Multistate Outbreak of Human Salmonella Infantis Infections Linked to Dry Dog Food (Final Update)

Posted July 18, 2012 6:00 PM ET

Salmonella is an important cause of human illness in the United States. More information about Salmonella, and steps people can take to reduce their risk of infection, can be found on the CDC Salmonella Web Page and the CDC Vital Signs Web Page.

Highlights
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  • A total of 49 individuals (47 individuals in 20 states and two individuals in Canada) infected with the outbreak strain of Salmonella Infantis were reported.
    • The number of ill persons identified in each state is as follows: Alabama (2), Arkansas (2), California (3), Connecticut (2), Georgia (2), Illinois (4), Indiana (1), Kentucky (1), Michigan (2), Minnesota (1), Missouri (3), New Jersey (2), New York (5), North Carolina (5), Ohio (3), Oklahoma (1), Pennsylvania (3), South Carolina (2), Texas (1), and Virginia (2).
    • Among the 24 patients with available information, 10 (42%) were hospitalized. No deaths have been reported.
  • Epidemiologic and laboratory investigations conducted by officials in local, state, and federal public health, agriculture, and regulatory agencies linked this outbreak to dry dog food produced by Diamond Pet Foods at a single production facility in Gaston, South Carolina.
  • Consumers should check their homes for recalled pet food and discard them.
  • Salmonella is an important cause of human illness in the United States. More information about Salmonella infection, and steps people can take to reduce their risk of infection, can be found on the CDC Salmonella Web Page.
  • Information for Pet Owners »
  • Information for Veterinarians »

Introduction

CDC collaborated with public health and agriculture officials in multiple states, the Public Health Agency of Canada, and the US Food and Drug Administration (FDA) to investigate an outbreak of human Salmonella Infantis infections. Public health investigators used DNA “fingerprints” of Salmonella bacteria obtained through diagnostic testing with pulsed-field gel electrophoresis, or PFGE, to identify cases of illness that may be part of this outbreak. They used data from PulseNet, the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections. The outbreak strain is rare and typically 0-3 isolates are reported per month.

Multiple brands of dry dog food produced by Diamond Pet Foods at a single production facility in Gaston, South Carolina were linked to human illnesses.

A total of 49 cases (47 cases in 20 states, and two cases in CanadaExternal) of human infections with the outbreak strain were reported. The number of ill persons identified in each state was as follows: Alabama (2), Arkansas (2), California (3), Connecticut (2), Georgia (2), Illinois (4), Indiana (1), Kentucky (1), Michigan (2), Minnesota (1), Missouri (3), New Jersey (2), New York (5), North Carolina (5), Ohio (3), Oklahoma (1), Pennsylvania (3), South Carolina (2), Texas (1), and Virginia (2). The median patient age was 28 years (range: less than 1 year–82 years); 57% were female. Among 25 persons for whom information was available, the majority of illnesses began between January 4 and June 26, 2012. Among the 24 patients with available information, 10 (42%) were hospitalized. No deaths have been reported.

The numbers of new cases have declined substantially since the peak in April–May, but illnesses are still being reported among people who came into contact with the recalled product after the recall. The outbreak is expected to continue at a low level for the next several months, because the expected shelf life of dry pet food is generally one year from the date of manufacture, and consumers who are unaware that they have recalled pet foods in their homes may continue to come into contact with these products. Consumers should check their homes for recalled pet food and discard them.

Investigation of the Outbreak

Epidemiologic and laboratory investigations conducted by officials in local, state, and federal public health, agriculture, and regulatory agencies linked this outbreak to contaminated dry dog food produced by Diamond Pet Foods at a single production facility in Gaston, South Carolina.

On April 2, 2012, the Michigan Department of Agriculture and Rural Development detected Salmonella bacteria in an unopened bag of Diamond brand dry dog food collected during routine retail testing. Public health investigators used PulseNet, a national molecular subtyping network, to identify recent human infections with the same strain of Salmonella found in the dog food sample.

In interviews, 22 (79%) of 28 ill persons interviewed reported contact with a dog in the week before becoming ill. Of 17 ill persons who could recall the type of dog food with which they had contact, 11 (65%) identified dry dog food produced by Diamond Pet Foods that may have been produced at a single facility in South Carolina.

