Diamond Pet Foods is facing its first lawsuit in the recall of its salmonella-contaminated pet foods.

A New Jersey man is suing the company with claims that his 8-week-old son went to the hospital with an infection caused by a rare strain of salmonella Infantis, the strain linked to contaminated dog food.

The family took the child to the pediatrician, who sent him to the emergency room at St. Peter’s University Hospital, where he was hospitalized for three days. According to MSNBC, tests of stool samples were positive for salmonella, and were later confirmed to be salmonella Infantis.

The father said he had been buying bulk bags of Costco dry dog food for months for the family’s two dogs, who did not get sick. However, samples of the pet food did not test positive for salmonella, though the family’s lawyer suggested that contamination with the rare salmonella strain may have come from an earlier batch of dog food.

The father is also suing Costco, the store that sold the contaminated dog food from Diamond.