For the third time this school year, the state Department of Health is investigating possible tuberculosis exposure in a public school.

About 106 students and five staff members at Farrington High School will be tested for the contagious disease after possibly being exposed to a student with active TB, Health Department officials said yesterday. Testing is scheduled to begin on May 13.

The first case of possible TB exposure this school year occurred in December at Roosevelt High School. Then in February, a teacher at Kahuku High & Intermediate School tested positive for the disease, prompting screening of more than 100 students and staff at the school.

This school year is the first time in about five years that the Health Department is responding to TB exposure in the schools, said Janice Okubo, DOH spokeswoman.

"This is unusual. We haven't had any investigations in the schools for several years," Okubo said.

NO CONNECTION

Even as school-related TB cases have suddenly increased this year, Health Department officials say there is no cause for alarm.

"There is no relationship between any of these particular cases. Each one appears to be unique and unrelated. We don't see there being any type of serious trend or issue because none of the cases are related," Okubo said.

Tuberculosis is spread through the air. It commonly affects the lungs, but also may affect other parts of the body. Symptoms of TB include prolonged coughing, weight loss, fever, weakness and fatigue.

If left untreated, the disease can be fatal.

New tuberculosis cases in the state have increased slightly over the past two years. Hawai'i has the highest rate in the nation, due in part to a relatively high percentage of foreign-born residents, according to the DOH.

INCREASE IN CASES

In 2006, Hawai'i reported 115 cases of TB, up from 112 cases in 2005, according to Health Department data. About 8.9 new cases are reported each year, according to DOH.

Health officials could not reveal any identifying information about the sick student from Farrington High. However, officials did say that student initially had latent TB, which later became active TB.

In January, the student was admitted to a local hospital where test samples were taken, which confirmed the student had active TB.

Dr. Glenn Wasserman, chief of the state's Communicable Disease Division, said the Farrington High School testing is precautionary and that there is currently no risk to the community.

Wasserman said laboratory tests conducted on the Farrington student found that while the student had active TB, the chances of infectivity are low.

"We're testing to be cautious," Wasserman said. "We want to encourage people who we've identified to have been in contact with the patient to be skin tested as a precaution to make sure we're not missing any potential cases."

The students and staff who will be tested may have been in contact with the ill student by being in the same classroom.

School administrators mailed letters on April 29 to inform parents and guardians of students about the situation. The student is no longer attending Farrington High School.

Farrington High School principal Catherine Payne did not immediately return a phone call seeking comment.

Wasserman also pointed out that Hawai'i tends to be relatively thorough in its screening for TB in school-age children.

State law requires students entering a DOE school to be screened for TB through a skin test. After that, no additional TB screenings are required.

A student who is found to have latent TB is allowed to attend school, because latent TB is not infectious. A pupil found to be contagious is not allowed to enter school.

"We're actually a little bit more aggressive than most places," Wasserman said.

He said some states conduct TB skin tests only if a student exhibits one or more of the risk factors: born outside of the U.S., traveled or lived outside of the U.S., previously tested positive for TB, received treatment for TB or has immune system deficiencies.