Travel Medicine and Infectious Disease (2014) 12, 557e558
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevierhealth.com/journals/tmid
EDITORIAL
Rabies e An important zoonotic threat for travelers In this special issue of Travel Medicine and Infectious diseases dedicated to zoonosis, a number of papers address rabies epidemiology and rabies vaccination following exposure to potentially rabid animals. Rabies is an important topic in travel medicine. During last two conferences of the International Society of Travel Medicine, rabies in travelers was addressed in a symposium on “low risk e high consequence disease” in 2011, in Boston and in a symposium on “difficult vaccine decision” in 2013, in Maastricht. These symposia show the importance that travel medicine experts attach to this zoonotic disease. Rabies is estimated to cause more than 60,000 human deaths annually based on a probability decision-tree approach [1]. Primarily resulting from dog bites, rabies is a public health concern in most countries in Asia and Africa, where the spread of canine rabies is uncontrolled and is far from being eliminated [2]. Rabies cases among travelers are much less frequent. Sixty cases of travel-associated rabies cases were retrieved from a literature search over the 1990e2012 [3]. Most exposures occurred in Asia, notably in India, the Philippines, and in Mexico, Morocco and Algeria. A significant proportion of the cases were observed in migrants or their descendants when emigrating from their country of origin or after a trip to visit friends and relatives whilst the remaining cases were in individuals traveling for tourism, business or expatriation. The cases were not necessarily associated with long-term travel; instead, some cases were observed in travelers after short trips of two weeks or less. In more than half of the cases, diagnosis was challenging, with multiple missed diagnoses and transfers from ward to ward before reaching the final diagnosis of rabies. This happened notably because many patients did not report a history of animal bite at the first medical encounter. Since this review was published, six additional cases were reported on Pro-Med posts, including a Filipino migrant bitten by a dog in his country of origin prior to immigrating to Taiwan, a Guatemala migrant infected by a canine rabies virus variant common in Central America before http://dx.doi.org/10.1016/j.tmaid.2014.10.010 1477-8939/ª 2014 Published by Elsevier Ltd.
immigrating to the US, two Dutch travelers injured by a dog in Haiti and India respectively, a migrant from Mali returning to France after visiting his family in Mali and a woman of South Asian ethnicity, injured by a dog in India and diagnosed in UK. If rabies cases among travelers remain rare, the exposure of travelers to potentially rabid animals is much more frequent with an estimated incidence of 0.4% per month of stay, according to a metaanalysis of more than 1,270,000 individuals [4]. The following risk factors for injury caused by potentially rabid animals may be identified: traveling to Southeast Asia, India, and North Africa, young age, and traveling for tourism. The duration of travel however, does not appear to be a risk factor [4,5]. According to studies conducted in travelers seeking rabies post-exposure prophylaxis (PEP), 3 in 10 expatriates and 1 in 10 tourists were vaccinated against rabies before travel [4,5]. Furthermore less than 1 in 10 travelers received rabies immune globuline (RIG) in the country of injury and those who received RIG on returning to their home country had a substantial delay between injury and administration of RIG [4,5]. In this context, education of travelers about avoiding contact with animals and the need for early washing and disinfection of any animal-related injuries, followed by rabies PEP needs to be reinforced during the pre-travel consultation. Pre-travel vaccination against rabies eliminates the need for RIG following potential exposure but is expensive in many countries [6], although the long-lasting resulting immunity may make this investment attractive for some patients in the light of cumulative risk due to multiple travels [7]. Pre-travel vaccination should be considered, notably where access to tissue culture-derived rabies vaccine and human RIG is limited or where no reliable information can be obtained. Less expensive intra-dermal preventive vaccination schedules are recommended by the World Health Organization, including for use in travelers. Shorter, less expensive pre-exposure vaccine schedules have been shown to be effective in several preliminary studies [6,8]. However, they are not yet widely
558 available for travelers. The use of the economical intradermal route for travelers could be generalized to avoid wasting this vaccine. This usage, nonetheless, requires that regulatory issues related to vaccine dose-sparing methods can be resolved first. International partnerships for strong, coordinated rabies surveillance and response are vital for effective global rabies prevention and control [9].
