Tuberculosis or TBI. Introduction Print sectionTuberculosis (TB), a chronic or acute bacterial infection that primarily attacks the lungs, but can also affect the kidneys, bones, lymph nodes and brain. The disease is caused by Mycobacterium tuberculosis, a rod-shaped bacteria. Symptoms of TB include cough, chest pain, shortness of breath, loss of appetite, weight loss, fever, chills and fatigue. Children and people with weakened immune systems are most susceptible to tuberculosis. Half of all untreated TB cases are fatal. In 1993, the World Health Organization (WHO) declared tuberculosis a global emergency, the first such designation ever made by that organization. According to the WHO, one person is infected with tuberculosis every second and every year, 8 million people contract the disease. Tuberculosis causes 2 million deaths per year. The WHO predicts that between 2000 and 2020, almost a billion people will be infected with tuberculosis bacteria and 35 million people will die.II. Transmission and infection Print section Tuberculosis is spread from person to person, usually through inhalation of air droplets carrying bacteria. When a person with TB coughs, sneezes, or speaks, small particles carrying two to three bacteria surrounded by a layer of moisture are released into the air. When another person inhales these particles, the bacteria can lodge in their lungs and multiply. A less common route of transmission is through the skin. Pathologists and laboratory technicians who handle tuberculosis samples can contract the disease through skin injuries. Tuberculosis has also been reported in people with tattoos and in people circumcised with unsterilized instruments. A person can be infected with TB bacteria without developing the disease. Their immune system can completely destroy the bacteria. In fact, only 5 to 10 percent of people infected with TB actually get sick. If a person contracts the infection, the disease can develop in two stages: primary and secondary.A. Primary Tuberculosis Print SectionIn primary tuberculosis, a person has been infected with tuberculosis bacteria, but is often unaware of it because this stage of the disease does not produce visible symptoms. Primary tuberculosis is not contagious at this early stage. Macrophages, immune cells that detect and destroy foreign bodies, ingest tuberculosis bacteria and transport the...... middle of paper ......esizing additional vaccines. Incidence of tuberculosis, United States Many researchers attribute the sharp increase in the early 1990s in the spread of acquired immunodeficiency syndrome (AIDS). People with AIDS have weakened immune systems and are particularly susceptible to contagious diseases such as tuberculosis. Poorly supervised treatment of tuberculosis has also led to an increase in drug-resistant strains of the bacteria that causes tuberculosis, thereby promoting the spread of the disease. Renewed emphasis on control and prevention has brought the incidence of tuberculosis to record levels. Tuberculosis in the Lungs Calcification of lung tissue, resulting from pulmonary tuberculosis, appears as yellow spots in the chest region of this human x-ray. When airborne mucus contaminated with the bacillus Mycobacterium tuberculosis is inhaled, nodular lesions, called tubercles, can form in the airways. 1882. 1905.