Eight people in Montana are receiving rabies shots as a precaution after a middle school student found a bat at home and brought it to science class in a bag, health officials said Friday.

The seventh-grade boy released it in a field before officials could test it for rabies. But the boy's family of seven and a classmate who touched the bat Tuesday at North Middle School in Great Falls started the series of shots, officials said.

Rabies is transmitted through saliva, most often through bites and scratches, and it can be fatal if it is not treated soon after exposure.

The school district is notifying as many as 150 families of students who could have been exposed to the bat while they were on the bus or in the classroom.

The boy's mother found the bat in the basement of her Great Falls home on Tuesday morning and put a container over the top of it that he discovered after she went to work, according to epidemiologist Elton Mosher with the Montana Department of Health and Human Services' Communicable Disease Control Bureau.

Because most of the family was sleeping when the bat was found, health officials could not rule out that it had flown into another room and bitten someone.

"Bats can bite you and you won't even be able to tell - the punctures are so small," Mosher said.

The boy then brought the bat to a science teacher in a plastic bag. The teacher had him put it in a box with a lid and kept it in the classroom for the day, sending it home with him, according to Tom Moore, assistant superintendent for secondary schools in Great Falls.

The teacher will not face disciplinary action, Moore said, adding that she told everyone not to touch the bat and to leave it alone. The teacher should have taken the bat away so it could have been sent to a lab for rabies testing, health officials said.

At some point, at least one other student touched the bat. The youth said that when he did, it moved and he squealed, according to Moore.

Cascade City-County Health Department officials got involved after a student posted a picture of the bat on social media. By then, it had been released.

Mosher said anyone who touched the bat should report it to the county health department immediately. Rabies is 99 percent fatal once symptoms occur, which include worsening neurologic signs and partial paralysis, he said.