Two more people - including a second Pennsylvania resident - have become ill after being exposed to salmonella-tainted dry dog food, bringing the total to 16, say federal officials.

The illnesses are linked to at least 11 brands of dog food manufactured in a Gaston, S.C. plant operated by Diamond Pet Foods. Among the brands distributed by the plant is the store brand at Cosco. Other brands affected include Chicken Soup for the Pet Lovers Soul, Canidea and Taste of the Wild, as well as several Diamond brands.

People in nine states, including New Jersey and the Canadian province of Quebec, have become sickened, five of them were hospitalized. Surprisingly, the Pennsylvania Department of Health has issued no notice of the recall or provided any infomation about the individuals who fell ill here.

Lab tests indicated those who fell ill were infected with a rare strain of salmonella Infantis, which was detected Apr. 2 after a routine test of dry dog food revealed contamination, a report from the Centers for Disease Control and Prevention said.

Public health investigators used DNA fingerprints of the bacteria to identify past cases of illness linked to the outbreak. People infected with the outbreak strain became sick between Oct. 8, 2011 and April 22, 2012.

Three cases have been reported each in North Carolina and Missouri, two each in Ohio and Pennsylvania and one each in Alabama, Connecticut, Michigan, New Jersey and Virginia.

Diamond Pet Foods has voluntarily expanded its recall of certain brands of dry dog and cat food manufactured at the South Carolina plant between Dec. 9, 2011 and April 7, 2012 because of the potential contamination.

People can become sick by handling the tainted pet food or through contact with an animal that has eaten the contaminated food. Experts advise washing hands thoroughly after feedig pets or picking up animals. Also, clearn litter boxes daily.

Consumers should discard any of the recalled product. For full recall information see the Diamond recall web site here.

Pet owners who are unsure if the product they purchased is included in the recall, or who would like replacement product or a refund, may contact Diamond Pet Foods toll free at 1-866-918-8756, Monday through Sunday, 8 a.m. – 6 p.m. EST.

Salmonella infections can cause diarrhea, fever and abdominal cramping 12 to 72 hours after infection. The illness can last up to a week and most people recover without treatment. In some cases, severe diarrhea can require hospitalization.