Chapter 15 study guide Flashcards
An ____ occurs when microbes
establish themselves in the body.
infection
A _____ is any condition in which the
normal structure or functions of the body
are damaged or impaired.
disease
of disease are objective
* measurable or observable by an outside
observer
* e.g., blood pressure, temperature,
blood counts, etc.
signs
of disease are subjective
* felt or experienced by the patient
* e.g., pain, fatigue, nausea, etc.
symptoms
A set of signs and symptoms associated
with a particular disease is a
syndrome
Many diseases are _____ or subclinical
* no noticeable signs or symptoms
* e.g., Herpes Simplex Virus (HSV-1 or HSV-2), Hepatitis C
asymptomatic
a disease that is spread from one host to
another
communicable diseases
: a disease that is not spread from one
host to another
non communicable disease
transmitted by an animal
* vertebrates (e.g., rabies)
* invertebrates (e.g., West Nile virus, Lyme disease)
zoonotic disease
Diseases acquired in hospital settings are
known as _________.
* also called Hospital Acquired Infections
(HAI)
* Affect 1 in 31 hospital patients
* over 70,000 deaths/yr
nosocomial diseases
Diseases that are contracted as the result of a medical procedure
are known as
iatrogenic diseases.
is a fire causing molecule that causes your body set point temperature to be higher
pyrogen
symptoms
develop rapidly but the
disease lasts only a short
time
* cold, flu, strep throat
acute
symptoms
develop slowly
* hepatitis B or C, HIV
chronic
causative
agent is inactive for a time but
then activates and produces
symptoms
* genital herpes, Epstein-Barr virus
latent
summarized his method for determining whether a
particular microorganism was the cause of a particular disease.
Kochs postulates
Kochs Postulates
(1) The suspected pathogen must be found in every case of disease and not be found in healthy individuals.
(2) The suspected pathogen can be isolated and grown in pure culture.
(3) A healthy test subject infected with the suspected pathogen must develop the same signs and symptoms of
disease as seen in postulate 1.
(4) The pathogen must be re-isolated from the new host and must be identical to the pathogen from postulate 2.
The ability of a microbial agent to cause disease is called
pathogenicity
the degree to which an organism is
pathogenic is called
virulence
molecular Koch’s postulates
- The phenotype (S/Sx) should be associated only with pathogenic strains
of a species. - Inactivation of the suspected gene(s) should result in a measurable loss
of pathogenicity. - Reversion of the inactive gene should restore the disease phenotype.
ID50 for Selected Foodborne Diseases4
Pathogen
ID50
Hepatitis A virus
10–100
Norovirus
1–10
Rotavirus
10–100
A _____ can cause
disease in a host regardless of
the host’s resident microbiota or
immune system.
* influenza virus
* rabies virus
* Streptococcus pyogenes
primary pathogen
An ______ can
only cause disease in situations
that compromise the host’s
defenses.
* Staphylococcus epidermidis*
* Candida albicans*
* Pneumocystis jirovecci
opportunistic infection
State of pathogenesis
To cause disease, a pathogen must achieve 4 steps of
pathogenesis:
exposure (contact)
* adhesion (colonization)
* invasion
* infection
An encounter with a potential
pathogen is known
as
exposure
An anatomic site through which
pathogens can pass into host
tissue is called a ______
portal of entry
is the ability of
pathogenic microbes to attach to
the cells of the body
adhesion
molecules for binding to
host cells
* biofilm formation
adhesin
involves the
dissemination of a pathogen
throughout local tissues or the
body.
invasion
An initial infection is called a ____
infection.
primary
Sometimes a primary infection can
predispose the host to a ______.
* an infection caused by a
pathogen
different
* enabled because the host was
compromised by the primary infection
secondary infection
the presence of bacteria in blood
bacteremia
virus found in blood
viraemia
toxins found on blood
toxemia
When bacteria are not just
present, but are multiplying in
the blood, the condition is called
septicemia.
septicemia
may lead to a life-threatening
inflammatory condition called
a life-threatening decrease in blood
pressure (systolic pressure <90 mm Hg) that prevents cells and organs from receiving enough oxygen and nutrients.
septic shock
Hyaluronidase S in
Staphylococcus
aureus
Degrades hyaluronic acid that cements cells together to promote
spreading through tissues
Glycohydrolases
DNAse produced
by S. aureus
Degrades DNA released by dying cells (bacteria and host cells) that
can trap the bacteria, thus promoting spread
Nucleases
Phospholipase C of
Bacillus anthracis
Degrades phospholipid bilayer of host cells, causing cellular lysis, and
degrade membrane of phagosomes to enable escape into the
cytoplasm
Phospholipases
Collagenase in
Clostridium
perfringens
Degrades collagen in connective tissue to promote spread
Proteases
flaccid paralysis: stops muscle contraction
blocks the release of acetylcholine
botulinum toxin
spastic paralysis: stops uncontrollable muscle contraction. acetylcholine is continuous
tetanus toxin
Many eukaryotic pathogens express virulence factors similar
to prokaryotes
* Common fungal virulence factors include:
* Phospholipases
* Mycotoxins
* ergot
* causes gangrene or hallucinations & convulsions
* aflatoxin
* carcinogenic
* proteases (e.g., elastase)
fungal virulence
toxins that come from fungus
mycotoxin
- Large size limits effectiveness of immune factors
- Outer cuticle on some provides a protective barrier
- Antigenic variation
- Proteases suppress immune responses
- Host mimicry
- expression of surface glycans that mimic those on human cells
- May trigger exaggerated and/or inappropriate immune responses
helminth virulence factors
