Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Infections Related to Pets and Exotic Animals
Contact with animals can provide significant educational and emotional benefits for children and adults. However, exposure to pets in the home and animals in public settings poses potential risks to children, including allergies, injuries and transmission of pathogenic organisms. Risks can be minimized or prevented by knowledge and use of educational materials, regulations, and guidelines developed for this purpose. , Pediatricians, other healthcare personnel (HCPs), and veterinarians can provide advice on selection of appropriate pets as well as prevention of disease transmission from pets and when children contact animals in public settings.
Most households in the US include one or more pets. In national surveys conducted by the American Pet Products Manufacturers Association, the percentage of US households with one or more pets has steadily increased from 56% in 1998 to 67% (84.9 million homes) in 2019−2020. Numbers of households in the US owning pets were as follows: dogs, 63.4 million; cats, 42.7 million; freshwater fish, 11.5 million; birds, 5.7 million; small animals (including sloths, porcupines, kinkajous, wallabies, sugar gliders, hedgehogs), 5.4 million; reptiles, 4.5 million; horses, 1.6 million; and saltwater fish, 1.6 million. Total US expenditures in the pet industry in 2020 were estimated at $99.0 billion.
Categories of Pets
Animals that become pets can be classified as traditional and nontraditional . In recent years, the number of families choosing nontraditional pets has increased. Traditional pets generally include dogs and cats. Nontraditional pets include exotic animals, defined either as imported, nonnative species or species that originally were nonnative but now are bred in the US; indigenous wildlife; and wildlife hybrids (wildlife crossbred with domestic animals, producing offspring known as hybrids). The definition of nontraditional pets includes reptiles, amphibians, and certain species of mammals. In addition to exposure to animals in their homes, children may come in contact with animals in a variety of public settings. Contact with animals in public settings can be associated with substantial risks to children, and these potential risks are exaggerated when there is inadequate understanding of disease transmission, methods of transmission prevention, animal behavior, or lack of appropriate facilities for the care of animals.
Traditional Pets
Pets have become part of many families and are often considered to be extended family—living, eating, and even sleeping with human family members. Among dog owners in the US, 53% consider their dog to be a member of the family, and 56% of dog owners sleep with their dogs next to them. In developed countries, 21%–23% of dogs and 60% of cats sleep on or in their owner’s bed. Transmission of zoonotic agents by close contact between healthy traditional pets and family members through kissing, licking, or biting by pets or through vectors has been documented. ,
In children, bite injuries are caused by a wide variety of traditional and nontraditional pets, but most wounds result in minor injuries and are not reported. Most systematic studies are limited to dog or cat bites. Bacteria from animal bites are reflective of the oral flora of the biting animal or less commonly of victim’s own skin. The oral flora of the biting animal also may contain flora of ingested prey and other foods.
Nontraditional Pets
Nontraditional pets are increasing in popularity among families in part because lifestyle choices of owners may favor smaller or more unusual pets. A survey by the American Veterinary Medical Association (AVMA) estimated that at the end of 2016, 13% of US households owned “specialty or exotic pets” such as fish, ferrets, rabbits, hamsters, guinea pigs, gerbils, turtles, snakes, lizards, poultry, livestock, and amphibians. This was a 25% increase from the prior AVMA survey in 2011. Table 88.1 provides examples of animals that are considered nontraditional pets as well as animals to which children may be exposed in public settings.
TABLE 88.1
Animals That Are Considered Nontraditional Pets and Animals That Can Be Encountered in Public Settings
Modified from Pickering LK, Marano N, Bocchini JA, et al. Exposure to nontraditional pets at home and to animals in public settings: risk to children. Pediatrics . 2008:122;876–886.
| Categories | Examples |
|---|---|
| Amphibians | Frogs, toads, newts, salamanders |
| Fish | Many types |
| Mammals | |
| Wildlife | Raccoons, skunks, foxes, coyotes, civet cats, tigers, lions, bears, kinkajous, coatis, olingos, ringtails, nonhuman primates |
| Domesticated livestock | Cattle, pigs, goats, sheep |
| Equines | Horses, mules, donkeys, zebras |
| Weasels | Ferrets, minks, sables, skunks |
| Lagomorphs | Rabbits, hares, pikas |
| Rodents | Mice, rats, hamsters, gerbils, guinea pigs, chinchillas, gophers, lemmings, squirrels, chipmunks, prairie dogs, hedgehogs |
| Feral animals | Cats, dogs, horses, swine |
| Birds | Canaries, finches, sparrows, parrots, parakeets, love birds |
| Reptiles | Turtles, lizards, iguanas, snakes, alligators |
| Arachnids | Spiders, scorpions, tarantulas |
| Insects | Madagascar hissing cockroaches, millipedes, stick insects |
Most of the international live wild animal trade is for the pet industry. Fish, birds, mammals, and herpetofauna are common imports. The number of wildlife shipments doubled between 2000 and 2013. In addition to legal importation, there is a worldwide illegal trade in exotic animals, estimated at a cost of $5-20 billion annually, which is comparable to the trafficking of arms and drugs. This illegal trade subverts rules established by regulatory agencies to reduce introduction of disease and potentially dangerous animals through importation restriction, inspection, and quarantine.
Human contact with nontraditional pets and, specifically, with exotic animals raises several public health concerns. Most imported nonnative species are caught in the wild rather than bred in captivity. Health screening generally is not performed before shipment of these animals to the US, and often there is mixing of animal species in holding locations where healthy animals can be exposed to animals that might be ill, incubating, or asymptomatically carrying potential pathogens. In addition, the significant wildlife black market, through which a large number of exotic animals enter the US, compounds the risks for introduction of zoonoses. After making the initial decision to acquire a nontraditional pet, owners may discover 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, posing risks for introduction of zoonotic disease, disruption of ecosystems, and injury to people, domestic wildlife, and the environment.
