Pathology of infections Flashcards
What are the different classes of infectious agents?
Bacteria, viruses, fungi, parasites, prions.
Why do infectious diseases differ?
Some organisms are capable of living in any tissue e.g staph aureus. Some organisms are capable of releasing products that damage widely e.g E-coli.
How do bacteria damage tissues?
Pili on the surface of bacteria attach to cell walls, allowing adhesion.
What do exotoxins do?
Produced by intact bacteria. Typically have specific effects.
What do endotoxins do?
Attack components of cell walls, trigger complement cascade, trigger coagulation cascade, induce interleukin 1 causing fever.
What are the examples of aggressins?
Coagulase, streptokinase, collagenases. They damage tissue.
How do bacteria damage tissue using immune reactions?
Antibody-antigen complexes deposited in glomerulus or skin.
How else can bacteria damage tissues?
Immune cross-reactions. Cell mediated immunity e.g TB
How do viruses damage tissue?
Direct cytopathic effects e.g influenza and Hep A. Immune reactions e.g Hep B and C and DMT1. Incorporation of viral genes into host genome.
What is an example of a fungal infection?
Aspergillus spp. Causes asthma, aspergilloma, invasive aspergillosis, hepatocellular carcinoma.
What is an example of a yeast infection?
Candida Albicans - causes thrush.
What are the different types of parasites?
Protozoa, trematodes (flukes), nematodes (roundworms), cestodes (flatworm or tapeworms)
What are protozoal diseases?
Amoebiasis and Giardiasis. Malaria. Trichomoniasis.
