Chapter 14: Pathogens, Disease, and Epidemiology Flashcards
Define: microbiome
the collection of fungi & archaea found (in) & on the human body
Define: normal flora
REDIDENT FLORA
organisms colonized w/after birth stay w/you rest of life
Define: transient flora
Occasionally picking up some pathogenic some aren’t
3:1 (microbial cells: human cells)
Define: microbial antagonism
competition cover attachment sites that might be available to pathogen
Help develop the immune system
Define: opportunistic
pathogen
microorganisms that cause disease when the immune system is suppressed when microbial antagonism is reduced or when introduced into an abnormal area of the body
Define: reservoir of infection
a site where pathogens are MAINTAINED as a source of infection (for a long time)
1)human reservoirs
2)human carriers
3) nonliving reservoirs
Define: virulence
the degree of pathogenicity of a microbe (how good it is @ causing disease)
Define: virulence factor
Aviralent
traits that allow pathogens to cause disease → traits that aid growth & avoid immune cells
1) An Adhesion mechanism
2) Extracellular Enzymes
3) Toxins
4) Antiphagocytic Factors
Aviralent: pathogen that loses its ability to make a virulence factor (can’t cause disease)
Define: fomites
objects inadvertently used to transfer pathogens to new hosts, such as glass or towel
Define: epidemiology
the study of the spread of disease in population
-helps determine source of infection & control methods
Define: incidence
of NEW cases of disease in a population or area
Define: prevalence
total # (new+existing) of a disease in a given population/geographical area
Define: endemic
disease that occurs in that REGION (always have some level of disease)
Define: sporadic
rare
Define: epidemic
can have disease
-more than normal # for specific population or area
Define: pandemic
many epidemic occurring in different areas
Define: disease
adverse body conditions that interferes w/normal body conditions
Define: symptoms
SUBJECTIVE(things that can’t be measured)
-complaints, what pt feels, includes headache, nausea, pain
Define: signs
OBJECTIVE (characteristics of a disease)
-can be seen by others
-swollen lymph nodes, fever, swelling
Define: syndrome
when a group of symptoms & signs collectively characterize a disease (AIDS)
Define: asymptomatic
if a disease has no symptoms (but may have signs)
Define: acute
disease that is rapid onset, brief (duration of symptoms)
Define: chronic
disease that is slow onset, continual or recurrent
Define: latent
inactive for a long time (long period of inactive months, years, no definitive reoccurrence
Describe the importance of the human microbiome.
WHERE DID ALL THESE MICROBES COME FROM?
-What microbes exist in certain diseases or pregnancy, bowel disease, type-2 diabetes
Distinguish between contamination and infection
Infection successful invasion of the body’s defenses the microbe can grow & have change in immunity infection but no disease or can get disease
Contamination acquiring microbes (@ birth contaminated w/microbes may not cause disease)
-transient or normal flora
List the 3 types reservoirs of infection in humans
- Animal reservoirs: disease spread by animals area called ZOONES
-Transmission: eating animal, contract w/waste, biological vectors (mosquito, flies), animal bites (transmit microbial pathogens)
-can be hard to control if reservoir is large and sylvatic wild animals - Human carriers: asymptomatic infected individuals, may or may not have previously shown disease symptoms
-Typhoid Mary - Nonliving reservoirs:
Water (Giardia/E.Coli)
Soil (Clostridium/Bacillus)
Food (E.Coli)
-fecal oral route
List the portals of entry that organisms can use to get into the body
1) Skin (good barrier)
Direct(burrow, digest)
Hair follicles & sweat glands
2) Mucus Membrane
Easier to cross than skin
Most common
3) Placenta
Not good barrier
List and describe the five stages of an infectious disease
INCUBATION PERIOD: time differ based on pathogen
PRODROMAL PERIOD: time of first mild, vague symptoms (# of microbes ↑)
ILLINESS PERIOD: symptoms are most severe & obvious most damaging to host ( highest # of pathogens)
DECLINE PERIOD: undergo treatment and/or full immune response to limit & destroy pathogen
CONVALESCENCE PERIOD: recovery w/ no signs/ symptoms there could be some pathogens in body. Tissue/damage is repaired
List the portals of exit that pathogens use to get out of the body
SKIN (broken- blood)
MUCUS MEMBRANES
BODY SECRETIONS
BODY WASTES
Describe the main types of virulence factors
o Describe the importance of adhesion to a pathogen.
1) Adhesion
infection requires attachment to a host
-adhesion factors ligands; bacteria
attachment proteins; viruses
provide host cell specificity
BIOFILMS indirect attachment via glycocalyx
2) Extracellular Enzymes
Secreted enzymes that aid the pathogens to survive in the host get nutrition/ evade immune cells
3)Toxins
chemicals that harm tissues or trigger immune responses that harm tissues
-Exotoxins secreted outside of cell/pathogen (s. aureus)
-Endotoxins: structural component of a pathogen (part of cell) that is released when the organism dies (lipid A)
4) Antiphagocytic Factors: against immune cells destroy invaders
-Chemicals or structures that prevent the completion of phagocytosis
-CAPSULES prevent phaygocyte from attaching pathogen
Distinguish between contact, vehicle, and vector transmission of disease
o List an example of each mode of transmission
1) Contact: pathogens spread by people or objects (fomites) people have touched
-Direct: “person to person”
ex: kissing, sex, placenta
-Indirect: Via fomites inanimate objects that carry pathogens
ex: toys, needles, money
Droplet Transmission: droplets travel less that 1 meter
2) Vehicle: pathogens spread by air, food, water, or donated fluids
-Airborne: droplets that travel more than 1 meter (by AC)
-Waterborne: any contaminated water source (fecal oral route)
-Foodborne: spoilage in food
-Bodily Fluid: handled outside of the body
ex: blood products, clinical fluid samples
3) Vector: pathogen spread by insect
-Biological vectors: pathogen reproduces within vector transmission of pathogen when vector bites animals
ex: mosquito, ticks. fleas
-Mechanical vectors: pathogen doesn’t reproduce within vector pathogen on feet or other body parts
ex: cockroach houseflies crawl through contamination & crawl on food to contaminate)
Explain how epidemiology is important to human health.
it helps determine the source of infection & control methods
Define Symbiosis
two organisms living in assocatition w/one another
Define Symbiosis
two organisms living in assocatition w/one another
3 types of symbiotic relationships
- Mutualism both organisms benefit
ex bacteria in human colon - Commensalism: one benefits other neither benefits nor is harmed
ex: staphylococcus on skin - Parasitism: one benefits other is harmed
ex: tuberculosis bacteria in human lungs
-parasite benefit @ harm of it’s host
