Mycobacterium tuberculosis - Essay Example

Particles that are 1-5 mm in size may be kept airborne for prolonged periods, and when inhaled by a susceptible individual, the droplet traverses through the nasal passages, towards the lung alveoli where they are engulfed by macrophages and distributed throughout the body. The bacteria may remain dormant but still viable for many years (this is called latent TB infection). People with latent TB infection are not infectious, but have 10% chance of developing an active TB infection later in life.

Persons who have poor immune systems or who have other sicknesses have higher risks of being actively infected; for example, persons with HIV have the highest risk of getting TB (Gandhi, et al., 2006). Co-infection with other diseases increases the difficulty in treating the tuberculosis. A TB patient that has high chances of enhancing transmission has the following characteristics: a) lung disease; b) has cough; c) positive for presence of acid-fast bacilli (AFB) in the sputum; d) does not cover mouth and nose when coughing or sneezing; e) has chest cavitations as observed in the chest radiograph or X-ray; f) and did not finish the whole range anti-TB drug therapy (Centers for Disease Control and Prevention, 2005).

The likelihood of transmitting TB to others is enhanced in relatively small, enclosed spaces with inadequate local ventilation that does not ensure the removal of the air droplets containing the bacterium. M. tuberculosis by itself does not cause harm because it does not produce any toxin. However it can steadily build up and increase in number in the body. It attaches to surfaces in the lungs and produces deposits called tubercles. The tubercles cause inflammation and parasitically deplete the nutritional requirements of the host resulting in what is known as the condition of “consumption”.

This condition results in loss in appetite, over-all weakness and coughing as more tubercles are formed in the patient. Tuberculosis is a global problem; in 2006, the disease killed 1.7 million people and is the main cause of deaths in people with HIV/AIDS (World Health Organization, 2009). Eight million people worldwide, and in the US, 1 in 14,801 or 0.01% of the population are actively infected. The World Health Organization estimates that one-third of the world’s population harbor the TB bacterium, with potential of becoming actively infected.

Tuberculosis can also be transmitted from persons who have the bacterium but are not being treated for TB, or from persons with TB, but are unaware that they have it. Infectiousness of individuals also vary; some patients are never infectious, while those that are unaware that they have TB and are not receiving treatment could be infectious for prolonged periods (Centers for Disease Control and Prevention, 1994). Symptoms of TB are persistent cough, bloody sputum, weight loss, night sweats and fever.

Tests for TB are available and should be performed if a person is thought to be infected especially in countries or regions where TB is prevalent. To diagnose TB, chest radiography (or X-rays), skin tests, and sputum microscopy and culture are performed. All of these tests may be necessary to make a diagnosis. The purified protein derivative (PPD)-tuberculin skin test is the only known test that can detect the infection of Mycobacterium tuberculosis, but care should be given in interpreting the results.

Chest x-rays are suggestive of TB if cavitation