The Wisconsin Department of Health Services is investigating a mysterious outbreak of a blood infection caused by the bacteria Elizabethkingia.
The outbreak is confusing because the bacteria don’t usually cause illness in humans—states usually see around six cases per year. The outbreak in Wisconsin is unprecedented: between November 1, 2015 and March 16, 2016, there have been 54 infections, predominantly in people over age 65. DHS reports that the illness includes, “fever, shortness of breath, chills, or cellulitis,” a bacterial skin infection that can cause pain or redness. So far, 15 people have died, although doctors haven’t determined whether their deaths were caused by the bacteria or by another underlying health condition.
The state has since contacted the Centers for Disease Control and Prevention—specifically the team of around 70 doctors and epidemiologists that helps to figure out how outbreaks spread, and they are stumped.
At first, the CDC suspected the tap water. Just this January, the CDC’s emerging diseases journal published a report about a nearly two-year long Elizabethkingia outbreak in a London critical care unit that ended up originating with contaminated taps in hospital sinks. But the tap water in Wisconsin turned up negative for the bacteria.
Adding to the mystery, this outbreak doesn’t match the pattern of other infections, which appeared in clusters in the same facility. Most of Wisconsin patients were elderly; some lived in nursing homes and others had gone to the hospital, but they lived across 12 different counties. At the same time, the genetic signature of the bacteria points to a single source. The infection seems, to use the language of epidemiology, to be community-acquired. This makes tracing a source more difficult: The CDC’s officials can’t just order up medical records from a single hospital and test the area exhaustively.
So, the medical detectives are traveling around the state, interviewing people to see if there are any related behaviors that might be connected (for example, eating lettuce). Scientists have found, however, that all the specimens studied have the same genetic “fingerprint,” meaning they probably all came from the same source.
Michael Bell, deputy director for the Division of Healthcare Quality Promotion at the CDC, says that Elizabethkingia are extremely common in places like water and soil.
“We can assume that bacteria like this are in normal tap water, in the food and vegetables that we eat regularly, and it doesn’t harm us because we have natural defenses,” he said in an interview with Wisconsin Public Television. “It’s only a problem when those defenses are somehow compromised.”
Damn, I bet there are a whole bunch of Elizabethkingia inside us right now.
Image via bogdanhoda/Shutterstock.