Author: Justin Tanimoto
Date: December 7, 2010
Abstract:Tuberculosis (TB) is a disease caused by the bacteria Mycobacterium tuberculosis that mainly affects both lungs. It is a highly curable disease, as long as the proper medications are administered and taken correctly. Tuberculosis is one of the primary causes of death from infectious diseases. In North American less than 10 per 100,000 people die from TB. However, in underdeveloped countries (Africa) there are about 100-300 deaths per 100,000. There is a death from TB every 15 seconds and about eight million people develop TB every year. Of these people who don’t get treated, 60% of them die. Most cases of TB are in third world countries because of poor sanitation. TB is also a global crisis because even though third world countries have the antibiotics able to treat TB, there is an inferior quality and they are also used very insufficiently. (American Society for Microbiology, 2010)
Introduction: I was interested in studying and researching tuberculosis because I used to be a carrier of the disease. 3 years ago I took a 10 day trip to Japan with some of my friends. When I came back and got a job summer of 2008 I needed a TB skin test so I could work. Strangely, it came out positive and then I knew that it was because I went to Japan. I took a chest X-Ray and it came out negative, therefore I had latent TB which means that the virus was inside of me but it wasn't active. My doctor prescribed medication for me and after that I became interested in TB. Tuberculosis is a very highly infectious disease, however, treatment is fairly simple. What also got me interested in this topic was the incidence of TB and how the majority of the people in the United States with TB were minorities. (CDC, 2009)

Discussion:History:Tuberculosis is a disease that has been around along time. Evidence of its existence dates back to the time of ancient Egypt. (Global Tuberculosis Institute, 2010) Historians have found deformities in mummies, and also evidence has been found in Neolithic sites of Italy, Denmark, and countries in the Middle East. Scientists feel that TB became an epidemic when an explosion of it happened in the second millennium A.D. (American Society for Microbiology, 2010) The disease peaked at its highest in the first half of the nineteenth century when it has been estimated that one-quarter of the population in Europe died from TB (American Society for Microbiology, 2010). However, with sanitation and housing improvement in the late nineteenth century, TB mortality decreased. Historians feel that people who survived from dying from TB in beginning of the 19th century never caught the virus because they became immune to it. (American Society for Microbiology). Researchers feel tuberculosis came to the United States by the Europeans when they immigrated here. In the 1800s death due to TB was around 6-7 per every thousand (American Society for Microbiology). The mortality of deaths however, increased yet again by the introduction of AIDS and the increase of homelessness and also poverty.

Signs of Tuberculosis
  • Bad Cough
  • Chest Pain
  • Coughing up Blood
  • Weight Loss
  • Weakness
  • Chills
  • Fever

The cause of the disease happens when Tubercle bacillus forms tubercules which are hard nodules in the lungs. These hard nodules interact with bacteria and the host’s immune system causing the bacteria to grow and multiple. When the bacteria M. tuberculosis enters the lungs' cells of the host’s immune system it engulfs the pathogen but is unable to digest the bacteria all the way because of its waxy cell wall. (Mayo Clinic, 2009)

There are two forms of Tuberculosis which are TB Infection and TB Disease. TB Infection is when a person is infected with the TB bacteria and the the person’s immune system is able to fight off the bacteria from multiplying in the body. However, the bacteria doesn’t leave the body and doesn’t die completely, it just becomes dormant and is stored in the body. A person with TB Infection had no symptoms and can’t spread the bacteria to other hosts. TB Disease is when a person’s immune system can’t fight off the Tuberculosis bacteria and then the bacteria becomes active in the body.