References [1] World Health Organization. Rabies vaccines. WHO expert consultation on rabies. Second report. WHO technical report series. Geneva: WHO Press, World Health Organization; 2013. [2] Wunner WH, Briggs DJ. Rabies in the 21 century. PLoS Negl Trop Dis 2010;4(3):e591. [3] Carrara P, Parola P, Brouqui P, Gautret P. Imported human rabies cases worldwide, 1990e2012. PLoS Negl Trop Dis 2013; 7:e2209. [4] Gautret P, Parola P. Rabies vaccination for international travelers. Vaccine 2012;30:126e33. [5] Gautret P, Parola P. Rabies pretravel vaccination. Curr Opin Infect Dis 2012;25:500e6. [6] Warrell MJ. Current rabies vaccines and prophylaxis schedules: preventing rabies before and after exposure. Travel Med Infect Dis 2012;10:1e15.
Editorial [7] Leder K, Chen LH, Wilson ME. Aggregate travel vs. single trip assessment: arguments for cumulative risk analysis. Vaccine 2012;30:2600e4. [8] Lau CL, Hohl N. Immunogenicity of a modified intradermal pre-exposure rabies vaccination schedule using a purified chick embryo cell vaccine: an observational study. Travel Med Infect Dis 2013 NoveDec;11(6):427e30. [9] Lembo T, Attlan M, Bourhy H, et al. Renewed global partnerships and redesigned roadmaps for rabies prevention and control. Vet Med Int 2011 Jun 1. Epub.
Philippe Gautret* Aix Marseille Universite´, Unite´ de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Unite´ Mixte de Recherche (UMR) 63, Centre National de la Recherche Scientifique (CNRS) 7278, Institut de Recherche pour le De´veloppement (IRD) 198, Institut National de la Sante´ Et de la Recherche Me´dicale (INSERM) 1095, 13005 Marseille, France *Institut Hospitalo, Universitaire Me ´diterrane ´e Infection, 13005 Marseille, France. Tel.: þ33 (0)491 96 35 35, þ33 (0) 491 96 35 36; fax: þ33 (0)491 96 89 38. E-mail address: [email protected] 11 October 2014 Available online 22 October 2014
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevierhealth.com/journals/tmid
EDITORIAL
Rabies e An important zoonotic threat for travelers In this special issue of Travel Medicine and Infectious diseases dedicated to zoonosis, a number of papers address rabies epidemiology and rabies vaccination following exposure to potentially rabid animals. Rabies is an important topic in travel medicine. During last two conferences of the International Society of Travel Medicine, rabies in travelers was addressed in a symposium on “low risk e high consequence disease” in 2011, in Boston and in a symposium on “difficult vaccine decision” in 2013, in Maastricht. These symposia show the importance that travel medicine experts attach to this zoonotic disease. Rabies is estimated to cause more than 60,000 human deaths annually based on a probability decision-tree approach [1]. Primarily resulting from dog bites, rabies is a public health concern in most countries in Asia and Africa, where the spread of canine rabies is uncontrolled and is far from being eliminated [2]. Rabies cases among travelers are much less frequent. Sixty cases of travel-associated rabies cases were retrieved from a literature search over the 1990e2012 [3]. Most exposures occurred in Asia, notably in India, the Philippines, and in Mexico, Morocco and Algeria. A significant proportion of the cases were observed in migrants or their descendants when emigrating from their country of origin or after a trip to visit friends and relatives whilst the remaining cases were in individuals traveling for tourism, business or expatriation. The cases were not necessarily associated with long-term travel; instead, some cases were observed in travelers after short trips of two weeks or less. In more than half of the cases, diagnosis was challenging, with multiple missed diagnoses and transfers from ward to ward before reaching the final diagnosis of rabies. This happened notably because many patients did not report a history of animal bite at the first medical encounter. Since this review was published, six additional cases were reported on Pro-Med posts, including a Filipino migrant bitten by a dog in his country of origin prior to immigrating to Taiwan, a Guatemala migrant infected by a canine rabies virus variant common in Central America before http://dx.doi.org/10.1016/j.tmaid.2014.10.010 1477-8939/ª 2014 Published by Elsevier Ltd.
