lecture 35 Flashcards
what are the 5 stages in human response to disease
incubation period , prodromal period, illness, decline and Convalescence
describe the incubation period
the pathogen is beginning to multiply but the population is not yet big enough to cause any symptoms, but the pathogen has at this point invaded the host tissue.
describe the prodromal period
this is when we see the onset of the first vague symptoms of the disease.
describe the illness stage
for most infections this is when the symptoms are at their peak, this is the most infectious time during the immune response
describe the decline
the immune system, drug or therapy is at its highest level in the response. As these are in their highest response in this time there is the decrease in the pathogen population
describe the convalescence stage
all signs of the virus are now disappearing, still infectious in this stage.
what’s the cause of the common cold
a rhinovirus
what temp does a rhinovirus prefer to grow at and where does it find these conditions
32 degrees, this is not the temperature of core body but the air temperature in the nasal cavity
whats the chain of infection
the six required components for an infection to spread from one person to another
whats the study of disease transmission called
it is called epidemiology
what are the 6 key components of the chain of infection
Causative agent, A reservoir or source of infection, means of exit, mode of transmission, portal of entry and person at risk
define causative agent:
what causes the disease in the first place
define “ A reservoir or source of infection”
where can the bug be stored and be waiting for transmission
reservoir examples
Human / Animal / Fomite /
Food / Water
whats a fomite
objects or materials which are likely to carry infection, such as clothes, utensils, and furniture.
define means of exit
how does it leave the body? or leave the reservoir
means of exit examples
Via droplets, secretions or excretions
define the mode of transmission
how microorganisms are transmitted from one person/place to another
mode of transmission example
Contact / Airborne / Vector
define a vector
Vectors such as mosquitoes, fleas, and ticks may carry an infectious agent through purely mechanical means or may support growth or changes in the agent
define portal of entry
how does it enter the body?
examples of portal of entry
Respiratory, GI, GU, Mucous, Skin
define persons at risk and who is it
the people who are susceptible to the disease, mostly elderly children and the immunocompromised
stoping one link in the chain does
it prevents disease spreading, so if we cover the entry of portal for example. the virus can get in so no spread
whats a way to prevent the means of exit
So preventing the rhinovirus exit from the body by covering our mouths and nose with the elbow when cough or sneeze.
how can we stop the mode of transmission
disinfecting surfaces to stop the virus from gathering on a fomite. Also washing hands prevents the skin to skin contact transmission.
whats a method of preventing portal into the body
dont touch nose or face
define mortality
the rate of death in a population
define morbiditity
Morbidity: the number of people with the disease fatally or non fatally.
define incidence
Incidence: the number of new cases of a disease in a given time
define prevalence
Prevalence: total number of people with the disease in a population
define endemic
Endemic: a disease that is present in a population at all times
define sporadic
Sporadic: a disease that occurs infrequently or irregularly
define epidemic
Epidemic: an increase, often sudden, in the number of cases of a disease above what is normal.
define pandemic
Pandemic: an epidemic that has spread over countries or continents, usually infecting a large number of people.
