Twenty two people in 13 states have now been infected with Salmonella Infantis linked to contaminated dog food, according to the Centers for Disease Control and Prevention.

Multiple brands of dry dog food produced by Diamond Pet Foods at a South Carolina facility have been linked to some of the Salmonella infections, which would likely have been acquired via cross contamination from feeding a pet or from contact with a sick pet.

The five new cases are from: Alabama (1), California (1), Illinois (1), New York (1), and South Carolina (1). Two others have been reported in Canada.

Of the cases CDC has detailed information about, illnesses began between October 2011 and May 11, 2012, and ages range from less than one-year-old to 82, but the median age is 46.5. Sixty-eight percent of patients are female. Of the 17 patients CDC has information about, 6, or 35 percent, were hospitalized. No deaths have been reported.

Public health officials noted that any illness that may have occurred after May 11 might not be reported yet.

Anyone who thinks they might have become ill after contact with dry pet food or with an animal that has eaten dry pet food should consult a health care provider.

The investigation into Diamond Pet Foods contaminated dog food goes back to early April, when the Michigan Department of Agriculture and Rural Development found Salmonella in an unopened bag of Diamond Naturals Lamb Meal & Rice dry dog food, which had been collected in mid-March as part of routine retail pet food testing.

Public health investigators then used PulseNet to find recent cases of human illness with a PFGE pattern indistinguishable from Salmonella Infantis, which was isolated from the dog food sample. After interviewing patients, investigators figured out that the majority had had contact with either a dog or dry dog food before falling ill.

As part of the investigation, Ohio public health and agriculture officials also collected and tested dry dog food produced by Diamond Pet Foods. They found the outbreak strain in an opened bag of Diamond Brand Chicken Soup for the Pet Lover’s Soul Adult Light Formula dry dog food.

The U.S. Food and Drug Administration also found Salmonella in Diamond Puppy Formula dry dog food collected during an inspection at the South Carolina production facility, which has been linked to the contaminated pet food.

CDC said that Diamond Pet Foods is cooperating with public health and agricultural officials in the investigation.

In response to the outbreak, the FDA has recalled various types of dog food — and expanded the recall several times. For information on the recall and sick pets, see here and here. To lodge a complaint about a sickened pet, see here. and here.