November , 2008
FIGURE 2. Number of cases* of Salmonella Schwarzengrund human infection associated with contaminated dry dog food, by state — United States, January 2006–September 2008
N = 79.
attack rate supports the hypothesis that infection might have resulted from practices in a limited number of households that brought humans into contact with the contaminated pet food and led to amplification of the organisms (e.g., cross- contamination in the kitchens or irregular cleaning of pet food bowls that might promote bacteria growth). In addition, the strain might primarily affect persons (e.g., young children) who are more susceptible to lower infective doses.
is outbreak is the first documented outbreak to associate
human Salmonella infections with contaminated dry dog food and to trace human illness to a contaminated pet food plant.
e original source of contamination and mechanisms for con-
tinued contamination in the Everson plant over a 3-year period are unknown. e absence of cases during January–March 2008 suggests that cleaning and disinfection of the plant might have had some effect. FDA is working with Mars Petcare US to better understand this problem.
Since 2006, at least 13 recall announcements involving 135 pet products (e.g., dry dog food and cat food, pet treats, raw diets, and pet supplements) have been issued because of Salmonella contamination.¶ ese recalls have resulted from contamination with multiple serotypes of Salmonella and have been associated with multiple pet food manufacturing plants in the United States. Pet products typically are recalled after product testing indicates contamination with Salmonella. To date, no human illness has been associated with these other pet food recalls.
Although the last reported case in this outbreak was tested on September 18, 2008, additional cases might occur. e
¶ Available at http://www.accessdata.fda.gov/scripts/petfoodrecall.
September 2008 recall involved approximately 23,109 tons of dry pet foods, representing 105 brands. However, dry pet food has a 1-year shelf life, and contaminated product might still be in the homes of purchasers and could produce illness.
State and local health departments that identify ill persons with the outbreak strain should query ill persons or their caregivers to find out about pet-related exposures, including brands of dry pet food used in the home. When possible, pet stool specimens and samples of dry pet food should be collected and submitted for laboratory testing. Hypothesis-generating interviews for enteric infections should routinely include ques- tions on contact with pets and other animals, pet food, pet treats, and pet supplements.
Consumers and health departments should be aware that all dry pet food, pet treats (3), and pet supplements (4) might be contaminated with pathogens such as Salmonella, and consumers should use precautions with all brands of dry pet food, treats, and supplements. In contrast, canned pet food is unlikely to be contaminated with such pathogens because the manufacturing process should eliminate bacterial contamina- tion. To prevent Salmonella infections, persons should wash their hands for at least 20 seconds with warm water and soap immediately after handling dry pet foods, pet treats, and pet supplements, and especially before preparing and eating food for humans. Infants should be kept away from pet feeding areas. Children aged <5 years should not be allowed to touch or eat dry pet food, treats, or supplements.
In addition to transmission of Salmonella from contact with dry pet food, humans can acquire Salmonella infection from contact with the feces of animals that acquired Salmonella infection from contaminated dry pet food or other sources. Effective hand washing after handling pets and animal feces will prevent such infections. Persons who suspect that contact with dry pet food or pets has caused illness should consult their health-care providers. Additional information on the transmis- sion of Salmonella from pets to humans is available at http:// www.cdc.gov/healthypets/diseases/salmonellosis.htm.
CDC. Multistate outbreak of human Salmonella infections caused by contaminated dry dog food—United States, 2006–2007. MMWR 2008; 57:521–4.
Voetsch AC, Van Gilder TJ, Angulo FJ, et al. FoodNet estimate of the burden of illness caused by nontyphoidal Salmonella infections in the United States. Clin Infect Dis 2004;38:S127–34.
CDC. Human salmonellosis associated with animal-derived pet treats— United States and Canada, 2005. MMWR 2006;55:702–5.
Food and Drug Administration. e Hartz Mountain Corporation recalls Vitamin Care for Cats because of possible health risk. Rockville, MD: Food and Drug Administration; 2007. Available at http://www.fda.gov/ oc/po/firmrecalls/hartz10_07.html.