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Health

Tuberculosis remains a threat despite city's eradication efforts

Baltimore once suffered the highest rate of tuberculosis infection of any large city in the country — 75 cases per 100,000 people in 1966.

Since the 1980s, however, the city has served as a model for tuberculosis control and prevention, helping to reduce rates of the potentially deadly lung infection to historic lows. In 2013, there were just 24 cases in the city, a rate of 4 per 100,000 people.

That success, though, has meant that funding for the city's tuberculosis clinic has been slashed to about half of what it was a decade ago even as TB remains a stubbornly persistent health threat. Experts say these reductions could undermine the city's efforts to prevent future tuberculosis outbreaks amid concerns of drug-resistant forms of the disease among immigrant populations.

"The numbers are much smaller now, but they've sort of hit a plateau," said Richard Chaisson, director of the Johns Hopkins Center for Tuberculosis Research. "What's making TB control and elimination here in Baltimore more difficult is that we have a growing number of immigrants here that are from places where TB is common."

Though the mention of TB often invokes the Victorian era — when it was sometimes called "consumption" — the disease remains a modern foe. An estimated one-third of the world's population is infected with latent TB.

A contagious bacterial infection, TB involves the lungs and can spread to other organs, such as the bones and kidneys. It is treatable and curable, but involves a standard six-month regimen of treatment with antibiotics under the care of a nurse caseworker. Untreated, it is often fatal.

Even though tuberculosis may be contained in Baltimore, a new case could be carried from anywhere. Though overall TB rates have declined, most cases increasingly come from foreign-born residents. A Centers for Disease Control and Prevention report released in October said 63 percent of TB cases in the United States occurred among foreign-born people in 2012. In 1993, foreign-born cases accounted for less than 30 percent of TB cases.

The biggest barrier to preventing an outbreak in foreign-born populations is identifying the people most at risk for having TB and getting them screened, said Chaisson, who also served as the medical director at the Eastern Chest Clinic — the city's public TB clinic —from 1991 to 1998.

"That's just not happening very much, in large part because the people themselves are not aware of the need, and there aren't really good outreach services available to these people," Chaisson said. While immigrants who come to the United States legally are typically given a TB test, it's those coming here under the radar that don't get screened, he said.

This presents a potential public health problem because in other parts of the world, drug-resistant TB is increasing. Drug-resistant TB is far more complicated and expensive to treat.

"Over the last few years we've seen decreased cases of TB, but the percentage of those cases that end up being drug-resistant is now on the rise. We are alarmed about that," said Donna Wegener, executive director of the National Tuberculosis Controllers Association.

Some of the toughest TB cases to treat are multidrug-resistant TB, meaning they're invulnerable to the most effective TB drugs, also called first-line drugs. Then there's extensively drug-resistant TB, which is even more rare and difficult to treat because it is resistant to both first-line drugs as well as at least one of three injectable second-line drugs. The average cost to treat one multidrug-resistant TB patient is about $100,000 to $150,000. An extensively drug-resistant TB case costs about twice that.

While drug-resistant tuberculosis is rising around the globe, Dr. Patrick Chaulk, acting deputy commissioner of the Baltimore Health Department's division of disease control, said it's not yet a problem in Baltimore.

In the past 10 years, Baltimore has seen only four cases of drug-resistant tuberculosis, one of which was multi-drug resistant.

"What we're concerned about is extensively drug-resistant tuberculosis, which is virtually impossible to treat," Chaulk said. But it's very unlikely that an extensively drug-resistant case would be homegrown, Chaulk said.

Baltimore's Eastern Chest Clinic is one of several big-city TB programs that are directly funded by the CDC. Given the nation's steady decline in TB cases, the CDC has been reining in that funding since 2004, when Baltimore's clinic received $927,078 — about 69 percent of its total funding — from the federal government to run its operations, according to city documents obtained by a public information request. This year, funding from the CDC has dropped to $296,773 — or about 55 percent of its total budget.

Chaulk described it as a classic conundrum in public health funding: If disease rates drop, then funding for prevention and control efforts likely follows suit.

The rest of the clinic's funding comes from a combination of state and local money. Still, the clinic's total budget has dropped to $544,328 this year from $1.34 million 10 years ago.

"We've lost about half of our budget, but that's reflective of the fact that we're dropping in cases," said Maria Martins-Evora, acting bureau administration of clinical services at the Baltimore City Health Department. Martins-Evora is the program director of Baltimore's STD, HIV and TB clinics.

Baltimore's success in bringing down TB rates can be credited to an outreach tactic called directly observed therapy, first introduced in 1978. With such therapy, a nurse caseworker visits patients with active TB and watches them take their medications on a daily basis. Rolled out in Baltimore and replicated in other cities afterward, the directly observed therapy model increased patient compliance and medication adherence, leading to better TB control.

Eastern Chest Clinic's nursing staff still conducts such observation, but faced with fewer resources, its nurses aren't able to do as many contact investigations as they once did. Contact investigations are visits to places like schools or homeless shelters to test people who have potentially been exposed to TB. Without these, some cases could be going undiagnosed.

Though Chaulk said the Eastern Chest Clinic is able to manage its caseload with its available resources, he's concerned that the program will eventually reach a tipping point.

Increased CDC funding and a boost in medical research to develop better, cheaper drugs to treat TB, as well as new diagnostic tools to identify the disease, are essential, Wegener said. Until then, she said, public TB clinics such as Baltimore's should work with their local private health care providers on outreach and education efforts to keep TB rates in check.

"We're always worried that we're going to get cut more," Chaulk said.

Copyright © 2014, The Baltimore Sun
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