Howard County health officials are investigating whether the county's first tuberculosis case this year, diagnosed in a student, spread the bacterial illness to staff members or other students at Hammond High School.
The students and staff members at the Columbia school were told of the diagnosis yesterday. The county Health Department sent letters Saturday to 50 students who ride the bus with the student, warning them that they might have been exposed and encouraging them to get tested.
Officials learned about the infected student four weeks ago, said Dr. Peter L. Beilenson, the county health officer.
"We hopped on it as soon as we learned of the case," Beilenson said. "There is no significant urgency in this because the child has already been treated and we have not identified new converters."
Tuberculosis is an airborne, communicable disease caused by the Mycobacterium tuberculosis bacterium. It typically attacks the lungs but can affect any part of the body. Without proper treatment, the disease can be fatal.
Eight people who have had close contact with the student have tested negative for the disease, Beilenson said.
It is not known how the student contracted the disease, Beilenson said. He said the student does not have multidrug-resistant tuberculosis, which is more serious.
"TB is extremely treatable," Beilenson said. "The treatment is usually several medications daily for several months."
The letter sent home with students yesterday said: "Tuberculosis is spread through the air, usually by coughing or sneezing. Generally, a person must have prolonged exposure to the person with TB disease in order to breathe in a sufficient number of TB germs to cause TB infection."
Citing confidentiality requirements, school officials would not identify the gender of the student or say what grade the student is in.
"The individual who was diagnosed is being treated medically," said Donna Heller, coordinator of health services for the Howard schools.
Heller also would not say whether the student is attending classes at the 1,268-student school.
The tuberculosis case is the first in the school system this year, Heller said.
"I haven't had to address tuberculosis in a very long time," she said.
Eight cases of tuberculosis were diagnosed in Howard County last year, six in 2006, 12 in 2005 and 14 in 2004.
Health officials will answer questions at a community meeting scheduled for 7 o'clock tonight at Hammond High.
john-john.williams@baltsun.com