Mech lec 5 infectious Diseases Flashcards
What are commensal type diseases?
microbes that reside on the surface of the body without harming the human
What are opportunistic type diseases?
organism that normally does not harm host but will wait for the right time when the host will have low resistance
What are pathogenic type diseases?
organisms that cause disease
What are obligatory intracellular?
Viruses that must be inside the cell to survive
What is extracellular?
ex: strept
exist as free living organisms in their environment
What are the steps necessary for microorganism invasion of host?
- Access- exposure
- Attachment -receptor
- Colonization-local replication
- Invasion- virulence factor (spread)
- Dissemination and replication- escape from regional defenses
What are direct transmissions of infections?
-sexual
-touching, kissing
-fomites( anything that you can touch such as a pencil or table)
What are indirect transmission?
- Vehicle borne: air, water, food
- Vector borne: mosquitoes, ticks
blood transfusion, organ transplants, congenital
What are factors that contribute to establishment of disease:
A. factors of pathogens
1. virulence
2.evasion of host immunity
3. # of infectious agents(infective dose 50)(lethal dose 50)
B. factors of the host
1. age
2. nutritional status
3.genetic constitution
4. immune system status
What are categories of infectious agents?
-prions
-viruses
-bacteria
-chlamidiae, mycoplasmas
fungi: yeasts, hyphae
parasites: worms, protozoa(single cell , intestinal or blood), arthropods
What are prions?
An abnormal protein that can trigger other normal proteins in the brain to fold abnormally in cows
What are viruses:
-Small
-DNA/RNA core genome
-protein capsid
-sometimes a lipid envelope
-limited # of genes coding for all other structures
-no consistent naming system
What are some insects?
lice, bedbugs, fleas
What are arachnids:
mites, ticks, spiders
What are some barriers:
-skin
-GI
-Respiratory
-Urogenital
