MANKATO (AP) -- The Minnesota Department of Health is investigating a tuberculosis outbreak among people associated with Minnesota State University, Mankato.

Health officials believe the bacteria originated with an international student and spread to at least seven others. The majority are MSU students or former students. About 700 people who may have interacted with them, such as roommates and significant others, have been contacted. And, of those, health officials identified another 30 individuals who have tested positive for TB, but didn't have any symptoms.

TB is caused by a bacterial infection and usually affects the lungs, though the bones, spine or other organs can also be infected.