The bubonic plague, polio, and tuberculosis: These are all diseases we don't have to worry about anymore, right? Not so fast! According to ABC News, a town in China was recently quarantined for 10 days after three people died from a type of bubonic plague. Dr. D. A. Henderson is the author of Smallpox: the Death of a Disease. He actually headed the World Health Organization's efforts to eradicate smallpox, which was wiped out in 1977. He says as far as other infectious diseases go - they're still out there. For example:* Polio. Like smallpox, polio has a vaccine, which means it can be eradicated someday. It can cause paralysis in the legs and even the lungs. That's why people were put in "iron lungs" during polio epidemics decades ago - to make sure they didn't stop breathing. Since polio has subtle symptoms - like achy muscles and a fever - it's hard to diagnose. Your best bet - get vaccinated and make sure your kids do.* Then there's the bubonic plague. While the pneumonic form recently struck China, the type that infects the lungs - bubonic plague, which infects the lymph nodes - is still carried by rats and fleas in the United States. The disease is caused by bacteria, and is very treatable with antibiotics. However, without treatment, Bubonic plague kills about half of infected patients within a week. The primary symptom is painful, swollen lymph glands. There are only about a dozen cases reported in the U.S. each year. * There's tuberculosis, an infectious disease that attacks the lungs. According to Dr. Douglas Hornick, a professor of internal medicine at the University of Iowa, most tuberculosis can be treated with standard drugs that are widely available. It has become more of a threat than it once was, because new forms of TB have developed that are resistant to these drugs. According to some estimates, up to a third of the world's population may be infected. However, most of these people will only carry the disease - they won't develop it. Still, there is a vaccine, and all babies should be inoculated. Vanderbilt University Medical Center recently created a new vaccine that will be more effective.