Twenty-two women attending a vocational school in southern Ibaraki Prefecture have been infected with the tubercle bacillus and three of them have developed symptoms of tuberculosis, Ibaraki health officials said Tuesday.
The outbreak of the disease came to light after Ibaraki health authorities were alerted by a medical report that a student in the school -- a woman in her 20s -- was infected with tuberculosis.
Ibaraki health authorities conducted TB tests on 197 people, including members of the patient's family and her schoolmates. Twenty-one students tested positive.
Doctors said they found matching DNA patterns from the tubercle bacillus in the first patient and the two other women suffering from the disease.
The woman believed to be the source of the infection was diagnosed with tuberculosis in late January after she complained of fever and a cough.
The woman withdrew from her school in October and is convalescing at her home outside the prefecture, Ibaraki health officials said.
Ibaraki health officials said the two women who developed symptoms of tuberculosis are receiving medical treatment as outpatients.