed if a traveler has the potential geographic exposure risk. Compared with short-term travelers, long-term travelers experience more chronic diarrhea and postinfectious irritable bowel syndrome (possibly because some become less adherent to food and water precautions over time) and should be advised to continue food and water precautions in order to reduce the risk for these conditions.
Since injuries are the leading cause of preventable death in travelers, long-term travelers should be educated about safety. Road and vehicle safety should be stressed, and travelers should choose the safest vehicle options available. Roads are often poorly constructed and maintained, traffic laws may not be enforced, vehicles may not have seatbelts or be properly maintained, and drivers may be reckless and poorly trained.
The stress of long-term travel can trigger or exacerbate psychiatric reactions. A long-term traveler should be assessed for preexisting psychiatric diagnosis, depressed mood, recent major life stressors, and the use of medications that may have psychiatric effects. These conditions may suggest a need for further screening. All long-term travelers should be urged to take care of their physical and mental health by exercising regularly and eating healthfully. They should be able to recognize signs of anxiety and depression and have a plan for coping with them. Having photographs or other mementos of friends and family at hand and staying in close contact with loved ones at home can alleviate the stress of long-term travel.
LONG-TERM TRAVELERS WITH OPEN ITINERARIES
Offering pretravel care to travelers with no itinerary (or those who present with only vague travel plans) presents unique challenges. These travelers benefit from broad immunization coverage for all potential exposures to vaccine-preventable diseases, although some prioritization may be necessary. Because their plans are unclear, these travelers must understand that they may need to diagnose and treat themselves for common ailments, including travelers’ diarrhea, upper respiratory tract infections, urinary tract infections, vaginitis, skin disorders, and musculoskeletal problems. For travelers such as backpackers who may go in and out of malarious areas, a sensible approach is to provide a supply of atovaquone-proguanil with instructions on how to administer it when they do visit risk areas. In addition to strategies to prevent health problems and injuries during their long sojourns, traveler education is imperative regarding health resources, signs, and symptoms that require urgent medical evaluation, and medical evacuation.
SCREENING LONG-TERM TRAVELERS AND EXPATRIATES AFTER RETURN
Long-term travelers, whether they are expatriate workers, Peace Corps volunteers, or highly adventurous travelers, need a thorough medical interview to assess potential infectious exposures after return to their country of origin. A careful itinerary-specific history with detailed questioning about potential high-risk exposures including food, water, animal, and human contact is the foundation of the post-travel evaluation. A physical examination focused on specific signs and symptoms and a selected array of tests, including tuberculin skin test or interferon-γ release assay for tuberculosis screening, a complete blood count with differential, hepatic transaminases, and serologic markers depending on types of exposure (but most importantly for strongyloidiasis and schistosomiasis), are helpful to detect subclinical infections and determine whether seroconversion to the more common pathogens (where treatment would be advised) has occurred. A benefit of the post-travel evaluation is preventive counseling for potential future travel.
Source: Centers for Disease Control and Prevention: wwwnc.cdc.gov