One new illness in Louisiana has brought the case count to 15 in the ongoing E. coli O145 outbreak in the southern U.S. and California, according to the U.S. Centers for Disease Control and Prevention. A 21-month-old girl died on May 31 after falling ill to the outbreak strain. The source of the outbreak remains unknown as state and federal health officials continue to investigate the outbreak, but experts believe it originated in food. Four people have been hospitalized. The case count by state is as follows: Alabama (2 illnesses), California (1), Florida (1), Georgia (5), Louisiana (5) and Tennessee (1). The ill range in age from 1 to 79 years old with a median age of 31. Seventy-three percent are female. According to the CDC, the last reported illness onset dates back 6 weeks, meaning the outbreak may have ended. Regardless, health officials will remain alert for any additional cases to arise. Last week, Food Safety News spoke with Dr. William Keene, senior epidemiologist for Oregon Public Health, to get an expert perspective on how health officials may be trying to determine the source of this outbreak. Images courtesy of CDC