Tuberculosis, the deadliest infectious disease, is still around - UCHealth Today
You may think COVID-19 is the world's deadliest infectious disease, but it's actually tuberculosis or TB, and cases of TB are on the rise this year after a 10-year decline.
While the total number of TB cases is relatively low in Colorado, confirmed infections have increased 59% since the fall of 2022, according to the Colorado Department of Public Health and Environment (CDPHE).
Here are some key facts about TB:
- TB kills more than 4,300 people each day around the globe.
- More than 10 million people around the world develop TB every year.
- In Colorado, cases were declining in recent years with 52 confirmed cases in 2020, 58 in 2021 and 57 in 2022, according to CDPHE.
- So far, in 2023, the number of confirmed TB cases has spiked to 80, and two people have died from TB in Colorado.
To learn more about TB, we consulted with Dr. Michelle Barron, UCHealth's senior medical director of infection prevention and control.
She said TB is challenging to diagnose because the most common symptom parallels that of many other illnesses: a stubborn cough. Especially during the fall and winter — when multiple respiratory illnesses like flu, RSV and COVID-19 are spreading — TB can fly under the radar.
"TB investigations require a lot of detective work," said Barron, who is also a professor at the University of Colorado School of Medicine on the Anschutz Medical Campus.
"People have this smoker's cough that can come from a lot of causes, and TB can get missed when people come to an ER or urgent care," Barron said.
What are some of the biggest challenges with TB?
Barron said TB is especially challenging to detect and cure for the following reasons:
- Many infected patients don't know they have it.
- Some people can have a highly infectious form of TB and become "super spreaders," who unknowingly give the disease to many others.
- Treatments for TB take a long time and can be difficult for some people to access.
What are the common symptoms for TB?
The most common symptoms of TB are a persistent cough, low-grade fevers and night sweats. Sometimes, people cough up blood and unintentionally lose weight. When experts view a patient's chest X-rays, they sometimes see a telltale sign of TB called a cavitary lesion.
"It looks like a walled-off area of your lungs," Barron said. "It's basically your immune system trying to protect your lungs."
Is TB curable?
"Yes. This is a curable disease. But it requires very long treatments," Barron said. "We give people antibiotics. There's a cocktail (of medications) that you have to take. You have to be treated for six months to a year."
Why is TB so deadly?
"TB can be deadly because many people don't have access to testing and treatment," Barron said.
Or, even if they can get medications, they might not finish taking them.
"Imagine having to take meds for nine months. That's hard. There also can be stigma with this disease. Some people who think they might have TB don't want to come forward," she said.
How does TB kill people?
"Without treatment, it destroys your lungs, and you waste away. It produces chemicals in your body that suppress your appetite. You stop eating, and your body stops functioning," Barron said.
TB is hard to detect.
"You're almost looking for needles in a haystack," Barron said.
She said it's vital for people to know that TB cases are on the rise even in places where few people usually see this infectious disease.
"We don't want to alarm anyone, but we want to raise awareness," Barron said.
How do public health experts respond when a person tests positive for TB?
The first step is to report the positive TB test to county and state public health authorities.
Then the detective work begins.
"It's really interesting," said Barron. "We do contact tracing and test everyone in the house."
If others who have been in tight quarters with the person who has TB also test positive, then medical experts know the person has a highly infectious case of TB, and they need to keep moving out in concentric circles, finding and testing others who may have been infected.
"We had a case in the spring where the person was so infectious that more than half of the family and coworkers also tested positive," Barron said. "Sometimes we can have super spreaders. Other times, a person won't transmit it to the people in their home. There's a lot of variability."
Finding the source of an outbreak can be challenging. Barron recalled a large TB outbreak years ago in Michigan. Public health experts searched and searched for the common vector among patients. It turned out to be an underground poker ring that was operating out of a junkyard.
Is there a vaccine to prevent TB?
Yes, there's a vaccine. But Barron said it does not work well.
Where is TB endemic around the world?
TB is endemic in most countries around the globe. It's most common in parts of Mexico, South America, Africa, East Asia, Russia and India, Barron said.
"When people think of deadly diseases, they think of COVID-19, malaria, HIV and diarrheal diseases," Barron said. "Many are surprised to find that TB kills the highest number of people in the world."
Barron said that doctors in the United States and Europe rarely see patients who test positive for TB. People in the U.S. who have a higher risk for getting TB are those who have lived or traveled to areas with higher rates of TB, people who live in crowded settings like jails or prisons and those who are experiencing homelessness.
Health care workers also can be exposed more frequently than others and therefore are tested frequently.
