I
S
T
M
384
REVIEW
Dengue Fever and International Travel Irani Ratnam, FRACP,∗† Karin Leder, FRACP,∗‡ Jim Black, FAFPHM,† and Joseph Torresi, FRACP§|| ∗
The Royal Melbourne Hospital, Victorian Infectious Disease Service, Melbourne, Victoria, Australia; † The Nossal Institute of Global Health, The University of Melbourne, Melbourne, Victoria, Australia; ‡ Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia; § Department of Infectious Diseases, Austin Hospital, Melbourne, Victoria, Australia; || Department of Medicine, Austin Health, The University of Melbourne, Melbourne, Victoria, Australia
DOI: 10.1111/jtm.12052
See the Editorial by Annelies Wilder-Smith, pp. 341–343 of this issue.
Background. Dengue is a leading public health problem with an expanding global burden. Dengue virus is also a significant cause of illness in international travelers with an increasing number of cases of dengue fever identified in travelers returning from dengue-endemic countries. Methods. This review focuses on the clinical illness of dengue infection in international travelers and provides a summary of the risk of infection for travelers, clinical features of infection, and an overview of dengue vaccines and their potential applicability to travelers. Results. Four prospective studies of travelers to dengue-endemic destinations have shown that the dengue infection incidence ranges from 10.2 to 30 per 1,000 person-months. This varies according to travel destination and duration and season of travel. Dengue is also a common cause of fever in returned travelers, accounting for up to 16% of all febrile illnesses in returned travelers. Although the majority of infections are asymptomatic, a small proportion of travelers develop dengue hemorrhagic fever. The diagnosis of dengue in travelers requires a combination of serological testing for IgG and IgM together with either nucleic acid or NS1 antigen testing. Several vaccine candidates have now entered into clinical trials including ChimeriVax Dengue, which is currently in phase 3 trials, live-attenuated chimeric vaccines (DENV-DENV Chimera, Inviragen), live-attenuated viral vaccines, recombinant protein subunit vaccines, and DNA vaccines. Conclusions. Dengue infection in international travelers is not infrequent and may be associated with substantial morbidity. Furthermore, an accurate diagnosis of dengue in travelers requires the use of a combination of diagnostic tests. Although a vaccine is not yet available a number of promising candidates are under clinical evaluation. For now travelers should be provided with accurate advice regarding preventive measures when visiting dengue-endemic areas.
D
engue is the most common arthropod-borne viral infection in the world and is endemic in over 100 countries throughout Africa, the Americas, Asia, Eastern Mediterranean, and Western Pacific. Dengue fever (DF) is transmitted by mosquitoes that remain in close proximity to humans and can be caused by any of the four dengue virus serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) belonging to the genus Flavivirus, family Flaviridae. The main vectors for dengue viruses are Aedes aegypti and Aedes albopictus, Corresponding Author: A/Prof Joseph Torresi, FRACP, Department of Infectious Diseases, Austin Hospital, 145 Studley Road, Heidelberg, Melbourne, Victoria 3084, Australia. E-mail: [email protected] © 2013 International Society of Travel Medicine, 1195-1982 Journal of Travel Medicine 2013; Volume 20 (Issue 6): 384–393
both of which are widely spread throughout Asia, the Pacific, and the Americas. There has been a dramatic increase in the number of dengue cases worldwide with an estimated 30-fold increase of documented dengue infections in the last 50 years. Regional surveillance data of dengue infections by the Pan American Health Organization (PAHO) reflects this upward trend in global dengue disease burden (Figure 1). The World Health Organization (WHO) estimates that each year over 100 million cases of DF and 500,000 cases of dengue hemorrhagic fever (DHF) are reported resulting in 25,000 deaths, although it is likely that significant underreporting occurs.1,2 However, Bhatt and colleagues have recently shown that each year there are approximately 390 million dengue infections, of which 96 million are clinically
385
Dengue Fever and International Travel A
rates ranging from
S
T
M
384
REVIEW
Dengue Fever and International Travel Irani Ratnam, FRACP,∗† Karin Leder, FRACP,∗‡ Jim Black, FAFPHM,† and Joseph Torresi, FRACP§|| ∗
The Royal Melbourne Hospital, Victorian Infectious Disease Service, Melbourne, Victoria, Australia; † The Nossal Institute of Global Health, The University of Melbourne, Melbourne, Victoria, Australia; ‡ Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia; § Department of Infectious Diseases, Austin Hospital, Melbourne, Victoria, Australia; || Department of Medicine, Austin Health, The University of Melbourne, Melbourne, Victoria, Australia
DOI: 10.1111/jtm.12052
See the Editorial by Annelies Wilder-Smith, pp. 341–343 of this issue.
