(CNN) - A non-contagious, fungal form of meningitis has sickened 26 people in five states, killing four, the U.S. Centers for Disease Control and Prevention said Wednesday.
Five additional cases were reported in Tennessee, health officials said Tuesday. The total number of cases in that state is 18.
Three cases have been reported in Virginia, two each in Florida and Maryland and one in North Carolina, the CDC said. Two people have died in Tennessee, one in Virginia and one in Maryland.
All of those infected had received steroid injections to the spine.
The Tennessee victims range in age from 49 to 89, state Health Commissioner Dr. John Dreyzehner said Wednesday. Department spokesman Woody McMillin said Tuesday 11 patients were hospitalized.
"The prime suspect for this outbreak is methylprednisolone acetate," Dreyzehner said Wednesday.
Methylprednisolone acetate is an injectible steroid product used to treat pain and inflammation.
Food and Drug Administration officials identified the manufacturer as New England Compounding Center (NECC), which conducted a voluntary recall of three lots of methylprednisolone acetate 80mg/mlinjection produced at NECC. The lot numbers are #05212012@68, #06292012@26 and #08102012@51.
The FDA continues to work with state health departments and the Massachusetts Board of Pharmacy to investigate the scope and cause of the outbreak of the fungal meningitis, according to FDA spokesperson Erica Jefferson.
"We expect to see more cases," Dreyzehner said, noting the infection can take up to 28 days to develop.
Three pain treatment centers in Tennessee received the steroids that were part of the three recalled lots, officials said.
They are the Specialty Surgery Center in Crossville, Tennessee; the PCA Pain Care Center in Oak Ridge, Tennessee; and the St. Thomas Outpatient Neurosurgery Center in Nashville.
Biopsies from two patients are consistent with the aspergillus fungus found in another patient, according to Dreyzehner, but he was careful to note that the findings need to be confirmed by the CDC.
The investigation is ongoing and evolving, he said. "Though we are closer to identifying the cause, we have not concluded there is one factor at this time."
The investigation is also looking at anesthetic or the antiseptic as possible causes of infection, he said.
The dates of the investigation have also been widened, and now include patients treated between July 1 and September 20. "We are casting a wider net as a precaution," Dreyzehner said.
The Nashville facility contacted 737 patients who had lumbar epidural steroid injections between July 30 and September 20, health officials said previously.
The facility was temporarily closed on September 20 and will remain closed until investigating authorities "are confident the current concerns have been resolved," the health department said.
Between 100 and 200 patients at the Crossville facility may have been exposed or put at risk because of lumbar injections during the same time period, according to McMillin.
No cases have been identified from the Oak Ridge facility, Dreyzehner said.
Meningitis is a general term for swelling of the protective membranes that cover the brain and spine.
The swelling is typically caused by an infection of the fluid surrounding the brain and spinal cord that can be caused by bacteria, viruses, parasites or fungus, although meningitis also be caused by injury, cancer or medications.
For this type of meningitis, symptoms include worsening to severe headache, nausea, dizziness and fever, Dreyzehner said. Other symptoms can include slurred speech, unsteady gait, urinary retention, weakness and sensory deficit.
CNN's Miriam Falco, Saundra Young and Joe Sutton contributed to this report.