An infected employee exposed nearly 800 people to tuberculosis at Emory University Hospital in Atlanta, the hospital confirmed today.
"At this time, there are 680 patients, and approximately 100 employees who have been identified as having been in contact with the infected individual," Lance Skelly, a spokesman for the hospital, said in a statement. "Each person has been contacted and provided proactive screening instructions. Post-exposure follow-up will also be provided free of charge through the patient's local county health department."
TB, a bacterial infection, can be transmitted through a cough or sneeze. And although it responds well to treatment when caught early, it can cause permanent lung damage, and even death if left untended.
"The vast majority of TB strains are quite susceptible to drugs," said Dr. William Schaffner, chairman of preventive medicine at Vanderbilt University Medical Center in Nashville, Tenn. "If a patient is adherent to the treatment program, which can last nine months, they can be cured and quickly rendered safe for interaction with others."
The most widely used screening test involves injecting a tiny amount of TB-derived liquid under the patient's arm skin and monitoring the body's immune reaction. The injection immediately causes a mosquito bite-size welt that dissipates if the person tests negative. But if the skin turns red and puffy within three days, the test is positive and doctors will order a chest X-ray to reveal whether the infection is dormant or active.
"Some people can have a positive TB skin test but no symptoms," Schaffner said. "We call this latent TB -- the bear in the cave, so to speak."
An active infection will show up as a white cloud in the lungs on a chest X-ray. But even if the TB is latent, doctors will treat it with antibiotics to eliminate the patient's risk of developing the active infection. Untreated, about one in 10 people with latent TB will develop active TB, which can cause a cough (sometimes with blood), a fever, sweating, fatigue and weight loss.
"They used to call this disease 'consumption,' because it would consume you -- you would literally become smaller and smaller," Schaffner said.
Elderly people, infants and people with weakened immune systems are at a higher risk for active TB. The infection is a leading killing among people with HIV, according to the U.S. Centers for Disease Control and Prevention.
Roughly 11,500 TB cases were reported in the United States in 2009, 59 percent of which occurred in people born outside the U.S., according to U.S. Centers for Disease Control and Prevention. There were 544 deaths from TB in 2007, the most recent year for which the CDC has data. Frequent contact with people who have TB, poor nutrition and unsanitary living conditions are risk factors for the disease.
But how the Emory University Hospital employee became infected is unclear. Most hospitals, Emory University Hospital included, require staff to have a TB skin test before they are hired and every year after, Schaffner said.
"The question is: Did this employee evade the TB screening process, or did this person develop their illness between screenings," Schaffner said. "This is a kind of unsettling event, but it's an event that occasionally happens despite our best efforts to prevent it."