Tuberculosis Is A Bacterial Disease Biology Essay

Published: Last Edited:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

Primary infection is the term used when a host's initial infection. This is usually caused by air droplets containing viable Mycobacteria being inhaled, or by inhalation of infected dust particles. The bacteria will settle in the lungs and the most common form of TB in the lungs Tuberculosis, will occur. The bacteria are engulfed by macrophages cells where they can live and multiply. Non resident macrophages are attracted to the site where they engulf bacteria and also bring them to local lymph nodes where an immune response is activated. 2-6 weeks after the initial infection that T-cells are released.These induce the migration of large numbers of macrophages in the lungs where they will form a granulomatous lesion called a tubercule around the infection. tubercule It starts releasing lytic enzymes that build up to a high concentration killing off healthy cells nearby. The result is an area of ​​necrotic tissue with a caseous consistency. They are seen in an X-ray and it is called Ghon complexes. This response contains the infection and usually protects against infection again later. However about 10% of the people to be extra sensitive and you know being tuberculin-positive. It is the individual post-primary infection may occur.1, 2

A post-primary infection may occur months or years after primary infection. During this infection, large concentrations of mycobacterial antigens within tubercules lead to continuous T-cell activation and thus the transfer of an increasing number of macrophages. The higher concentration of lytic enzymes causing caseous necrotic legions to melt. It is an ideal medium for bacteria previously contained within macrophages sa tubercule to grow extracellularly. The legions grow to a point where they rupture, releasing bacteria into the lungs. New legions form and the process repeats itself, slowly destroying the lung tissue. Legion eventually a rupture a blood vessel hit the circulatory system. From this bacterium can infect the plural cavity, bones, urino-genital system, meningis, peritoneum or skin.2

Tuberculosis meningitis

The meninges are the system of membranes that envelop the central nervous system.They provide protection to the CNS and contains blood vessels that supply it. An infection M. Tuberculosis of the meninges causing meningitis Tuberculosis.Tuberculosis bacilli enter the meninges through the blood means that the patient should have a focus of infection in other areas. From here they form necrotic legions in the same way they do in the lungs. The legions disrupt the subarachnoid layer causes an infection of the cerebrospinal fluid and an inflammation of the lining of the brain. This results in damage to blood vessels, nerves and brain tissue itself. Onset of the disease is usually very slow to begin with malaise, apathy and loss of appetite but within a few weeks proceeds with neck stiffness, photophobia and loss of consciousness.Occasionally however onset may be very fast and can often be mistaken for a sub-arachnoid haemorrhage. About 70-80% of people survive TB meningitis.3 But many are left with symptoms such as:

    * Memory loss, difficulty retaining information, lack of concentration

    * Clumsiness or co-ordination problems

    * Remaining headaches

    * Deafness, hearing problems, dizziness, loss of balance

    * Learning difficulties

    * Epilepsy, seizures

    * Weakness, paralysis or spasms of the body (cerebral palsy)

    * Speech problems

    * Loss of or changes in sight4


Miliary tuberculosis

Miliary tuberculosis is a form of tuberculosis that is characterized by a wide dissemination in the human body and by the small size of the lesions. It is named for a distinctive pattern seen on a chest X-ray several small spots distributed throughout the lungs that look like millet seeds. Miliary TB is a very serious condition and nearly always fatal if untreated. About 25% of patients with this form of TB also develop tuberculosis meningitis.5

Kidney tuberculosis

If a bacteria from the lungs gain access to the vascular system that organisms can then spread throughout the body. However, the bacilli have strict demands of growth and generally tend to grow in a small number of sites. One of them is the rock. In the kidney, the site of preference is the medulla. Form calcified lesions that lead to local tissue destruction. If left untreated TB can lead to kidney stones failure.6


 Spread, treatment and the difficulty of consuming

Mycobacterium tuberculosis is a very contagious disease. When an infected individual coughs they release many bacilli in the air that can be inhaled. This means that the disease is a major problem in high places. It is also a major problem in areas where AIDS is common. Because TB is an infectious disease as there are strict rules set down the U.S. job Safety and Health Administration for the protection of health care workers responsible for the care of infectious TB patients. Patients should be hospitalized in negative pressure rooms and caregivers should be given a personal face mask fitted with high-energy particulate air filter. The filter will not allow potentially contaminated dust particles or sputum to be inhaled.1


M. tuberculosis is difficult to treat effectively. First it has a high lipid levels in its capsule.This makes it very impermeable to nutrients, which is why it is slow growing, but also antibiotics. Another factor increasing its antibiotic resistance is its intracellular location within the macrophages. These cells are also often surrounded by a layer of caseous tissue making contact with the bacteria difficult. These factors mean that long term treatment with antibiotics is necessary. This presents a problem, long term therapy makes the emergence of resistant strains far more likely after short treatment. The cost of long term treatment is also an increased sense of treatment in developing countries where the incidence of TB is extremely high difficult.3


There are a number of anti-tuberculosis drugs available. Most of it is kept restricted to treatment of tuberculosis to prevent drug resistance developing in other organisms can then be transferred to the TB causing bacteria. These drugs are also frequently toxic so they are usually suitable for general use.3


The BCG vaccine (attenuated tubercle bacillus Calmette and Guerin's) has been used for over 70 years to protect people from tuberculosis. In the UK the vaccine is given to children entering secondary school but in high risk countries is given at birth. Although it is used for so long that the level of its effectiveness is still in debate. Trials in the UK and the USA show that it provides clear protection. Also test the South American and African countries show the efficiency of over 70%. But in two trials in southern India and southern parts of America it has been shown to have little or no protective effect and actually seemed to increase the incidences of the disease. One difficulty in obtaining accurate test results from the shifting background level of infection depend on factors other than the BCG vaccine. Also the strain of the vaccine has not been standardized and it is possible that different strains are experiencing varying success. Another theory put forward is that genetic differences between populations caused by differences in the way that vaccines works.3


With the increasing world population it becomes easier to do for this very contagious disease that spreads from person to person. The problem in the treatment of individual patients combined with not completing their course of antibiotics and newly emerging strains resistant to current drugs mean that tuberculosis is a difficult disease to eradicate in this country. The problem is far worse in developing countries where the hospital can not afford a long course of expensive drugs. Furthermore the AIDS pandemic is making it even easier for tuberculosis infection in the population.