Chapter 265

In the broadest terms, zoonoses are infectious or parasitic diseases that are common to both animals and humans. True zoonoses are those that are transmitted to people directly from animals, their secretions, or shared fomites or vectors. This chapter addresses zoonoses associated with companion cats and dogs.

In the United States, more than 60% of households own pets (Bingham et al, 2010; Glaser et al, 2012; Oehler et al, 2009), with an estimated 78.2 million owned dogs and 88 million owned cats. The attachment between people and their pets cannot be underestimated. Dog owners spend an average of $248 per year on veterinary visits, whereas cat owners spend slightly less, at $219 per year. Companion animals have become an integral part of many families. Cohabitation with companion animals provides humans physiologic and emotional benefits that are multifaceted and that have been recognized for years. The benefits to owners of having companion animals include decreased blood pressure, decreased cholesterol and triglyceride levels, decreased anxiety and depression, and increased physical activity and socialization (Barker and Wolen, 2008; Parslow and Jorm 2003).

According to the World Health Organization, there are over 200 zoonotic diseases, with approximately 40 true zoonoses associated with dogs and cats. Among public health professionals, veterinarians are uniquely prepared to educate clients regarding the risks of pet-associated illnesses and to provide treatment and prevention methods (Chomel and Marano, 2009; Glaser et al, 2012). Veterinarians generally receive more training in the zoonotic diseases than most physicians except human infectious disease specialists. Surprisingly, surveys have shown that veterinarians and physicians rarely communicate about zoonotic disease; however, physicians believe veterinarians should be involved in the prevention of zoonotic diseases.

There are several major routes of transmission for infectious diseases to move from animals to humans, and these provide the sections for this chapter. These include transmission by percutaneous contact through a scratch, bite, or skin wound; transmission by inhalation or ingestion of infectious bodily secretions or excretions; transmission by aerosolized infectious particles; transmission by contact with contaminated feces or urine; transmission by direct or indirect mucosal contact; transmission by ingestion of infected or infested tissue; and transmission by shared vectors (Table 265-1). Additional information on individual organisms can be obtained from the Centers for Disease Control and Prevention (CDC) website at www.cdc.gov as well as in the book chapters listed in Table 265-1.