If you suspect that you are a carrier of the TB bacteria then you have the option of a couple of tests. The first and most common test is the skin test. The skin test entails an injection of a small amount of fluid called Tuberculin into the skin. A patient who has been given this test will return within 48-72 hours after injection to see if there is a reaction on their arm. If a patient's skin test result is positive than the person will form a red and swollen bump at the site of injection. Depending on the age and health status of the individual, the size of the bump will vary. Even the smallest bump under a person’s skin could be a sign of infection. However, not all test are always correct. A positive test of TB could also mean a patient received a Bacille CalmetteGuerin vaccination. This vaccine is not found in the US but is largely used in countries who have a high correlation of TB. If a positive test does occur, than further tests will be taken. For example, a chest x-ray can be taken to see if there are any signs of the TB bacteria. If it turns out that the patient is infected with the TB bacteria, the x-rays will show white spots and cavities in the lungs signifying a breakdown of the lungs tissue. A negative test of TB is a result of no rise of skin or redness. (Lab Tests Online, 2007)

The second test that can be administered to see if a person is a carrier of the TB disease is a blood test called interferon-gamma release assays or IGRAs. This test measures the immune system and it’s reaction to the TB bacteria. If a doctor administers a IGRA instead of the skin test, then only one visit to your doctor's is necessary. The blood tests that are used are called the QuantiFERON-TB Gold test, QuantiFERON-TB Gold In-Tube test and T-SPOT TB test. (CDC, 2010) All of these tests are approved by the Food and Drug Administration and results happen around 24-48 hours after the test. (CDC, 2010)

The treatment for TB solely depends on the patient and if they have latent TB or the TB disease. Patients with the latent TB infection do not show any symptoms and cannot spread the bacteria because it is
inactive in a person's body. A patient with latent TB has less bacteria than a normal TB diseased patient which is why it only takes one medication to be perscribed which is called isoniazid (INH) (CDC, 2010). INH is usually taken over a 9 month period and slowly kills all the TB bacteria in the body. However, a person who has the TB disease is treated with several drugs, usually over the span of around 6 to 12 months. If a patient has the TB disease, than it is very important for the patient to takes their medication exactly the way the doctor perscribes or it will not work or the TB may become resistant to the antibiotics. The usual regimen for taking medication for a person with the TB disease is taking medication daily for the initial phase of 2 months. After 2 months, than other options of continuation can be done. Treatment for latent and TB disease usually last under 12 months. However, if antibiotics are taken improperly than treatment can last a lot longer.(CDC, 2010)


Drug-Susceptible Tuberculosis:
If the TB disease becomes resistant to medication given by a practitioner than a more aggressive treatment occurs. Instead of taking around 4 antibiotics than a person will need to take around 10 drugs. (CDC 2010). A preferred regiment for a person with drug resistant Tuberculosis is:

Preferred Regimen
Alternative Regimen #1
Alternative Regimen #2
Initial Phase
Daily isoniazid, rifampin, ethambutol, pyrazinamide
56 doses (8 weeks)
Daily isoniazid, rifampin, ethambutol, pyrazinamide
14 doses (2 weeks), then twice weekly for 12 doses (6 weeks)
Thrice-weekly isoniazid, rifampin, ethambutol, pyrazinamide for 24 doses (8 weeks)
Continuation Phase
Daily isoniazid and rifampin for 126 doses (18 weeks) or
Twice-weekly isoniazid and rifampin for 36 doses (18 weeks)
Twice-weekly isoniazid and rifampin for 36 doses (18 weeks)
Thrice-weekly isoniazid and rifampin for 54 doses (18 weeks)
*From CDC website

Literature Cited
Mayo Clinic Staff. Tuberculosis. Published online January 28,2009.

Lab Test Online. TB Skin Test. Published March 2007.

Smith, I.Mycobacterium tuberculosis Pathogenesis and Molecular Determinants of Virulence. Published online in American Society for Microbiology vol.16, No. 3 (2003).

Croft, J., Croft, N. The History of Tuberculosis. Published online. (2005).

Lainez, Y. B., Todd, C.S., Ahmadzai, A., Doocy, S., Burnham, G. Prevalence of respiratory symptoms and cases suspicious for tuberculosis among public health clinic patients in Afghanistan, 2005-2006: Perspectives on recognition and referral of tuberculosis cases. Published online in Tropical medicine & International Health. Vol. 14, No. 5. pg.564-570. (2009).