An astute veterinarian was the first to alert public health authorities to the monkeypox outbreak in the Midwest in May 2003, said Dr. Jim Kazmierczak, the Wisconsin state public health veterinarian.
The practitioner became concerned when a client's young daughter was hospitalized, and a veterinary technician developed symptoms after being bitten by the client's pet prairie dog, Dr. Kazmierczak said. The prairie dog, which was also showing signs of illness, had been euthanatized. Fearing that the animal may have been infected with tularemia or another zoonotic disease, the veterinarian removed the animal's enlarged lymph node, and sent it to a veterinary diagnostic laboratory for diagnosis.
The monkeypox outbreak, which was eventually traced back to the importation of infected giant Gambian rats and other African rodents, brought national attention to trade in captive wildlife as pets. It also highlighted the practical and ethical challenges facing veterinarians treating these captive wildlife pets.
It's hard to quantify the scope of the U.S. trade in wildlife as pets, though most organizations tracking the trade say it's a more than $10 billion industry. The wildlife trade has grown over the past decade, partly fueled by increased popularity of exotic pets in the United States, according to testimony given last summer by Marshall P. Jones Jr., the deputy director of the U.S. Fish and Wildlife Service, at a Senate hearing on the topic last summer.
Between 1992 and 2002, U.S. trade in wildlife and wildlife products grew 62 percent, and the number of species traded increased 75 percent, to 352,000 species, Jones said. There is also a multibillion-dollar illegal trade in wildlife. Additionally, there are many people in the United States who breed captive wildlife for the pet trade.
The Internet has helped fuel the U.S. trade in captive wildlife as pets, allowing would-be pet owners to browse through a range of available wildlife—including kinkajous, armadillos, marmosets, and monitors.
Unusual pets, unusual diseases
"We're very concerned about bioterrorism, but I think we're more likely to have a disease brought in from an imported wild animal than to have a purposeful transmission of a disease," said Dr. Darryl Heard, the head of the wildlife service at the University of Florida College of Veterinary Medicine.
This puts veterinarians and their staff on the front line of dealing with emerging zoonoses.
"There's limited knowledge on some of the diseases that can be transmitted to humans from these animals, and as a consequence, even the smallest animal that may bite someone may transmit a disease. There also may be disease transmission from other secretions," Dr. Heard said.
He added that restraint and handling by veterinarians and veterinary staff can increase the risk of disease transmission, so he and his staff anesthetize these animals for examinations, sample collection, and diagnostic procedures.
Native wildlife can also become vectors of exotic diseases when mixed with exotic wildlife. The monkeypox outbreak illustrated this possibility. Prairie dogs have become a fairly popular pet, and veterinarians are aware that they can carry a variety of zoonoses such as tularemia and plague, Dr. Kazmierczak said.
But when prairie dogs were housed with monkeypox-infected rodents at the facility of an animal dealer, they were exposed to a disease no one knew they could be infected with. The prairie dogs then transmitted the disease to humans. The national Centers for Disease Control and Prevention confirmed 37 cases of monkeypox in humans; of those, nine involved veterinarians and veterinary staff.
"I don't think veterinarians expected a foreign animal disease in native wildlife," said Dr. Jennifer McQuiston, a veterinary epidemiologist at the CDC.
The National Association of State Public Health Veterinarians and many veterinarians feel that the best way to prevent exotic disease transmission is to prevent species likely to transmit these diseases from entering the country and the pet trade.
The CDC currently restricts the importation of primates, turtles under 4 inches long, and bats. In 2003, the CDC placed new import restrictions on African rodents, civets, and some Asian birds in response to monkeypox, severe acute respiratory syndrome, and avian influenza, respectively. The Department of Agriculture restricts the importation and transportation of tenrecs, which can transmit foot-and-mouth disease.
The NASPHV and the Council of State and Territorial Epidemiologists have urged government agencies to enact a more comprehensive ban on importation and exportation of exotic and native wildlife that may negatively impact public health, and to more closely monitor interstate movement of native and exotic wildlife.
"This is an issue that needs to be addressed now," said Dr. Mira Leslie, the Washington state public health veterinarian and an author of the NASPHV and CSTE's joint position statement on the issue.
