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chapter 14
infection, infectious disease, epidemiology
53
Microbiology
Undergraduate 2
10/16/2015

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Term
symbiotic relationship
Definition
relationship between 2 organism, often required due to nutritional needs

3 types: mutualism, commensalism, parasitism
*relationships between organisms may change over time
Term
mutualism
Definition
both members benefit from their interaction, some mutualistic relationships are required by one or both members while others are not required
Term
commensalism
Definition
one member benefits whiteout significantly affecting the other
Term
parasitism
Definition
the parasite derives benefit from its host while harming it, harm may range from slight to death
Term
which symbiotic relationship is often required by at least one of the organism?
Definition
mutualism
Term
normal microbiota in hosts usually have symbiotic relationships ___________, but sometimes may be ________
Definition
usually commensalism
others parasitic sometimes
Term
normal flora also known as
Definition
indigenour microbiota

microbes that colonize surfaces of body without normally causing disease
Term
which areas are colonized by microbiota
Definition
the areas that normally come in contact with the external environment SKIN, EXTERNAL EAR, MOUTH, STOMACH
Term
resident microbiota
Definition
part of the normal microbiota throughout life, most commensalism
Term
transient microbiota
Definition
remain in the body for only a few hours/days/month before disappearing
*dont persist because resident microbiota was initially established during your first months of life
Term
can normal microbiota become opportunistic pathogens?
Definition
YES!
- this happens when microbiota are found in unusual site of the body
- OR immune system is suppressed
-OR with changes in numbers or kinds of microbiota
Term
how can we be defensively compromised
Definition
hiv, cancer, chemo, smoking, stress bad diet, lack of sleep
Term
under what 3 circumstances would normal microbiota be beneficial?
Definition
1. right number and kinds
2. right places
3. we are defensively competent
Term
establishment of a pathogen
Definition
it must contaminate( or evade host, multiply) and then infect,(evade and damage host) and then cause disease
Term
infectious dose
Definition
the minimum number of pathogens that must enter to cause infection
Term
infection implies what?
disease implies what?
Definition
infection implies the pathogen can still increase in the host,
disease implies that the host is being damages in some way
Term
at state of infection are we damaged?
Definition
no not in any way
Term
damage due to pathogens is via
Definition
1. enzymes
2. toxins
3. antiphagocytic factors
Term
pathogenicity is a __________
Definition
PHENOTYPE!
(means it has ability to make disease but not that it always will)
Term
2 types of pathogens
Definition
1. opportunistic pathogen- has ability but needs opportunity (probably reduced immunity or opportunity needed)
2. true pathogen- can cause infection and disease no matter the state or health of host (DOES NOT MEAN IT IS MORE SEVERE) common cold and hiv are true pathogens
Term
examples of true pathogens
Definition
common cold
aids
Term
virulence
Definition
what allows for pathogenisity but also describes the intensity to which they are a pathogen (all pathogen have virulence but the level varies) HIV has high virulence, common cold has low virulence
Term
hiv has high ____________ common cold has low _______
Definition
virulence
Term
what gives an organism virulence?
Definition
virulence factors
(more of your genotypic characteristic)
(if flagella is present for purpose of causing infection, this is a virulence factor) (enzymes, toxins are also virulence factors)
Term
reservoirs of infectious disease of humans
Definition
the site where the pathogens are maintained as a source of infection
Term
what are three types of reservoirs?
Definition
1. animal:
-domesticated or wild
-zoonases- diseases spread naturally from usual animal hosts to humans (lyme disease, ring worm, malaria, rabies)
-direct contact with animals and their wastes, eating animals or via blood sucking arthropods

2. human
3. nonliving (soil, water, food)
Term
what are zoonases
Definition
disease spread naturally from usual animal hosts to humans
-rabies
-lyme disease
-ring worm
-malaria

