CLINICAL REPORT |
| ABSTRACT |
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Key Words: nontraditional pets exotic animals farm animals pets reptiles rodents indigenous wildlife
Abbreviations: FDA—Food and Drug Administration AVMA—American Veterinary Medical Association NASPHV—National Association of State and Public Health Veterinarians CSTE—Council of State and Territorial Epidemiologists CDC—Centers for Disease Control and Prevention
| INTRODUCTION |
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Many pet owners and people in the process of choosing a pet often are unaware of the potential risks posed by certain animals, especially nontraditional pets. These risks are associated with changes in physical and behavioral characteristics as young animals reach maturity. Pediatricians, veterinarians, and other health care professionals are in a unique position to offer advice on proper pet selection, to provide information about safe pet ownership and responsibility, and to minimize risks to infants and children.
In addition to exposure to animals in their homes, children may come in contact with animals in a variety of public settings.2 Although there are many benefits to experiences with animals outside the home, contact with animals in public settings also can be associated with significant risks to children, including infections and injuries. These potential risks are enhanced when there is an inadequate understanding of disease transmission, methods of preventing transmission, animal behavior, or appropriate facilities for animals.
This report deals with the potential exposure of infants, children, and adolescents to nontraditional pets in the home and to animals in public settings. The objectives of this report are to (1) summarize information regarding emerging and reemerging infectious diseases, injuries, and allergies associated with exposure to nontraditional pets in the home and to animals in a variety of public settings, (2) outline regulations and recommendations applicable to these exposures, and (3) define measures to minimize or prevent illness and injury in children from exposure to these animals and cite resources for additional information for health care professionals and families.
| METHODS |
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Studies were assessed as to whether they should be included in this review on the basis of their reporting or summarizing original data that examined infections or injuries in children resulting from nontraditional pets in the home or animals in public settings. Previously published recommendations to prevent infections and injuries were reviewed.
For the purpose of this report, nontraditional pets include exotic animals, defined either as imported, nonnative species or species that originally were nonnative but now are bred in the United States; indigenous wildlife; and wildlife hybrids (wildlife crossbred with domestic animals producing offspring known as hybrids). The definition of nontraditional pets includes reptiles and certain species of mammals.
| NONTRADITIONAL PETS |
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A number of public health concerns are related to human contact with nontraditional pets and, specifically, to exotic animals. Most imported nonnative species are caught in the wild rather than bred in captivity. Health screening often is not performed before shipment of these animals to the United States, and there is mixing of animal species in holding locations, including animals that might be ill or incubating illness or carriers of potential pathogens. In addition, the significant wildlife black market, through which a large number of exotic animals enter the United States, compounds the risks of introduction of zoonoses.6
Despite the popularity of nontraditional pets, after making the initial decision to acquire a nontraditional pet, owners may discover that they are unable to provide the animal with the environment or nutrition required for a healthy life and often subsequently abandon or release the animal into the wild, which poses risks for zoonotic disease and injury to people and other animals.
| ZOONOSES ASSOCIATED WITH NONTRADITIONAL PETS |
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Exotic animals imported to the United States have been associated with introduction of infectious agents otherwise not present in the United States. Contact between animals from different areas of the world can lead to the appearance of disease in a new species and establishment of a pathogen in a new geographic area. An example occurred in 2003 when human monkeypox was introduced into the United States. Investigators determined that the source of monkeypox was importation of African Gambian rats, which, in turn, ultimately infected prairie dogs being sold as pets, which infected humans in close contact with the prairie dogs.11 In this case, prompt recognition and public health efforts controlled this outbreak and may have been responsible for preventing establishment of monkeypox in North America.
