An estimated more than 800 million travelers worldwide cross international boundaries each year. However, whether associated with tourism, humanitarian efforts, globalization of industry, or migrant workers, studies suggest only a small number seek pre-travel health advice. In addition, the composition of those traveling continues to become more diverse and medically complex, creating a vastly different perspective on travel-associated medical concerns, preparations, and required medical knowledge.

With these decreasing boundaries and increasing activities, travel medicine has become a rapidly evolving field of medicine. Classically, travel medicine focused on individuals traveling to developing countries with prevention and treatment of malaria, traveler’s diarrhea, and general vaccinations as its primary goal. Travel medicine has subsequently become a dynamic multidisciplinary specialty that encompasses aspects of infectious disease, public health, tropical medicine, wilderness medicine, and appropriate immunization. Although these aspects are broad in reach, they are tightly integrated within the realm of travel medicine and require appropriate understanding prior to venturing out.

So, whether you are a humanitarian aid worker in Tanzania, an educator in Latin America, a tourist, or a businessperson for a multinational corporation, understanding the dynamics of travel and the interplay of healthcare will minimize the adverse effect of travel-related illnesses and concerns while maximizing enjoyment and success for the trip.

Travel Medicine: The Big Picture

The specialty of travel medicine is dynamic and vast in its medical knowledge requirements. Areas of expertise include vaccinations, epidemiology, region-specific travel medicine, pre-travel management, travel-related illnesses, and post-travel management.

Although the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) provide the backbone of current medical considerations, several groups have taken a paramount role in developing a structured curriculum to better identify the realm and role of travel medicine as a subspecialty of care. Two such examples are the International Society of Travel Medicine (ISTM) and the American Society of Tropical Medicine and Hygiene (ASTMH). The formation of such groups has allowed for a more open dialogue about the required body of knowledge for the practice of travel medicine and thereby improved related resources to an ever-expanding diversity of travelers.

In addition, recent establishment of collaborative sentinel surveillance networks specifically to monitor disease trends among travelers offers new supplemental options for evaluating travel health issues. These networks can inform pre-travel and post-travel patient management by providing complementary surveillance information, facilitating communication and collaboration between participating network sites, and enabling new analytical options for travel-related research.TropNetEurop and GeoSentinel represent two major networks currently available. Data obtained from studying health problems among travelers may provide significant benefits for local populations in resource-limited countries. However, given their limitations, they should be considered as complementary tools and not relied on as an exclusive basis for evaluating health risks among travelers.

Pre-travel Medical Preparation

Annually, Americans make more than 300 million trips to other countries. An increasing number of these trips are to developing countries, and, according to the CDC, 30-60% of these travelers, estimated at greater than 10 million people, become ill as a result of their travel.

With a heightened interest in adventure travel, international destinations, and ecotourism, more patients return from vacations with presentations of possible exotic disease that are beyond the scope of an emergency physician’s daily practice. However, much of the illnesses encountered could be eliminated with adequate pre-travel education and preparation. In the circumstance when prophylactic treatment and lifestyle modification fail, physicians need to know what to look for and where to find information on exotic diseases beyond the scope of daily practice. Further information can be quickly and easily accessed through the CDC Yellow Book, an online resource providing country-specific information.

Pre-travel preparation

Whether the participant is on an excursion to Nepal, is serving at a medical mission in Belize, or is the adventure-seeking traveler, preparation is paramount to a successful venture. All people planning travel should become informed about the potential hazards of the countries they are traveling to and learn how to minimize any risk to their health. Forward planning, appropriate preventive measures, and careful precautions can substantially reduce the risks of adverse health consequences. Although the medical profession and the travel industry can provide a great deal of help and advice, the traveler is responsible to ask for information, to understand the risks involved, and to take the necessary precautions for the journey. In addition, consideration should be given to any underlying medical or comorbid condition of each traveler as medications and emergency planning should be established prior to leaving.

Travelers should ascertain the associated travel health information for their specific itinerary several months in advance of departure. This should include general health information such as vaccine requirements, prophylactic medications, disease outbreaks, political environment, and medical resources.

Although often overlooked, dental, and for women, obstetric/gynecologic (OB/GYN), check ups are advisable before travel to developing countries for prolonged travel to remote areas. This is particularly important for people with chronic or recurrent dental or OB/GYN problems.

Approach to medical preparation for travel

Prior to departure for any extended or overseas travel, the information below should be obtained.

Travel information should be obtained, including the following:

• Geographic itinerary
• Duration and month(s) of travel
• Urban travel versus rural travel
• Anticipated living conditions
• Purpose of travel
• Medical care resources during travel

Personal health information should be obtained, including the following:

• Personal health status (eg, age, weight, pregnant)
• Medications and allergies
• Past medical history
• Medical or physical limitations

Basic health travel kit

A medical kit is an essential item that should be carried by all travelers to developing countries or where local availability of such resources remains in doubt. The kit should include standard first-aid items, simple medications for common ailments, and any items specific for that traveler. In addition, consider having a list of medications along with a medical attestation signed by a physician authenticating the need of those medications for personal use. Standard toiletry items sufficient for the entire travel period are recommended.

