Tuberculosis is the deadliest infectious disease globally. While it’s more common in developing countries, the U.S. has recently experienced outbreaks in Kansas and North Carolina.

TB is often called the “silent killer” because it can go unnoticed—and show no symptoms—in its inactive or latent state. The CDC estimates that up to 13 million people live with inactive TB in the U.S. 

The bacteria that cause TB can hide “in a very small area in the lungs or a lymph node, stay there, and in a sleepy state, remain [there] for weeks to several years before emerging and causing disease,” says Dr. Patricio Escalante, a critical care medicine specialist and pulmonologist at Mayo Clinic. Once it reappears, it can cause symptoms and illness, and transmit to others by air, he adds. 

Because people can have TB without experiencing symptoms, controlling the disease’s spread requires investment in public health systems to detect and treat it, explains Dr. Peter Chin-Hong, a professor of medicine and infectious disease physician with University of California, San Francisco Health. 

Read on to learn more about TB and why we’re seeing more outbreaks in the U.S. 

What is tuberculosis? 

TB is an infection caused by bacteria called Mycobacterium tuberculosis. It usually affects the lungs, but it can also affect other organs, including the brain, larynx (voice box), kidneys, spine, and lymph nodes. 

TB is spread through the air when someone with active TB disease coughs, talks, or sings. 

There are two types of TB: 

• Inactive TB: Also known as latent TB, this form occurs when a person has TB germs in their body but no symptoms. They don’t feel sick and can’t spread it to other people. According to the Centers for Disease Control and Prevention, one in 10 people with inactive TB who don’t get treatment will get sick with active TB. 
• Active TB: This form occurs when TB germs multiply in your body, creating symptoms.  The bacteria can multiply and turn into active TB when the immune system is under stress, like during an illness. With active TB disease, you can spread the disease to others. Without treatment, active TB can be deadly. 

Both inactive and active TB can be treated with antibiotics. 

What are the symptoms of active TB disease?

Symptoms for active TB disease in the lungs include: 

• Chest pain
• A cough that lasts three or more weeks 
• Weakness or fatigue 
• Fever
• Weight loss
• Night sweats
• Coughing up blood or phlegm
• Loss of appetite

Active TB disease outside of the lungs can cause other symptoms. For instance, TB disease in the lymph nodes can cause red or purple swelling under the skin.

Why are we seeing more cases of TB in the U.S.? 

Chin-Hong explains that public health efforts to prevent TB have been underfunded for years and continue to be defunded. “Public health is really the backbone of how you control TB, because many people don’t know they have TB,” he adds. 

“People have to go out and trace [it], see that the people who have TB take the medicines, and check the people who they’ve been in contact with to see if they [got] infected, even if they have no symptoms.” 

When public health efforts are successful, there’s “a tendency to decrease investments on those public health organizations and programs because they are no longer seeing a lot of patients,” which can eventually cause outbreaks, adds Escalante. 

Another possible reason for why we’re seeing outbreaks in the U.S. is the COVID-19 pandemic, says Chin-Hong. People may have delayed medical care for possible TB, so they could be spreading it to others in their communities.

Who’s most at risk for tuberculosis?

While anyone can get TB, certain people are at higher risk, including: 

• People who are immunocompromised (because of conditions like HIV or cancer)
• People who live in group settings like prisons, jails, or homeless shelters. 
• People who travel frequently or were born in places where TB is more common than in the U.S., including some countries in Asia, Africa, and Latin America.
• People who recently interacted with someone with active TB.

Is there a vaccine for TB? 

Yes, there is a vaccine for TB called Bacille Calmette-Guérin. However, because there are usually not too many cases of TB in the U.S., the vaccine is not routinely administered here. The BCG vaccine is given to infants and young children in countries where TB is common. 

How is TB treated?

Both inactive and active TB can be treated with antibiotics. 

“It takes several antibiotics to treat active TB effectively” and to prevent the bacteria from mutating while on treatment, adds Escalante. Active TB requires a prolonged antibiotics treatment, which usually takes 6 months and can sometimes take up to nine months.

“We have to treat [TB patients] very carefully, with antibiotics delivered under close direct observation, because if the patient starts feeling well after a few weeks of treatment, they tend to stop the antibiotics, and that’s when the bacteria becomes resistant, if treatments are not appropriately completed,” he explains. “And, therefore, they need to be supervised to make sure they continue and complete treatment.”

How do I know if I have TB?

If you’ve been exposed to someone with TB or you think you may have it, you should contact your health care provider or state or local health department to get tested with a TB blood test or TB skin test. 

How can I protect myself from TB? 

Chin-Hong says it’s important to watch out for symptoms like fever, night sweats, and weight loss. In the U.S., he adds, “the only way you can really prevent TB as somebody who doesn’t have it or is not exposed is to continue to think of symptoms that you might have and [seek] medical attention.” 

Additionally, if you work or live in a high-risk environment where you might be exposed to TB—such as a nursing home, hospital, homeless shelter, or prison—you should get screened for TB. Chin-Hong adds that most employers in those settings already offer screening to employees. 

Other things you can do include:

• Cover your mouth when coughing or sneezing.
• If you have an inactive or latent TB infection, follow your treatment plan and doctor’s recommendations.
• Avoid close contact with people with active TB.
• Wash your hands often.
• If you’re traveling to an area where TB is more common, talk to your doctor about how you can protect yourself.

Find out more about TB here.

This article first appeared on Public Good News and is republished here under a Creative Commons Attribution-NoDerivatives 4.0 International License.