Tuberculosis Still a Threat
By Douglas J. Gillert
American Forces Press Service
PEARL HARBOR, Hawaii, Aug. 1, 1996 A story used to make the rounds of American military bases in Korea about a strain of tuberculosis that, if caught, would keep service members from returning home. The tale led to some dread of the TB skin test everyone gets as part of an outprocessing physical.
"Physicians certainly would make sure you weren't actively spreading TB before they put you on an airplane," countered Navy Dr. (Capt.) H. James Beecham III. "But a positive skin test doesn't preclude people from departing on assignments out of Korea. It only means the person has the TB germ in the body."
For those who test positive, DoD begins a six-month regimen of up to three antibiotic drugs, said Beecham, director of tropical medicine for the Environmental and Preventive Medicine Unit Six. The regimen may last longer, he said, if the initial antibiotics don't work.
Growing drug resitance of TB, particularly in developing countries, concerns physicians. Additional drugs may help, Beecham said, but 40-60 percent of TB cases resistant to more than one drug are fatal.
Multidrug-resistant TB most likely will occur among citizens of developing nations, including immigrants to the United States. Cases also have shown up in New York and Miami and along the West Coast, particularly among HIV-positive people whose weakened immune systems make them vulnerable to pulmonary TB, Beecham said. DoD doctors worry about foreign-born spouses and other family members from places like the Philippines and Korea, where tuberculosis is prevalent, he said.
"Drug resistance also is a major concern during humanitarian assistance operations, where we're deploying to places with poverty and social disruption," said Dr. (Capt.) Ben S. Mitchell, officer in charge of Unit Six. "These are breeding grounds for multidrug-resistant infections. We don't want to expose service members to any more risk than is necessary during the course of their duties."
The TB germ is spread through inhalation, Beecham explained. "One in 25 people who inhale the germ actually comes down with pulmonary tuberculosis." In the other 24, he said, the germ enters the lymphoid system -- the body's filters -- and acquires a cellular wall that holds the germ in abeyance, basically for life. Stress to the body's immune system or simply old age may reactivate the TB germ, however, Beecham said.
Although TB can attack any body tissue, the germ most commonly attacks the lungs, where it forms lesions. Symptoms include fever, sweats and emaciation. More acute TB can attack a variety of organs through the blood stream. It is highly toxic and fatal.
Airborne germs like TB particularly concern the Navy, where sailors live in close quarters aboard ships for long periods of time. "A study cites that it's easier to transmit tuberculosis within a shipboard setting than anywhere else," Mitchell said. "On ship, you live, eat and work with a larger group; therefore, you can have many common exposures. For that reason, the Navy is particularly diligent about maintaining a good screening program and follow up if people test positive."
Dr. (Lt. Cmdr.) Laurel May, an epidemiologist assigned to the Pearl Harbor unit, is currently working on a shipboard TB outbreak. "We had decommissioned the ship and given it to Chile," May said. "The American crew stayed on board to train the Chileans, so the ship was twice as crowded as normal." Apparently, one Chilean sailor had active, contagious tuberculosis and infected many of the American sailors. One of the Americans since developed active TB, she said.
The 4 percent who develop TB after testing positive will usually show symptoms within two years, Mitchell said. The services provide drug treatment and monitoring to any service member who tests positive, he added.
Even though only 4 percent of those who test positive for TB get sick, nobody takes it lightly, May added. "Tuberculosis is a very old and common disease," she said, "and still a problem."