Chapter 2The Pre-Travel ConsultationCounseling & Advice for Travelers
HUMAN INTERACTION WITH ANIMALS: A RISK FACTOR FOR INJURY AND ILLNESS
Animals tend to avoid humans, but they can attack if they perceive threat, are protecting their young or territory, or are injured or ill. Although attacks by wild animals are more dramatic, attacks by domestic animals are far more common, and secondary infections of wounds may result in serious systemic disease. In addition, animals can transmit zoonotic infections such as rabies. Of the estimated 35,000–55,000 rabies deaths every year worldwide, more than 95% occur as a result of dog bites in the developing countries of Africa and Asia. A recent 10-year retrospective review of dog bites in Austria showed that 75% of the bites were preventable because the person had intentionally interacted with the dog.
BITE OR SCRATCH WOUNDS
Animal bites present a risk for rabies, tetanus, and other bacterial infections. Animals’ saliva can be so heavily contaminated with bacteria that a bite may not even be necessary to cause infection if the animal licks a preexisting cut or scratch. Young children are more likely to be bitten by animals and to sustain more severe injuries from animal bites.
Before departure, travelers should have a current tetanus vaccination or documentation of having received a booster vaccination within the previous 5–10 years. Travel health providers should assess a traveler’s need for preexposure rabies immunization according to the guidelines in Table 3-15. While traveling, people should never try to pet, handle, or feed unfamiliar animals (whether domestic or wild), particularly in areas where rabies is endemic. To mitigate the risk of exposure to rabies, dogs and other mammals should be avoided.
In order to prevent infection, all wounds should be promptly cleaned with soap and water, and the wound promptly debrided, if necrotic tissue, dirt, or other foreign material is present. These steps of wound care are especially important for tetanus- or rabies-prone wounds (see the Rabies and Tetanus sections in Chapter 3). Travelers who might have been exposed to rabies should contact a reliable health care provider for advice about rabies postexposure prophylaxis. Travelers who received their most recent tetanus toxoid-containing vaccine more than 5 years previously, or who have not received at least 3 doses of tetanus toxoid–containing vaccines, may require a dose of tetanus toxoid–containing vaccine (Tdap, Td, or DTaP) according to the guidelines in Table 3-18.
Macaques are native to Asia and North Africa. They are also housed in research facilities, zoos, and wildlife or amusement parks and are kept as pets in private homes throughout the world. Monkey bites occasionally occur in certain urban sites, such as temples in Nepal or India, and can transmit herpes B virus.
Herpes B virus is related to the herpes simplex viruses that cause oral and genital ulcers. Herpes B infection is rare in humans. The virus was discovered in 1933, and since that time approximately 50 cases have been reported in humans, with an 80% case-fatality ratio. No cases of herpes B infection have been reported in people exposed to monkeys in the wild. Most documented cases have resulted from occupational exposures. However, travelers to areas where macaques range freely should be aware of the potential risk. A monkey infected with herpes B may appear completely healthy.
Documented routes of human infection with herpes B virus include animal bites and scratches, exposure to infected tissue or body fluids from splashes, and in one instance, human-to-human transmission. Even minor scratches or bites should be considered potential exposures, because, experimentally, herpes B virus has been isolated from surfaces for up to 2 weeks after it was applied. The incubation period ranges from <1 week to a month or longer. Neurologic symptoms develop as the virus infects the central nervous system and may lead to ascending paralysis and respiratory failure. Increased public and clinician awareness about the risks associated with an injury from a macaque, improved first aid after exposure, the availability of better diagnostic tests, and improved antiviral therapeutics have decreased the case-fatality ratio to 20% in treated people. As a result, from 1987 through 2004 only 5 infections were fatal.
Although only macaque bites pose a herpes B virus threat, any monkey bite may pose a threat for rabies.
Travelers should never attempt to feed, pet, or otherwise handle any monkeys.
After a monkey bite or scratch, travelers should be advised to thoroughly clean the wound and seek medical care immediately to be evaluated for possible rabies and herpes B postexposure prophylaxis. Additional information and photos of macaques can be found at the website for the National B Virus Resource Center at the Georgia State University Viral Immunology Center (www2.gsu.edu/~wwwvir).
Bats can be found almost anywhere in the world except the polar regions and extreme deserts. Bats are reservoir hosts for viruses that can cross species barriers to infect humans and other domestic and wild mammals. Viruses such as rabies and viral hemorrhagic fevers can be transmitted from bats to people. It is not possible to tell if a bat has rabies; however, any bat that is active by day, is found where bats are not usually seen (for example, indoors or outdoors in areas near humans), or is unable to fly is far more likely to be rabid. A recent example of an imported case of Marburg fever in a tourist who had visited a “python cave” in western Uganda illustrates the risk of acquiring diseases from contact with cave-dwelling bats. This same cave was the source of a fatal case of Marburg hemorrhagic fever in a Dutch tourist in 2008. Exposure to bats can occur during adventure activities such as caving or spelunking, and can include bites, scratches, and mucosal or cutaneous exposure to bat saliva. Like any other wild animal, bats, whether sick or healthy, will bite in self-defense if handled.
