pathogenesis bio220 – introductory microbiology copyright 2009, john ireland
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Copyright 2009, John Ireland
Pathogenesis
BIO220 – Introductory Microbiology
Copyright 2009, John Ireland
Key Concepts
• Portal of Entry• Attachment• Initial Evasion• Growth and Development• Portal of Exit
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Disease Progression
Entry into Host
Attachment
Evasion of Immune System
Damage to Host Cells
Exit from Host
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Portals of Entry
Skin
Mucosal Membranes
Parenteral
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Attachment
Some form of attachment is utilized to keep a microbe in a specific location through a type of protein interaction.
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Evasion of the Immune System
Evasion
Cell Wall & Capsule
EnzymesIntracellular Growth
Invasins Antigen Variation
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Damage
Effects
Nutrient Acquisition
ToxinsDirect Damage
Lysogenic Transformation Cytopathic Effects
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Nutrient Acquisition
Human blood has a free concentration for iron of 10-24 mol/L
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Toxins
Exotoxin (G+) Endotoxin (G-)
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Cytopathic Effects
The visible effects of viral infection, varied in severity and form.
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Lysogenic Transformation
Many pathogenic microbes are made pathogenic by a phage infecting them and either activating or carrying pathogenic components
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Direct Damage
Contrast the effects of toxins with those of Direct Damage
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Portals of Exit
Skin
Mucosal Membranes
Parenteral
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Case Study – Cholera
“If everybody contemplates the infinite instead of fixing the drains, many of us will die of cholera.”John Rich (Drexel University)
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Number of People in Refugee Camps
Over 21 million people are classified as refugees by the United Nations High Commissioner for Refugees in 2007
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Clean Water
Only Forty-Six Percent of Africa have access to safe drinking waterWHO, 2006
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Start of Outbreak
The UNHCR has only 6300 employees in over 110 countries
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Pathology and Exit from Host
Three Billion people worldwide do not have access to adequate sanitation facilities.WHO, 2006
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Cholera in Africa
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