Microbe-Human Interactions: Infection

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Microbe-Human Interactions Infection Disease
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• I. Introduction
• A. Recall _______ Postulates (experimental steps
  to establish the
• microbe that causes a disease)
• 1. isolate a pathogen from a diseased host
  grow pathogen in pure
• culture
• 2. inoculate a healthy organism with the
  cultured pathogen
• 3. organism must get the same disease
• 4. isolate the same pathogen from the new
  host
• B. Exceptions to Kochs postulates
• 1. Microbes that cant be grown on
  artificial media
• examples
• 2. More than one microbe produces the same
  disease
• examples
• 3. One microbe that causes multiple diseases
• examples
• 4. Strictly human diseases with no animal
  model

Kochs
Rickettsia
Viruses
Treponema
meningitis
pneumonia
Strep throat
Streptococcus pyogenes
Scarlet fever
Rubella (German measles)
smallpox
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Normal Flora

• II. ____________ (microbes that normally live
  in/on the body w/o harm)
• A. _______ vs _________ flora
• (always there) (only present for a short
  time or on and off)
• B. Establishment of Normal Flora __________
• 1. Newborns are free of flora, but
  established as infant is exposed to
• organisms from _______, _____, ______ etc.
• 2. Colonization is a selective process due to
  physiological conditions in
• the body such as _____, ___________, ____,
  ________, etc.
• 3. Takes about ____________ to fully
  establish normal flora
• C. __________ (different organisms living
  together)
• 1. __________ (both partners benefit)
• E. coli produces vitamins K some B, and
  ___________
• (chemicals that ward off harmful species)
• 2. ___________ (one partner benefits, other
  is neutral)
• skin organisms live off of secretions/sloughed
  cells
• 3. _________ (one partner benefits while the
  other is harmed) many
• bacteria, fungi, protozoans, worms
  and even viruses

Resident
Transient
Colonization
food
vagina
air
temperature
O2
nutrients
pH
12-18 months
Symbioses
Mutualism
bacteriocins
Commensalism
Parasitism
parasite
host
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• D. ____________ organisms (organisms that
  are usually nonpathogenic,
• but that can become pathogenic under certain
  circumstances)
• 1. when host health is compromised
• 2. when there is a reduction of normal
  flora
• 3. if an organism gets in a different_______
  (part of the body)
• III. Mechanisms of ____________ (disease
  development)
• A. Production of disease is actually a process
  of steps
• 1. ____________ to a susceptible host
• 2. ___________ to appropriate target
  tissue(s)
• 3. ________
• 4. __________
• 5. ________ to host while evading defenses
• 6. _____ from body
• 7. _________ outside long enough to be
  transmitted to another host

Opportunistic
habitat
E. coli from gut to urinary tract
Klebsiella pneumoniae from gut to respiratory
Pathogenesis
Transmission
Adherence
Invasion
Colonization
Damage
Exit
Survival
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B. Transmission must be to the correct portal of
entry 1. typically to exposed surfaces such
as ______ or _______ membranes (which is not
an easy thing to do!) 2. entry aided by
_____, ____, ________, _________etc. a.
Gastrointestinal tract (via ______, _____)
bacteria, especially Gram- _______ bacilli
viruses such as polio and Hepatitis
A protozoans such as Entamoeba and Giardia b.
Respiratory tract (via ____) bacteria that
cause strep throat, diphtheria, pertussis
viruses such as influenza, measles, mumps,
rubella, chickenpox and the common cold
fungi such as Histoplasma and Pneumocystis
c. Urogenital tract (most are _____) (or
misplaced opportunists) bacteria such as
Neisseria, Treponema, and Chlamydia viruses
such as papilloma and herpes protozoans such as
Trichomonas fungi such as Candida
mucous
skin
bites
punctures
cuts
abrasions
food
water
enteric
air
STDs
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Infectious dose
3. ________ ____ minimum number of
microbes necessary to insure infection (ex only
10-100 Shigella but 1,000,000 Salmonella) C.
Adherence (attachment) _________ (projections
of microbe that match host receptors) 1. pili
tips, surface proteins, etc. (can change b/c of
mutations so previous Ab dont recognize
them!) 2. same organism can have different
ligands to adhere to different
parts of the body (ex Haemophilus influenzae)
3. some ligand genes on plasmids can
spread like antibiotic resistance! 4. why
people dont get a lot of other animal diseases
and vice versa D. Invasion (in order to establish
infection) 1. high concentrations, more
likely to invade successfully 2. ___________
presence of bacteria in the blood
________ presence of viruses in the blood E.
Colonization (when conditions are such that
invading microbes are successful enough to
_________) __________ blood infection where
bacteria are reproducing
Ligands
Bacteremia
Viremia
reproduce
Septicemia
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phagocytosis

