Chapter 13 content Flashcards
Define human microbiota
all the microbes that reside on or with human tissue or fluids
Microbiome
describes the collective genomes of the microbes that reside in an ecological niche
What is the ratio of microbiome
Microbe: human cell
When are humans fully sterile
when unborn
Upon birth we acquire ________
microbiota
What percent of non human genetic material consists of endogenous retroviruses
8 to 10%
Does the microbiota fluctuate with general health
yes
The precise content of microbiota is _____________, begins at birth, and varies with age, sex, and over the lifespan of the individual
unique to that human
What are axenic conditions
state of a culture in which only a single species, variety, or strain of organism is present and entirely free of all other contaminating organism
What is the significance that vitamin deficiency is in some animals
microbes can be a significant nutritional source of vitamins
What is the significance of underdevelopment of immune system in most animals
microbes are needed to stimulate development of certain host defenses
What is the significance of absence of dental caries and periodontal disease in dogs, rats, hamsters
microbes are key players in caries’ formation and gum disease
What are the three main things the microbiota do for us
provide essential nutrients
lead to development of healthy immune system
microbiota can protect against pathogens
What is the cause of infection and disease in terms of microbes
when there is a lack of balance between equilibrium with microbes
Define infection
microbes penetrates host defenses, invades sterile tissue organ and multiplies to cause disease
Define disease
defined as any deviation from health
Define infectious disease
infection causing damage/disruption to tissues or organ by microbes or their products
Define pathogens
organism capable of causing disease in healthy persons with normal immune defenses
Define opportunistic pathogens
not pathogenic to a normal healthy person, also organism causing disease when the host’s defenses are compromised or they grow in a part of the body not natural to them
how are infectious disease different from normal disease
communicable from person to person and will cause same disease
Define pathogenicity
ability of a microbes to establish itself in the host and cause damage/disease
Define virulence
the degree to which an organism is pathogenic, it determines a microbes abiltiy to establish itself and cause damage
Define virulence factor
genetically encoded structures, characteristics or products of the microbe that contribute to the infection or disease state
What are invasin
establishment of an alien microbial type in a resident community
what are virulence factors
invasin
vi antigen
endotoxin
exo enzyme
Define endotoxin
toxin present in a bacterial cell and is released when the cell disintegrates
What is an exoenzyme
excreted enzyme
What is the most lethal toxin known
C botulinum exotoxin
describe what C botulinum looks like
large protein with many subunits
Where does C botulinum bind to
binds selectively and irreversibly to nerve cell receptors, interfering with neural transmission by blocking the release of Ach, causing muscle paralysis
Define toxins
specific chemical products of microbes that promote infection and disease by directly damaging host tissues and disabling the immune system
What are exotoxins
proteins with a strong specificity for a target cell and extremely powerful, deadly effects, by damaging the cell membrane and initiating lysis or disrupting intracellular function
What are exotoxins produced by
bacteria and fungi
What are hemolysins
exotoxins that cause lysis of red blood cells
What does the exotoxin C. botulinum do
interfere with transmission of nerve muscle stimuli
What does C. tetani exotoxins do
block the action of certain spinal neurons
Do viruses produce toxins
no
Define symptom
subjective evidence of disease as sensed by the patient
Define assymptomatic
infections that do not produce overt indication
define syndrome
when a disease can be identified or described by a defined collection of signs and symptoms
What are signs
evidence of disease by an observer
Define incubation period
time from initial contact with the infectious agent to the appearance of first symptoms; agent is multiplying but damage is insufficient to cause symptoms
Define prodromal stage
vague feelings of discomfort; nonspecific complaints
Define period of invasion
mulitplies at high levels, becomes well established, more specific signs and symptoms
Define convalescent period
as person begins to respond to the infection, symptoms decline; in an event that the patient does not recover and dies the infection is terminal
What does it mean when disease is communicable
capable of spreading person to person
Define contagious
how easy an infectious disease spreads from person to person
What does the severity of contagion depend on
pathogen and mode of transmission
T/F infectious disease can be contagious during any stage of disease
T
which periods of disease are more likely to be associated with transmissibility
depends on the pathogen
Define nosocomial infection
infections acquired during a hospital/clinical visit that was not there originally
What does duration of infection depend on
pathogen
immune response
medical treatment received
Define acute infeciton
rapid onset with severe but short lived effects
Define chronic infection
infections that progress and persist over long periods of time
Define latent infection
casual pathogen goes dormant for extended periods of time with no active replication and therefore no host symptoms and signs
Which portal is most used by pathogens
respiratory
Define infectious dose
minimum number of microbes to cause disease
Bacterial, fungal, and protozoal pathogens attach most often by appendages and surface structure such as
fimbriae, pili, or adhesive slimes
Define adhesion
microbes gain a stable foothold at the portal of entry; depend on binding between specific molecules on host and pathogen
What do virulensce factos directly contribute to with phase 3
tissue damage
What is the initial response of phase 3
white blood cells called phagocytes
Following invasion, successful multiplication of the pathogen leads to
infection
What is systemic infection
throughout the body
What is focal infection
breaks loose and disseminates
What is polymicrobial or mixed infection
more than one species
Define primary infection
can practically be viewed as the root cause of an individuals current problem
Define secondary infection
complication of the primary infection
Define latency
after the initial symptoms in certain chronic diseases, the microbe can periodically become active and produce a recurrent disease that may or may not shed during the latent stage
Define carrier
individual who inconspicuously shelters a pathogen and spreads it to others
incubation carriers
spread during incubation period
convalescent carriers
reoperating without symptoms
chronic carrier
individual who shelters the infectious agent for a long period
Define epidemiology
study of the frequency and distribution of disease and other health related factors in defined human populations
