Knoxville — Six children are being treated and a Knoxville childcare facility has been shut down as health officials work to determine the cause of an E. coli outbreak.

As of Friday, six children were being treated for E. coli at East Tennessee Children's Hospital. Four of them are in serious condition, one is in fair condition, and the latest is in good condition.

On Thursday, children's said it suspected five of the children it was treating at the time had contracted E. coli by drinking raw milk. Children's Hospital said the sixth child is believed to have been exposed to E. coli at the childcare facility.

The Knox County Health Department says more than 10 children have tested positive for the bacteria in the past week and a half. East Tennessee Children's Hospital said 10 of them were under the age of four.

The Knox County Health Department is investigating any and all possible causes including, but not limited to: The childcare facility itself, drinking raw milk, and coming in contact with some animals. An E coli alert was issued on Tuesday.

The Tennessee Department of Human Services ordered the Kids Place Inc. Millertown Child Care Center closed on Tuesday evening, but it was still operating when 10News visited it on Thursday.

According to a statement from Kids Place Inc., they have multiple buildings across more than 20 acres, including pre-school and after-school care and summer camps. They initially closed the Baby House for toddlers after a sick child came to the day care that was later sent home.

Per a state order, the entire Kids Place, Inc. Millertown campus is now shut down.

On Friday, Tennessee Department of Human Services said it's not ready to allow children to return to the child care facility as it continues to evaluate the circumstances surrounding the case. However, the Knox County Health Department said it has lifted its closure order and Kids Place, Inc. is waiting for approval from the Tennessee Department of Human Services.

"Additionally, we are continuing to reach out to child care providers in the Knox County area to assist efforts to find available child care options for parents while Kids Place Inc. remains closed," TDHS said.

Knox County Health Department head Dr. Martha Buchanan said Kids Place, Inc. successfully completed mitigation steps which included environmental cleaning, infection control education of the staff by the health department, a written infection control plan regarding animal exposure, closing of the pool at the facility until June 18 and completion of food and facilities inspections.

“Thank you for your cooperation with the Knox County Health Department in our efforts to reduce the spread of E. coli,” Buchanan wrote to Kids Place. “As discussed, the Tennessee Department of Human Services as your regulatory authority will have final say regarding lifting their closure; however, from the public health perspective, the imminent health threat has been mitigated and it is safe for the Baby House to resume operations.”

TDHS issued the following statement to 10News Thursday afternoon:

"The Tennessee Department of Human Services (TDHS) issued a safety plan that required Kids Place Inc. Millertown Child Care Center to close Tuesday evening amid concerns about E.coli.

Thursday it came to our attention the child care center had not, in fact, ceased operations throughout the entire facility. TDHS representatives informed the center that no child care operations are to occur anywhere on the property. The owners of Kids Place Inc. Millertown Child Care Center are cooperating with this order.

Kids Place Inc. Millertown Child Care Center will not be allowed to reopen until the Knox County Health Department provides written documentation that the center is clear and free of E-coli or any other pathogen that may be present.

TDHS is additionally in the process of reaching out to child care providers in the Knox County region to assist efforts to find available child care options for parents while Kids Place Inc. remains closed."

"The child was brought to our Millertown Pike day care facility last week and sent home the same day because of illness. In addition to the child who was initially diagnosed, three other children were identified as having the E. coli infection. None of the four children who were in our care needed to be hospitalized and are being treated by their doctors," according to the statement from Kids Place Inc.

E. coli can be passed from person to person.

"The safety of all children is the top priority at Kids Place. When we learned that a child was diagnosed with E. coli infection, we took several immediate proactive steps. Kids Place quickly notified all parents; contacted the Knox County Health Department; disinfected classrooms and common areas; installed a new outdoor surface; and closed the Baby House for toddlers," according to the statement.

The Baby House is for children up to 2 1/2 years old, and they said they hoped to reopen it on Monday, but on Thursday afternoon, officials with the Department of Human Services visited the center to tell them they needed to temporarily shut down the entire Millertown facility. In an updated statement, Kids Place Inc said they were just notified of the need to close on Thursday, and plan to do that, but still hope to reopen on Monday. Satellite locations will remain open.

There is livestock located on an adjacent private farm, according to Kids Place Inc, but they say their children do not interact with those animals. There are also dogs, goats and ducks contained to an area on the Kids Place Inc property. They say they have contacted agricultural experts to examine those animals.

Officials with the Knox County Health Department have taken environmental samples from the areas of the operation that may have been impacted. Health officials do not know how long it will take to get the results of the tests.

"The child care center is under investigation by the Knox County Health Department and will not be allowed to reopen until the Knox County Health Department provides written documentation that the center is clear and free of E-coli or any other pathogen that may be present. The safety of children at the Kids Place Inc. Millertown Child Care Center is our foremost concern," said the state Tennessee Department of Human Services in a press release.

While testing continues, local health department officials are working with the staff at Kids Place to implement better infection control practices, no matter what the results show.

Many of the children who are sick consumed raw milk from a local cow-share dairy, according to KCHD. Due to possible contamination with E. coli 0157 and out of an abundance of caution, the health department advises the public not to consume raw milk or any other unpasteurized products from French Broad Farm in Knoxville, Tennessee, which is currently closed.

The health department said it is investigating whether these two sources could be linked.

When it comes to milk, health workers say pasteurized is the only way to drink it. The Centers for Disease Control and the American Academy of Pediatrics recommend against drinking raw milk.