Zoonotic transmission of infections by household pets or animals with which children come in contact in their homes or public settings is a common event. Infections can be caused by bacteria, viruses, fungi, and parasites. Transmission may be direct or indirect through contact, aerosols, bites or scratches, contamination of the environment, food or water, or disease-carrying vectors. Animals may become ill or, more commonly, are asymptomatic carriers of specific organisms and may contaminate the environment to which children are exposed. Infants and children younger than 5 years are at the greatest risk, in part because they have less-than-optimal hygiene practices, attraction to or curiosity about animals, and developing immune systems12 but also because these infections tend to be more severe in infants and young children. People of all ages with primary or secondary immunodeficiencies are at risk of more severe disease, as are pregnant women and elderly people.13
Reptiles
Among nontraditional pets, reptiles pose a particular risk because of high carriage rates of Salmonella species, the intermittent shedding of Salmonella organisms in their feces, and persistence of Salmonella organisms in the environment.12, 14–16 The US Food and Drug Administration (FDA) ban on commercial distribution of turtles with shells less than 4 inches long in 1975 resulted in an important and sustained reduction of human Salmonella infections as a result of prevention of transmission of Salmonella from these reptiles, although illegal distribution of small turtles with subsequent disease in humans continues to occur.17, 18 Amphibians also can serve as a source of salmonellosis in households.12 Six percent of all sporadic Salmonella infections in the United States (11% among people younger than 21 years)—approximately 74000 cases annually—are the result of direct or indirect contact with reptiles or amphibians.12
Rodents
Multistate outbreaks of salmonellosis attributable to contact with hamsters19 and other rodents20 purchased from retail pet stores have been described. Hamsters also have been associated with outbreaks of disease attributable to lymphocytic choriomeningitis virus.21 Hedgehogs, originally from Europe, Asia, and Africa and now estimated to be in approximately 40000 US households, have proven to be an important source of Salmonella serotype Tilene in the United States.22 Other Salmonella serotypes as well as Yersinia pseudotuberculosis, Mycobacterium marinum, and rabies also have been shown to be zoonotic diseases carried by hedgehogs.
The natural reservoir of plague is wild rodents, with humans becoming infected through bites of infected rodent fleas and through handling infected animals, especially rodents, lagomorphs, and domestic cats.23, 24 In parts of the United States where plague is endemic, people with rodent-seeking animals can be exposed to Yersinia pestis through direct contact with plague-infected pets or their fleas.24 People who live in areas where plague is endemic should follow a flea-control program designed by their veterinarians to keep their cats and dogs free from fleas.
Skin infections also can be acquired from nontraditional pets and include ringworm, monkeypox, orf, cutaneous anthrax, tularemia, erysipeloid, ectoparasites, and endoparasites.25–30 Hedgehogs pose a significant risk, because their spines readily penetrate skin and can be the source of M marinum and Y pseudotuberculosis infections.22
Nonhuman Primates
Herpes B virus (cercopithecine herpesvirus 1) is a zoonotic agent that can be found in macaque monkeys that are kept as pets or displayed in public exhibits. The virus is endemic in macaque monkeys, which may remain asymptomatic or may develop mild oral lesions. Herpes B virus infections in humans have been reported after animal bites, scratches, or percutaneous inoculation with infected material or splashes to mucous membranes. Human infections most often result in fatal meningoencephalitis.31
Fish
Mycobacterial infections are among the major zoonoses that can be transmitted by aquarium fish,32 but other organisms have been reported after exposure to aquarium water, usually sporadically or in immunocompromised people. These organisms include Aeromonas species, Vibrio species, Edwardsiella species, Salmonella species, Streptococcus iniae, and Erysipelothrix rhusiopathiae.33
Other Sources of Infection
Infection attributable to Salmonella species can be acquired from other sources. Outbreaks of Salmonella species infections in people who have been in contact with chicks and other baby poultry purchased at agricultural feed stores have been reported.34 Parents who purchase these birds for their children generally are not aware that Salmonella infections can be transmitted from poultry to humans. In addition to direct exposure to animals, exposure to animal-derived pet food treats and pet food has resulted in human infections attributable to Salmonella.35, 36 Animals may become colonized with Salmonella after ingesting contaminated pet food treats or raw meats. These animals may remain asymptomatic and become unrecognized sources of contamination in the household. Handling of pet food treats by humans may result in infection.36 In the United States, pet treats are regulated by the FDA. Salmonella-contaminated pet treats are considered adulterated under the Federal Food, Drug, and Cosmetic Act (21 USC
301–399). The American Pet Products Manufacturers Association published guidelines to educate its members about risks of contamination of pet treats.37 In 2004, the FDA initiated annual nationwide testing of pet treats for Salmonella species.