Bats should never be handled. Travelers should be discouraged from going into caves or mines that have large bat infestations. Depending on the country being visited, preexposure rabies vaccination may be recommended for people engaged in activities such as caving.
If a bite occurs or if infectious material (such as saliva) from a bat gets into the eyes, nose, mouth, or a wound, the traveler should wash the affected area thoroughly and get medical advice immediately. Any suspected or documented bite or scratch from a bat should be grounds for seeking postexposure rabies immunoprophylaxis in any destination in the world.
People usually know when they have been bitten by a bat. However, bats have tiny teeth, and not all wounds may be apparent. Travelers should seek medical advice even in the absence of an obvious bite wound if they wake up to find a bat in the room or see a bat in the room of a sleeping child.
Rodents carry a variety of viral, bacterial, and parasitic agents that may pose a threat to human health. Human exposure can occur directly by a bite or scratch, or indirectly by exposure to surfaces or water contaminated with urine or feces. Rodents should never be handled. Travelers should avoid places that have evidence of infestation with rodents and should avoid contact with rodent feces. Travelers should not eat or drink anything that is suspected to be contaminated by rodent feces or urine.
Wild rodents are unlikely to have rabies; however, each exposure needs to be evaluated as follows:
- If the bite was provoked (such as through feeding, petting, or playing with the animal) and the animal appeared healthy, the animal was probably not rabid at the time of the bite. Most experts would not recommend postexposure prophylaxis in this situation.
- If the bite was unprovoked or the animal appeared unhealthy and is unavailable for testing, rabies postexposure prophylaxis should be considered.
Travelers who were exposed to rodents and who develop febrile illness shortly after returning home should be evaluated by a clinician. Depending on the history and symptoms, diseases such as yersinia, plague, leptospirosis, hantavirus and rickettsial infections, Lyme disease, tickborne encephalitis, poxvirus, and bartonellosis (all discussed in further detail in Chapter 3) should be included in the list of diagnostic differentials.
Poisonous snakes are hazards in many locations, although deaths from snakebites are rare. Snakebites usually occur in areas where dense human populations coexist with dense snake populations, such as Southeast Asia, sub-Saharan Africa, and tropical areas in the Americas.
Common sense is the best precaution. Most snake bites are the direct result of startling, handling, or harassing snakes. Therefore, all snakes should be left alone. Travelers should be aware of their surroundings, especially at night and during warm weather when snakes tend to be more active. For extra precaution, when practical, travelers should wear heavy, ankle-high or higher boots and long pants when walking outdoors in areas possibly inhabited by venomous snakes.
Travelers should be advised to seek immediate medical attention any time a bite wound breaks the skin or when snake venom is ejected into their eyes or mucous membranes. Immobilization of the affected limb and application of a pressure bandage that does not restrict blood flow are recommended first-aid measures while the victim is moved as quickly as possible to a medical facility. Incision of the bite site and tourniquets that restrict blood flow to the affected limb are not recommended. Specific therapy for snakebites is controversial and should be left to the judgment of local emergency medical personnel. Specific antivenoms are available for some snakes in some areas, so trying to ascertain the species of snake that bit the victim may be critical.
ARTHROPODS AND INSECTS
Bites and stings from spiders and scorpions can be painful and can result in illness and death, particularly among infants and children. Other insects and arthropods, such as mosquitoes and ticks, can transmit communicable diseases; these diseases are discussed in more detail in Chapter 3. Bites and stings can occur without the traveler’s awareness of the bite, particularly when camping or staying in rustic accommodations.
There has been a recent resurgence in bed bug infestations worldwide, particularly in developed countries, thought to be related to the increase in international travel and insecticide resistance. Bed bug infestations have been increasingly reported in hotels. Bed bugs may be transported in luggage and on clothing.
Insect bites can be avoided by using repellents and insecticides, wearing long sleeves and pants while hiking, sleeping under mosquito nets, and shaking clothing and shoes before putting them on (see the Protection against Mosquitoes, Ticks, and Other Insects and Arthropods earlier in this chapter). Exposure to bed bugs can be avoided by inspecting the premises of hotels or other unfamiliar sleeping locations for bed bugs on mattresses, box springs, bedding, and furniture. Keep suitcases closed when they are not in use and try to keep them off the floor when traveling (see Box 2-03).
