May 4, 2012 (CIDRAP News) – The detection of Salmonella during routine tests on dry dog food has uncovered an outbreak linked to a rare strain that has so far sickened 14 people in nine states, the US Centers for Disease Control and Prevention (CDC) said yesterday.
On Apr 2, Michigan officials detected Salmonella Infantis in an unopened retail sample of Diamond Naturals lamb meal and rice dry dog food. Public health investigators then used PulseNet, a national molecular subtyping network for identifying foodborne bacteria, to identify human cases involving the same genetic fingerprint.
The CDC said the outbreak strain is infrequently reported, with from 0 to 3 isolates confirmed each month.
During the outbreak investigation, interviews with 10 of the sick patients revealed that 7 had contact with a dog the week before becoming ill. Of 5 who recalled the type of dog food, 4 identified dry products made by Diamond Pet Foods.
Diamond Pet Foods recalled the implicated product on Apr 6. It then expanded the recall to two more types on Apr 26 and Apr 30 after Ohio outbreak investigators found the outbreak strain in an opened bag of Diamond Brand Chicken Soup for the Pet Lover's Soul Adult Light Formula collected from a sick patient's home and the Food and Drug Administration (FDA) found Salmonella in a sample of Diamond Puppy Formula collected from the company's production facility in Gaston, S.C.
The products were distributed mostly to eastern states, though the company said the dog food may have been sent to other states through pet food channels. So far states reporting illnesses are Alabama (1), Connecticut (1), Michigan (1), Missouri (3), North Carolina (3), New Jersey (1), Ohio (2), Pennsylvania (1), and Virginia (1).
Of nine patients with available information, five have been hospitalized. No deaths have been reported. The CDC said that illnesses began between Oct 8, 2011, and Apr 22. Patients' ages range from less than 1 year to 82 years. Eleven of the patients are female.
The CDC said further investigations are ongoing to determine of other brands of dry dog food produced at the facility have links to human illnesses. It said Diamond Pet Foods is cooperating with investigators.
Pet food recalls due to possible Salmonella contamination are fairly common, but few have involved known human illnesses or outbreaks.
In 2006 and 2007, a Salmonella Schwarzengrund outbreak linked to dry pet food made by Mars Pet Food US at a facility in Pennsylvania sickened at least 79 people in 21 states, according to a previous CDC report. It was the first known human salmonellosis outbreak linked to dry pet food.
At the time, the CDC raised concerns about the long shelf life of the products and that they were still likely to be in consumers' homes. New cases cropped up more than a year after the outbreak came to light.
In 2012, routine product testing for contamination has prompted two other recalls for Salmonella in pet food, one for rodent food and the other for fish.
The CDC advised consumers to check their homes for the recalled dog food and discard implicated products promptly. The most important step for preventing illnesses linked to dry pet food is washing hands with water and soap after handling pet food and treats, especially before preparing, serving, or eating food or preparing baby bottles, the agency said. Children younger than 5 should be kept away from pet food and pet feeding areas, it added.
The CDC advises feeding pets in areas other than the kitchen and to regularly wash pet food bowls and utensils in hot soapy water, preferably away from kitchen sinks or other areas where cross-contamination can occur.
May 3 CDC outbreak announcement
Apr 6 Diamond Naturals lamb meal and rice dry dog food recall notice
Apr 26 Diamond Brand Chicken Soup for the Pet Lover's Soul adult light formula recall notice
Apr 30 Diamond puppy formula recall notice
CDC Salmonella from dry pet food and treats background information
FDA animal and veterinary recall page
Nov 6, 2008, CIDRAP News story "More Salmonella cases linked to dry pet food"