Medical Microbiology And Epidemiology Flashcards
Define Pathology
- study of disease
- refers to the disease “process” of a particular pathogen
Define Etiology
- studies of the causes of disease
- refers to a specific cause
Define Pathogenesis
- development of disease
- refers to all the processes of damage that a microbe does when it establishes an infection
Define case
- a person with a specific infection
- can be obvious (Frank Case)
- not obvious: carrier
Define carrier
- a person who doesn’t know they have an infection
- asymptomatic
- subclinical
Define reservoir
- where you expect to find a particular microbes (source)
- Specialists (people)
- zooonotic (animals)
- environment (soil)
What are portals of entry? Examples?
- ways a pathogen can enter a body
- Respiratory tract (inhalation)
- gastrointestinal tract (ingestion, sexual)
- urinary tract (urethra)
- reproductive system (sexual)
- skin (wounds, bites)
- direct contact with mucosa or compromised skin
What are portals of exit? Examples?
- How a pathogen gets out of the body
- respiratory secretions
- gi tract (fecal matter)
- blood transfusions
- urogenital tract
What is a communicable disease?
- infectious diseases where person to person transmission is possible
- some are easy to transmits (in casual contact)
What does contagious mean in terms of transmission
-easy to transmit from person to person
What are non communicable diseases
-come fro microflora (displaced microbes) or from environmental reservoir or from zoonotic pathogens
What some examples of vehicles? (3)
- water
- food
- air
What are fomites?
- inanimate objects that can carry a pathogen
- Examples-latches in a bathroom, stehscopes
Types of direct transmittion
- contact: kissing, sex
- droplets: colds, chickenpox
- vertical: HIV syphillis
Types of indirect transmission (3)
- formites
- food, water, biological products
- air
What are vectors?
- invertebrates animals that can carry pathogens from one host to another
- tick bite
What is an infectious dose (ID)?
- # of microbes to establish an infection
- ID 50: dose the infects 50% of lab animals
Describe how high/low IDs effect how infectious it is
- Lower ID: more infectious/virulent
- higher ID: less infectious
What is the most infectious virus?
Measles: takes 1 virion to be infectious
What is the chain of infection?
Organism > Reservoir > transmission > susceptible host
What is morbidity?
-disease/ illness
What does incidence refer to?
- new cases
- time/100000
Define prevalence
-# of existing cases
What are the measures of morbidity?
-incidence > prevalence
Define remission
- disease is “on hold”
- patient has recovered, but pathogen is still present and can cause future relapse
What is seroprevalence?
- rate of positive antibody test in a population vs a pathogen
- detects active cases + recovered cases (latent too)
Endemic
-Where you expect to find the pathogen/disease
Define Sporadic (occurrence)
- diseases that pop up randomly
- timing is inconsistent
What is an outbreak?
- sharp increase in cases
- limited to one geographic area
What is an epidemic?
-more cases that is not limited to one geographic location
Define Pandemic
- when an epidemic crosses one continent to another
- rapid increase in cases in multiple continents
Define Latency
-when a person seems to have recovered, but the pathogen is still in the body
What is a chronic carrier?
-a person who is either recovered or has mild symptoms but continue to transmit the pathogen
Define sequelae
-long term consequences that persist after recovery because of the damage done during the infection
What are nosocomial infections?
- aka healthcare associated infections
- infections that people get after they have been admitted in a healthcare facility
What are the most common types of nosocomial infections? (3)
- urinary tract (40%): Ecoli, P. Aeruginosa
- lower respiratory tracts (18%): S. Aureus, P. Aeruginosa
- surgical wounds (17%): Ecoli, P. Aeruginosa
What are the causes of Nosocomial infections (healthcare associated infections)? (3)
- microorganisms in healthcare associated environment
- chain of transmission (healthcare workers, fomites)
- compromised host
