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29 Cards in this Set
- Front
- Back
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Portals of Exit
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-how the pathogen exits a host
: respiratory tract : digestive : urogenital -symptoms often spread disease : diarrhea, cough, STDs |
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Reservoirs
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-human
: good ones for vaccination campaigns : asymptomatic carriers can spread disease, too -animal : can be occasional host :typical animal-to-animal, occasionally to human is called a ZOONOSIS -environmental : soil, water : impossible to eradicate |
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Transmission
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-horizontal/vertical
-contact :direct : indirect-formites : respiratory droplets -fecal-oral -foodborne -airborne -vector-borne |
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horizontal vs. vertical transmission
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-horizontal= person to person
-vertical= mother to fetus or baby : breast feeding : cross placenta : during birth process |
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contact transmission
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-direct: physical touch-organism does not survive well
outside the host because they need moisture -indirect: person touches an item (formite), then another person touches the item |
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contact transmission
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-indirect: person touches an item (formite), then
another person touches the item |
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contact transmission
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-droplets: carry about a meter from infected source,
close range, but no actual contact : important in crowded settings : try to keep beds, desks > 1 meter apart : need moisture |
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Fecal-oral
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-fecally contaminated hand to mouth
-wash hands after toile,t diaper changing |
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foodborne/waterborne
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-originate in animal (95% of chickens in IN are positive
for Campylobacter) -meat contaminated during slaughter or packaging -veggies contaminated by "organic" fertilizer (bean sprouts, and E. coli) -cross contamination by fomites (cutting board) -waterborne are widespread in community |
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airborne
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-dry droplets
-droplet nuclei can carry a few organisms far -dust particles as fomites -negative pressure hoods or rooms reduce spread -HEPA filters trap organisms |
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vector borne
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-mechanical
-biological |
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portals of entry
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-sometimes infection is portal-related (Shigella on
your hand can't hurt you unless you ingest it) -sometimes more than one portal for same disease : Anthrax- cutaneous, ingested, inhalational : plague- bubonic, pneumonic |
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incidence and prevalence
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-incidence= NEW cases in a given time period
: # of people who get flu in december -prevalence=TOTAL cases in a given time period : new + continuing -prevalence> incidence |
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seasonal incidence
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-rate can vary
: closer contact in winter : more immunocompromised in winter (cold) |
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RSV
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-respiratory syncytical virus
-common in winter than summer because people closer together in winter |
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propagated
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-host to host
-low incidence -slow onset -influenza |
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common source
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-many cases all at once
-100 people get sick from eating at a restaurant -hard to trace |
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index case
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-when disease gets transmitted to other people
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endemic disease
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-disease in constant low level
-bubonic plaque |
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epidermic disease
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-high incidence in particular location
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pandemic disease
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-in multiple location
-flu |
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Control
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-destroy reservoir host or vector
-quarantine : TB, other highly contagious disease -surveilance : notifiable disease : MMWR -eradicate pathogen : smallpox : Rinderpest (cattle) : polio is very close-key will be to prevent transmission in Nigeria and India |
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newly emerging disease
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-population shifts
-travel and tourism -war, famine, refugees -new "superbugs" |
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nosocomial infections
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-commonly spread organisms
: Enterococcus, Staph, E.coli, Pseudomonas -Hospital reservoirs :sick and immmunocompromised people : health care workers -unique routes of transmission : via medical devices (implants, catheters) : health care workers (wash hands!) : airborne (positive pressure in rooms if designed right to try to minimize it) -some viruses infect people more in hospital |
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nosocomial infections
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-urinary tract: E. Coli
-respiratory tract: pseudomonas -surgical: staph, enterococcus |
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prevention of nosocomial infections
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-handwashing (50% reducing)
-gloves (body substance) -masks and eye protection (blood and body fluids) -supplemental (based on route of transmission) : airborne, droplets, contact precautions -private rooms - hospital infection control practitioner |
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a patient who had strep 3 weeks ago presents with cardiac sufficiency and valve malfunctions. what has happened?
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-his body is producing anti-strep antibodies
(immune mimicry) |
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Chronic illness
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-prevalence>>incidence
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what method does shigella use to spread disease:
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-oral
cause diarrhea |