immigrating to the US, two Dutch travelers injured by a dog in Haiti and India respectively, a migrant from Mali returning to France after visiting his family in Mali and a woman of South Asian ethnicity, injured by a dog in India and diagnosed in UK. If rabies cases among travelers remain rare, the exposure of travelers to potentially rabid animals is much more frequent with an estimated incidence of 0.4% per month of stay, according to a metaanalysis of more than 1,270,000 individuals [4]. The following risk factors for injury caused by potentially rabid animals may be identified: traveling to Southeast Asia, India, and North Africa, young age, and traveling for tourism. The duration of travel however, does not appear to be a risk factor [4,5]. According to studies conducted in travelers seeking rabies post-exposure prophylaxis (PEP), 3 in 10 expatriates and 1 in 10 tourists were vaccinated against rabies before travel [4,5]. Furthermore less than 1 in 10 travelers received rabies immune globuline (RIG) in the country of injury and those who received RIG on returning to their home country had a substantial delay between injury and administration of RIG [4,5]. In this context, education of travelers about avoiding contact with animals and the need for early washing and disinfection of any animal-related injuries, followed by rabies PEP needs to be reinforced during the pre-travel consultation. Pre-travel vaccination against rabies eliminates the need for RIG following potential exposure but is expensive in many countries [6], although the long-lasting resulting immunity may make this investment attractive for some patients in the light of cumulative risk due to multiple travels [7]. Pre-travel vaccination should be considered, notably where access to tissue culture-derived rabies vaccine and human RIG is limited or where no reliable information can be obtained. Less expensive intra-dermal preventive vaccination schedules are recommended by the World Health Organization, including for use in travelers. Shorter, less expensive pre-exposure vaccine schedules have been shown to be effective in several preliminary studies [6,8]. However, they are not yet widely
558 available for travelers. The use of the economical intradermal route for travelers could be generalized to avoid wasting this vaccine. This usage, nonetheless, requires that regulatory issues related to vaccine dose-sparing methods can be resolved first. International partnerships for strong, coordinated rabies surveillance and response are vital for effective global rabies prevention and control [9].
References [1] World Health Organization. Rabies vaccines. WHO expert consultation on rabies. Second report. WHO technical report series. Geneva: WHO Press, World Health Organization; 2013. [2] Wunner WH, Briggs DJ. Rabies in the 21 century. PLoS Negl Trop Dis 2010;4(3):e591. [3] Carrara P, Parola P, Brouqui P, Gautret P. Imported human rabies cases worldwide, 1990e2012. PLoS Negl Trop Dis 2013; 7:e2209. [4] Gautret P, Parola P. Rabies vaccination for international travelers. Vaccine 2012;30:126e33. [5] Gautret P, Parola P. Rabies pretravel vaccination. Curr Opin Infect Dis 2012;25:500e6. [6] Warrell MJ. Current rabies vaccines and prophylaxis schedules: preventing rabies before and after exposure. Travel Med Infect Dis 2012;10:1e15.
Editorial [7] Leder K, Chen LH, Wilson ME. Aggregate travel vs. single trip assessment: arguments for cumulative risk analysis. Vaccine 2012;30:2600e4. [8] Lau CL, Hohl N. Immunogenicity of a modified intradermal pre-exposure rabies vaccination schedule using a purified chick embryo cell vaccine: an observational study. Travel Med Infect Dis 2013 NoveDec;11(6):427e30. [9] Lembo T, Attlan M, Bourhy H, et al. Renewed global partnerships and redesigned roadmaps for rabies prevention and control. Vet Med Int 2011 Jun 1. Epub.
Philippe Gautret* Aix Marseille Universite´, Unite´ de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Unite´ Mixte de Recherche (UMR) 63, Centre National de la Recherche Scientifique (CNRS) 7278, Institut de Recherche pour le De´veloppement (IRD) 198, Institut National de la Sante´ Et de la Recherche Me´dicale (INSERM) 1095, 13005 Marseille, France *Institut Hospitalo, Universitaire Me ´diterrane ´e Infection, 13005 Marseille, France. Tel.: þ33 (0)491 96 35 35, þ33 (0) 491 96 35 36; fax: þ33 (0)491 96 89 38. E-mail address: [email protected] 11 October 2014 Available online 22 October 2014
