A third-grader stuck 19 schoolmates with her mother's diabetes (search) blood-testing needle this week, and one pricked student tested positive for HIV (search) on a preliminary test, officials said.

Health officials said the virus could not have been contracted from the needle stick, and they noted that preliminary tests can yield false positives. The risk to students who were stuck after the possibly infected child depends on factors including the depth of the stick, health officials said.

The 8-year-old stuck her Taylor Elementary (search) schoolmates Wednesday at the school's breakfast, at lunch and in the classroom, using a needle that was about one-third of an inch long, on the end of a device that looks like a pen, school officials said. They were unsure why the girl did it.

She was suspended and will probably be moved to another school, said Paul Vallas, the school district's chief executive.

Most of the students involved were taken to a hospital for testing and treatment, school officials said.

According to the Centers for Disease Control and Prevention (search), the risk of HIV infection after a needle stick is low, with an average of one in 300 cases leading to infection.