The World Health Organization has declared tuberculosis a global health emergency.
There is already a TB vaccine given to infants in countries other than the United States but it was developed more than sixty years ago. That vaccine protects babies from the worst forms of TB but it does not protect adolescents and adults from a type of tuberculosis which accounts for most cases of the disease.
Tuberculosis bacteria, shown here under a high-powered microscope, become active, and begin to multiply, if the immune system can't stop them from growing. The bacteria attack the body and destroy tissue.
The Illinois Department of Public Health says the state experienced a record low number of new tuberculosis cases last year, but the news isn't all good.
Health officials say Illinois still ranks fifth in the nation when it comes to the number of TB cases. And Health Department Acting Director Arthur Kohrman says many of the new cases are the drug-resistant type, which are harder to overcome.
Officials say 359 cases of active TB were reported in Illinois in 2011. That's a decrease from 372 cases reported in 2010.