Path means disease Pathogens refer to microorganism capable to cause a disease Pathology the study of structural and functional manifestation of disease Pathologist a physician who has specialized in pathology ID: 361565
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Slide1
Pathogenesis of infectious diseaseSlide2
Path means disease
Pathogens refer to microorganism capable to cause a disease.
Pathology : the study of structural and functional manifestation of disease.
Pathologist : a physician who has specialized in pathology.
Pathogenicity
: the ability to cause a disease
Pathogenesis : is the step or mechanisms involved in development of a diseaseSlide3
Phs
in the
corse
of an infectious disease:
Incubation period: is the time that elapses between arrival of the pathogens and the onset of symptoms. And it is varies by many factor as health state-virulence of the pathogens- number of pathogens that enter the body.
Prodormal
period: is the time during which patient feels out of sorts but not yet experiencing actual symptoms of the disease.
Period of illness: is the time during which the patient experiences the typical symptoms associated with that particular disease .(headache – sore throat-sinus congestion) Slide4
The convalescent period: is the time during which the patient recover.
Localized infection
Systemic infection
Acute infection : rapid infection followed out by rapid recovery (measles-mumps-influenza)
Chronic infection : slow insidious and last for long time
Symptoms of a disease: define as some evidence of a disease that is experienced by the patients.
( headache-fever-pain-itching)
Asymptomatic disease
Sign of a disease: define as some objective evidence of a disease that is experienced by the patients. (skin rash-
enlargment
of the spleen)Slide5
Latent infection : an old infection that was contained by the body but may re-activate at any time as ( ?)
Primary infection: is the infection that the body get exposed to for the first time .
Secondary infection : is an infection that follows a primary infection. Slide6
Step in the pathogenesis of infections disease:
Entry:
of the pathogen into the body by: (Penetration, inhalation, ingestion and introduction of the pathogens directly into the blood. [shades needles]
Attachment:
of the pathogen to some tissues within the body.
Multiplication:
with local or system
Invasive / spread
of the pathogens
Evasion of a host defenses
.
Damage to host tissue (s).
extensive or death.Slide7
Virulence:
is measure or degree of
pathogenecitiy
. different organism vary in their ability to cause disease some strain
virulence
some is
a virulence
.
Virulence factor:
are the phenotypic characteristics of a microorganism that enable it to cause disease. Slide8
Structural
features
as
pili
,capsule, flagella
. It
help
adhesion: which is molecule on the surface of the pathogens that able to recognize the reception on the host cell: that is glycoprotein molecule on the surface of the host cell that the adhesion on the pathogen attach to it.
Obligate intracellular pathogens
.
Facultative intracellular pathogens
.
Capsules:
antiphagocytic
by WBC. (No receptor).
Flagella
: move and invade the aqueous area in the body it avoid
phagocytosis
.Slide9
Exoenzymes
:
is the two major virulence factors by which bacteria cause disease the
exoenzyme
as
(a)
coagulase
as in
staphaurus
: clot plasma → sticky coat → protect it from phagocytes.
(b)
kinases
: →
streptococcus &
stophausus
: body produce
fibricolt
→
kinases
→
lysis
.
(c)
hyaluronidase
: enable organism to spread through connective tissue by breaking down
hyaluronic
acid.
(d)
collagenase
: Break down the collagen to invade tissue.
(e)
hemolysins
: damage RBC.
(f)
lecithinase
: damage extensive area of tissue.Slide10
Toxins:
there are
endotoxins
that
is integral part of
the cell wall of the gram-negative
bacteria can cause a number of adverse physiologic effect.
Exotoxins
are
the toxins
that produced within the cells and then releases from the cell example
:
Neurotoxins= that cause paralysis.
Enterotoxins
= gastro intestinal disease.Slide11
Mechanisms by which pathogens escape immune responses:
The pathogens
change their surface antigens example:
influenze
virus, HIV and
nisseria
.
The pathogen's surface antigens closely resemble host antigens and therefore not recognized by immune system = molecular mimicry.
Destruction of the host antibodies by producing enzyme as (
IgA
protease) that destroy
IgA
.