Lecture 1: Infection and Disease Flashcards
Microbiota
personal unique mix of bacterial species colonize: nose mouth, eye, upper resp. tracts, intestine and urogenital, and skin.
Deaths from infectious disease per year
15 million
one pathogen can… (3)
…cause more than one disease
-new diseases coming. old diseases re-emerging
…be used in bioterrosism (ex. anthrax)
superbugs
become resistant to antimicrobials- *awareness when rxing antibiotics
Phylogenic tree of life
is organism a Bacteria, fungus, protozoan, or virus
Proakaryoitc cells
small, no nucluear membrane of nucleoli, no membrane enclosed organells, no carbohydrates on plasma membrane, no cytoskeleton or cytoplasmic streaming, ribosomes are small
binary fission for cell division.
*think, loft/studio apartment
Eukaryotic cells
larger than prokaryotes, true nucleus with membrane and nucleoli, membrane bound organelles present, sterols and carbs on plasma membrane as receptors, cytoskeleton, larger size, mitosis
**think mansion with many rooms
Gram- negative cell wall
peptidoglycan later surrounded by outer membrane
Gram-Positivie cell wall
layers in peptidoglycan with no outer membrane
Viral Pathogens
Viruses not microbes and are not cells- they have DNA or RNA care and are surrounded by a protein coat (capsid)
Viruses cannot replicate withouth replication machinery in a host cell (obligate parasite)
Ex: SARS-coV-2, COVID-19, HIV, Hep A/B, Measles, Influenza
Fungi
- may cause human disease
- others produce useful antibiotics
- can cause food spoilage
ex) Candida albicans, aspergillus fumigatus, blastomyces dermatitis, pneumocystis jirovecii
* alexander flemming-penicillin won nobel prize
Typles of Parasites (5)
1) Flagellates- with flagella (ex. giardia, trichomonas, trypanosomes)
2) Amebae- entanomoeba, neagleria, and acanthamoeba
3) Sporozoa- cyptosporidium, toxoplasma, malarial parasies
4) ciliates- rare, only 1 human parasite
5) heminths- parasitic worms
Mutulism
symbiotic relationship that benefits both participants
Commensalism
symbiotic relationship that benefits microbe but does not affect host
parasitism
symbiotic relationship that benefits microbe and harms host
Sterile Sites
blood, CSF, internal organs, muscles bone and brain
* if site has organisms something is very wrong
Contributors to microbtiota development
breast feeding, delivery (cesarian vs. vaginal), feeding from maternal skin, hands and feet introduced to mouth, hands on floor, siblings and pets
Pathogenicity
qualitative trait referring to genetic capacity to cause disease/ liklihood that infection will results in disease
Virulence
quantitative trati: related to the extent of pathology (degree of disease) caused by microorganism.
expresses interaction between pathogen and host.
ex: cold-low virulence while ebola-high virulence
For disease to occurr…
…pathogen must come in contace with proper body part in sufficient numbers
portal of entry is the route an exogenous pathogen uses to enter body
infectious dose is number of microbes entering body
Respoiratory portal
inhalation of pathogens in air
GI portal
fecal oral
urogenital portal
sexually transmitted
parenteral
peircing skin or muccous membranes through cuts, bites, injections
translocation
organism moves from one area to another (e coli from GI to urethra to bladder)
Letal Dose
50% LD50, number of bacteria or virus particles required to kill 50% of an experimenl group of animal hosts
**Low LD50 is highly virulent
Infectious dose
50% ID50, infectious dose to colonize 50% experimental hosts
measured by determining how many microbes are required to cause disease symptoms in half of an experimental groups of hosts
not easy to measure
Primary infections
occur in otherwise healthy individuals
Secondary infections
occur in a body weakend by a primary infections
ex) post-influenze bacterial pneumonis
local disease
restricted to single area
systemic disease
disseminate to organs and systems
bacteremia
-emia in blood
transient, septicemia is proliferation of bacterial cells in blood
signs of disease
evidence/ fever, bacterial cells in blood
symptoms of disease
changes in body function, sore throat & headache
syndrome
collection of signs and symptoms