"Every health care worker gets tested when they start a job. If you work in the emergency department or you're a pulmonologist or respiratory therapist, and your potential exposure is higher, you get tested more often, Barron said.
How does TB spread?
"It's airborne, and it can be very infectious. What does that mean? If I cough, and I have tuberculosis, the microbacteria can hang out in the air. I might leave the room, but you could come in, and if you inhale the bacteria, it can get in your lungs. Your body can wall it off. It doesn't kill you. It just puts the TB bacteria in jail," Barron said.
"A person who has been exposed might have latent TB," Barron said.
That means the person might test positive, but would not have any active symptoms.
How do you get tested for TB?
Doctors use blood tests.
"They're not perfect, but they're pretty good," Barron said.
"When a person coughs, you get sputum, and we can detect the mycobacterium," she said.
The bacteria that causes TB are very distinctive.
"They look like little, pinkish red rods, so they're called red snappers. It doesn't always show up, but if the smear is positive, you can visualize them under a microscope," Barron said.
What happens if you've been exposed to TB, but you don't receive treatment?
"If a case of TB is not treated, the person can go on to develop a full-blown infection," Barron said.
How worried should the average person be about getting TB?
Most people in the U.S. don't need to worry about TB. But, a person's risk depends on their job, travel history and exposures to others who might have TB.
If a person was born elsewhere and lived in a place where TB was quite common, it's possible that they could have picked up TB in the past. If a person recently spent considerable time in an area where TB is endemic, they, too, could have been exposed.
"If you have a cough that won't go away, you might get diagnosed with asthma or COPD (chronic, obstructive pulmonary disease) but you could potentially also have TB," Barron said.
"Risk factors include exposure to someone who has tested positive, travel to a country where TB is endemic, experiencing homelessness and working in or spending time in a jail or prison," she said.
Why are cases increasing in Colorado?
Public health experts aren't sure. It's possible that, as with other illnesses, the pandemic caused fewer people to go to the doctor, and fewer people who had TB received a diagnosis.
Barron said people with TB also may not realize they have it since the primary symptom — a chronic cough — is so similar to other infectious diseases.
What should I do if I suspect I might have been exposed to TB?
Contact your doctor and get tested right away.
"If you were exposed and you have a latent case, we can give you medications for a couple of months that eradicate it. Then you don't have to worry about it coming back later in life," Barron said.
"Anybody who had a persistent cough that hasn't gone away for months and who has experienced weight loss or night sweats should be tested. It doesn't mean you'll have TB, but it's worth getting tested. "TB is rare, but it's progressive and treatable."
Barron said some people who have served in the military can be vulnerable. Regular testing is part of military service, but people can get TB once they are civilians.
"If people were stationed in places where TB is endemic, they can get it," Barron said. "If anyone is concerned, they should get a blood test."
So, I've heard of TB in the lungs. Can people also get a tuberculosis infection elsewhere in the body?
"Yes. We worry about the lungs, but you can have it anywhere. I had a patient who originally was from Africa and was immunosuppressed and kept having fevers," Barron said.
It turned out that the patient had a TB infection in the ankle. TB can also show up as a swollen lymph node, a mass in the belly or ovary and can manifest in the spine (which is also known as Pott's disease).
"It's the wildest disease I've ever seen," Barron said
I understand that TB played a big role in Colorado's history. Please tell me more about 'cure chasers' who came to Colorado and helped launch the state's tourism industry.
TB brought more people to Colorado than gold and silver mining.
Back in the 18th and 19th centuries, TB was known as "the great white plague" or "consumption" and was the leading cause of death in the United States and Europe at that time.
There were no known cures for the illness, but a diet of fresh air, rest and nutritious food were thought to be therapeutic.
Promoters in Colorado began to advertise the state's crisp, dry air. Colorado Springs sold itself as the "Switzerland of the Rockies," and the state soon filled up with wheezing TB patients.
In 1899, a special hospital opened to care for TB patients. It was then known as the National Jewish Hospital for the Treatment of Consumptives. Other sanatoriums and treatment centers soon followed.
Medical providers back then had no treatments that actually worked, but they tried all sorts of crazy notions, including having people live in close proximity to cows to inhale their supposedly curative fumes and drink fresh cow's milk in Denver's Historic Montclair neighborhood.
Living at high altitude was also thought to be healthy.
"TB grows well in high-oxygen concentration environments. So patients thought it would be helpful to come to Colorado and starve their lungs of oxygen," Barron said. "They had the idea that being in the mountains could cure you."
While the mountains did not cure TB, they did dazzle people. And the state's highly successful tourism industry was born.
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