Nina Marano, G. Gale Galland

Human Interaction with Animals: A Risk Factor for Injury

Animals in general tend to avoid human beings, 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. Animals cause injury through bites, kicks, or blunt trauma, or by the use of horns or claws. Further damage can occur if injuries become secondarily infected, as these infections may result in serious systemic disease. In addition, animals can transmit zoonotic infections such as rabies. A recent 10-year retrospective review of dog bites in Austria showed that 75% of the bites were preventable because the person intentionally interacted with the dog.

Bite Wounds

Prevention

• Before departure, travelers should have a current tetanus vaccination or should have documentation of receiving a booster vaccination within the prior 5–10 years. An assessment of the traveler’s need for pre-exposure rabies immunization should be made according to guidelines in Table 2-17.
• During travel, travelers should never try to pet, handle, or feed unfamiliar animals, domestic or wild, particularly in areas of endemic rabies. Young children are more likely to be bitten by animals and sustain more severe injuries from animal bites.

Management

• All wounds should receive prompt local treatment by thorough cleansing and debridement of the wound if necrotic tissue or dirt is present to prevent infection and illness, especially tetanus or rabies-prone wounds (see the Rabies and Tetanus sections earlier in this chapter).
• Any animal bite should be evaluated by a health-care provider as soon as possible, after cleaning the wound. Travelers who might have been exposed to rabies should contact a reliable health practitioner for advice about rabies postexposure prophylaxis (see the Rabies section earlier in this chapter). Since rabies immune globulin or rabies vaccine may not be available in the destination country, travelers should have a strategy in place prior to travel as to how to respond to a possible rabies exposure. This strategy may require the traveler to fly to a different country to obtain the appropriate treatment.
  • Travelers who have purchased medical evacuation insurance should contact their insurance provider for guidance on seeking medical care.
  • U.S. citizens can contact the local U.S. Embassy or Consulate in the country they are visiting for assistance in locating a health-care professional at their destination. Consular personnel at U.S. Embassies and Consulates abroad and in the United States are available 24 hours a day, 7 days a week, to provide emergency assistance to U.S. citizens. To contact the U.S. Department of State’s Overseas Citizens Services:
    • Dial: 888-407-4747 if calling from the U.S. or Canada
    • Dial: 202-501-4444 if calling from overseas
• Travelers who received their most recent tetanus toxoid-containing vaccine >5 years previously or who have not received at least three 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 2-21.

A wide variety of animals and insects can cause illness and injury to travelers; a short synopsis of risks by species is provided below.

Monkeys

• Macaques, a type of monkey, pose a threat for rabies and herpes B virus. Macaques are native to Asia and Northern Africa. They are also housed in research facilities, zoos, 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.
• Herpes B virus is related to the herpes simplex viruses, which cause oral and genital ulcers. Herpes B virus was discovered in 1933, and since that time approximately 50 cases have been reported in humans, with an 80% mortality rate. Herpes B infection is rare in humans, and most documented cases have resulted from occupational exposures. No cases of herpes B infection have been reported in travelers or others exposed to monkeys in the wild. However, travelers to areas where free-ranging macaques exist should be aware of the potential risk. An infected monkey may appear completely healthy.
• Documented routes of human infection include animal bites and scratches, exposure to infected tissue or body fluids from splashes, and, in one instance, human-to-human spread. Even minor scratches or bites should be considered potential exposures as, experimentally, herpes B virus has been isolated from surfaces for up to 2 weeks after it was applied (unpublished data, National Institutes of Health B Virus Reference Laboratory).
• The incubation period for herpes B may be less than 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 physician awareness about the risks associated with an injury from a macaque, improved first aid postexposure, the availability of better diagnostic tests, and improved anti-viral therapeutics have decreased the mortality rate to 20% in treated individuals. As a result, from 1987 to 2004 there have been only five fatal infections.

Prevention

Travelers should never attempt to feed, pet, or otherwise handle any monkeys.

Management

• Travelers should seek first aid immediately after being bitten or scratched by a monkey. The wound should be thoroughly cleaned, and travelers should seek health care immediately.
• If the history is strongly suggestive of exposure to herpes B through contact with monkeys, there are published guidelines for the prevention of herpes B infection after exposure and for the treatment of established infection. These guidelines have recommendations for serologic tests and postexposure prophylaxis. When potentially exposed travelers return home, they should follow up with their health-care providers for care. 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/.

Snakes

• 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 (e.g., Southeast Asia, sub-Saharan Africa, and tropical America).
• Common sense is the best precaution. Most snakebites are the direct result of startling, handling, or harassing snakes. Therefore, all snakes should be left alone. Travelers should maintain awareness 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 at night in areas possibly inhabited by venomous snakes.

Management

• 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 antivenins are available for some snakes in some areas, so trying to ascertain the species of snake that bit the victim may be critical.

Insects

Bites and stings from insects such as spiders and scorpions can be painful and can result in significant morbidity and mortality, particularly among infants and children. Many insects can transmit communicable diseases, even without the traveler’s awareness of the bite. This is particularly true when camping or staying in rustic accommodations.

Prevention

Exposure to insect bites and scorpion envenomations can be avoided by wearing long sleeves and pants while hiking, sleeping under mosquito nets, and shaking clothing and shoes before putting them on.

Management

Travelers should be advised to seek medical attention if an insect bite or sting causes redness, swelling, bruising, or persistent pain. Those 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 autoinjector (EpiPen) to use in case of recurrence (both in general and especially while traveling).

Bats

• 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 virus can be transmitted directly 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 in a place where bats are not usually seen (for example, indoors or outdoors in areas in close proximity to humans), or is unable to fly is far more likely than others to be rabid.
• Human exposure to bats can occur during adventure activities such as caving. Exposure can include bites, scratches, and mucosal or cutaneous exposure to bat saliva. Like any other wild animal, any bat, whether it is sick or healthy, will bite in self-defense if handled.

Prevention

Bats should never be handled. Travelers should be discouraged from going into caves that have a large bat infestation. Depending on the country being visited, pre-exposure rabies vaccination may be recommended for persons engaged in outdoor activities such as caving and spelunking.

Management

• 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.
• People usually know when they have been bitten by a bat. However, bats have tiny teeth and not all wounds may be apparent. There are situations in which travelers should seek medical advice even in the absence of an obvious bite wound, such as upon awakening and finding a bat in the room or seeing a bat in the room of a child.

Marine Animals

• Venomous injuries from marine fish and invertebrates are increasing with the popularity of surfing, scuba diving, and snorkeling. The majority of species responsible for human injuries and envenomation reside in tropical coastal waters and include stingrays, jellyfish, stonefish, and scorpionfish.
• Travelers should be advised to use protective footwear and maintain vigilance while engaging in recreational water activities. Traumatic injury, envenomation and wound infection are common sequelae. Identification of the species involved is helpful in determining the best course of treatment.

Birds

• When traveling in an area that is experiencing an outbreak of avian influenza (www.cdc.gov/flu/avian/outbreaks/current.htm), travelers should avoid all contact with poultry (e.g., chickens, ducks, geese, pigeons, turkeys, and quail) or any wild birds, and avoid settings where 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 poultry blood.

References

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