Public health experts say tuberculosis cases are on the rise. An infectious disease characterized by chest pain and coughing up sputum and blood, active tuberculosis—only about ten percent of people infected with the tuberculosis bacterium develop active disease—involves growths called granulomas in the area where the upper lobe of the lung meets the lower lobe. There are estimated to be as many as two million tuberculosis deaths every year, and that number is increasing as more and more people get the disease.
Only active tuberculosis is contagious. People with an asymptomatic latent infection cannot spread the disease; however, in active disease, bacteria can be spread when the person coughs, sneezes, spits, or even laughs—anything that sprays sputum. The disease spreads most readily and is most common among people living in crowded and unsanitary conditions with poor access to quality medical care, and is thus associated with impoverished urban areas. Many people with tuberculosis are HIV-positive, both because the weakening of the immune system makes a latent tuberculosis infection more likely to go active and because the tuberculosis bacterium and HIV strengthen each other’s effects.
In addition, more and more, tuberculosis doesn’t respond to the standard treatments. The first-line medications are antibiotics that have been found to work in the past, though even when they are effective, treatment can take as long as nine months. However, as with any antibiotics, the bacteria have gradually developed resistance, and so the medications are becoming less effective. Doctors are increasingly reporting strains of tuberculosis that are resistant to the two most powerful and common medications, isoniazid and rifampin. These strains are called multidrug-resistant tuberculosis; when multidrug-resistant tuberculosis is also resistant to any of a family of broad-spectrum antibacterial drugs called quinolones and to one of the second-line antibiotics, it is known as extensively drug-resistant tuberculosis.
Tuberculosis strains that have developed drug resistance can be treated with medications to which the strains are not yet resistant. A newly developed class of antibiotics called spectinamides has shown promise for treating tuberculosis in laboratory testing. Spectinamides can be used in combination with other drugs, and it is hoped that this will help enhance it’s effectiveness. Other research is focused on avoiding the arms race entirely, and either using non-antibiotic treatments or eradicating the disease through prevention.