PERSPECTIVE Confronting Zoonoses, Linking Human and Veterinar y Medicine Laura H. Kahn* Many of the emerging infectious diseases, including those caused by bioterrorist agents, are zoonoses. Since zoonoses can infect both animals and humans, the medical and veterinary communities should work closely together in clinical, public health, and research settings. In the clinical setting, input from both professions would improve assess- ments of the risk-benefit ratios of pet ownership, particular- ly for pet owners who are immunocompromised. In public health, human and animal disease surveillance systems are important in tracking and controlling zoonoses such as avian influenza virus, West Nile virus, and foodborne pathogens. Comparative medicine is the study of disease processes across species, including humans. Physician and veterinarian comparative medicine research teams should be promoted and encouraged to study zoonotic agent-host interactions. These efforts would increase our understand- ing of how zoonoses expand their host range and would, ultimately, improve prevention and control strategies. Zand domestic animals to humans and are public health oonoses are diseases that can be transmitted from wild threats worldwide. Because these diseases come from ani- mals, prevention and control strategies need to be innova- tive and require the combined efforts of many fields. For example, closer collaborations are needed between veteri- narians, physicians, and public health professionals in 3 areas: individual health, population health, and compara- tive medicine research. In the individual health setting, assessing the potential for zoonotic disease transmission from animals to humans should include input from both physicians and veterinarians, especially for patients at high risk such as those who are immunocompromised. In popu- lation health, zoonotic disease threats should be addressed through surveillance systems that include domestic and wild animal and human populations, which would help lead to effective control measures. Since physicians and veterinarians would be the key professionals to recognize and report outbreaks, enhanced communications between *Princeton University, Princeton, New Jersey, USA hospital epidemiologists, veterinarians, and local public health officials would not only help expedite a local response, but also help identify whether unusual diseases or outbreaks involving animals and humans were related or separate events. In the research setting, collaboration between physicians and veterinarians in comparative med- icine would improve our understanding of zoonotic agent- host interactions. Individual Health Collaborations At the individual health level, zoonotic diseases are a concern for all who live or work with animals. This risk is especially problematic for persons, such as companion ani- mal owners, who are immunocompromised. Grant and Olsen found that physicians are generally not comfortable discussing the role of animals in the transmission of zoonoses and would prefer that veterinarians play a role (1). However, most patients do not view veterinarians as a source of information for human health. The authors found that only 21% of HIV patients asked their veterinarians about the health risks of pet ownership (1). Zoonotic risks from companion animals are not limited to those living with HIV. One patient who was taking infliximab for longstanding rheumatoid arthritis became infected with Cryptococcus neoformans after cleaning a cockatiel’s cage the week before hospitalization (2). Human lymphocytic choriomeningitis virus (LCMV) infection is associated with pet rodents and also causes serious infections in immunocompromised persons (3). These risks extend beyond the pet owners and can involve the recipients of the animal owners’ donated organs. For example, LCMV has been responsible for the deaths of 3 organ transplant recipients who received their organs from donors who had owned infected pet rodents (3). Exotic or unusual pets can pose a risk to the healthy. Salmonellosis developed in 4 children, 1 mother, and an 80-year-old woman after exposure to small pet turtles (4). Salmonellosis has also been associated with pet rodents. For example, during the summer of 2004, two young chil- 556 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 12, No. 4, April 2006