Disease, Illness and Condition Library
Tuberculosis
of Death” by John Bunyan in 1680, tuberculosis or T.B has been found on all continents and in all civilizations throughout history. It afflicted the early Egyptians, ancient Andean tribes in South America, and early Indian tribes of North America. While always present to some degree, the disease has at times caused prolonged epidemics, some stretching over many centuries. Europe and North America are at the end of a 300-400 year epidemic cycle which at its peak resulted in the death of 10 to 15 percent of the population. Due presumably to the acquisition of the herd immunity (group resistance to an infection), to incidental improvements in living conditions in terms of crowding, hygiene, and nutrition, and to deliberate human intervention (including isolation of infectious causes and the development of effective drug therapy), the incidence of the disease waned steadily in these regions over the past 100 years. By contrast, tuberculosis is epidemic now in most of African and Asia, with attack rates in some countries 100 times higher than rates in the United States and Europe. However, beginning in 1986, public health officials started to become aware of a distinct resurrection of Tuberculosis in the United States, particularly in the nations inner cities. This trend has continued and in 2007 there were a couple of high profile TB cases which made front page news. In general, the epidemic cycles of tuberculosis has resulted from the introduction of the infecting organism into a population that is relatively more vulnerable because of genetically determined aspects of immunity as well as aggravating environmental factors, such as poor housing and overcrowding, malnutrition, and poor sanitation. Unlike the influenza virus, which can cause global recurring epidemics by means of viral mutations that circumvent previously acquired immunity, the tuberculosis microorganism does not appear to have undergone significant biological modifications to promote its prevalence. However, the appearance of the AIDS epidemic threatens to have a massive impact on the prevalence of tuberculosis throughout the world. The Germ Tuberculosis is a chronic wasting disease that primarily attacks the lungs, although it can also affect other parts of the body. It can be fatal if not treated. Tuberculosis is caused by a type of bacterium (a bacillus) that belongs to a highly unusual family of microbes, the mycobacteria. The cell walls of mycobacteria are substantially different from those of most other disease causing bacteria, such as staphylococci or streptococci. Instead of being composed largely of carbohydrates and proteins, mycobacterial cell walls are composed largely of lipids, or waxes. And in contrast to most bacteria, which multiply under suitable circumstances in as little as 12 to 20 minutes, Mycobacterium tuberculosis requires roughly 24 hours to replicate. The basic attributes play prominent roles in the transmission and course of the disease. The chemical structure of the cell walls of M. tuberculosis means that the body’s usual mechanisms of defense against bacterial infections – antibodies and polymorphonuclear leukocytes, the type of white blood cells that fight off acute infective agents – are largely ineffective. The barrier provided by its cell wall also makes the tubercle bacillus resistant to most standard antibiotics. The slow replication rate means that there is a substantial incubation time between the primary infection and the manifestations of illness – a few months at minimum and commonly many years. Further complicating the control of tuberculosis is the extraordinarily long period required for a cure: 6 to 18 months of continuous medication. This is due both to the relative resistance of M. tuberculosis to standard antibiotics and its indolent metabolism and replication rate. (Bacteria are most vulnerable to antibiotics while they multiply.) Transmission and Immunity Tuberculosis is spread almost exclusively by human to human aerosol transmission of the bacilli. A patient with pulmonary tuberculosis (tuberculosis of the lungs), the most common form of the disease, coughs the bacilli into the air to be inhaled by someone else. Unlike some of the virulent, aggressive respiratory infections that may invade the body through the lining of the upper airways. Tuberculosis can take hold only if the bacilli are inhaled deep into the lungs, into the microscopic air sacs called alveoli. Once the bacilli reach the alveoli, the battle between host and parasite commences. Even though the classic antibody defense system does not offer significant protection against tuberculosis, humans have evolved a modestly successful defense: cell-mediated immunity, in which a team of specialized cells of the immune system, macrophages and T-lymphocytes, combine to inhibit replication of the bacilli. Macrophages (literally, “large eaters”) may reasonably be compared to figures in the popular video game of the 1970’s fame, Pac-Man. Macrophages patrol many of the tissues of the body, alert the presence of foreign material, both organic and inorganic. Their response on encountering a tubercle bacillus is to engulf it. However, the macrophage by itself does not fare well in its battle with the mycobacterium. In order to exert a significant inhibitory effect on the organism’s survival and replication, the macrophage requires assistance from two types of T-lymphocytes, helper and killer T-cells. Once activated by chemical interaction with these T-cells, macrophages can curtail the growth and spread of the bacilli. In most immunologically normal people, tuberculosis never takes hold: Of 100 people infected with the bacilli, only 10 will come down with the disease during their lifetime. In the others, the bacilli will lie dormant in the lungs and other tissues, producing no symptoms. This is called latent tuberculosis. Sometimes, however, the cell-mediated immunity system fails, and the bacilli multiply and spread throughout the body. They lodge in a variety of organs and ultimately may cause progressive infection and destruction of vital tissue. Although the great preponderance of tuberculosis cases involves the lungs, 5 to 20 percent of cases involve other parts of the body, such as the lymph nodes, kidneys, bones, or central nervous system. Among AIDS patients the percentage of cases in which organs or tissues outside the lungs are affected is much higher, ranging up to 65 percent. AIDS and Tuberculosis Unfortunately, the human immunodeficiency virus (HIV), the virus that causes AIDS, destroys “helper” T-cells. Thus, patients with HIV infection are rendered incapable of mounting or sustaining an effective defense against tuberculosis (and many other infections against which the major defense is cell-mediated immunity). Most cases of tuberculosis seen among HIV infected individuals represent reactivation of a latent tuberculosis infection which antedated the HIV infection, often by decades. Tragically, the epidemiological patterns of HIV and tuberculosis infections demonstrate considerable overlap. In many of the nations of sub-Sahara Africa, the march of HIV through the population has been shadowed by exploding rates of tuberculosis. Similar parallel epidemics are being witnessed among the inner city population of the United States, where high rates of HIV infection coincide with other factors that increase the risk of getting TB, including homelessness, drug use, alcoholism, malnutrition, and the presence of immigrants from countries where TB rates are high. Medical authorities anticipate that as HIV infection spreads, the incidence of tuberculosis worldwide will rise substantially. In recent years there have been approximately 10 million new cases of TB and 3 million deaths from the disease annually worldwide-without a major contribution from HIV infection rates in Africa, the United States, and Brazil. The biggest disaster could occur if AIDS becomes widespread in Asia, where, in addition to a very high prevalence of latent tuberculosis, there is severe over crowding, which could promote a rapid spread of tuberculosis even to those without HIV infection. Helpful Natural Supplements for Tuberculosis |
Symptoms of Pulminary Tuberculosis
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