An Auburn toddler is home after battling the same E. coli-related illness that killed a 20-month-old Poland boy last week.

Myles Herschaft, 17 months old, left the hospital this week, according to a Facebook post by his father, Victor.

“Little update. I forgot to tell everyone Myles spent his first night home last night,” he wrote Thursday night.

Last week, he said his son was being treated at Maine Medical Center in Portland.

Herschaft has been chronicling his son’s progress on Facebook since the boy contracted hemolytic uremic syndrome, known as HUS, after being exposed to E. coli bacteria.

Colton Guay of Poland died last week after battling HUS.

The illness, which is frequently preceded by severe diarrhea, often attacks the liver and kidneys. In Colton’s case, his father has said, it attacked his brain.

State officials said last week that the two boys carried the same strain of E. coli and officials were investigating where the bacteria had come from. 

Although the boys’ families had reported that both toddlers petted farm animals at the Oxford County Fair in Oxford in September, a Maine Center for Disease Control and Prevention spokesman said Friday that the state has so far been unable to pinpoint the source of the E. coli. 

Spokesman John Martins said tests were recently completed at the Maine Health and Environmental Laboratory but do not provide conclusive information. The Maine CDC will send samples to the national Centers for Disease Control and Prevention in Atlanta for more comprehensive testing.

Martins said he did not know how long it would take for testing to be completed, but the state CDC hopes Maine’s tests can be prioritized.

William Marler, a Seattle-based lawyer who specializes in civil cases involving E. coli and who represented families in the infamous Jack in the Box E. coli outbreak in the 1990s, said Friday that he’s been hired by the Guay and Herschaft families to investigate their cases.

Although the CDC has not been able to determine how the boys contracted the bacteria, Marler believes the source is likely the petting zoo at the Oxford County Fair.

“These people don’t know each other,” Marler said. “There’s no evidence they did anything (the same) other than go to the fair, the petting zoo.” 

Experts say it’s difficult to pinpoint the source of E. coli through lab tests; often it can’t be found.

Marler said he’s told the families to fully cooperate with the Maine CDC’s investigation, including detailing where they went and what they did in the week before the boys got sick because it can take days for E. coli to incubate and cause illness.

He said he will wait for the CDC’s investigation to finish, then will request the records and results.

“We’ll look at it with sort of a different set of eyes, with 15 years of experience dealing with these cases,” he said. “Then we’ll decide what, if anything, the families are going to do.”

Marler said the families’ options include pushing for more stringent state laws to prevent such cases from happening again and filing a lawsuit against the person or group responsible for the outbreak.