• F. Evade host defenses (mainly by avoiding
  ____________)
• 1. ________ (Streptococcus, Salmonella,
  Neisseria)
• 2. __________ are substances that are toxic to
  WBCs
• 3. _________ breaks down H2O2 produced by
  phagocytes, preventing
• digestion of the engulfed microbe
• Cause Damage/Disease
• 4. _______ (poisonous substances) (________
  when in the blood)
• a. _____ toxic soluble proteins secreted
  (botulism, tetanus)
• ___________ cause lysis of RBCs
• b. _____ cell wall components released when
  cell dies, toxic to
• host (lipopolysaccharides in Gram-negative
  cell walls)
• 5. ____________ (act on host cells/tissues)
• a. __________ activates prothrombin to
  coagulate fibrinogen in
• plasma, forming a fibrin clot that hides the
  microbe from
• phagocytosis
• b. ___________ breaks down blood clots in
  order to spread
• c. _____________ spreading factor breaks
  down hyaluronic acid

Capsules
Leukocidins
Catalase
Toxins
Toxemia
Exo-
Hemolysins
Endo-
Can lead to Septic shock
Exoenzymes
Coagulase
Fibrinase
Hyaluronidase
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The effects of Hyaluronidase can be drastic!
Late stage necrosis of epidermis, subcutaneous
layers, fascia, and musculature of upper lateral
leg. Necrosed peripheral nervous tissue results
in no perception of pain at wound site!
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G. Development of Disease 1. __________
period (between infection and 1st
signs/symptoms) Depends on dose of
microbes, which microbes, virulence, host health
a. typhoid fever 10-14 days b.
AIDS 10 years! (allows more spreading!) (2).
_________ period of 1-2 days follows incubation
in some diseases ( early, mild
signs/symptoms such as _______, _______,
____________, etc. ) 3. ______ period when
the disease is acute and ______most likely
a. _______/______ b. ? numbers of
___________ (gt 10,000/ml) c. swollen
_____ _____ d. ______________
e. ____________ f. severe ____ 4.
Recovery ________ period (1-few days)
when signs/symptoms are subsiding
BUT most susceptible to secondary, ___________
infections ____________ period needed to
regain strength
Incubation
Prodromal
malaise
fatigue
muscle aches
Illness
Death
Chills
Fever
Leukocytes
lymph nodes
Nausea/diarrhea
Rashes/lesions
pain
Decline
Opportunistic
Convalescent
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H. Disease Terminology 1. _____ infection
(limited to point of entry) Vs _____
infection (spreads to a new location) Vs
________ (infection that spreads to several sites
and the blood) 2. ______ diseases
develop fast but for a short duration Vs
_______ diseases develop slow but for a long
duration Vs ______ diseases may be
inactive for long periods of time 3. ________
(identification) of a disease is dependent upon
_________ of a disease are subjective
changes in body function Vs _____ of a
disease are objective (measurable) changes
Local
wart
boil
Focal
rabies
Hepatitis A
appendicitis
tonsillitis
Systemic
Tooth abscess
syphilis
measles
chickenpox
influenza
Acute
cold
Chronic
TB
leprosy
Latent
Cold sores
Genital herpes
Diagnosis
Symptoms
sore throat
pain
aches
malaise
Signs
fever
rash
inflammation
lesions
edema
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A _________ is a group of symptoms/signs
characteristic of a certain disease.
A _________ infection is asymptomatic,
but patient is still infectious
(more common in children)
Syndrome
Rubella syndrome
Subclinical
I. Exit by means of 1. ______/_______ 2.
________ 4. ____________ 3. ____ /_______
5. _____ J. Survival outside long enough to
gain entry into a new host 1. Some can also live
in the environment 2. Some are hardy and can
survive for as long as several weeks
before a new host comes along 3. Some hang out
in animal__________ 4. Some require direct
contact b/c they are fragile K. Pathogenesis
depends on many factors 1. Genetics, both
species and individual 2. state of host
health 3. age (_______ ________have less
capable immune systems) 4. ________ (causes ?
corticosteroids that are immunosuppressive)
Sneeze
Cough
Insect bites
Diarrhea
Sex!
Pus
Blood
Clostridium tetani
Mycobacterium tuberculosis
reservoirs
Rabies, RMSF
Treponema pallidum
Infants
Elderly
Stress
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Epidemiology The study of Disease in
Populations
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Epidemiology

• IV. ___________ study of frequency and
  distribution of disease in
• order to set guidelines for disease
  prevention and control.
• like detective work to determine the cause,
  reservoirs, transmission, portals of entry/exit,
  etc.
• A. ____________ is essential to make
  predictions
• 1. National ________________________
  Prevention (CDC)
• located in Atlanta, Georgia
• 2. _______________________________
  (MMWR) tracks over
• 50 diseases carefully b/c hospitals,
  Drs., coroners, etc. REPORT
• them AIDS, STDs (such as gonorrhea,
  syphilis, Herpes), measles,
• tetanus, TB, hepatitis, rabies, chicken pox,
  malaria, etc.

