Means of Transmission: Droplets (Airborne) (1,2,3)
Reservoirs: Lungs of humans (2,3)
Historical Information: On March 24, 1882, Robert Koch stained the tuberculosis bacterium with two different dyes. One dye caused the color of the necrotic tissue to stain brown and the other caused the tubercle shaped bacteria to stain a bright blue. Koch was the first to grow the bacteria in the lab and called the bacterial disease Tuberculosis due to the tubercle shape of the bacteria. (2)
Signs and Symptoms: None while in the latent state (3)
S/S of TB disease (1,3):
Other symptoms (1,3):
Microbial Virulence/Mechanisms (1,5):
Mechanisms of the disease process: In a new tuberculosis infection the bacteria travel from lesions in the lung(s) to the lymphatic system that contain lymph nodes that drain the lung. Enlarged lymph nodes cause compression on the bronchial tubes, which results in coughing. Sometimes lymph nodes in the neck swell and can become large enough to secrete pus. In men the infection may spread to the prostate, epididymis or seminal vesicles causing a lump on the bottom of the scrotum. In women, tuberculosis may scar the ovaries and fallopian tubes, resulting in sterility (1).
Microbial virulence of Mycobacterium Avium Complex (MAC) increases due to the following factors (5):
1) Misdiagnosis of the infection/disease
TB is often mistaken as other diseases due to prolonged smoking, emphysema, bronchitis and other URTIís. TB may also become active in people who have previously had the infection/disease but now have weakened immune systems. People who fit this category are people with AIDís (primary host for tuberculosis disease), people who have lived in close proximity with others (prison inmates)
2) Poor compliance with DOT (directly observed therapy) programs
3) Misprescribed treatment plans
4) Poor drug supplies (often the reason for miscompliance with DOT programs)
5) Microbial strains that develop due to the factors above
Control/Treatment of the Disease (1,4): The DOT Strategy
1) Microscopic examination of sputum for acid-fast bacilli
2) Rifampin medication in specific regimen series
3) Reliable supply of quality medications and supplies
4) Monitoring and reporting of treatment/drug regimen performance
5) Political commitment from government agencies
The duration of treatment for most tuberculosis infections/diseases is 6mo. at the least. A combination of isoniazid, rifampin, ethambutol, streptomycin and pyrazinamide are used during the first two months of treatment and a pill is available in order to combine the drugs and decrease non-compliance. Ethambutol helps to decrease the number of bacteria quickly during the first two months of treatment and then is reduced to decrease ocular damage (1).
Current Research about the Prevention of Tuberculosis:
Germicidal ultraviolet light can be used to kill bacteria in the air where people with a variety of sicknesses including Tb may be located. Isoniazid may be used in people that are at high risk for Tb. People that are in close proximity with a large number of people, such as health care workers and inmates, fall under this category. In developing countries, a vaccine called BCG is being used to prevent Mycobacterium tuberculosis (1).
Fewer than 1% of the past 1200 drugs manufactured have been for infectious diseases. Efficacy trials are long and complex and require the most experienced medical professionals. Most drugs are compared with the current ones being used for a 6-month short course run. The common acceptance for most drugs is no relapse of the disease within 2 years (4).
Drug development is costly but still continues to thrive despite obstacles mentioned above.
Works Cited
1. Tuberculosis. The Merck Manual of Medical InformationóHome Edition, Section 17. Infections. Chapter 181. http://www.merck.com/pubs/mmanual_home/sec17/181.htm
2. Tuberculosis: Ancient Enemy, Present Threat. http://www.niaid.nih.gov/newsroom/focuson/tb02/optimism.htm
3. Tuberculosis: Frequently Asked Questions. Texas Department of Health. http://www.tdh.state.tx.us/tcid/TB-FAQs-Pg.htm<o:p</o:p
4. O'Brein & Nunn. The Need for New Drugs Against Tuberculosis. American Journal of Respiratory and Critical Care Medicine, Vol. 163, Number 5, April 2001, 1005-1058. http://www.who.int/tdr/diseases/tb/tbdrugs-paper.htm
5.Fighting Multidrug-Resistant TB. www.tballiance.org/3_mdrtb.cfm?rm=abouttb&sub=mdrtb