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Introduction to Travel Medicine
SECTION 1
CHAPTER 1
THE PRACTICE OF TRAVEL MEDICINE
Introduction to Travel Medicine Phyllis E. Kozarsky and Jay S. Keystone
KEYPOINTS n
espite the risks of emerging and re-emerging infectious diseases D and the threat of terrorism, international tourist arrivals remain high, as does travel from industrialized to developing countries
n
ravel medicine is the discipline devoted to the maintenance of T the health of international travelers through health promotion and disease prevention
n
he global focus and knowledge base of travel medicine T distinguishes this unique specialty from other fields of medicine and nursing
n
here is a need for improvement in the evidence base in travel T medicine in order to provide the most accurate pre-travel health advice
INTRODUCTION In spite of the global threat of emerging and re-emerging infectious diseases and concerns about international terrorism, travel remains one of the largest ‘businesses’ in the world. Over the last decade, the number of travelers crossing international borders has grown from 457 million in 1990 to 763 million in 2004.1 To keep this in perspective, the number of international tourist arrivals was only 50 million in 1950, 150 million in 1970, 500 million in 1993, and reached 842 million in 2006 (Fig. 1.1).1 At the current rate of growth, tourist arrivals are expected to top 1.6 billion by the year 2020 (Fig. 1.2).1 The market share of international tourism receipts has altered somewhat, though Western European countries, such as France and Spain continue to attract huge numbers of travelers (Fig. 1.3). More people than ever before are traveling to exotic and remote destinations. Over centuries of exploration and migration, diseases such as the plague, yellow fever, smallpox, malaria and cholera, and influenza spread around the world through travel. The time to circumnavigate the earth has decreased over the last one and a half centuries, from about 1 year to roughly 36 h – that is, to go from one spot on the globe to any other. Although today’s travelers are better protected from ancient diseases by better sanitation, immunizations and prophylactic medication, they face the threat of acquiring new, emerging, and re-emerging illnesses such as drug-resistant tuberculosis and
malaria, leptospirosis, tick-borne encephalitis, and novel respiratory illnesses such as Severe Acute Respiratory Syndrome (SARS) or even avian influenza (H5N1).2 In addition, and far more important in terms of traveler mortality, is the threat of problems such as injury (due to motor vehicle accidents) or the exacerbation of underlying illness (e.g. cardiac disease). Given these many challenges, during the 1970s and 1980s several visionary clinicians began exploring the medical requirements and recommendations that would better ensure healthy travel. This initial exploration into the prevention of travel-related illness has now grown in parallel with the escalation of travel itself, and has become a highly specialized area of medicine devoted to the maintenance of the health of international travelers through health promotion and disease prevention. It is still a fledgling multidisciplinary field encompassing a wide variety of specialties and subspecialties, including infectious and tropical diseases, public health and preventive medicine, primary care, and geographic, occupational, military, and wilderness medicine. For some time, travel medicine education has been incorporated into many infectious disease training programs.3 Also, travel medicine has broadened to include migration medicine, immigrant health, and has touched on the impact of travel on receiving countries. Unlike many other healthcare specialties, in a number of countries travel medicine is practiced by nurses, pharmacists and physicians alike. The worldwide focus and knowledge base of travel medicine distinguishes it from other fields of medicine and nursing. Travel medicine practitioners must be aware of infectious disease risks and their magnitude, patterns of drug resistance, current outbreaks of illness, civil and military conflicts, and political barriers to travel at border crossings. In addition, they must have access to the most up-to-date information on travel-related vaccines and medications. For some travel medicine providers, the assessment and management of the ill-returned traveler is an important component of their responsibilities. The challenge remains that for practitioners in this new field there is still a relative paucity of texts, journals, courses and apprenticeships that are devoted to teaching the basics of travel medicine as well as the latest information in the field. Currently, there are only two journals devoted to travel medicine. In recent years, national travel medicine societies in various countries have emerged to provide a meeting place for those with similar interests in travel health. Also, the International Society of Travel Medicine was started in 1991 with a mission to address educational needs for professionals and the public. Their conferences, journal, and newsletter have provided a centralized place for the gathering of this unique body of information. In addition, along with the annual or biennial publication of authoritative information from institutions such as the World Health Organization and the Centers for Disease Control and Prevention (CDC), new global surveillance systems, including GeoSentinel
SECTION 1: THE PRACTICE OF TRAVEL MEDICINE
800 700
Million
600 500 400 300
South Asia Middle East Africa East Asia/Pacific Americas Europe
East Asia and the Pacific 18%
200
Europe 50%
100 0 1950
1960
1980
1970
1990
2000
Americas 26%
Year Figure 1.1: Population growth circumnavigating the globe. Africa 3%
Middle East 2%
South Asia 1% Actual 1600 1400 1200 Million
1000 800 600
South Asia Middle East Africa East Asia/Pacific Americas Europe
Forecasts 1.6 bn
1 bn 694 mn
400 200 0 1950
1960
1970
Figure 1.3: International tourism receipts: market share 2001 (WTO, 2007).1
1980 1990 Year
2000
2010
2020
Figure 1.2: Forecast of international tourist arrivals: 2020.
