Microbiology, Chapter 20

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Microbiology, Chapter 20

• 1. Plague Yersinia pestis caused the black
  death of the middle ages - pandemics
• a. Small gram negative rod, rodent reservoir,
  and insect vector
• b. Rats, small rodents, ground squirrels
• c. Humans acquire it from fleas

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Microbiology, Chapter 20
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Microbiology, Chapter 20

• d. Disease starts at site of bite, and the
  organisms enter blood stream where the bacteria
  are phagocytized, grow in phagocyte and the
  organisms proliferate to infect lymph nodes
  (form bulbous swellings buboes (619) thus
  bubonic plague)
• e. Can spread to lungs pneumonic form and can
  be spread by respiratory droplets very serious
  form of disease and can often be fatal
• f. Septicemia is also seen
• g. Now found in the us west and seem to be more
  cases (people and rodents are coming together
  more often) endemic in rodents
• h. Antibiotics streptomycin and tetracycline
  are effective if caught early enough vaccine
  is available

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Microbiology, Chapter 20

• 2. Tularemia Francisella tularensis 90
  acquired by handling wild rabbits (skinning),
  can be transmitted by ticks, even infected wild
  meat streptomycin, gentamycin drugs of choice
  so infective in such small doses that
  researchers have to be extra careful

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Microbiology, Chapter 20

• 3. Brucellosis Brucella species undulant
  fever small gram (-) rod, fastidious, cattle,
  sheep, goats, wild animals like elk
• a. Brucellosis usually mild, self limiting
  disease, fever rises and peaks at night thus
  undulant fever
• b. Used to be passed to humans through
  unpasteurized milk
• c. With current vaccination programs and
  pasteurization occurs infrequently

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Microbiology, Chapter 20
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Microbiology, Chapter 20

• Brucella

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Microbiology, Chapter 20

• 4. Lymes disease Borrelia burgdorferi (pg.
  625 life cycle) spirochete transmitted by tick
  bite, deer tick in Texas - probably the most
  common tick borne disease in the us
• a. Circular rash (bulls eye) at site of bite (pg
  624)
• b. Systemic progression of disease aches,
  pains, fever, fatigue, chronic arthritis symptoms
  
• c. Caught early, antibiotics are useful, in later
  stages, large doses are required
• d. Lyme county Conn. first described in 1970s

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Microbiology, Chapter 20
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Microbiology, Chapter 20
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Microbiology, Chapter 20

• 5. Rickettsial diseases small gram obligate
  intracellular parasites
• a. Rocky mountain spotted fever tick borne
• b. Typhus lice or fleas
• c. Systemic diseases, caught early then
  antibiotics are effective

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Microbiology, Chapter 20

• Rocky mountain spotted fever, microbe in cells,
  rash on childs hand

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Microbiology, Chapter 20

• 6. Yellow and dengue fever hemorrhagic viral
  diseases, spread by mosquitos
• a. Panama canal was halted because of yellow
  fever a serious infection with a high
  mortality rate
• b. US finished it after Walter Reed discovered a
  vaccine for yellow fever
• c. Dengue fever similar to yellow fever, break
  bone fever so painful, person feels bones
  are breaking

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Microbiology, Chapter 20, Walter Reed and Yellow
fever vaccine
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Microbiology, Chapter 20

• Oh, so much more, too little time

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Microbiology, Chapter 20

• 7. Epstein-Barr virus Infectious mononucleosis
  large enveloped DNA virus that can survive
  outside host. Infects the lymphatic system and
  can last for weeks

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Microbiology, Chapter 20

• 8. Plasmodium species Malaria mosquito
  born-look at our lab manual complex life cycle
  (see page 633 for life cycle) chloraquinone is
  drug used to treat it, now have resistant
  strains, old quinine treatment had lots of side
  effects

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Fig. 20.18
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Microbiology, Chapter 20, Malaria sexual and
asexual phase
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Microbiology, Chapter 20

• 9. Emerging viral hemorrhagic diseases See page
  627, checkpoint 20.7
• a. Marburg filament virus, from monkeys
  imported from Africa to Marburg germany
• b. Ebola another filo virus, 90 mortality
  rate, shepherds crook
• c. Lassa fever African disease, rodents involved
  see pg 641 these bugs make good thriller
  movies

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Microbiology, Chapter 20
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Microbiology, Chapter 20

• 10. Toxoplasma protozoan with complex life
  cycle. Transmitted to humans usually by cats.
  Particularly a problem with fetus, organism can
  cross placenta. HIV patients are at higher risk

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Toxoplasma cycle and CNS cytopathology
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Microbiology, Chapter 20

• 11. Schistosoma species Flukes Trematode
  helminth.
• Not a problem in us, but fairly wide spread in
  the orient.
• Complicated life cycle with an intermediate host
  like a snail.
• Could be eliminated with proper sanitation.

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Schistosoma egg, symptoms
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Schistosoma, free swimming larvae
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Microbiology, Chapter 20

• 12. Filarial diseases oh there is so much more
  but so little time.
• another course PARASITOLOGY

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Microbiology, Chapter 20

• HIV handout on line
• Separate power point on HIV
• virion Sarcoma