Establishment of Disease Flashcards
Which of the following is a mis-match?
A. Urogenital- often associated with sexually transmitted pathogens
B. Gastrointestinal- often involves fecal-to-oral transmission
C. Parenteral- pathogen is passed from mother to child through th eplacenta
D. Respiratory- spread by sneezing
E. Conjunctiva- involving eyes
C
Place the following steps for infection in order from first to last:
1. Invade tissues and spread
2. Adhere to host tissues
3. Enter the host
4. Exit the host
5. Evade immune defenses
3, 2, 1, 5, 4
What are the three portals of entry?
- mucous membranes
- skin
- parenteral route
What are adhesins?
surface molecules on the pathogen that bind to receptors on the surface of the host cell
What are some examples of adhesins?
Receptors, spikes, capsules, BIOFILMS
Which step MUST be done to cause disease?
penetration
How is Hyaluronidase the “spreading factor?”
Destroys hyaluronic acid (in basement membrane), allows them to move easier inside cell
What is the significance of IgA Proteases?
If IgA is destroyed -> penetration a LOT easier
What does Streptokinase do?
Dissolves clots (digests fibrin), allows it to not be blocked -> allows spread
What does Collagenases do?
breaks down collagen
How does hemolysis evade the immune system?
Hemolyze RBCs
Alpha- partially digests -> greenish
Beta: completely digests -> clear
What do Leukocidins do?
Destroy neutrophils - WBC (phagocytosis)
How do enzymes evade the immune system?
Production allows them to destroy connective tissue, muscles, immune system, etc
What are the most resistant cell wall components?
Mycobacteria- acid fast/waxes (mycolic acid)
Neisseria gonorrhoeae - fimbriae (opa proteins)
Streptococcus pyogenes- protein M (attach and evade)
How do capsules evade the immune system?
helps evade phagocytosis + attachment
How do capsules evade the immune system?
helps evade phagocytosis + attachment
If phagocytosis occurs AFTER entry, will there be damage to the cell?
no
How can damage to cells occur?
Lytic
using host nutrients
causing direct damage by injury
bacterial toxins
What are toxins?
poisonous substance produced by some M/O
What is the difference between toxemia and intoxication?
Toxemia: presence of toxin in blood
Intoxication: Diseases due to ingestion of toxin (vs M/O)
What are some ways the virus can exit the body?
Gastrointestinal tract
Urogenital tract
Blood (contaminate equipment or insects)
Respiratory tract
What is the difference between endotoxin and exotoxins?
exotoxins are proteins, endotoxins are lipids
exotoxins can be denatured, endotoxins cant
endotoxins are only found in gram -ve
exotoxins exit, endotoxins exit when cell wall is broken
What are major producers of exotoxins?
tetanus (Clostridium tetani), Diphtheria (Corynebacterium diphtheriae), Botulism (Clostridium botulinum)
Are toxoids from endotoxins or exotoxins?
exotoxins
