TUBERCULOSIS FACTS

Prevalence of Tuberculosis

One third of the world's population is infected with Tuberculosis. It kills an estimated 1.5 to 2 million people each year. Tuberculosis is one of the world's leading killers; on average it kills one person every 15 seconds. About 95% of people infected with tuberculosis live in developing countries. In low-income countries tuberculosis is one of the world's top ten causes of death. The low and middle-income countries account for more than 90% of tuberculosis cases and deaths. Tuberculosis is one of the leading causes of death among women in developing countries. More than 900 million women are infected with tuberculosis worldwide.

The World Health Organization estimates that 8.8 million people develop active Tuberculosis disease every year.  Active Tuberculosis had a case fatality of about 50% before the dawn of antibiotics.

Impact

Tuberculosis has significant impact on economy and development. More than 75% of tuberculosis-related disease and death occurs in people between the ages of 15 and 54–the most economically active segment of the population. Tuberculosis interfere individual’s ability to work for months. It is estimated that the lost of earnings totals up to 30% of annual household income, while some families may lose 100% of their income. The impact of tuberculosis further aggravates poverty.

The World Bank and WHO has reported tuberculosis as a leading cause of "healthy years lost" among women of reproductive age. Women bear a disproportionate burden of poverty, ill-health, malnutrition, and diseases worldwide. Tuberculosis causes more deaths among women than all causes of maternal mortality combined. Women of reproductive age, once infected with tuberculosis are more susceptible to develop tuberculosis than their male counterpart. Further women of this age group are at greater risk of infection with both tuberculosis and HIV.

Causes

Tuberculosis is a disease caused by the bacterium Mycobacterium Tuberculosis. Poverty is the underlying cause of (tuberculosis) infection in rural areas. Overcrowded housing, lack of proper food, proper sanitation contributes to development of tuberculosis. About 70% to 80% patients have tuberculosis of the lungs. Although tuberculosis can infect any part of the body, it usually infects the lungs. The tuberculosis of the lungs is known as pulmonary tuberculosis, it can be either latent tuberculosis infection (aka/inactive) or active tuberculosis disease (infectious).

The individual with latent tuberculosis infection have no symptoms of tuberculosis, they don’t feel sick and are non-contagious. However, they usually react positively to a tuberculin skin test (TST) even though chest x-ray and sputum tests are normal. While individual with active pulmonary tuberculosis have symptoms of tuberculosis infection. They are contagious and usually react positively to a tuberculin skin test, may have abnormal chest x-ray and a positive sputum smear or tissue culture.

Types

Tuberculosis that occurs outside the lungs is known as extra-pulmonary tuberculosis. Besides the lungs, other parts of the body that can be commonly affected are the lymph nodes, brain, kidneys, bone. Tuberculosis can be latent in these sites as well. A person can concurrently have pulmonary and extra-pulmonary tuberculosis. Extra-pulmonary tuberculosis can be seen more often in immune-suppressed people and in children.

Tuberculosis is not spread by insects, blood supplies, water, dishes, or clothing, or by someone with latent tuberculosis. In a healthy person, the two major transmission factors for tuberculosis are: concentration of infected respiratory droplets in the air and, the period of time exposed to contaminated air.  Each person with active pulmonary tuberculosis can infect 10 to 15 people per year. Only patients having active tuberculosis of the lungs (pulmonary tuberculosis) or throat (laryngeal tuberculosis) can infect others. Anyone can become infected with tubercular bacilli; a person has to inhale only a small number of active tuberculosis bacilli to become infected. Tuberculosis bacilli may reside in the tissues of the body, but may not be active (growing, reproducing, and causing increasing damage in the host). 
Latent tuberculosis infection: Inactive tuberculosis is called as latent tuberculosis infection. In such cases tuberculosis bacteria are asleep. As long as the tuberculosis bacteria remain latent, they do not harm the body and are not contagious. People with latent tuberculosis infection are the ones who have been exposed to tuberculosis and have acquired the tuberculosis organism. Latent tuberculosis infection may develop into active tuberculosis infection when the immune system weakens. When latent tuberculosis gets “activated” it develops into a case of pulmonary tuberculosis (sputum smear positive) that is infectious and can be transmitted to others. The typical symptoms like cough, fever, night sweats, weight loss, and lack of energy develops. In some instances, the person may cough up blood when active pulmonary tuberculosis is more advanced. 
Some of the factors that increase the risk for progression from latent tuberculosis infection to active tuberculosis disease are HIV, weakened immune system, poor health status (e.g., cancer, substance abuse, diabetes). Women are more likely to progress from latent tuberculosis infection to active tuberculosis disease whereas; men are more likely to have latent tuberculosis infection.