As part of this outbreak investigation, Ohio public health and agriculture officials collected and tested dry dog food produced by Diamond Pet Foods. The outbreak strain of Salmonella Infantis was isolated from an opened bag of Diamond Brand dry dog food collected from the home of an ill person, and an unopened bag of the product was collected from a retail store. An inspection sample from the South Carolina production facility and several retail samples of dry dog food collected by FDA also yielded Salmonella. FDA’s list of observations found during their inspection is available.Cdc-pdfExternal In addition to the outbreak strain with the initial PGFE pattern, a Salmonella Infantis strain with a second PFGE pattern was isolated. Sixteen human cases were identified with the second PFGE pattern. Salmonella bacteria with the second pattern was isolated from a dog food sample collected from the home of an ill person in Canada, who was infected with a non-outbreak strain of Salmonella.

The results of product testing by multiple agencies and production codes provided by ill persons led to multiple recalls by Diamond Pet Foods and several other companies with products manufactured at the implicated production facility in South Carolina. The recalls included 17 brands representing >30,000 tons of dry dog and cat food produced at the facility. More information on the investigation and recalls  is available at FDA Investigation of Multistate Outbreak of Human Infections Linked to Dry Pet FoodExternal.

Pet illnesses associated with recalled products were reported to FDA’s Pet Food Complaint SystemExternal. The outbreak strain of Salmonella was isolated from one ill dog and one asymptomatic dog by the Ohio Department of Agriculture; both dogs consumed recalled products.

This is the second documented outbreak of human salmonellosis linked to dry pet food in the United States. People should be aware that dry pet food may be contaminated with Salmonella bacteria. Additional advice for consumers is available here. Salmonella is an important cause of human illness in the United States. More information about Salmonella infections, and steps people can take to reduce their risk of infection, can be found on the CDC Salmonella Web Page and the CDC Vital Signs Web Page.

July 18, 2012

Final Case Count Update

A total of 49 individuals infected with the outbreak strain of Salmonella Infantis have been reported. Forty-seven ill persons have been reported from 20 states; 2 ill persons have been reported from CanadaExternal. The 27 new cases, including 16 cases with a second PFGE pattern associated with this outbreak, are from: Arkansas (2), California (2), Connecticut (1), Georgia (2), Illinois (3), Indiana (1), Kentucky (1), Michigan (1), Minnesota (1), New Jersey (1), New York (4), North Carolina (2), Ohio (1), Oklahoma (1), Pennsylvania (1), South Carolina (1), Texas (1), and Virginia (1). Among persons for whom information is available, the majority of illnesses began between January 4 and June 26, 2012. Ill persons range in age from less than 1 year to 82 years old and the median age is 28 years. Fifty-seven percent of patients are female. Among the 24 patients with available information, 10 (42%) were hospitalized. No deaths have been reported.

Final Investigation Update

An inspection sample from the South Carolina production facility and several retail samples of dry dog food collected by FDA yielded Salmonella. FDA’s list of observations found during their inspection is available Cdc-pdf[PDF – 2 pages]External. In addition to the outbreak strain with the initial PGFE pattern, a Salmonella Infantis strain with a second PFGE pattern was isolated. Sixteen human cases were identified with this second PFGE pattern. A Salmonella strain with the second PFGE pattern was isolated from a dog food sample collected from the home of an ill person in Canada, who was infected with a non-outbreak strain of Salmonella.

June 13, 2012

Case Count Update

A total of 22 individuals infected with the outbreak strain of Salmonella Infantis have been reported. Twenty ill persons have been reported from 13 states. The five new cases are from: Alabama (1), California (1), Illinois (1), New York (1), and South Carolina (1). Additionally, two ill persons have been reported from CanadaExternal.

Among persons for whom information is available, illnesses began between October 2011 and May 11, 2012. Ill persons range in age from less than one year old to 82 years old and the median age is 46.5 years. Sixty-eight percent of patients are female. Among the 17 patients with available information, 6 (35%) were hospitalized. No deaths have been reported.

