REVIEWS ON ENVIRONMENTAL HEALTH VOLUME 16, NO. 2, 2001  Direct Exposure to Animal Enteric Pathogens Carlos Enriquez lf , Nena Nwachuku 2 , and Charles P. Gerba 1  1 Department ofSoil, Water & Environmental Science, University of Arizona, Tucson, AZ 85721; 2 U.S. Environmental Protection Agency, Health and Ecological Criteria Division/ Office of Water, 401 Μ Street SW (4304), Washington, D.C. 20460, USA. SUMMARY Humans have very close interactions with working, food-producing, and companion animals. According to the American Veterinary Medical Association, there are more than one hundred million cat and dog pets in the United States. Furthermore, non-traditional pets like reptiles and exotic birds are not unusual companion animals in households. In addition to sharing with animals our living and/or working space and time, we also share, unfortunately, many disease causing microorganisms. In the past few years, we have become aware that several enteric pathogens that were thought to be mostly restricted to animals are a major cause of human disease. Examples of such pathogens include the protozoan parasiteyxvutsrponmlihgedcbaTSHGEC Cryptosporidium parvum and bacteria such as Campylobacter spp. This review will examine the characteristics of zoonotic enteric pathogens including bacterial (Helicobacter spp., Campylobacter spp., Salmonella spp., and vero- toxin-producing Escherichia coli); parasitic (Toxoplasma gondii, Giardia spp., Cryptosporidium spp.); and viral (rotavirus, norwalk-like virus, hepatitis Ε virus), and the status of our knowledge with regard to the impact of such pathogens on human health. Present correspondence address:  The Clorox Company, Technical Center  P.O. Box 493, Pleasanton, CA 94566  fax: +(925) 847-6382  e-mail: carlos.enriquez@clorox.com  KEYWORDS zoonoses, animals, enteric pathogens, bacteria,  viruses, parasites, gastroenteritis  INTRODUCTION Zoonoses are infectious diseases that under  natural conditions are transmitted from vertebrate  animals to humans /l/. Although this definition  includes indirect transmission through contaminated  foods of animal origin, this review will consider  only the direct exposure of humans to infected  animals.  Most direct enteric zoonoses are pet-related  /2/. Pets have been an important part of human  society. In the United States (U.S), more than 58  million households have a dog, cat, bird, or other  companion animal as a family member /3/. The  most common pets in the U.S. are cats (59.1  million), followed by dogs (52.9 million), birds  (12.6 millions) and horses (4 million) /3/ (Table  1). Although such traditional pets remain the most  common, specialty- or exotic-pet ownership increased  from 6.7% of all U.S. households in 1991 to  10.7% in 1996 /3/. Fish, ferrets, rabbits, and  rodents top the list, but such reptiles as turtles,  © Freund Publishing House Ltd. 2001  117  Brought to you by | HEC Bibliotheque Maryriam ET J. Authenticated Download Date | 6/20/15 10:43 AM