| DISEASES ASSOCIATED WITH ANIMALS IN PUBLIC SETTINGS |
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| RABIES |
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| INJURIES AND ALLERGIES |
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An estimated 4 to 5 million animal bites occur in the United States annually. Although approximately 90% of bites are from dogs or cats, severe and fatal bites can occur from large or aggressive nontraditional pets. Animal bites or scratches often become infected. Infectious organisms, depending on the biting animal, include Pasteurella multocida, Francisella tularensis, Capnocytophaga canimorsus, Streptobacillus moniliformis, Spirillum minor, Bartonella henselae, leptospira, and herpes B virus. Tularemia occurred in a 3-year-old child who was bitten by an infected hamster that was purchased at a pet store.30 Reptiles can produce injuries by bites, with claws, or with tails. Severe hand injury29 and cellulitis26 have been reported after green iguana bites. Unprovoked attacks by ferrets on children, particularly infants sleeping or lying down, can be severe, with mutilation of the ears or nose.66, 67 Attacks on sleeping infants are similar to those inflicted by rats.68
Although the frequency is not known, the potential for having an allergy to nontraditional pets is likely to be significant. The American Academy of Allergy Asthma & Immunology estimates that approximately 15% of the population experiences allergies to dogs and cats.69 Allergy to animals usually is attributable to sensitization to their dander, scales, fur, feathers, body waste, or saliva. Flea bites also can lead to allergic manifestations. Hives have been described in people who have contact with hedgehogs.70 Although scaly animals are not as likely to be as allergenic as furry animals, there are case reports of allergic rhinitis, asthma, and contact hypersensitivity reactions to iguanas. In 1 case, a person with respiratory allergic symptoms was found to be allergic to iguana scales.28 In addition, an iguana bite–induced hypersensitivity reaction has been reported.29
| REPORTABLE DISEASES ACQUIRED FROM NONTRADITIONAL PETS AND ANIMALS IN PUBLIC SETTINGS |
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| IMPORTATION LAWS AND REGULATIONS REGARDING EXOTIC ANIMALS |
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Among the federal agencies, the CDC is responsible for regulations regarding importation of dogs and cats; nonhuman primates, small turtles, terrapins, and tortoises; African rodents; civets; and birds from countries with H5NI influenza. In addition, CDC regulations include etiologic agents, hosts, and vectors, under which importation of bats is regulated. The US Fish and Wildlife Service requires permits to import fish, reptiles, spiders, wild birds, rabbits, bears, wild members of the cat family, and other wild or endangered animals. The FDA regulates interstate transactions involving turtles, molluscan shellfish, psittacine birds, prairie dogs, and African rodents. Many states also have laws that make it illegal to own or keep certain wild animals or a variety of exotic pets, including nonhuman primates.
The Animal Welfare Act (7 USC
2131-216) covers the sale and exhibition of wild/exotic animals and the wholesale distribution of pet animals. Wholesale breeders, dealers, exhibitors, and research laboratories are covered by this act. Birds, rats, and mice are exempted; dogs, cats, and other animals have limited coverage; and cold-blooded species such as reptiles are not regulated under this act. Small retail breeders and pet shops that sell only domestic pet animals are not regulated under this act; these animals usually are covered by local (state, county) anticruelty laws and, in some instances, by local animal regulations or public health laws. The US Department of Agriculture has issued a position statement on risks of ownership of large, wild, and exotic cats (www.aphis.usda.gov/animal_welfare/downloads/big_cat/position.pdf).
CDC efforts are underway to galvanize partner agencies into further actions to enhance protection of humans from zoonotic diseases. A meeting of stakeholder organizations was held at the CDC in 2006, a summary of which was published in the Federal Register.71 The AVMA, CSTE, and NASPHV have each issued position statements calling for a coordinated federal approach to better control of infectious disease risks associated with the exotic-animal trade (these publications are available through the Web sites of the respective organizations). Uniform importation laws, better quarantine and surveillance methods for animals coming into the country, and prevention of illegal wildlife trade are necessary components of an overall plan to protect the public.
| PREVENTION MEASURES AND THE ROLE OF PEDIATRICIANS AND VETERINARIANS |
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Pediatricians and veterinarians together can remind parents, children, and pet owners about the importance of measures to avoid illness. Simple and effective advice includes frequent hand-washing and avoiding direct contact with animals and their environments. This is particularly important with animals from which transmission of enteric pathogens is a risk, including young ruminants, young poultry, reptiles, rodents, amphibians, and animals that are ill. Young children always should be supervised closely when in contact with animals in public settings. The NASPHV has developed an excellent compendium with standardized recommendations for use by public health officials, veterinarians, animal venue operators, animal exhibitors, and others who are concerned with disease control and minimizing risks associated with animals in public settings.2
To reduce the possibility of injury, health care professionals should remind pet owners about matching the size and temperament of a pet to the age and behavior of their infant or child, providing close supervision of younger children, and educating all children about appropriate human-animal interactions.
