(CNN)An outbreak of E. coli linked to romaine lettuce from the Yuma, Arizona, growing region has spread to four additional states, the US Centers for Disease Control and Prevention announced Wednesday. Florida, Minnesota, North Dakota and Texas are the latest states to report illnesses, bringing the total to 29. The CDC also reported 28 additional cases of illness, bringing the total to 149 since the outbreak began in March. Symptoms of the most recent illnesses reported began April 25. However, the CDC warned that due to a lag in reporting, any illness that occurred in the past two to three weeks may not have been counted in this update. Last week, the CDC announced that one person had died; the death, in California, was the first known fatality. Previously, the CDC warned that the strain of E. coli identified, O157:H7, is particularly virulent and known to be associated with higher hospitalization and complication rates.