A Boston Latin School student has been diagnosed with tuberculosis, a disease spread by airborne germs that usually affects the lungs, school officials said Thursday afternoon. Parents were notified of the diagnosis on the school’s website and by a letter sent home with students.

“The student who has TB is being treated with medicine and will not return to school until it is safe for that student to return,” the letter from headmaster Lynne Mooney Teta said.

Although tuberculosis is not usually spread by brief contact, about 60 students and staff members will be tested by the Boston Public Health Commission for the disease, a Boston Public Schools spokesman said.

“It is a small group of students and faculty who, out of an abundance of caution, were asked to have a TB test to make sure they do not need to seek further medical assistance,” Matthew Wilder said.

Boston Latin is working closely with public health officials to ensure that the disease has not spread through the school, Wilder said.

‘The student who has TB is being treated with medicine and will not return to school until it is safe for that student to return.’

“What we do in a school setting is identify people who have been in closest contact to the case when the case was contagious, and we start by testing those people who had the most contact,” said Anita Barry, a physician and director of the infectious disease bureau at the health commission.

“So if someone is in five classes with [the diagnosed student], we would worry about that more than someone who is in one class with them.”

The disease is spread when a person who has tuberculosis germs in their lungs coughs or sneezes, releasing the germs into the air.

“TB is caused by bacteria that is spread through the air,’’ Barry said. “When someone who has active TB in their lungs coughs, or shouts, or sings, the people around that person can breathe in TB germs and become infected. It doesn’t happen with a short duration of contact. Usually you need many hours of fairly close contact to get TB from someone who had TB active in their lungs.”

The disease, which is both treatable and curable, is not very common in Boston.

Last year, just 44 Boston residents were diagnosed with the active form of the disease.

Barry said patients who are diagnosed with active tuberculosis are typically put on four or five medicines at once and usually fully recover in about two weeks.