News / Health

Tuberculosis Evades Detection by Hiding in Bone Marrow

A man (L) is x-rayed to detect tuberculosis during a medical examination, Jan. 29, 2013.
A man (L) is x-rayed to detect tuberculosis during a medical examination, Jan. 29, 2013.
Jessica Berman
It's been a long-standing medical mystery: how tuberculosis (TB), a potentially fatal respiratory infection, can spring to life in a patient after lying dormant for many years.  Scientists have discovered that the bacterium which causes TB hides in cells in the bone marrow, making it hard to treat with antibiotics. 

Unlike other bacterial infections, tuberculosis is notoriously difficult to treat.  Despite the availability of antibiotics for 50 years, treatment for TB involves a rigorous multi-drug regimen of up to six months' duration.  

That’s led researchers to conclude that Mycobacterium tuberculosis, the pathogen that causes the deadly lung ailment, is lurking in tissue, where neither antibiotics nor the body’s protective immune system can kill it.

One potential hiding place is bone marrow, a spongy tissue inside bones containing stem cells responsible for manufacturing a variety of blood cells.  Marrow has mechanisms for keeping out foreign substances, including antibiotics.

Researcher Antonio Campos-Neto, director of the Forsyth Center for Global Infectious Diseases in Cambridge, Massachusetts, and his colleagues at Stanford University School of Medicine in California conducted test tube, or in vitro, experiments to see what happened when bone marrow cells and the TB bacterium were mixed together.

“And sure enough, you know, in vitro experiments show the microorganism could be internalized very easily inside the stem cells,” said Campos-Neto.

That finding, according to Campos-Neto, may explain why the lung disease exists in two forms -- a latent phase in which individuals can be infected for decades without symptoms, and an active phase, characterized by extreme illness and, without treatment, death.

And it may have implications for the treatment of TB, explaining why antibiotics do not always rid patients of the disease.

“Many, many [TB] patients who have been successfully treated, later on in their life they can come back with tuberculosis again.  And nobody ever understood why this was so difficult, and now we start to have this firsthand [knowledge] that it’s because the TB is hiding itself in some protective niche that drugs cannot reach,” explained Campos-Neto.

An estimated 2.2 billion people around the world live symptom-free with latent tuberculosis.  Once active, the illness kills upwards of 1.7 million people every year.  

Campos-Neto says researchers need to learn more about this complex disease so new diagnostic tests and effective treatments can be developed.

An article by Antonio Campos-Neto and colleagues on latent tuberculosis is published in the journal Science Translational Medicine.

You May Like

Video Five Patients Given Experimental Ebola Drug Said To Be Improving

Experimental drugs have been tried on six people: three Westerners and now, three African pyhysicians More

Video In Ukraine, Fear and Distrust Remain Where Fighting has Stopped

As Ukrainian military reclaims control of eastern cities residents rebuild their lives, but many say everyone is being treated with suspicion More

Video In Rural Kenya, Pressure Builds Against Female Circumcision

Girls learn to object; FGM practitioners face penalties from jail sentences to stiff fines More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Five Patients Given Experimental Ebola Drug Said to Be Improvingi
X
Carol Pearson
August 19, 2014 11:43 PM
The World Health Organization has approved the use of experimental treatments for Ebola patients in West Africa. The Ebola outbreak there is unprecedented, the disease deadly. The number of people who have died from Ebola has surpassed 1,200. VOA's Carol Pearson reports on the ethical considerations of allowing experimental drugs to be used.
Video

Video Five Patients Given Experimental Ebola Drug Said to Be Improving

The World Health Organization has approved the use of experimental treatments for Ebola patients in West Africa. The Ebola outbreak there is unprecedented, the disease deadly. The number of people who have died from Ebola has surpassed 1,200. VOA's Carol Pearson reports on the ethical considerations of allowing experimental drugs to be used.
Video

Video In Ukraine, Fear and Distrust Remain Where Fighting has Stopped

As the Ukrainian military reclaims control of eastern cities from pro-Russian separatists, residents are getting a chance to rebuild their lives. VOA's Gabe Joselow reports from the town of Kramatorsk in Donetsk province, where a sense of fear is still in the air, and distrust of the government in Kyiv still runs deep.
Video

Video China Targets Overseas Assets of Corrupt Officials

As China presses forward with its anti-graft effort, authorities are targeting corrupt officials who have sent family members and assets overseas. The efforts have stirred up a debate at home on exactly how many officials take that route and how likely it is they will be caught. Rebecca Valli has this report.
Video

Video Leading The Fight Against Islamic State, Kurds Question Iraqi Future

Western countries including the United States have begun arming the Kurdish Peshmerga forces in northern Iraq to aid their battle against extremist Sunni militants from the Islamic State. But there are concerns that a heavily-armed Kurdistan Regional Government, or KRG, might seek to declare independence and cause the break-up of the Iraqi state. As Henry Ridgwell reports from London, the KRG says it will only seek greater autonomy from Baghdad.
Video

Video In Rural Kenya, Pressure Builds Against Female Circumcision

In some Kenyan communities, female genital mutilation remains a rite of passage. But activists are pushing back, with education for girls and with threats of punishment those who perform the circumcision. Mohammed Yusuf looks at the practice in the rural eastern community of Tharaka-Nithi.
Video

Video For Obama, Racial Violence is Personal Issue

The racial violence in the St. Louis suburb of Ferguson is presenting U.S. President Barack Obama with an issue to which he has a deep personal connection. To many Americans, Obama's election as America's first black president marked a turning point in race relations in the United States, and Obama has made ending the violence a policy priority. On Monday he issued a new call for calm and understanding. Luis Ramirez reports from the White House.
Video

Video Clinton-Obama Relationship Could Impact 2016 Election

President Barack Obama and former Secretary of State Hillary Clinton have a long and complicated relationship. That relationship took another turn recently when Clinton criticized the president’s foreign policy. VOA National Correspondent Jim Malone reports there is renewed attention on the Clinton-Obama relationship as Hillary Clinton considers running for
Video

Video Iran Looks to Maintain Influence in Baghdad With New Shia PM

Washington and Tehran share the goal of stopping Syrian-based militants in Iraq. But experts say it's Iran, not the United States, that will most influence how the new government in Baghdad approaches internal reforms and the war in Syria. VOA State Department Correspondent Scott Stearns has the story.

AppleAndroid