Principle of Disease and Epidemiology Flashcards
Define pathology
the study of disease
Define etiology
the cause of a disease
Define pathogenesis
the development of disease
Define infection
invasion or colonization of the body by pathogens
Describe disease
an abnormal state in which the body is not performing normal functions
Define translet microbiota
may be present for days,weeks, or months
not our normal microbiota
Define normal microbiota
permanently colonize the host and do not cause disease under normal conditions
Define human microbiome project
analyzes relationship between microbial communities on the body and human health
Describe4 factors distribution and composition is determined by … (normal microbiota)
nutrients
physical and chemical factors ( pH.temp)
host defenses
mechanical factors
Where is the normal microbiota located
nose throat eyes mouth skin large intestine urinary reproduction
Region: Skin give examples (3)
Staphylococcus, corynebacterium,micrococcus candidal ( fugus)
Region: Eye
example(3)
staphlococcus epidermidis
S.aureus
micrococcus
Region: nose (2) and throat ( upper respiratory system) (3)
example
staphylococcus areus, s.epidermidis -mose
s.epidermidis, s aureus, neisseria-throat
Region: mouth
example (3)
streptococcus
lactobacillus
neisseria
region: large intestine
example (4)
e.coli
lactobacillus
enterococcus
candida ( fungus)
Region: urinary and reproductive system
example(4)
staphylococcus
micrococcus
enterococcus
klebsiella
What are 3 terms of relationship between microbiota and host
microbial antagonism ( competitve exclusion)
probiotics
symbiosis
Describe microbial anatagonism
a competition between microbes
What are 3 ways normal microbiota protect the host by
1) competing for nutrients
2) producing substances harmful to invading microbes
3) affecting pH and available oxygen
Describe probiotics
live microbes applied to or ingested into the body,intended to exert a beneficial effect
Describe symbiosis and 3 types
relationship b/t normal microbiota and the host
commensalism
mutalism
parasitism
Define commensalism
one organism benefits and the other is unaffected
ex. corynebacteria
Define mutalism
both organisms benefits
ex. E.coli ( synthesis vitamin B, K; we give nutrients to E.coli)
Describe parasitism
one organism benefits at the expense of the other
ex. pathogens
What is opportunistic pathogens
e.coli making way to other part of body
Define epidemiology
study of occurrence distribution and determinants of health and disease in a population
Define incidence of a disease
number of people in a population developing the disease during a particular time period ( number of new cases)
Define prevalence of a disease
total number of people in a population affected by the disease at a particular time period ( # of old and new cases)
Define mortality
incidence of death in a population due to a particular disease
Define morbidity
incidence of a disease in a population which includes a fatal and non-fatal cases
Define infectious disease
disease caused by microorganisms
What are 4 classification of infectious disease
1) According to the spread of the disease
2) According to the severity or duration of the disease
3) According to the frequency of occurrence of the disease
4) According to the extent to which the human body is affected
What are the 3 diseases according to the spread of the diseases
1) Communicable disease
2) Contagious disease
3) Non-communicable disease
Define communicable disease
spread from 1 host to another
ex.tuberculosis,typhoid, measles,chickenpox
Define contagious disease
a communicable disease that spreads very easily and rapidly from 1 host to another
ex. chickenpox and measles
Define non-communicable disease
does not spread from 1 host to another
ex. tetanus
What are 4 disease type according to severity or duration of the disease
1) acute disease
2) chronic diseases
3) subacute disease
45) latent disease
Define acute diseases
symptoms develop rapidly but last only a short time
ex. cold,pneumonia
Define chronic diseases
symptoms developed slowly ) months to year)
ex. tuberculosis,hep B
Define subacute disease
intermediate between acute and chronic
Define latent disease
disease with a period of no symptoms when the causative agent is inactive
What are 4 diseases according to the frequency of occurence of the disease
sporadic disease
endemic disease
epidemic disease
pandemic disease
Define sporadic disease
disease that occurs inly occasionally
ex. typhoid,malaria,dengue - in the US)
may not be sporadic in other parts of world
Define endemic disease
a disease that is constantly present in a population or a region
ex. cold and malaria
Define epidemic disease
dissease acquired by many people in a given area in a short time
ex. influenza, food poisoning,viral diarrhea
Define pandemic disease
an epidemic disease that occurs worldwide
ex. avian influenza
What are 2 infections according to the extent to which the human body is affected
Local infection
systemic ( generalized ) infection
Define local infections
infections that affects a small area of the body
Define systemic infections
infections that spread throughout the body
Define bacteremia
bacteria in the blood
Define septicemia
also known as blood poisoning; growth of bacteria in the blood
Define toxemia
presence of microbial toxins in blood
Define viremia
presence of viruses in blood
Define subclinical infections
infections that are present in the body but do not cause any apparent illness or disease
ex. hep A virus, typhoid bacteria, HIV
What are 8 predisposing factors
1) gender
2) inherited traits
3) climate and weather
4) fatigue
5) age
6) lifestyle
7) nutrition
8) chemotherapy
What are the 5 periods for development of disease
1) incubation period
2) prodromal period
3) period of illness
4) period of decline
5) period of convalescence
Define incubation period
time interval between the initial infection and the 1st appearance of signs and symptoms
Define prodromal period
short periods after incubation; early,mild symptoms
Define period of illness
disease is the most severe
pt can die during this period
Define period of decline
signs and symptoms subside
Define period of convalescence
body returns to its pre-diseased state
What are the 3 reservoirs of infection
Human reservoirs
animal reservoirs
nonliving reservoirs
Define human reservoirs
carriers: may have inapparent infections or latent diseases
ex. typhoid, AID, hep B, Covid
Define animal reservoir
zoonoses are diseases transmitted from animals to humans
ex. wild/ doesmotic animals ( via direct contact/aerosol)
Define nonliving reservoirs
soil and water
ex. tentus,ringworm, gi disease ( typhoid,cholera)
What are 3 modes of transmission of disease
1) contact transmission
2) vehicle transmission
3) vector transmission
What are 3 forms of contact transmission
direct contact transmission
indirect contact transmission
droplet transmission
Define direct contact transmission
requires close association b/t the infected and a susceptible host
ex. aid, hep, influenza. measles
Define indirect contact transmission
spreads to host by a nonliving object called a fomite
ex. towels,drinking cup
hep B,aid, conjugivitis
Define droplet transmission
transmission via airborne droplets less than 1 meter
ex. sa;via,mucous, flu, URT
What are 3 vehicle transmission
transmission by an inanimated reservior
1) waterborne
2) foodborne
3) airborne
What are 2 forms of vector transmission
arthropods, especially fleas,ticks, mosquitos
mechanical transmission
biological transmission
Define mechanical transmission
arthropod carries pathogen on its feet
ex. flies on food
Define biological transmission
pathogem reproduces in the vector; transmitted via bites or feces
ex. tapeworm
Define nosocomial infection
healthcare-associated infection
acquired while recieving treatment in a healthcare facility
affects 1 in 25 hospital patients
Define compromised host
an individual whose resistance to infection is impaired by disease, therapy or burns
Give 4 examples of nosocomial infections
1) e.coli (UTI)
2) Staphylococcus aureus ( surgical wound)
3) candida ( UTI)
4) Klebsiella pneumoniae ( all sites)
What are 4 ways of control of nosocomial infection
1) handwashing
2) disinfecting tubs used to bathe patients
3) cleaning instruments scrupulously
4) using disposable banages and intubation
2 big ways of controlling nosocomial infection
1) reduce number of pathogens
2) infection control committees