First-aid items include the following:

• Antiseptic wound cleanser
• Antihistamines
• Adhesive bandages/bandages
• Eye drops/rewetting drops
• Hand antiseptic
• Insect repellent
• Insect bite treatment
• Medical tape
• Nasal decongestant
• Oral rehydration powder
• Scissors and safety pins
• Simple analgesics (eg, ibuprofen, acetaminophen)
• Sterile gauze/dressing
• Thermometer (oral/rectal)

Additional considerations include the following:

• Antidiarrheal medication
• Antifungal medication
• Malaria prophylaxis
• Personal medications (current medical illnesses)
• Sleeping medications/sedatives
• Water purifier/disinfectant

Resource utilization

Improvisation (ie, creative use of unusual supplies for diagnosing, treating, splinting, transporting) is an invaluable skill taught in Wilderness Medical Society (WMS) courses. Efficient use of medications lightens the medical kit. For example, rather than carrying multiple antibiotics of choice for several possible infections, consider carrying a medication, such as ciprofloxacin, which treats travelers’ diarrhea (TD) as well as respiratory, wound, bladder, and other infections. Another example is diphenhydramine, which is excellent as an injectable local anesthetic as well as treatment for nausea, allergic reactions, and insomnia.

Unique circumstances

Physicians planning to serve as an expedition physician are advised to take a course provided by the WMS or a similar course by other providers. Detailed logistical planning, skills, equipment, medications, and resources for varied groups and destinations are beyond the scope of this article. Such information is readily available in both courses and textbooks from the WMS and the International Society of Travel Medicine (ISTM).

Almost any expedition has a unique set of possible emergencies, varying by destination and by the types of participants. Possible injuries and risks range from unusual envenomations and exotic flora and fauna to bear or shark attacks to snakebite or frostbite. Below is a list of possible scenarios that foster preparatory thought:

• An extended expedition in the Rocky Mountains with a group of Boy Scouts
• An emergency with a patient who has end-stage renal disease while aboard a luxury cruise ship
• Team physician on an Everest expedition
• Marine biology study of the Great Barrier Reef
• A bird-watching group in the Amazon
• A photo safari in Africa
• A fishing trip to Alaska

Requisite emergency skills may vary based on location, weather, activities, and availability of medical care. A physician may need knowledge of unusual diseases and injuries specific to certain activities or locations. These could include extrication and rescue skills in various environmental situations and improvisational skills and treatment of many medical emergencies. Many of these skills can be easily identified with adequate travel preparation and an understanding of the environment in which one will be traveling. However, regardless of the level of preparation, unplanned emergencies often occur, and one’s level of preparation may dictate the success with which care is provided.

Vaccination and Immunization

In anticipation of upcoming travel, it is essential that one is well educated regarding the regions that will be visited and how one’s current level of health may be impacted. Vaccinations are a vital part of any preparatory process. Once the regions of anticipated travel are identified, scheduling a visit to one’s doctor or a travel medicine provider is essentialideally 4-6 weeks before the trip because most vaccinations require a period of days or weeks to become effective. Reviewing current recommendations for the region of travel is recommended prior to the scheduled medical appointment. In addition, if uncertain regarding previous immunizations, variable tests are available to identify appropriate titer levels and whether updated boosters are indicated.

When discussing vaccinations, considering which are essential based on the region of travel and planned activities and what may be recommended is prudent. The CDC separates vaccines into 3 categories: required, recommended, and routine.

Routine vaccinations

Routine vaccinations are the immunizations that are routinely provided as a part of one’s normal health maintenance. These vaccines are necessary for protection from diseases that remain common in many parts of the world, although infrequently in the United States. If you are uncertain if you are up-to-date on routine immunizations, check with your medical provider.

Recommended vaccinations

Recommended vaccinations are predicated on a number of factors including one’s travel destinations, planned activities, season, previous immunizations, urban/rural location, one’s age, and current health status. In general, these vaccinations are recommended to protect travelers from illnesses present in other parts of the world and to prevent the importation of infectious diseases across international borders.

Special considerations for aging, immune compromised, pregnant, immigrant, chronically ill, students, and disabled travelers are essential.

Required vaccinations

International Health Regulations requires yellow fever vaccination for travel to certain countries in sub-Saharan Africa and tropical South America. In addition, those traveling during the Hajj are required by the government of Saudi Arabia to obtain the meningococcal vaccination.

Common Medical Considerations

Whether dealing with altitude sickness, malaria, cholera, or dengue fever, having a basic understanding of the common illnesses specific to the region of travel is essential. However, the list of potential considerations globally is enormous and far beyond the scope of this section. A great resource to identify more specific information can be found online through the Diseases Related to Travel section of the CDC. However, one of the most commonly experienced illnesses related to travel is diarrhea.

Travelers’ diarrhea

By far, the most common health risk for travelers, especially those visiting developing countries, is traveler’s diarrhea (TD), which can range from mildly annoying to prolonged, painful, and debilitating. According to the US CDC, high-risk destinations include the developing countries of Latin America, Africa, the Middle East, and Asia. Persons at particular high-risk include young adults, immunosuppressed persons, persons with inflammatory bowel disease or diabetes, and persons taking H2 blockers or antacids.

Every year, the CDC reports that between 20% and 50% of international travelers (an estimated 10 million people) develop diarrhea, usually within the first week of travel. TD, however, may occur at any time while traveling, even after returning home. The primary cause is contaminated food or water, typically found in areas with poor sanitation.

Common symptoms of TD include the following:

• Abrupt onset
• Increased frequency, volume, and weight of stool
• Altered stool consistency
• Nausea and/or vomiting may be associated
• Abdominal cramping, bloating, flatus
• Fever
• Malaise