Background. Dengue is a leading public health problem with an expanding global burden. Dengue virus is also a significant cause of illness in international travelers with an increasing number of cases of dengue fever identified in travelers returning from dengue-endemic countries. Methods. This review focuses on the clinical illness of dengue infection in international travelers and provides a summary of the risk of infection for travelers, clinical features of infection, and an overview of dengue vaccines and their potential applicability to travelers. Results. Four prospective studies of travelers to dengue-endemic destinations have shown that the dengue infection incidence ranges from 10.2 to 30 per 1,000 person-months. This varies according to travel destination and duration and season of travel. Dengue is also a common cause of fever in returned travelers, accounting for up to 16% of all febrile illnesses in returned travelers. Although the majority of infections are asymptomatic, a small proportion of travelers develop dengue hemorrhagic fever. The diagnosis of dengue in travelers requires a combination of serological testing for IgG and IgM together with either nucleic acid or NS1 antigen testing. Several vaccine candidates have now entered into clinical trials including ChimeriVax Dengue, which is currently in phase 3 trials, live-attenuated chimeric vaccines (DENV-DENV Chimera, Inviragen), live-attenuated viral vaccines, recombinant protein subunit vaccines, and DNA vaccines. Conclusions. Dengue infection in international travelers is not infrequent and may be associated with substantial morbidity. Furthermore, an accurate diagnosis of dengue in travelers requires the use of a combination of diagnostic tests. Although a vaccine is not yet available a number of promising candidates are under clinical evaluation. For now travelers should be provided with accurate advice regarding preventive measures when visiting dengue-endemic areas.
D
engue is the most common arthropod-borne viral infection in the world and is endemic in over 100 countries throughout Africa, the Americas, Asia, Eastern Mediterranean, and Western Pacific. Dengue fever (DF) is transmitted by mosquitoes that remain in close proximity to humans and can be caused by any of the four dengue virus serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) belonging to the genus Flavivirus, family Flaviridae. The main vectors for dengue viruses are Aedes aegypti and Aedes albopictus, Corresponding Author: A/Prof Joseph Torresi, FRACP, Department of Infectious Diseases, Austin Hospital, 145 Studley Road, Heidelberg, Melbourne, Victoria 3084, Australia. E-mail: [email protected] © 2013 International Society of Travel Medicine, 1195-1982 Journal of Travel Medicine 2013; Volume 20 (Issue 6): 384–393
both of which are widely spread throughout Asia, the Pacific, and the Americas. There has been a dramatic increase in the number of dengue cases worldwide with an estimated 30-fold increase of documented dengue infections in the last 50 years. Regional surveillance data of dengue infections by the Pan American Health Organization (PAHO) reflects this upward trend in global dengue disease burden (Figure 1). The World Health Organization (WHO) estimates that each year over 100 million cases of DF and 500,000 cases of dengue hemorrhagic fever (DHF) are reported resulting in 25,000 deaths, although it is likely that significant underreporting occurs.1,2 However, Bhatt and colleagues have recently shown that each year there are approximately 390 million dengue infections, of which 96 million are clinically
385
Dengue Fever and International Travel A
rates ranging from
