Two unrelated E. coli deaths at the end of May — a 6-year-old Massachusetts boy and a 21-month-old girl in Louisiana — still have public health officials searching for possible sources and explanations. In Millbury, Massachusetts, Owen Carrignan died May 26 after developing hemolytic uremic syndrome (HUS), a kidney disease brought on severe E. coli O157:H7 infections. How he got the infection, however, still has investigators stumped. Meanwhile, an E. coli infection killed New Orleans toddler on May 31 and has sickened at least two other adults in Louisiana. Health officials suspect that these illnesses are linked to an outbreak spread across multiple southern states, but just like in Massachusetts, they are still looking for answers to how the infections might have occurred. “At this stage, we have no idea,” said Louisiana State Epidemiologist Dr. Raoult Ratard. Ratard said that the E. coli strain that infected the New Orleans children was not O157:H7, but he did not have information on the specific strain readily available (Update: The Georgia Department of Health has confirmed the outbreak strain as E. coli O145). While most E. coli strains do not pose harm to humans, a handful produce the potentially deadly Shiga toxin responsible for E. coli outbreaks. A spokesman for the Louisiana Department of Health & Hospitals said that while the infections could have been transmitted via any food, drink or animal contact, health officials have tentatively ruled out the Audubon petting zoo as a possible source after it was suspected early on in the investigation. So far, the U.S. Centers for Disease Control and Prevention has declined to name the other states involved in the multistate investigation. A CDC spokeswoman told Food Safety News that they are working with various state health officials to release any potentially relevant information when ready. Graffagnini first showed signs of E. coli infection more than a month before her death and was hospitalized for several weeks, Ratard said. According to MSNBC, Carrignan fell ill on May 20, six days before he passed away. Ratard offered a few suggestions to help avoid E. coli infection: Wash hands thoroughly after touching animals, and don’t let children play in areas where animals are kept. When preparing meals, cook foods to the recommended internal temperatures.