Infections (Zoonoses) Associated With Nontraditional Pets
Zoonotic diseases or zoonoses are infections transmitted between other vertebrate animals and humans. Most emerging infectious diseases in humans are zoonotic in origin. Of 1415 human pathogens, 61% are known to be zoonotic, and pathogens with multiple host species are twice as likely to be associated with an emerging infectious disease. From 1980 to 2003, >35 new infectious diseases emerged in humans, many of which are zoonoses. The leading causes of their emergence are human behavior and modifications of natural habitats, including expansion of human populations and encroachment on wildlife habitats, changes in food production processes, changes in agricultural practices, and global trade in wildlife. , , Wild animals also can serve as reservoirs for transmission of zoonotic agents to domesticated animals and to humans. Domestic animals and humans also can acquire zoonotic pathogens from exposure to nontraditional pets. An outbreak of tularemia in wild prairie dogs caught in the US and held in a commercial facility in Texas led to human transmission. Some of the infected animals were distributed to a pet shop in Texas and were exported as far away as the Czech Republic.
Contact between animals from different areas of the world, including exotic animals imported into the US, can lead to disease in a new species and establishment of a pathogen in a new geographic area. In 2003, human monkeypox was introduced into the US. The source of monkeypox was imported African Gambian rats that were held in close proximity to prairie dogs being sold as pets. The prairie dogs became infected, which ultimately led to infection of humans with whom they had close contact. Prompt recognition and public health efforts controlled this outbreak and may have prevented the establishment of monkeypox in North America.
Zoonotic transmission of bacteria, viruses, fungi, and parasites from household pets or animals to children through contact in their homes or public settings is common. Transmission can be direct or indirect—through contact, aerosols, bites or scratches, contamination of the environment or food or water sources, or disease-carrying vectors. Animals can become ill but more commonly are asymptomatic carriers of specific organisms and can contaminate the environment to which children are exposed. Infants and children aged <5 years are at greatest risk, in part because they have suboptimal hygiene practices, have attraction to or curiosity about animals, and have developing immune systems, 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 also at risk for more severe zoonotic disease, as are pregnant women and the elderly.
Contact with animals or their environment is responsible for approximately 14% of all illnesses associated with five common enteric pathogens. An estimated 17% of Campylobacter spp., 16% of Cryptosporidium spp., 11% of nontyphoidal Salmonella enterica , 8% of non-O157 Shiga toxin producing Escherichia coli (STEC), and 6% of O157 STEC cases are attributable to direct animal contact. In 2017, 59 outbreaks of enteric disease associated with animal contact were reported to CDC. Cryptosporidium was the most common cause of single-etiology outbreaks, followed by Salmonella . Livestock and poultry were the most common types of animals implicated.
Reptiles and Amphibians
Reptiles pose a significant risk because of high carriage rates and intermittent shedding of Salmonella in their feces and because of persistence of Salmonella organisms in the environment. A federal prohibition against commercial distribution of turtles with shells <4 inches in diameter was enacted in 1975 after investigations demonstrated that small turtles were a major source of human salmonellosis, particularly in children. This resulted in an important and sustained reduction of human salmonellosis. Despite this ban, illegal distribution of small turtles, with subsequent outbreaks of human disease, continues to occur. In addition, young children without direct turtle exposure are at risk for turtle-associated salmonellosis through person-to-person transmission in childcare settings. Amphibians also serve as a source of salmonellosis in households. , In the US, 6% of all sporadic Salmonella infections (11% among people <21 years of age)—approximately 74,000 cases annually—are the result of direct or indirect contact with reptiles or amphibians.
Rodents
Contact with hamsters, guinea pigs, and other rodents purchased from retail pet stores has resulted in multistate outbreaks of salmonellosis. Hedgehogs, originally from Europe, Asia, and Africa, have proven to be an important source of Salmonella in the US. Yersinia pseudotuberculosis, Mycobacterium marinum, rabies virus, and other Salmonella serotypes also are zoonotic pathogens carried by hedgehogs. Antibiotic resistance has been documented in a number of animal associated infections. Hamsters have been associated with outbreaks of disease attributable to lymphocytic choriomeningitis virus (LCMV). Guidelines for minimizing risk for human LCMV infection associated with pet rodents (i.e., mice, hamsters, guinea pigs) have been published.
Plague, caused by Yersinia pestis, is enzootic among rodents in the western US. Humans become infected through bites of infected rodent fleas, inhalation of respiratory secretions from infected animals or humans, and handling of infected animals, especially rodents, lagomorphs, and domestic cats and dogs. Animal interaction was present in over 50% of plague cases reported in the U.S. from 1970 through 2017. In parts of the US where plague is endemic, people with rodent-seeking animals can be exposed to Y. pestis through direct contact with plague-infected pets or their fleas. , 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.
Association with nontraditional pets also can result in skin infections, including ringworm, monkeypox, orf, cutaneous anthrax, Serratia , tularemia, erysipeloid, ectoparasites, and endoparasites. Orf virus infections have been reported from household exposures and in children visiting petting zoos and livestock fairs. , Hedgehogs pose a significant risk because their spines readily penetrate skin and can be the source of M. marinum and Y. pseudotuberculosis infections.
You're Reading a Preview
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here