The Unwelcome Comeback Kid: Tuberculosis

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TUBERCULOSIS CASES in the United States, while rare, rose in 2015 for the first time in almost a quarter century — thwarting hope of eradicating one of the world’s deadliest diseases from this country.  Numbers rose in 29 states and D.C., with D.C. totals remaining in the lowest category (under 36 cases), while more highly populated Maryland and Virginia fall into the next highest: 90 to 600 cases.

“We are really at risk of a resurgence of TB … like we saw in the late 1980s and early 1990s, and potentially worse,” Robert Belknap, president of the National Tuberculosis Controllers Association told the Wall Street Journal.  Before that, the numbers of cases had been declining for several decades.

TB is an “airborne” disease that spreads when someone with active TB — versus latent TB, which is detectable by tests but causes no symptoms — coughs, sneezes, speaks or sings; but not from sharing toothbrushes, food or drink, or from kissing.  The risk of acquiring TB is related to the duration of exposure — usually longer than three months — and frequency; also to ventilation and degree of intimacy with the affected person.

Within a family, the spouse of the affected person is more likely than the children to catch it.  When a school bus driver in rural New York with active TB drove 258 students over several months, 83 children acquired TB with 51 getting the active disease.  In countries where TB is endemic, the risk of catching the disease increases only for “long-term travelers,” those remaining for more than three months.

In two cases of infected airplane passengers, the most famous occurred in 2007 when Atlanta lawyer Andrew Speaker took an overseas (long duration) flight without telling anyone he had active, drug-resistant TB — and was later sued by eight fellow passengers in a Canadian court.

Multi-drug resistant TB (MDR-TB), which is increasing around the world, is most often caused when people stop before finishing a full course of antibiotics, and the surviving bacteria that has become resistant to the drug keep multiplying. MDR-TB is the most dangerous form of TB, because it can require difficult, lengthy, expensive and not always successful treatment.

After the Speaker incident, in 2007, the CDC created a “Do Not Board” list (different from the TSA’s “No Fly” list), updated every two weeks, although in 2013 someone on this list managed to board a two-hour flight from Austin, Texas, to Phoenix — with the CDC notifying the TSA only after the plane took off.  The passenger was removed in Phoenix before continuing on to Los Angeles.  In both airplane incidents, the risk of contracting TB was considered so low that health officials recommended passengers not seek medical care, and no passenger contracted TB.

“To date no case of active TB has been identified as a result of exposure on a commercial aircraft,” according to the World Health Organization — though, “with TB increasing worldwide, there is a small but real risk of infection being transmitted during air flights.”  Infectious TB patients are not supposed to travel by air until they have completed at least two weeks of adequate treatment, and patients with resistant TB must be proven by laboratory tests to be non-infectious.

The WHO reported 1.5 million TB deaths world-wide in 2014, more than those killed by HIV/AIDS, as well as 9 million new TB cases.  In 2015, the U.S. had 9,563 cases.  Compared with the 2014 numbers, Texas had 1334 cases or 5% more; and South Carolina had 104 cases, a 32% increase.  Four states — Texas, California, Florida and New York — have one-third of the U.S. population but almost half of reported TB cases.

Of foreign-born TB patients in the U.S., half come from China, India, Mexico, the Philippines and Vietnam. TB screening is required for those seeking permanent residence here but not for foreign-born temporary workers.

A bacterial disease that primarily attacks the lungs, TB can cause a bad cough lasting three weeks or longer, chest pain and coughing up blood or sputum (mucus).  It can also infect the kidneys, spine and brain.  Because TB was on the wane for decades starting in the early 1970s, U.S. doctors sometimes mistake symptoms, such as bad coughing, for the flu or other conditions.

For most people who breathe in TB bacteria, the body’s immune system prevents the bacteria from multiplying, although these individuals may get sick years later if their immune systems become depressed.  The risk of developing active disease following infection is about 5 to 10% during a lifetime.  About 85% of people in the U.S. who develop active TB previously had latent infections.

As a result, stopping the spread of TB requires finding and treating the up to 13 million people in this country with the latent disease.  Outbreaks in the U.S. occur mostly in homeless shelters and prisons.

Because the drug regimen for treating TB can last up to nine months, many are reluctant to be tested.  After an outbreak in a rural Alabama town had gone on for more than two years, a CDC grant enabled local officials to offer residents money — $20 each for taking the TB test, for the visit to learn the results, for getting a chest X-ray, and then $100 for completing treatment.  Of 2,257 tested, four had active TB, and there were 170 latent cases.

In Africa, where about 1,500 people die of TB every day, a new method of detecting TB in sputum uses specially trained TB-sniffing rats — also trained to detect landmines.  While a human technician can examine 100 samples a day, a “HeroRAT” can examine that number in 20 minutes.  In use since the early 2000s, the rats have increased TB detection rates by 45%.  With one untreated active-TB patient thought to infect an average of a dozen people/year, the rats have dramatically reduced new cases of TB.

The long-standing goal for the U.S. is to reduce TB to one case or fewer/million people.  Meanwhile, when traveling by plane, you could don a mask if you notice coughing and sneezing two rows ahead or behind you — the generally considered area of risk. Or, a more discreet method, coat your nostrils with an antibiotic ointment (like Neosporin) before flying.

— Mary Carpenter
Mary Carpenter is the well-being editor of MyLittleBird. See more of her posts here.