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Unformatted text preview: Pathology of Infection Intro and Basic Principles • Some diseases dramatically affect our history and society; ex small pox (Native Americans) and the black death (Europe) • **infectious disease occurs with a specific pathogenic organism causes signs and symptoms of inflammation or organ dysfunction; if it causes signs/symptoms it is an infectious disease! • Causes of cell injury: metabolic, physical, chemical, genetic etc • Infectious pathology=most common form of organic and cellular disease; often mild and goes unnoticed; many forms of infection are associated with tissue damage or loss of life; infectious disease=leading cause of death worldwide • Infectious micro-organisms have a variety of special abilities that enable them to infect, proliferate and move on to the next host • Whether or not you get an infectious (show signs and symptoms of the disease) depends upon a highly complex and regulated process that involves factors and features of the invading microorganisms (virulence or disease producing potential) AND the integrity of a number of host defense membranes • Both humoral and cell-mediated immune systems battle infectious organisms (humoral with bacterial infections and T cells with viral infections) and occasionally cause tissue toxicity that lead to illness and disease; different origins of infectious pathology show similarity and overlap in symptoms and pathology (our immune system has a limited repertoire of tools) • Specific symptoms depend on the LOCATION of the invading organism and its predilection for specific organs or tissues • Not all interactions with micro-organisms are harmful; internal and external exposed surfaces of the body are normally inhabited by normal microflora , and the host is not adversely affected; it can be mutually beneficial (human host provides nutrition and microorganism secretes essential metabolic by-products like vitamin K in the intestinal tract; these bacteria can also keep more virulent organisms at bay • Treatment of infectious disease most effective when: there is an IDENTIFICATION of the pathogenic organism and its SITE of infection; clinical signs and symptoms are the first step in identification (ex cough=respiratory infection; vomiting or diarrhea=GI infection) • 3 rd leading cause of death; responsible for disparity in average life span in rich and poor countries; many child deaths Koch’s Postulates • Set of criteria to determine whether bacteria caused disease; some exceptions and limitations; useful in establishing the infectious origin of a disease • For a disease to be attributed to a particular organism, the organisms: • 1. Must be found in lesions of the disease • 2. Must be isolated and cultured in vitro • 3. Must transmit the disease to another animal (must develop similar disease that you are studying) • 4. Must be recovered from lesions in that animal • **determines if the infectious organism caused the signs and symptoms; a specific organism has caused a specific disease...
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This note was uploaded on 02/08/2012 for the course PATHOLOGY 3245 taught by Professor X during the Spring '11 term at UWO.
- Spring '11