Minnesota health officials have identified two more cases of fungal meningitis, both involving men in their 50s or 60s who fell ill after receiving contaminated steroid injections.

A total of nine Minnesotans have now been linked to the month-long nationwide outbreak, said Richard Danila, deputy Minnesota state epidemiologist.

One of the newest cases, a Twin Cities man in his 60s had tested positive for the fungal infection weeks ago, but for some reason did not receive prompt treatment, Danila said.

"He should have been admitted and treated about two weeks ago," Danila said. "He fell through the cracks."

Danila said the Health Department discovered the case on Thursday and advised the man to seek immediate treatment. However, Danila had no details about the patient's condition.

The ninth case involved a man who had received the steroid injections in Minnesota but moved to Tennessee before his illness was diagnosed. Danila said it took several weeks to correctly identify it as a Minnesota case.

All nine Minnesota patients received steroids produced by the New England Compounding Center, a Massachusetts specialty pharmacy now under federal investigation. Federal authorities say that three lots of the firm's steroids were contaminated with fungus that caused the outbreak.

As of Thursday, 328 people have fallen ill and 24 have died in 18 states, according to the U.S. Centers for Disease Control and Prevention.

In Minnesota, health officials say they are continuing to investigate possible additional cases.