Meningitis outbreak: Incubation period is longer than first thought
New cases may show up through early November
2:51 AM, Oct 10, 2012

The incubation period for some patients who received tainted epidural steroid injections is longer than doctors initially realized, which means new cases of fungal meningitis may continue to appear through early November, state health officials said Tuesday.

And a recently identified fungus, exserohilum, is now indicated as the cause of nearly all of the fungal meningitis cases in Tennessee — a number that rose to 39, including six deaths, on Tuesday.

Based on analysis of Tennessee patients, a range for development of symptoms is six to 42 days — and “some experts believe vigilance for up to three months will be necessary,” Health Commissioner John Dreyzehner said.

That recommendation comes out of an “abundance of caution,” he said.

Previously, the incubation period had been estimated at two to 28 days. An initial case appeared to have a two-day incubation period, but that was misleading because the patient had multiple epidural injections and probably was infected before the most recent shot, Dreyzehner said.

To this point, the average time between epidurals and appearance of symptoms for Tennessee patients has been 16 days.

“We are investigating this carefully and will be keeping in touch with those patients who may be at risk for infection,” Dreyzehner said.

“Until we have evidence that the incubation period has passed, it’s important to understand the incubation period is an outer limit based on the best available science...

..Nationally, the number of epidural steroid reported deaths is 12 and the total meningitis cases climbed to 1211...

[link to www.tennessean.com]