Less than 24 hours after the federal Centers for Disease Control and Prevention (CDC) in Atlanta announced  the existence of  five cases of E. coli O26  associated with Chipotle Mexican Grill with different  DNA fingerprints than others in their ongoing multiple state outbreak investigation,  “CMG” stock crashed through the $500 per share floor. The way  the market read the latest CDC report was  to assume the Denver burrito maker is likely responsible for a sixth outbreak of food borne illnesses since July because CDC found a second  E. coli strain, a rare variant of O26. And clearly  it was that  CDC report that dropped Chipotle’s stock at  closing on Tuesday  to $495.62 per share or down 5.06 percent for a loss of  $26.30 on the day.  Chipotle has not traded at such levels since late 2013. And it was trading above $750 per share when the outbreaks began six months ago. Outbreaks with differing strains of a pathogen do occur and CDC could decide to include the new cases within the larger nine-state outbreak involving 53 cases with the original O26 strain. The five new cases involve customers of two Chipotle restaurants in Kansas and Oklahoma. It would likely help CDC make a determination on how many outbreaks are involved if  one or more responsible food sources could be found. Food sources for the Chipotle outbreaks remain elusive. It’s been difficult to determine which foods and ingredients were common to the various Chipotle locations, according to Dr. Ian Williams, the long time chief of outbreak response and prevention at CDC.   He blames a lack of record keeping by Chipotle. The new CDC report set off another round of financial and mass media reports on Chipotle’s troubles. Boston Health officials yesterday said the number of Norovirus cases associated with the Cleveland Circle Chipotle near the Boston College campus has reached 153.   BC campus officials say 141 are students who were sickened either by Chipotle or from classmates who dined there. The previous count for Norovirus victims was 136.    Total illnesses from all Chipotle related outbreaks since July now stands at 514.  That figure includes the additional O26 cases added by the new CDC report.   The summary to date includes: Seattle When: July 2015 Sickened: 5 people Culprit: E. coli O157:H7 Source: Unknown Simi Valley, CA When: August 2015 Sickened: At least 234 Culprit: Norovirus Source: Ill worker Minnesota When: August and September 2015 Sickened: 64 people Culprit: Salmonella Newport Source: Tomatoes CA, IL, KS, MD, MN, NY, OH, OK, ND, OR, PA, WA* When: Began October 2015 Sickened: 58 people Culprit: E. coli O26 Source: Unknown Boston When: December 2015 Sickened: At least 151 people Culprit: Norovirus Source: Ill worker * Includes 5 cases with different DNA fingerprint.  Possible 6th outbreak. (To sign up for a free subscription to Food Safety News, click here.)