In the meantime, veterinarians are urgued to report suspicious illnesses to local, state, and national public health authorities.
"The early warning system that veterinarians provide is critical to the public health system nationwide," Dr. Leslie said.
"The biggest problem with people owning nontraditional pets is that a lot of the (medical care they require) is related back to inappropriate or poor husbandry," Dr. Heard said.
He explained that many owners are unable to meet the animal's nutritional, housing, social, and behavioral needs. In some cases, the animal itself may be inappropriate as a pet because of aggression, or because of a serious risk of disease transmission to humans, other pets, or agricultural animals.
Another major welfare problem for captive wildlife pets is surgical procedures such as defanging or declawing intended to make them more suitable pets. These procedures do not change the essential nature of the animals, and may have negative effects on their health and well-being. The AVMA opposes declawing large cats and the removal of teeth from non-human primates.
Also, many captive wildlife pets are abandoned when they mature and become harder to manage. The Houston Humane Society, which has recently begun building a facility to house large and unusual animals, tries to place abandoned or neglected captive wildlife pets, said Sherry Ferguson, the director of the humane society. But with limited space in sanctuaries and most zoos not accepting cast-off pets, some of these animals end up being euthanatized.
"Education is a very important part of our jobs," Dr. Heard said. "If anything, I would discourage people from owning many of the animals that are considered pets in the exotic pet industry for those reasons."
The American Association of Zoo Veterinarians recommends that veterinarians provide their clients with fact sheets about the difficulties and dangerous aspects of owning captive wildlife. The fact sheets should also include information about the diseases the species may harbor and the position statements of the AVMA, the AAZV, the American Zoo and Aquarium Association, and the USDA, which all discourage the keeping of wild animals as pets.
The Captive Wild Animal Protection Coalition, which represents zoologic and animal welfare organizations opposed to private ownership of exotic animals, has a Web site, www.cwapc.org, with fact sheets on private ownership of captive wildlife in general, and about the health and welfare needs of various captive wildlife species.
Education has proved successful in discouraging ownership of certain species, and helping to point would-be owners to more appropriate species.
For example, armadillos were a popular pet in the Houston area for several years; however, as owners learned of the risk of transmission of plague and tuberculosis, they became less popular, Ferguson said.
Dr. Heard also has seen a shift away from owning green iguanas, which can become large and aggressive, to owning water dragons, which are more suitable pets.
There also are ethical concerns facing veterinarians who care for captive wildlife pets. One concern is that such pets may be purposefully or accidentally released and thrive, causing harm to native wildlife and plants. For example, several years ago, California outlawed keeping African clawed frogs as pets because they were being released and damaging native ecosystems.
The popularity of captive wildlife pets has created a demand for veterinary care; however, many veterinarians are uncomfortable working with these species.
And for good reason according to Dr. David S. Miller, co-chair of the AAZV animal welfare and legislation committee, because certain animals—nonhuman primates, large carnivores, and venomous reptiles—are capable of seriously injuring or killing the veterinarian or veterinary staff.
"While providing veterinary care is the humane thing to do, private practice veterinarians are often placed in a position where (personal and staff) safety is compromised if they respond to client requests for treatment for such animals," Dr. Miller said. "The advice that I have often given private practitioners is, that the potential to help the animal and the interest in the case are not worth the risk for permanent injuries, death, and lawsuits."
"One of the reasons we have a problem with keeping these animals as pets, is it's often difficult to find veterinary care," said Richard Farinato, the director of the captive wildlife program of the Humane Society of the United States.
There is a growing veterinary specialty in zoologic and exotic animal medicine and a growing number of veterinary associations devoted to this field. The AAZV, the AVMA, and other organizations provide continuing education and networking opportunities for veterinarians interested in developing their skills in this field.
Veterinarians who don't feel comfortable working with wildlife species should refer clients to veterinarians with experience in the field, and provide as much written information to clients as they can, Farinato said.
"The hardest part for us is that we want good veterinary care for animals in this situation, but we don't think they are good pets and we try to make clear that we don't support the situation," said Dr. Joanne Paul-Murphy, the head of the special species service at the University of Wisconsin School of Veterinary Medicine.