A general view of Texas Health Presbyterian Hospital in Dallas, Oct. 1, 2014. U.S. health experts in Dallas on Wednesday were examining how many people may have been exposed to Ebola, just one day after the first case of the deadly virus was diagnosed in the U.S., the nation's top public health official said. The patient, who wasn't identified for privacy reasons, arrived in Texas on Sept. 20, and sought treatment six days later at Texas Health Presbyterian, according to the CDC. Reuters

The U.S. Ebola patient being treated in Dallas may have exposed some school-aged children to the disease, Texas Gov. Rick Perry said Wednesday during a news conference. Health officials have identified the children and are monitoring them for symptoms, Perry said. The Ebola patient was sent home from the hospital when he sought care on Sept. 26 even after informing staff of his recent trip to Africa, new reports indicate.

The unidentified patient is now in critical condition and has been moved to intensive care at Texas Health Presbyterian Hospital in Dallas, according to the Centers for Disease Control and Prevention. The man returned to the hospital Sunday, two days after his initial visit. Blood tests confirmed the Ebola diagnosis Tuesday. The disease has killed more than 3,000 people across West Africa.

A Dallas County health official said they are monitoring 12 to 18 people, including five kids, who were in contact with the U.S. Ebola patient for symptoms. The kids attended Emmett J. Conrad High School, Sam Tasby Middle School, L.L. Hotchkiss Elementary School and Dan D. Rogers Elementary School, according to Dallas-Fort Worth broadcaster KDFW Fox 4. The students reportedly haven't shown symptoms but have been kept home as a precaution. “There is nothing to suggest that the disease was spread to others including students and staff," the school district said in a statement.

The patient arrived in the U.S. from Liberia on Sept. 20. He began showing symptoms of Ebola four days later. "We have a seven-person team in Dallas today helping to review that with the family and make sure we identify everyone that could have had contact with him," Dr. Thomas Frieden, director of the CDC, said in an interview Wednesday with NBC's "Today" show.