Tuberculosis epidemiology

Tuberculosis, or TB, is an airborne infection transferred from individual to individual by way of droplets that come from an infected person’s saliva, sneezing, and/or coughing. This infection is caused by the bacillus known as Mycobacterium tuberculosis. This infection will affect the lungs most typically, but it has the power to affect other bodily systems as well.

In the lungs, inflammation occurs and abscesses develop. These abscesses do heal; however, it leaves some scarring behind. The symptoms of tuberculosis are fatigue, coughing with or without blood, wheezing, weight loss, as well as a multitude of other symptoms. Highly contagious, the high-risk groups tend to be in infants, the elderly, those with poor nutrition and/or in a diminished environment, those who receive organs from others, and the immune compromised, namely HIV. In those who are relatively healthy, treatment is effective without damage to the lungs if treated promptly.

Diagnosis is made through microscopic evaluation of the sputum and of the blood and by a chest x-ray. Treatment is given by antibiotic therapy in addition to other medications. Prevention is available by a vaccination although not typically used in the United States due to a deficient need, but rather used in other countries. The effectiveness of the vaccination is questionable, however.

The vaccination, known as BCG, was first noted to be use during 1920. The first medication specifically used in the treatment of tuberculosis was in 1944. This medication is streptomycin. When affected with the Mycobacterium tuberculosis bacillus it is usually kept at bay by a healthy immune system. This explains why then it is more prevalent in those who are compromised. Five percent of healthy people do go on to become infected with tuberculosis.

There are over 8 million cases of tuberculosis and it has been responsible for over 1-1/2 million deaths. These figures represent a little over 5% in the developed countries. There are over 15 million people in the world who are afflicted with this dreadful infection with over 2 billion of those 15 million that are affected with it.

Declining occurrences brought hope, however, since the 1990s the TB infection has resurfaced. This resurfacing was most typically seen in the United States among those living in a poor environmental atmosphere. HIV infected individuals are among those with the most dismal prognosis, as their already compromised immune system makes it very difficult to treat successfully. Because of this factor, the HIV and TB combination has been the cause of the most deaths in this patient population.

To complicate matters further we have seen resistant strains of TB that are nonreactive to medication over the last decade. Multi-drug resistant, or MDR TB has become a major problem. It is on the increase according to the World Health Organization (WHO). MDR has affected approximately 45 countries.

RESOURCES

World Health Organization: Global Tuberculosis Report 2012

Center for disease Control and Prevention: OVerview of Epidemiology of Tuberculosis in the United States

Johns Hopkins Bloomberg School of Public Health: TB Eidemiology

Seminars in REspiratory Infection: Epidemiology of Tuberculosis

New Jersey Medical School Global Tuberculosis Insitute: Epidemiology of Tuberculosis