and TropNet Europe, have been developed to track travel-related morbidity, so that all can better understand the emerging health problems related to population movements. A GeoSentinel review of over 17 000 ill-returned travelers highlighted geographic-specific health risks such as malaria from sub-Saharan Africa, dengue from the Caribbean, Central America and SE Asia, typhoid from South Asia and African tick-typhus from Southern Africa.4 This and follow-up studies have confirmed that compared with the usual tourist, immigrants returning to their places of birth in developing countries, visiting friends and relatives, are at greater risk of malaria, typhoid fever, tuberculosis, intestinal parasites, and sexually transmitted infections.5 Although the first international conference of travel medicine practitioners took place in 1988, the beginnings of travel medicine may truly have dated back hundreds, or even thousands of years, when healers or practitioners advised explorers, missionaries and military conquerors of the extreme hazards of their occupations. Today, the focus of travel medicine is on recreational tourists, business persons, overseas volunteers, missionaries, the military, and migrant populations fleeing civil and other conflicts or looking for political asylum or economic opportunities. In addition, the current era of the increasing popularity of ecotourism and extreme travel has added a new dimension to the field, including the challenges faced as practitioners counsel increasing numbers of the elderly and the immunocompromised, such as those with HIV, cancer, autoimmune diseases, or organ transplants. The complexity and variety of travel itineraries, combined with the
many health issues of enthusiastic travelers of all ages, shapes, and sizes, ensure that it takes much longer than appreciated to acquire the expertise necessary to provide travel medicine services. It is no longer adequate for advice to pass informally from friends, family, or travel counselors to travelers – or even from healthcare specialists in other fields to their patients – warning them only about the potential hazards of tap water! Indeed, data gathered over the last decade have clearly shown that health information for travel continues to be sought by far fewer travelers than it should. For example, depending on the study of travelers to malarious areas, only about 50% seek travel health advice, and far fewer are adherent to recommendations for chemoprophylaxis and insect protection.6–8 Data obtained from the CDC have shown that fewer than one-third of US travelers to areas of the world at risk for yellow fever have received the vaccine (Martin Cetron, personal communication, 2002). In addition, similar studies in several different countries show that travelers often seek their pretravel health advice at the last minute, if at all.9–11 Thus, it is important for those devoted to this discipline to increase awareness of the field, to educate the clinician, and to promote greater use of travel medicine experts. The chapters in this textbook address the most important issues in this rapidly growing and ever changing field, and represent an important step in the education of all travel medicine providers.
REFERENCES 1. World Tourism Organization (WTO). Facts and figures. Madrid. Online. Available: http://www.world-tourism.org/facts/menu.html (accessed May 2, 2007). 2. Murphy GG, Nathanson NM. New and emerging virus diseases. Sem Virol 1994; 5:87–102. 3. Hill DR, Ericsson CD, Pearson RD, et al. Infectious Diseases Society of America. The practice of travel medicine: guidelines by the Infectious Diseases Society of America. Clin Infect Dis 2006; 43:1499–1539.
CHAPTER 1: Introduction to Travel Medicine
4. Freedman DO, Weld LH, Kozarsky PE, et al. GeoSentinel Surveillance Network Spectrum of disease and relation to place of exposure among ill returned travelers. N Engl J Med 2006; 354:119–130. 5. Leder K, Tong S, Weld L, et al. GeoSentinel Surveillance Network. Illness in travelers visiting friends and relatives: a review of the GeoSentinel Surveillance Network. Clin Infect Dis 2006; 43:1185–1193. 6. Provost S, Soto JC. Predictors of pretravel consultation in tourists from Quebec (Canada). J Travel Med 2001; 8:66–75. 7. Lobel HO, Baker MA, Gras FA, et al. Use of malaria prevention measures by North American and European travelers to East Africa. J Travel Med 2001; 8:167–172.
8. dos Santos CC, Anvar A, Keystone JS, Kain KC. Survey of use of malaria prevention measures by Canadians visiting India. CMAJ 1999; 160: 195–200. 9. Hamer DH, Connor BA. Travel health knowledge, attitudes and practices among United States travelers. J Travel Med 2004; 11:23–26. 10. Dahlgren AL, DeRoo L, Steffen R. Prevention of travel-related infectious diseases: knowledge, practices and attitudes of Swedish travellers. Scand J Infect Dis 2006; 38:1074–1080. 11. Toovey S. Malaria chemoprophylaxis advice: survey of South African community pharmacists’ knowledge and practices. J Travel Med 2006; 13:161–165.
