Tuberculosis is a tough bacteria to eradicate, as public health workers in the post-St. Helens era quickly learned when it was raging through much of the United States.
But what could stand in the way of rolling back tuberculosis is one thing: the hardy tuberculosis bacterium itself.
The germ has long coexisted with the human race, and it remains largely resilient in the face of virtually all modern attempts to kill it.
Stabilizing the condition — shrinking, bringing it under control — will take multiple and costly strategies over decades. That is why so much investment is lavished on health prevention. But we know much more about TB than we do about almost any other health problem. We have a better sense of its genetic makeup, its response to treatment and how microbes spread.
Here is a look at our knowledge.
Who is at risk?
In the United States, three of the top 12 infectious disease threats are tuberculosis infections.
Outbreaks among U.S. Latinos, African-Americans and Asians are frequent.
In India, Tanzania and other parts of Asia, TB kills a higher share of people, including two-thirds of people with HIV, which leads to a far greater leap in mortality rate.
And for countries where TB has long been endemic, the disease is now infecting both men and women.
Is it easy to avoid?
It’s complicated. Tuberculosis infections may occur not just in people living near people who have the bacteria, but in people who are exposed to or living in those same communities.
Does it survive outside the body?
TB is in fact almost impossible to kill once it has spread to the lungs or elsewhere, regardless of a person’s medical condition. Because tuberculosis acquires resistance to the medical agents that are used to treat it, tuberculosis is remarkably resilient in the human body, continuing to fester wherever it is, including lungs and other body sites that doctors might not have come to expect.
This makes TB a tricky patient. Effective antiretroviral therapy has enormous success rates, and all patients can receive it for years, no matter how tough their initial infection was.
Many people start seeing promising outcomes after about 10 years of therapy. But after 40 years or more, the vast majority of tuberculosis patients who are fully suppressed with antiretroviral therapy are still infected.
Colder temperatures might help.