The county’s 2011 tuberculosis rate of 7.6 cases per 100,000 people was more than double the national average of 3.6 cases per 100,000 people.
In 2011, 73 people were diagnosed with TB in Montgomery County, up from 69 in 2010.
The higher case rate is due in part to Montgomery County’s large immigrant and refugee population, said Dr. Ulder Tillman, Montgomery County Health Officer.
Tillman gave a presentation June 19 to the Montgomery County Council, updating members on the state of health issues in the county, and briefly addressed TB case rates in her report.
“The rate of TB goes up and down,” Tillman said. “This year isn’t an anomaly.”
Pulmonary tuberculosis — the official name of the airborne pathogen — is a contagious bacterial infection in the lungs that can spread to other parts of the body. Infants, the elderly and those with otherwise compromised immune systems are at the highest risk for tuberculosis, according to the U.S. National Library of Medicine.
Common symptoms of the disorder include fatigue, sweating and coughing up blood.
Because TB has a latent and active stage, people can be infected with TB for three to five years before they begin to feel sick, Tillman said.
“TB is a complicated disease,” said Anne Ginsberg, vice president of Scientific Affairs at Aeras, a nonprofit lab in Rockville that researches and produces TB vaccines.
Eight percent of the 2011 Montgomery cases were U.S.-born, according to Tillman’s report. Because people can be infected but not sick, they might come to the U.S. with the disease, or remain in close contact with an infected but not sick family member.
Part of the difficulty of treating TB is that it’s not easy to diagnose. The TB vaccine that’s been in use since the 1920s frequently gives false positive diagnoses. For this reason, there’s no TB vaccine given in the U.S.
The greatest struggle in treating the disease, especially in its latent form, is the length of drug regimens patients must follow. It can take six to 12 months to treat TB, and the drugs have side effects, said Aeras research specialist Victor Prikhodko.
“It’s very hard for individuals with latent TB to understand why they’re taking meds,” Tillman said.
When someone doesn’t complete his or her drug regimen, their TB becomes much more drug-resistant. The Food and Drug Administration recently approved some shorter drug regimens, Tillman said.
Montgomery County also is piloting a blood test to diagnose TB. Twenty percent of those who receive a positive diagnosis of TB with the current skin test actually have the disease, Tillman said.
“This is a much more sensitive test,” she said.
About 150 years ago, TB was the number one cause of death in the U.S., Prikhodko said. But living conditions and health care have drastically improved in the U.S. since then, leading to a significantly lower case rate in the U.S. than in many other countries. TB research in the U.S. also has received increasing funding in the last 10 years.
“Tuberculosis is a disease of poverty," said Aeras Media and Communications Manager Jamie Rosen.
Though the U.S. has very low rates of TB, the disease’s prevalence is increasing worldwide, as new drug-resistant strains of the disease become more common.
Aeras is a nonprofit primarily because TB vaccine research isn’t particularly lucrative, Rosen said. Developing countries are the primary consumers of TB vaccines, and suppliers of the vaccines charge about $5 for their product or risk it being cost-prohibitive, Prikhodko said.
Considering the enormous cost of researching and producing vaccines for TB, pharmaceutical companies have little motivation to focus on the disease.
"It's very cost-effective in the long run, but the investment is huge up front," Rosen said.
Ginsberg stressed the importance of learning more about TB.
“There's a saying: 'TB anywhere is TB everywhere.' It's airborne, so it knows no boundaries," she said. “What we really need are better tools — better vaccines and better treatments.”