Princ of Disease Path o Transmission

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Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Pathology (a.k.a. Host-Microbe Interactions)

The study of disease

Plague by rnold Boec!lin, "#$#

Etiology o% plague then&.

Yersinia pestis,'( (icrobelibrary

Etiology o% plague no)


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*rom ))). cen+online.org

ec. "-, 20"0


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.

umbero%hostsin%ected

time

Endemic

'poradic

Epidemic


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/ocalied 1s. 'ystemic In%ection

6. /ocal in%ection Pathogens are limited to small area

o% the body.

3. 'ystemic in%ectionn in%ection throughout the body.


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Primary 1s 'econdary In%ections

#. Primary in%ection Initial in%ection

$. 'econdary in%ection 4pportunistic in%ection )hich

%ollo)s primary 5opportunistic pathogen is one that isnt

7strong enough8 to cause a disease on its o)n9needs

a host that is already )ea!ened:


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cute 1s Chronic In%ection

"0. cute disease 'ymptoms de1elop ;uic!ly, but

se1ere, short+li1ed in duration..

"". Chronic disease isease de1elops slo)ly, less

se1ere, longer+lasting.


7/36Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings

osocomial 5



. (4s lur!ing in hospital

". hat are some common causes o% nosocomial

in%ections @esistant microbes 'ta%% patients *omites

2. hy arenosocomial strains o%ten more 1irulent than

non+hospital strains @esistance %actors trans%erred %rom mo to mo /ess resistant strains !illed o%% by antibiotics



@elati1e *re;uency o% osocomial In%ections

Dable "A.>



'ign 1s 'ymptom

"-. 'ign objecti1e change in a body that can be

obser1ed, measured Eamples

"A. 'ymptom 'ubjecti1e change in body %unctionEamples



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Prevent encounterswith phagocytes

C5a peptidase

Cytolytic toxins

Avoid recognitionand attachment

Capsules M protein

Fc receptors

C3b receptors

on phagocyte

Pseudopod

Survive within phagocytes

scape !rom the phagosome

Prevent phagosome"lysosome !usion

Survive within the phagosome

#ysosomes

$igestiveen%ymes

Phagolysosome

Phagocyte

Phagosome

C3b

Microbes

C5a

C3b

&

'

3

ntiphagocytic %actors



c;uisition and Dransmission

Communicable disease disease that is spread

%rom one host to another.

E


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B. Dransmission o% in%ection

a. irect contact Person+to+person touching, !issing,

se


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B. Dransmission o% in%ection

b. Indirect contact *omites contaminatedobjects

Eamples


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b. roplet: )et droplets li!e cough, sneeeF

tra1els less than " meter.


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2. GehicleDransmission by an

inanimate reser1oir

aterborne contaminated )ater

*oodborne improperly coo!ed

or handled


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c. irborne: )et droplets li!e cough, sneeeF

tra1els longer than " meter.


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-. Gectorsrthropods, especially %leas, tic!s, and

mos;uitoes. (echanicalrthropod carries pathogen on body. Biological Pathogen reproduces in 1ector.

Engorged %lea, CC


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/yme isease 7Bulls Eye8


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/yme isease in =.'., 20"A

5cdc.go1:


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Copyright 2006 Pearson Education, Inc., publishing as Benjamin CummingsFig. 23.14


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Buboes


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(mmm, yummyH


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ightmare on our


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G. e1elopment o% a isease Dhe 'tages

*igure "A.>

Severityofsymptoms


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e1elopment o% disease re%lects bacterial gro)th cur1e


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G. e1elopment o% a isease Dhe 'tages

. Incubation period

*rom eposure to "st

appearance o%

symptoms

B. Prodromal period

early, mild symptoms

Severityofsymptoms


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C. Period o% illness acute

stage. 'igns Jsymptoms at pea!

. Period o% decline 'igns

J symptoms reduced

E. Period o%con1alescence Body

reco1ers

Seve

rityofsymptoms

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Princ of Disease Path o Transmission