Download Infectious Diseases

Biotechnology I
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How is an infectious disease different from a
genetic or metabolic disease
What microbes are associated with infectious
disease?
What is the difference between emerging and
re-emerging infectious diseases?
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Definition: Anything
that can impair normal
tissue function in the
human body
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Two types
 Genetic or metabolic –
physiological disruption of
tissue function
▪ Ex. Cystic fibrosis: abnormal
production of thick mucus
because of impaired chloride
transport across cell
membranes.
▪ Ex. Atherosclerosis –Plaques
of cholesterol have built up
and partially blocked
arteries – lead to heart
attacks and strokes
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Two Types
 Infectious disease –
caused by the invasion
of the host by agents
that harm host’s tissues
(i.e. disease) and can be
transmitted to other
individual’s (i.e.
infectious)
 Ex. Measles virus
Why is atherosclerosis not
considered an infectious
disease?
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PROPERTY OF PIMA COUNTY JTED, 2010
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Microorganisms that cause
disease
Classified as either
 Bacteria- unicellular prokaryotes.
▪ Ex. Salmonella typhi – causes
typhoid fever
 Viruses – not living organismsno metabolism and cannot
reproduce on their own
▪ Ex. Ebola virus
 Fungi-eukaryotic, heterotrophic
▪ Ex. Ringworm; certain types
of yeast
 Protozoa –unicellular,
heterotrophic eukaryotes
▪ Ex. Plasmodium that causes
Malaria
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Infection –pathogen invades and begin
multiplying in host
Disease- when the pathogen causes harm to
host tissue
Infection does not always result in disease!!!
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Enter at one of four sites
 Respiratory tract (mouth,
nose) Ex. Influenza virus
 Gastrointestinal tract
(mouth oral cavity) Ex.
Vibrio cholerae which
causes cholera
 Urogenital tract Ex. E. coli
causes cystitis
 Breaks in the skin Ex.
Clostridium tetani which
causes tetanus
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To make us ill,
microbes have to
 Reach target tissue
 Attach to target site to
infect
 Multiply rapidly
 Obtain nutrients from
host
 Avoid and survive attack
by the host’s immune
system
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What are some past and current cause of
death and illness associated with infectious
diseases?
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Emerging infectious diseases
 Have not occurred in humans before
▪ Ex. Hantavirus pulmonary syndrome
 Occurred previously but only affected small
numbers of people in isolated areas
▪ Ex. Ebola virus
 Have occurred throughout human history but only
recently has been recognized as a distinct disease
caused by an infections agent
▪ Ex. Lyme disease
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Re-emerging infectious diseases
 Once major health problems in particular country
then declined dramatically
 Recently have reappeared -caused renewed
health problem
▪ Examples
▪ Tuberculosis- pathogen become resistant to antibiotics
▪ Malaria – vector mosquito that carries the pathogen become
pesticide resistant
▪ Measles – failure to vaccinate
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Take Five Disease Cards and classify
 Infectious agent
 Mode of transmission
 Emerging or RE-emerging disease
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