Case reporting
Centers for Disease Control
Morbidity Mortality Weekly Report
www.cdc.gov/mmwr/
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World Health Organization
3. _______________________ (WHO) plans which
diseases will be targeted for
eradication (such as smallpox, accomplished in
1979, and polio, targeted for 2009). B.
Epidemiologic Statistics Frequency of Cases
1. __________ total number of existing cases
with respect to the entire population
(usually expressed as a __________) a
snapshot to help assess the overall impact of a
disease example 100 people have a
disease.. a. out of 500,000 people
(0.02) not a big deal, but b. out of 500
people (20) is a big deal 2. _________ of
____ cases in a specific time period compared
with the general healthy population (usually
expressed as cases per 100,000
people) a. indicates both the _____ and ____ of
infection b. also called the__________ rate or
________ rate A class of 50 students w/o
influenza (P I both 0 because 0/50 have
influenza) becomes exposed to influenza 1st
week, 5 students become ill. P ____ and I __
in 10 2nd week 5 more students become ill P
____ and I __ in 10 2nd week 5 more students
become ill P ____ and I __ in 10 w/
1st 5 students recovered
Prevalence
percentage
Incidence
new
risk
rate
Disease
Morbidity
1
10
20
1
1
10
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Incidence of pneumococcal disease (per 100,000
people)
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3. _________ rate percentage of people who die
from a disease 4. Terms that describe disease
frequency a. _________ a disease that is
always present in a population
(steady frequency) b. ________ a
disease that only pops up occasionally at
irregular intervals in random locales
c. _________ a lot of people get a disease in
a short time (increasing frequency)
d. _________ a worldwide epidemic C.
Investigative Strategies of the Epidemiologist
1. Determining ________ ( continual ______ of
infectious organisms) a. ________ are
asymptomatic people that can spread disease
(1). _________ (50 of infected females are
asymptomatic!) (2). ________ Mary
precautions can be taken if humans
are the only reservoir, it should be easier to
control
Mortality
Endemic
common cold
Sporadic
Typhoid fever
diphtheria
Epidemic
Gonorrhea
Chlamydia
Pandemic
influenza
AIDS
Reservoirs
source
Carriers
Gonorrhea
Typhoid
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3. _________ rate percentage of people who die
from a disease 4. Terms that describe disease
frequency a. _________ a disease that is
always present in a population
(steady frequency) b. ________ a
disease that only pops up occasionally at
irregular intervals in random locales
c. _________ a lot of people get a disease in
a short time (increasing frequency)
d. _________ a worldwide epidemic C.
Investigative Strategies of the Epidemiologist
1. Determining ________ ( continual ______ of
infectious organisms) a. ________ are
asymptomatic people that can spread disease
(1). _________ (50 of infected females are
asymptomatic!) (2). ________ Mary
precautions can be taken if humans
are the only reservoir, it should be easier to
control
Mortality
Endemic
common cold
Sporadic
Typhoid fever
diphtheria
Epidemic
Gonorrhea
Chlamydia
Pandemic
influenza
AIDS
Reservoirs
source
Carriers
Gonorrhea
Typhoid
Dont go out
Dont drink after
Dont have sex!
Dont kiss
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b. Nonhuman animals (1) ________
vector (part of the pathogens life cycle)
(2) _________ vector (just carriers)
(3) _________ an animal disease we can get

biological
mosquitoes
cockroaches
mechanical
houseflies
Zoonosis
plague
RMSF
rabies
anthrax
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Environmental
c. ____________ (soil, water, food) 2. Terms
for transmission of infectious agents a.
___________ diseases are spread from one person
to another b. Communicable diseases are
called _________ if easily spread c.
______________ diseases (you cannot get them from
another person)
tetanus
Salmonella
cholera
Communicable
Herpes
measles
Common cold
Contagious
Chickenpox
Noncommunicable
tetanus
botulism
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3. Patterns of communicable disease transmission
a. _______(Physical, person-to-person) A
portal of exit meets a portal of entry! ? 1
meter (close proximity) common in crowds,
elevators (1) _______ spread (mother to
fetus/infant) (2) _________ spread (anybody
else to anybody else) b. ________
(1) _______ (inanimate objects) (2)
______/______ (especially GI parasites) (This
transmission can be from the ________
or from __________ fecal-oral) (3)
_______ nuclei (small, dried up on dust, carried
by air currents) good ventilation helpful
(dilutes) air filters help trap pressurized
air (out of operating rooms) damp mops better
than brooms
Direct
sex
kiss
Respiratory droplets/sneeze, cough
touch
Vertical
Rubella, STDs
Horizontal
Indirect
needles
used kleenex
Fomites
toys
eating utensils
Door knobs
Toilet seats
food
water
Source
Preparation
Salmonella eggs/chicken
Typhoid Mary
Droplet
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D. Areas of Epidemiology 1. _________
epidemiology occurs after disease outbreak and
describes the characteristics of ill people
a. ____ b. _____ c. ____
d. _________ e. ________
f. ___________ (to help figure out reservoirs)
g. ______ Common Source
Epidemic Propagated Epidemic
Descriptive
age
sex
race
occupation
Drug use?
lifestyle
Smoker?
Sexual activity?
Home location
Timing
Analytical
2. _________ epidemiology then determines which
risk factors identified by descriptive
studies are actually relevant by
_________ those with the disease to those without
the disease
comparing