CDC Investigation of E. coli Outbreak Unknown Source 1 Ends The FDA and CDC have announced that they have completed their investigation into two mystery E. coli O157:H7 outbreaks. Here we focus on the investigation into E. coli Outbreak Unknown Source 1. This outbreak is different from Unknown Source 2 and Unknown Source 3. And this outbreak is the number eight multistate outbreak of 2020 in terms of numbers of people sickened. The first completed investigation was into Outbreak Unknown Source 1, which has sickened 32 people in 12 states. The case count by state is: California (10), Illinois (3), Louisiana (1), Maryland (1), Michigan (2), Montana (2), New Jersey (1), Ohio (7), Utah (1), Virginia (1), Washington (1), and Wisconsin (2). Fifteen people were hospitalized because they were so sick, and one person who lived in Michigan died. One person developed hemolytic uremic syndrome (HUS), a type of kidney failure.