An outbreak of Elizabethkingia is sweeping across the Midwest, and health officials have yet to identify the source. The disease has been identified in 57 patients in Wisconsin since late last year, and 18 of them have died. One person has died of Elizabethkingia in Illinois. The Michigan Department of Health and Human Services reported a case in March.

Elizabethkingia is a bacterium that is commonly found in soil, river water, and reservoirs. It does not usually cause illness in people. Past outbreaks occurred in healthcare settings. Current research indicates that Elizabethkingia is not spread from person to person.

There is a greater risk of infection among people who have compromised immune systems or serious pre-existing medical problems. The patients all had at least one serious underlying medical condition, and most were over the age of 65. It is unclear whether the deaths were the result of the infection, the underlying health problems, or a combination of the two factors.

The Wisconsin Department of Health is investigating other possible cases, so the number of people infected could rise. After the outbreak was identified in Wisconsin, health departments across the United States were asked to look for other possible cases.

Elizabethkingia infection can cause symptoms that include fever, chills, shortness of breath, joint pain, and cellulitis, a bacterial skin infection. It is difficult to treat because it is often resistant to antibiotics.

Most of the Elizabethkingia infections that have been identified so far were in the bloodstream. The bacteria were isolated in the joints and respiratory systems of some other patients.

Officials in the states affected are working with the Centers for Disease Control and Prevention to pinpoint the source of the outbreak. Investigators have been interviewing patients and their families. They have been taking environmental samples and samples from family members and patients who were treated in the same facilities. The investigators are also reviewing patients’ medical records.