*contract b=via animal contact or animal waste contact, eating animals, or via blood sucking arthropods
Term
human reservoirs may be ________ or ________
Definition
symptomatic (carriers) or asymptomatic
Term
3 portals of entry for microbes
Definition
1. skin
2. micous membrane
2. placenta (for fetus)
Term
role of adhesion in infection
Definition
- some cells can change the adhesion factors overtime helping the pathogen evade the immune system and allowing the pathogen to attack more than one kind of cell.
Term
viruses and bacteria sometimes have surface lipoprotein and glycoprotein molecules called ___________ that do what
Definition
ligands
enable them to bind to complementary receptors on host cells (ADHESION FACTOR)
Term
bacterial cells that have lost the ability to make ligands- whether as a result of some genetic change or exposure to some physical of chemical agents become __________
Definition
harmless or avirulent
Term
disease
Definition
when injury from pathogen is significant enough to result in disfunction of the body

any change from a state of health

*disease is also known as morbidity
Term
signs vs symptoms
Definition
signs- objective
symptoms- what the patient feels (subjective)
Term
congenital vs hereditary disease
Definition
hereditary- genetically transmitted from parents to offspring

congenital diseases- present at birth, regardless of the cause (could be hereditary environmental or infectious)
Term
study of the cause of disease
Definition
etiology
Term
extracellular enzymes (virulence factor)
3 types
Definition
-pathogens secrete enzymes which enable them to dissolve structural chemicals in the body and thereby maintaing infection
-hyalaronidase and collagenase degrade molecules to enable bacteria to invade deeper tissues
Term
hyalaronidase
Definition
extracellular enzyme virulence factor
digests hyaluronic acid or "glue" holding animal cells together
Term
collagenase
and mucinase
Definition
extracellular enzyme virulence factor
breaks down collagen

micinase- breaks down mucus lining intestinal tract
Term
kinases
Definition
extra cellular enzyme virulence factor
staphylokinase and streptokinase
- digest blood clots allowing subsequent invasion into damaged tissues
Term
Toxins (virulence factor)
2 tpyes
Definition
toxins- harm or trigger host immune response causing damage
toxemia- toxins enter bloodstream

2 types: ENDOTOXIN AND EXOTOXIN

ENDOtoxin- central to their pathogenicity in that they destroy host cells or interfere with host metabolism
- cytotoxins: kill host cells in general affect their function
-neurotoxind- specificallyy interfere with nerve cell
-enterotoxins- affect cells lining the GI tract

ENDOTOXIN- gram negative bateria release lipid A or endotoxin which is part of the outer wall membrane when they die causing fever, inflammation, shock, bleeding, diarrhea, blood coagulation
Term
antiphagocytic factors include
Definition
- to limit the extent and duration of infections, the bodes phagocytic cells such as WBCS called macrophages engulf and remove invading pathogens
ANTIPHAGOCYTIC FACTORS INCLUDE

1. CAPSULES! are effective virulence factors because many capsules are composed of chemicals normally found in the body, as a result they do not trigger immune response and therefore phagocytes don't come. Capsules are also slippery stopping phagocytes.
Term
some bacteria produce chemicals that prevent the fusion of lysosomes with phagocytic vehicles, so the bacteria ____________
Definition
bacteria survives in the vesicle
Term
leukocidins
Definition
chemicals capable of destroying phagocytic white blood cells outright
Term
incubation period
Definition
the time between infection occurrence and the first symptoms or signs of disease.
- length depends on virulence of the infective agent, the initial number of pathogens, state and health of patient, nature of pathogen and reproduction time, and site of infection,
Term
prodromal period
Definition
- a short time of generalized, mild symptoms that precedes illness
- not all have this stage
Term
illness period
Definition
- the most severe starve of an infectious disease
- has not gotten too bad yet
-usually when physician sees patient
Term
decline period
Definition
- body gradually returns to normal
-symptoms subside
- immune products peak
- if patient doesn't recover, disease is fatal
Term
convalescence
Definition
patient recovers from illness, tissues repaired, returns to normal.
Term
portals of exit for pathogens
Definition
- earwax, tears, nasal secretions, saliva, sputum, respiratory droplets, blood, vaginal secretions, semen, milk, excreted bodily wastes
Term
modes of infectious disease transmission
Definition
1. contact transmission: direct contact, indirect contact(spread by fomites or inanimate objects that are inadvertently used to transfer to host), droplet
2. vehicle transmission: airborne, waterborne, foodborne, bodily fluids
3. vector transmission: biological, mechanical
Term
airborne transmission is what mode

aerosol?
Definition
contact transmisison (droplet) involves the spread of pathogens father than one meter to the respiratory mucous membranes of a new host via an aerosol or cloud of small droplets and solid particles suspended in air.

aerosols can contain pathogens in dust or droplets
Term
aerosols come from
Definition
sneezing coughing, air conditioning, sweeping, mopping, changing clothes or bed linens, or from flaming inoculation loops
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