Maryland could see new cases of meningitis for a month or more as health officials continue to search for new and past cases of the disease, which has sickened 50 people in several states who received injections of a tainted steroid.
In the cases health officials are already aware of, the incubation period for the infections has been between two days and four weeks, but it's possible the period could be even longer for some, said Dr. Lucy Wilson, chief of Maryland's infection prevention and outbreak response program. Health officials are basing their estimate on the existing cases, but it could change, Wilson said.
New cases cropped up in others parts of the country Friday. Michigan is the latest state with six cases, Reuters reported. Tennessee officials confirmed four more cases of the rare fungal meningitis in people who had preservative-free methylprednisolone acetate injected into their spines to ease back pain, Reuters reported. Five people across the country have died of the disease, including one in Maryland.
Seven clinics in Maryland that received some of the tainted lot of the steroid, distributed by New England Compounding Center in Framingham, Mass., continued reaching out to hundreds of patients who received injections, Wilson said. State health officials are meanwhile monitoring admissions to hospitals and urgent care centers to watch for new cases, she said.
The Food and Drug Administration urged doctors not to use any products by the company as regulatory officials worked to identify the source of the infection. The FDA released a list Friday of nearly 30 medications distributed by the company.
The agency said it has found fungal contamination in foreign matter taken from a sealed vial of methylprednisolone acetate collected by New England Compounding Center. The agency is doing additional testing to confirm the species of the fungus.
The most common types of meningitis are caused by viruses or bacteria; fungal meningitis is more rare. It is usually found in people with compromised immune systems.
"This fungus in particular is found in the soil and the environment, but it normally doesn't colonize people at all," said Dr. Michael S. Donnenberg, a professor of microbiology and immunology, and associate chairman for research in the department of medicine at the University of Maryland School of Medicine.
Fungal meningitis isn't spread from person to person but is picked up from the environment, Donnenberg said. He said the steroids used to treat back pain can inhibit immune response and may have given the fungus a better chance of establishing itself.
Mercy Medical Center received several calls from alarmed patients even though the Baltimore hospital did not use steroids from the New England center.
Dr. David Maine, director for the Center for Interventional Pain Medicine at Mercy, said he buys his steroids directly from the manufacturer, where he believes there is less chance of contamination than there is buying from a middle man like New England Compounding Center.
Maine said the only time the drug is exposed is when he injects the patient.
Maryland health officials urged people to watch out for symptoms and said the disease can be treated.
Kim Merrill, the nurse administrator at the Harford County Ambulatory Surgery Center, said the center continued to reach out to people who had received injections there. She estimated 200 to 300 people would eventually be contacted. No one had reported becoming ill.
Janice Stewart, nurse administrator of SurgCenter of Bel Air, said the facility had contacted six patients and that none had been sickened. Maryland Pain Specialists in Towson said none of its patients received a spinal injection of the steroid from the company.