Illnesses that occurred after May 11, 2012 might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported.

May 11, 2012

Case Count Update

A total of 15 individuals infected with the outbreak strain of Salmonella Infantis have been reported from 9 states. The number of ill persons identified in each state is as follows: Alabama (1), Connecticut (1), Michigan (1), Missouri (3), North Carolina (3), New Jersey (1), Ohio (2), Pennsylvania (2), and Virginia (1). One new ill person was reported from Pennsylvania. Additionally, one ill person has been reported from CanadaExternal.

Among persons for whom information is available, illnesses began between October 8, 2011 and April 16, 2012. Ill persons range in age from less than one year old to 82 years old and the median age is 47 years. Seventy-three percent of patients are female. Among the 10 patients with available information, 5 (50%) were hospitalized. No deaths have been reported.

Illnesses that occurred after April 13, 2012 might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported.

Initial Announcement

May 3, 2012

CDC is collaborating with public health and agriculture officials in multiple states and the US Food and Drug Administration (FDA) to investigate an ongoing multistate outbreak of human Salmonella Infantis infections. Public health investigators used DNA “fingerprints” of Salmonella bacteria obtained through diagnostic testing with pulsed-field gel electrophoresis, or PFGE, to identify cases of illness that may be part of this outbreak. They used data from PulseNet, the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections. The outbreak strain is rare and typically 0-3 isolates are reported per month.

Multiple brands of dry pet food produced by Diamond Pet Foods at a single manufacturing facility in South Carolina have been linked to some of the human Salmonella infections. People who think they might have become ill after contact with dry pet food or with an animal that has eaten dry pet food should consult their health care providers.

A total of 14 individuals infected with the outbreak strain of Salmonella Infantis have been reported from 9 states. The number of ill persons identified in each state is as follows: Alabama (1), Connecticut (1), Michigan (1), Missouri (3), North Carolina (3), New Jersey (1), Ohio (2), Pennsylvania (1), and Virginia (1).

Among persons for whom information is available, illnesses began between October 8, 2011 and April 22, 2012. Ill persons range in age from less than one year old to 82 years old and the median age is 48 years. Seventy-seven percent of patients are female. Among the 9 patients with available information, 5 (56%) were hospitalized. No deaths have been reported.

The outbreak can be visually described with a chart showing the number of persons who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after April 1, 2012 might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks. Please see the Salmonella Outbreak Investigations: Timeline for Reporting Cases for more details.

Investigation of the Outbreak

On April 2, 2012, the Michigan Department of Agriculture and Rural Development detected Salmonella in an unopened bag of Diamond Naturals Lamb Meal & Rice dry dog food, which had been collected March 14, 2012, during routine retail testing of dry pet food. Public health investigators used PulseNet to identify recent cases of human illness with a PFGE pattern indistinguishable from Salmonella Infantis which was isolated from the unopened bag of dry dog food produced by Diamond Pet Foods. In interviews, ill persons answered questions about contact with animals and foods consumed during the week before becoming ill. Seven of 10 (70%) ill persons interviewed reported contact with a dog in the week before becoming ill. Of 5 ill persons who could recall the type of dog food with which they had contact, 4 (80%) identified dry dog food produced by Diamond Pet Foods that may have been produced at a single facility in South Carolina.

As part of this outbreak investigation, Ohio public health and agriculture officials collected and tested dry dog food produced by Diamond Pet Foods. The outbreak strain of Salmonella Infantis was isolated from an opened bag of Diamond Brand Chicken Soup for the Pet Lover’s Soul Adult Light Formula dry dog food collected from the home of an ill person, and an unopened bag of the product collected from a retail store. A sample of Diamond Puppy Formula dry dog food collected by FDA during an inspection at the South Carolina production facility has also yielded Salmonella.

Epidemiologic, laboratory, and regulatory investigations are ongoing to identify if other brands of dry dog food produced at this facility may be linked to human illnesses. Diamond Pet Foods is cooperating with public health and agricultural investigators in this ongoing investigation.

At a Glance:
  • Case Count: 49
  • States: 20
  • Deaths: 0
  • Hospitalizations: 10
  • Recall: Yes