Travelers should seek medical attention if a bite or sting causes redness, swelling, bruising, rash, or persistent pain or fever. Travelers who have a history of severe allergic reactions to insect bites or stings should also ask their physician to evaluate them for the need to carry an epinephrine auto-injector (such as an EpiPen) to use, in case of recurrence (both in general and especially while traveling).
Venomous injuries from marine fish and invertebrates are increasing with the popularity of surfing, scuba diving, and snorkeling. Most species responsible for human injuries live in tropical coastal waters, including stingrays, jellyfish, stonefish, sea urchins, and scorpionfish.
Travelers should be advised to use protective footwear and maintain vigilance while engaging in recreational water activities. In case of injury, identifying the species involved can help determine the best course of treatment.
Symptoms of venomous injuries can range from mild swelling and redness at the site to more severe symptoms, such as difficulty breathing or swallowing, chest pain, or intense pain at the site of the sting, for which immediate medical treatment should be sought. Management will vary according to the severity of symptoms and can include medications, such as diphenhydramine, steroids, pain medication, and antibiotics.
Ill birds have been associated with outbreaks of highly pathogenic avian influenza in people. When traveling in an area that is experiencing an outbreak of avian influenza, travelers should avoid all contact with live poultry (such as chickens, ducks, geese, pigeons, turkeys, and quail) or any wild birds and should avoid settings where avian influenza A (H5N1)-infected poultry may be present, such as commercial or backyard poultry farms and live poultry markets. Travelers should not eat uncooked or undercooked poultry or poultry products, including dishes made with uncooked eggs or poultry blood. Other zoonotic diseases from birds may potentially infect humans through infected feces or by aerosol. These would include diseases such as histoplasmosis (see the Histoplasmosis section in Chapter 3), salmonella, psittacosis, or avian mycobacteriosis. Travelers should avoid contact with ill birds and should wash their hands if they come in contact with bird feces.
- Callahan M. Bites, stings, and envenoming injuries. In: Keystone JS, Kozarsky PE, Freedman DO, Nothdurft HD, Connor BA, editors. Travel Medicine. 2nd ed. Philadelphia: Mosby; 2008. p. 463–74.
- CDC. Dog-bite-related fatalities—United States, 1995–1996. MMWR Morb Mortal Wkly Rep. 1997 May 30;46(21):463–7.
- CDC. Nonfatal dog bite-related injuries treated in hospital emergency departments—United States, 2001. MMWR Morb Mortal Wkly Rep. 2003 Jul 4;52(26):605–10.
- Cohen JI, Davenport DS, Stewart JA, Deitchman S, Hilliard JK, Chapman LE. Recommendations for prevention of and therapy for exposure to B virus (cercopithecine herpesvirus 1). Clin Infect Dis. 2002 Nov 15;35(10):1191–203.
- Diaz JH. The global epidemiology, syndromic classification, management, and prevention of spider bites. Am J Trop Med Hyg. 2004 Aug;71(2):239–50.
- Feldman KA, Trent R, Jay MT. Epidemiology of hospitalizations resulting from dog bites in California, 1991–1998. Am J Public Health. 2004 Nov;94(11):1940–1.
- Gibbons RV. Cryptogenic rabies, bats, and the question of aerosol transmission. Ann Emerg Med. 2002 May;39(5):528–36.
- Gold BS, Dart RC, Barish RA. Bites of venomous snakes. N Engl J Med. 2002 Aug 1;347(5):347–56.
- Huff JL, Barry PA. B-virus (cercopithecine herpesvirus 1) infection in humans and macaques: potential for zoonotic disease. Emerg Infect Dis. 2003 Feb;9(2):246–50.
- Löe J, Röskaft E. Large carnivores and human safety: a review. Ambio. 2004 Aug;33(6):283–8.
- Meerburg BG, Singleton GR, Kijlstra A. Rodent-borne diseases and their risks for public health. Crit Rev Microbiol. 2009;35(3):221–70.
- Pan American Health Organization. Rabies. In: Acha PN, Szyfres B, editors. Zoonoses and Communicable Diseases Common to Man and Animals. 3rd ed. Washington, DC: Pan American Health Organization; 2003. p. 246–76.
- Schalamon J, Ainoedhofer H, Singer G, Petnehazy T, Mayr J, Kiss K, et al. Analysis of dog bites in children who are younger than 17 years. Pediatrics. 2006 Mar;117(3):e374–9.
- Warrell DA. Treatment of bites by adders and exotic venomous snakes. BMJ. 2005 Nov 26;331(7527):1244–7.
- World Health Organization. WHO Expert Consultation on rabies. World Health Organ Tech Rep Ser. 2005;931:1–88.