(CNN) -- Here's a look at what you need to know about Tuberculosis (also known as TB), an infection, caused by a bacterium called Mycobacterium tuberculosis, that mainly affects the lungs. It can also infect other parts of the body including the kidneys, spine and brain.
About TB: Two types of TB exist - Latent TB infection (non-contagious) and TB disease (contagious).
Latent TB infection: - A person infected with latent TB shows no sign of symptoms and may not feel sick. - A skin or blood test will indicate if a person has been infected with the bacteria. - It is not possible to spread the TB bacteria from the infected person to others. - TB bacteria can remain dormant and die with proper treatment, or become active and cause the active TB disease. - Treatment is required to ensure the infected person does not develop active TB disease. - According to the WHO, 5 to 10% of world's population infected with latent TB infection will develop active TB disease.
TB disease: - A person infected with TB disease shows signs of symptoms and usually feels ill. - Symptoms include coughing up blood, fever, chills, night sweats, shortness of breath, chest pains, loss of appetite, weight loss, and fatigue. - It is possible to spread the TB bacteria from the infected person to others. - A skin or blood test will indicate if a person has been infected with the bacteria. - Treatment with antibiotics for 4-9 months is required to treat active TB disease. - Persons with a weak immune system, such as those with HIV or diabetes, are more prone to catching the TB disease. - TB is a leading cause of death for people infected with HIV.
Facts: TB spreads through the air when a person with an active TB infection coughs, sneezes, speaks or sings. Germs can stay in the air for hours.
It cannot be spread through handshakes, sharing food or drink, or kissing.
According to the CDC, approximately one-third of the world's six billion people are infected with TB.
The World Health Organization reports that there were 8.7 million new cases of TB in 2011.
According to the CDC, 9,951 TB cases were reported in the United States in 2012. That is equivalent to 3.2 people out of every 100,000 becoming sick. It is the 20th consecutive year of declining rates and is the lowest rate since reporting began in 1953.
By comparison, in 1953, there were 84,304 cases of TB reported, for a rate of 52.6 people out of every 100,000.
Cases in California, Texas, New York, and Florida make up about half of all TB cases in the United States.
Timeline: 1768 - The first edition of "Encyclopædia Britannica" reports of an illness that consumes the lungs.
1865 - French army doctor Jean Antoine Villemin proves the illness can transmit from human to animal or from animal to animal.
1882 - German physician Robert Koch identifies the bacterial strain as Mycobacterium tuberculosis.
1900s - Tuberculosis causes one-quarter of all deaths in Europe throughout the 19th century and early 20th century. Famous people who die from tuberculosis include: John Keats, Frédéric Chopin, Charlotte, Emily and Anne Bronte, Anton Chekhov and Franz Kafka.
1921 - French bacteriologists Albert Calmette and Camille Guérin use a live but controlled bacteria strain to create a vaccine named bacille Calmette-Guerin (BCG).
1930 - The BCG vaccine is widely used to prevent TB after being used to vaccinate children in Europe and South America.
1943-1944 - Microbiologist Selman A. Waksman and his associates at Rutgers University discover an antimicrobial agent, streptomycin.
1944-1945 - Veterinarian W.H. Feldman and physician H.C. Hinshaw experiment with Waksman's streptomycin and discover its effect on inhibiting tuberculosis in animals and people. This prompts a wide use of streptomycin in combination with other drugs to attack resistant bacteria.
1952 - Isoniazid is released after successful tests in the United States and Germany. The antibiotic is used in combination with other drugs to treat TB, which are released the following years.
March 24, 1982 - The first World TB Day is sponsored by the World Health Organization and the International Union Against Tuberculosis. The event is created to recognized individuals who have found ways to raise awareness about TB.
Mid-1980s - Tuberculosis makes a sudden resurgence, resulting in deaths in developed countries. Scientists attribute this to inadequate health care systems, immigration from countries where tuberculosis is prevalent, and the spread of HIV.
1991-1992 - The Centers for Disease Control reports a rise in TB cases in the United States.
1993 - The World Health Organization declares tuberculosis a global emergency.
1993 - The number of reported cases of TB starts to decrease in the United States. The CDC is still investigating the reasons behind the decrease.
1995 - The World Health Organization launches Directly Observed Therapy Short-Course (DOTS). The program requires doctors to ensure TB patients take their medications while also monitoring their treatment.
Early 2000s - The number of reported tuberculosis cases drops in Africa due to programs launched by the World Health Organization.
May 2007 - American Andrew Speaker causes an international health scare after coming into contact with various passengers on international flights. Doctors later confirm Speaker's test results for a drug-resistant form of tuberculosis (XDR-TB) are negative.
2008 - The World Health Organization reports the highest rates of multidrug resistant TB (MDR-TB) worldwide. This type of TB develops after patients fail to complete their treatment and the most powerful antibiotics are not effective.
2009 - Foreign-born persons reported higher rates of TB cases compared to those born in the United States.
December 8, 2010 - The World Health Organization endorses a new test that diagnoses tuberculosis in 100 minutes instead of three months.
May 26, 2011 - Nearly 700 patients and 100 employees are exposed to tuberculosis at Emory University Hospital in Atlanta after interacting with a hospital employee carrying the disease.