A rare blood borne infection called Elizabethkingia has killed 15 people in Wisconsin with many more having been infected but survived. All of its victims have had an underlying illness and most were over 65 years of age. The outbreak is puzzling the CDC as it is very rare to have this many cases and for it to spread over a wide area. Another death was reported in Michigan at the beginning of March. Researchers have yet to identify the source of the surge in cases.