The study, along with an editorial by UC Davis Assistant Professor of Medical Microbiology and Immunology George R. Thompson, appears in the June 19 issue of the Journal of the American Medical Association.

"The study shows that patients exposed to the contaminated steroids can no longer be reassured that the lack of new or progressive symptoms equates to a lack of fungal infection," Thompson said. "Exposed patients may have paraspinal or spinal infections even though they do not notice any increase in pain or neuropathic symptoms. Magnetic resonance imaging at the injection site is recommended to screen for infection in high-risk patients, but it should not be widely adopted, particularly for patients who received injections in peripheral joints, which the study associated with a much lower attack rate."

In the fall of 2012, the U.S. Centers for Disease Control and Prevention (CDC), in collaboration with state and local health departments and the Food and Drug Administration (FDA), began investigating an unprecedented multistate outbreak of fungal meningitis among patients who received contaminated steroid injections for the treatment of back pain or neuropathic symptoms. While meningitis was the primary complication after the initial steroid injection, spinal or paraspinal infections can surface weeks to months later. To date, more than 740 patients in 20 states have been diagnosed with meningitis, spinal or paraspinal infections, joint infections or other complications at or near the injection site linked with compouding pharmacy formulations. Patients who received injections in peripheral joints only, such as the knee, shoulder or ankle, could be at risk for joint infection and are also included in the investigation.

"Continued vigilance and collaborative efforts with radiologists experienced in interpreting MRI findings of E rostratum are needed to detect late fungal infections in patients to improve health outcomes," Thompson said.

According to the CDC, Exserohilum is a common mold found in soil and on plants, especially grasses, and it thrives in warm and humid climates. While it is a very rare cause of infection in people, the mold has been known to cause several different types of infections, including infection in the skin or the cornea (the clear, front part of the eye), which are typically due to skin or eye trauma. Exserohilum can also cause more invasive forms of infection in the sinuses, lungs, lining of the heart and bone, which are thought to be more likely to occur in people with weak immune systems.