A hospital employee with tuberculosis may have exposed as many as 680 patients and 100 hospital workers at Emory University Hospital to the bacterial disease. (Centers for Disease Control and Prevention Public Health Image Library)

Tuberculosis is not the killer in this country that it once was, but it’s nonetheless a dangerous, lethal disease, killing nearly 2 million people worldwide each year. And even in this country, if a healthcare worker were to expose hospitalized patients and other healthcare workers to the bacterial infection, much consternation  -- and possibly, alarm – might ensue.

That appears to be what happened at Emory University Hospital in Atlanta recently. CNN reports that an employee with tuberculosis may have unknowingly exposed about 680 patients and 100 employees to the disease.

So far, there’s some consternation but little alarm. No symptoms have been reported. Tuberculosis, which usually attacks the lungs, can be fatal if left untreated.

Caused by the bacterium Mycobacterium tuberculosis, TB travels in the air, like the common cold. Sneezing, coughing and talking can spread TB, according to the CDC, but direct contact such as handshakes, sharing drinks or kissing won’t.

Getting infected with TB doesn’t always lead to disease. A person with a healthy immune system can breathe in the bacteria but not develop any symptoms or be contagious — this is known as latent TB.

But if the immune system is weakened and can’t control the bacterial growth, a latent case can flare into an active one — usually attacking the lungs but sometimes also the brain, kidneys or spine.

Here are the signs of the disease in the lungs, from Medline Plus:

-A bad cough that lasts 3 weeks or longer

-Weight loss

-Coughing up blood or mucus

-Weakness or fatigue

-Fever and chills

-Night sweats

Drug treatments exist for both active and latent TB. 

Meanwhile, in the U.S., TB headlines have been somewhat positive. In March, the CDC released all-time low numbers of TB cases in this country, just more than 11,000 during the last year, though the agency had hoped for a larger decline over previous years.

And last month, new research found that the standard nine-month treatment for latent TB – using daily doses of the antibiotic isoniazid – can be shortened to three months with a weekly duo of antibiotics.