Cases of salmonellosis in humans connected to contact with pig ear treats continue to rise and the U.S. Food and Drug Administration (FDA) is advising pet owners to take precautions to avoid illness.

The organization, in coordination with the Centers for Disease Control and Prevention (CDC), is reporting 143 cases of Salmonella human infection tied to exposure to pig ears, spread across 35 states.

Thirty-three people have been hospitalized, CDC says, with many cases classified as multidrug-resistant.