The decision to obtain a nontraditional pet by parents with children in the household is often not discussed with a physician or veterinarian. However, as trusted sources of health care information, pediatricians and veterinarians are in a unique position to offer information and advice to families considering the purchase of a nontraditional pet or to families who already have a nontraditional pet in the household. Informational brochures and posters available for display in physician and veterinarian offices could allow for parent education without significantly increasing time of a visit. Parents can be made aware of Web sites that provide guidelines for safe pet selection and appropriate handling of pets. Proper pet health maintenance, immunization, flea and tick control, deworming, and diet and activity can minimize the risk of infection or injury and ensure the health of the pet. Referral to a veterinarian also can be helpful when parents are contemplating purchase of a nontraditional animal. Veterinarians can provide information about appropriate pet selection, the size of an animal when it attains adulthood, the temperament and husbandry needs of an animal, and suitability as a pet.
A history of contact with pets in the home or animals in public settings should be part of every well-child evaluation and especially should be part of an evaluation of a suspected infectious disease. A history of nontraditional pets in the home or contact with animals in public settings can lead to specific testing and additional management recommendations and occasionally will result in early identification of an unusual infection from another part of the world.
| AVAILABLE RECOMMENDATIONS AND GUIDELINES |
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Guidelines for animals that might have contact with children in a child-care setting have been published by the National Resource Center for Health and Safety in Child Care and Early Education.75 These guidelines state that any pet or animal present at the facility, indoors or outdoors, should be in good health; show no evidence of carrying any disease; be fully immunized; and be maintained on a flea-, tick-, and worm-control program. A current (time-specified) certificate from a veterinarian should be on file in the facility and state that the specific pet meets these conditions. All contact between animals and children should be supervised by a caregiver who is close enough to remove the child immediately if the animal shows signs of distress or the child shows signs of treating the animal inappropriately. The caregiver should instruct children on safe procedures to follow when in close proximity to these animals (eg, not to provoke or startle animals or touch them when they are near their food). Potentially aggressive animals should not be in the same physical space with children. The facility should not keep or bring in turtles, iguanas, lizards, or other reptiles; ferrets; psittacine birds; or any wild or dangerous animals. Recommendations for hand-washing by staff, volunteers, and children as well as maintenance of animals housed on the premises are provided in the guidelines.75 In addition to exposures to animals within a center, child-care and school field trips can result in disease. A field trip to a petting zoo at which hand-hygiene facilities were not adequate resulted in 44 cases of E coli O157:H7 infection in British Columbia.76 Guidelines for infection control in health care facilities are not part of this document but are available (www.cdc.gov/ncidod/dhqp/pdf/guidelines/Enviro_guide_03.pdf).
| FUTURE |
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| SUMMARY |
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| COMMITTEE ON INFECTIOUS DISEASES, 2007–2008 |
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Henry H. Bernstein, DO
John S. Bradley, MD
Michael T. Brady, MD
Carrie L. Byington, MD
Penelope H. Dennehy, MD
Robert W. Frenck, Jr, MD
Mary P. Glode, MD
Harry L. Keyserling, MD
David W. Kimberlin, MD
Sarah S. Long, MD
Lorry G. Rubin, MD
| LIAISONS |
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Canadian Paediatric Society
Richard D. Clover, MD
American Academy of Family Physicians
Marc A. Fischer, MD
Centers for Disease Control and Prevention
Richard L. Gorman, MD
National Institutes of Health
R. Douglas Pratt, MD
Food and Drug Administration
Anne Schuchat, MD
Centers for Disease Control and Prevention
Benjamin Schwartz, MD
National Vaccine Program Office
Jeffrey R. Starke, MD
American Thoracic Society
| EX OFFICIO |
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Red Book Associate Editor
Larry K. Pickering, MD
Red Book Editor
| CONSULTANTS |
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H. Cody Meissner, MD
| CONTRIBUTORS |
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