CHAPTER 1
THE PRACTICE OF TRAVEL MEDICINE
Introduction to Travel Medicine Phyllis E. Kozarsky and Jay S. Keystone
KEYPOINTS n
espite the risks of emerging and re-emerging infectious diseases D and the threat of terrorism, international tourist arrivals remain high, as does travel from industrialized to developing countries
n
ravel medicine is the discipline devoted to the maintenance of T the health of international travelers through health promotion and disease prevention
n
he global focus and knowledge base of travel medicine T distinguishes this unique specialty from other fields of medicine and nursing
n
here is a need for improvement in the evidence base in travel T medicine in order to provide the most accurate pre-travel health advice
INTRODUCTION In spite of the global threat of emerging and re-emerging infectious diseases and concerns about international terrorism, travel remains one of the largest ‘businesses’ in the world. Over the last decade, the number of travelers crossing international borders has grown from 457 million in 1990 to 763 million in 2004.1 To keep this in perspective, the number of international tourist arrivals was only 50 million in 1950, 150 million in 1970, 500 million in 1993, and reached 842 million in 2006 (Fig. 1.1).1 At the current rate of growth, tourist arrivals are expected to top 1.6 billion by the year 2020 (Fig. 1.2).1 The market share of international tourism receipts has altered somewhat, though Western European countries, such as France and Spain continue to attract huge numbers of travelers (Fig. 1.3). More people than ever before are traveling to exotic and remote destinations. Over centuries of exploration and migration, diseases such as the plague, yellow fever, smallpox, malaria and cholera, and influenza spread around the world through travel. The time to circumnavigate the earth has decreased over the last one and a half centuries, from about 1 year to roughly 36 h – that is, to go from one spot on the globe to any other. Although today’s travelers are better protected from ancient diseases by better sanitation, immunizations and prophylactic medication, they face the threat of acquiring new, emerging, and re-emerging illnesses such as drug-resistant tuberculosis and
malaria, leptospirosis, tick-borne encephalitis, and novel respiratory illnesses such as Severe Acute Respiratory Syndrome (SARS) or even avian influenza (H5N1).2 In addition, and far more important in terms of traveler mortality, is the threat of problems such as injury (due to motor vehicle accidents) or the exacerbation of underlying illness (e.g. cardiac disease). Given these many challenges, during the 1970s and 1980s several visionary clinicians began exploring the medical requirements and recommendations that would better ensure healthy travel. This initial exploration into the prevention of travel-related illness has now grown in parallel with the escalation of travel itself, and has become a highly specialized area of medicine devoted to the maintenance of the health of international travelers through health promotion and disease prevention. It is still a fledgling multidisciplinary field encompassing a wide variety of specialties and subspecialties, including infectious and tropical diseases, public health and preventive medicine, primary care, and geographic, occupational, military, and wilderness medicine. For some time, travel medicine education has been incorporated into many infectious disease training programs.3 Also, travel medicine has broadened to include migration medicine, immigrant health, and has touched on the impact of travel on receiving countries. Unlike many other healthcare specialties, in a number of countries travel medicine is practiced by nurses, pharmacists and physicians alike. The worldwide focus and knowledge base of travel medicine distinguishes it from other fields of medicine and nursing. Travel medicine practitioners must be aware of infectious disease risks and their magnitude, patterns of drug resistance, current outbreaks of illness, civil and military conflicts, and political barriers to travel at border crossings. In addition, they must have access to the most up-to-date information on travel-related vaccines and medications. For some travel medicine providers, the assessment and management of the ill-returned traveler is an important component of their responsibilities. The challenge remains that for practitioners in this new field there is still a relative paucity of texts, journals, courses and apprenticeships that are devoted to teaching the basics of travel medicine as well as the latest information in the field. Currently, there are only two journals devoted to travel medicine. In recent years, national travel medicine societies in various countries have emerged to provide a meeting place for those with similar interests in travel health. Also, the International Society of Travel Medicine was started in 1991 with a mission to address educational needs for professionals and the public. Their conferences, journal, and newsletter have provided a centralized place for the gathering of this unique body of information. In addition, along with the annual or biennial publication of authoritative information from institutions such as the World Health Organization and the Centers for Disease Control and Prevention (CDC), new global surveillance systems, including GeoSentinel
SECTION 1: THE PRACTICE OF TRAVEL MEDICINE
800 700
Million
600 500 400 300
South Asia Middle East Africa East Asia/Pacific Americas Europe
East Asia and the Pacific 18%
200
Europe 50%
100 0 1950
1960
1980
1970
1990
2000
Americas 26%
Year Figure 1.1: Population growth circumnavigating the globe. Africa 3%
Middle East 2%
South Asia 1% Actual 1600 1400 1200 Million
1000 800 600
South Asia Middle East Africa East Asia/Pacific Americas Europe
Forecasts 1.6 bn
1 bn 694 mn
400 200 0 1950
1960
1970
Figure 1.3: International tourism receipts: market share 2001 (WTO, 2007).1
1980 1990 Year
2000
2010
2020
Figure 1.2: Forecast of international tourist arrivals: 2020.
