Tuberculosis is a serious infection caused most commonly by the Mycobacterium tuberculosis bacterium or one of three other organisms of the Mycobacterium genus. Tuberculosis primarily affects the lungs, but the infection can attack any part of the body. If left untreated, tuberculosis can cause lung damage, meningitis, and even death; the World Health Organization reported 1.3 million deaths due to tuberculosis in 2008. Those at highest risk for tuberculosis include those with weakened immune systems and those in areas of the world with poor nutrition and poor access to health care. Most...

Hepatitis means an inflammation of the liver, but it also refers to a group of viral infections that affect the liver. There are several types of viral hepatitis, but the most common are A, B, and C. Viral hepatitis is spread through contact with infected blood, bodily fluids, or feces, though it may also result from alcohol and drug use or from other diseases. Acute hepatitis refers to the initial infection and can be mild or severe; chronic hepatitis refers to a serious condition in which the infection lasts six months or longer. Currently, vaccines are available for the prevention of...