and TropNet Europe, have been developed to track travel-related morbidity, so that all can better understand the emerging health problems related to population movements. A GeoSentinel review of over 17 000 ill-returned travelers highlighted geographic-specific health risks such as malaria from sub-Saharan Africa, dengue from the Caribbean, Central America and SE Asia, typhoid from South Asia and African tick-typhus from Southern Africa.4 This and follow-up studies have confirmed that compared with the usual tourist, immigrants returning to their places of birth in developing countries, visiting friends and relatives, are at greater risk of malaria, typhoid fever, tuberculosis, intestinal parasites, and sexually transmitted infections.5 Although the first international conference of travel medicine practitioners took place in 1988, the beginnings of travel medicine may truly have dated back hundreds, or even thousands of years, when healers or practitioners advised explorers, missionaries and military conquerors of the extreme hazards of their occupations. Today, the focus of travel medicine is on recreational tourists, business persons, overseas volunteers, missionaries, the military, and migrant populations fleeing civil and other conflicts or looking for political asylum or economic opportunities. In addition, the current era of the increasing popularity of ecotourism and extreme travel has added a new dimension to the field, including the challenges faced as practitioners counsel increasing numbers of the elderly and the immunocompromised, such as those with HIV, cancer, autoimmune diseases, or organ transplants. The complexity and variety of travel itineraries, combined with the
many health issues of enthusiastic travelers of all ages, shapes, and sizes, ensure that it takes much longer than appreciated to acquire the expertise necessary to provide travel medicine services. It is no longer adequate for advice to pass informally from friends, family, or travel counselors to travelers – or even from healthcare specialists in other fields to their patients – warning them only about the potential hazards of tap water! Indeed, data gathered over the last decade have clearly shown that health information for travel continues to be sought by far fewer travelers than it should. For example, depending on the study of travelers to malarious areas, only about 50% seek travel health advice, and far fewer are adherent to recommendations for chemoprophylaxis and insect protection.6–8 Data obtained from the CDC have shown that fewer than one-third of US travelers to areas of the world at risk for yellow fever have received the vaccine (Martin Cetron, personal communication, 2002). In addition, similar studies in several different countries show that travelers often seek their pretravel health advice at the last minute, if at all.9–11 Thus, it is important for those devoted to this discipline to increase awareness of the field, to educate the clinician, and to promote greater use of travel medicine experts. The chapters in this textbook address the most important issues in this rapidly growing and ever changing field, and represent an important step in the education of all travel medicine providers.
REFERENCES 1. World Tourism Organization (WTO). Facts and figures. Madrid. Online. Available: http://www.world-tourism.org/facts/menu.html (accessed May 2, 2007). 2. Murphy GG, Nathanson NM. New and emerging virus diseases. Sem Virol 1994; 5:87–102. 3. Hill DR, Ericsson CD, Pearson RD, et al. Infectious Diseases Society of America. The practice of travel medicine: guidelines by the Infectious Diseases Society of America. Clin Infect Dis 2006; 43:1499–1539.
CHAPTER 1: Introduction to Travel Medicine
4. Freedman DO, Weld LH, Kozarsky PE, et al. GeoSentinel Surveillance Network Spectrum of disease and relation to place of exposure among ill returned travelers. N Engl J Med 2006; 354:119–130. 5. Leder K, Tong S, Weld L, et al. GeoSentinel Surveillance Network. Illness in travelers visiting friends and relatives: a review of the GeoSentinel Surveillance Network. Clin Infect Dis 2006; 43:1185–1193. 6. Provost S, Soto JC. Predictors of pretravel consultation in tourists from Quebec (Canada). J Travel Med 2001; 8:66–75. 7. Lobel HO, Baker MA, Gras FA, et al. Use of malaria prevention measures by North American and European travelers to East Africa. J Travel Med 2001; 8:167–172.
8. dos Santos CC, Anvar A, Keystone JS, Kain KC. Survey of use of malaria prevention measures by Canadians visiting India. CMAJ 1999; 160: 195–200. 9. Hamer DH, Connor BA. Travel health knowledge, attitudes and practices among United States travelers. J Travel Med 2004; 11:23–26. 10. Dahlgren AL, DeRoo L, Steffen R. Prevention of travel-related infectious diseases: knowledge, practices and attitudes of Swedish travellers. Scand J Infect Dis 2006; 38:1074–1080. 11. Toovey S. Malaria chemoprophylaxis advice: survey of South African community pharmacists’ knowledge and practices. J Travel Med 2006; 13:161–165.