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Black Death: Plague

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Black Death. Killed 17-28 million Europeans. 30-40% of the ... The Black Death: Europe 1347-1351. Third pandemic 1855-1930. 30 million cases, 12 million deaths ... – PowerPoint PPT presentation

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Title: Black Death: Plague


1
Black Death Plague
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Plague 1347-1351
5
Black Death
  • Killed 17-28 million Europeans
  • 30-40 of the population

6
Plague Memorial Vienna
  • Monument to Immunity

7
Plague Costume
  • Early protective clothing for physicians treating
    plague victims

8
Plague Pandemics
  • Justinians Plague Middle East and
    Mediterranean basin 541-544
  • The Black Death Europe 1347-1351
  • Third pandemic 1855-1930
  • 30 million cases, 12 million deaths
  • Cause and mode of transmission identified (Hong
    Kong 1894)

9
Yersinia pestis
Alexandre Yersin
Gram Negative Non-motile Non-spore forming
Paul-Louis Simond
10
Pneumonic Plague
  • 1910-1911 Manchurian outbreak
  • L-T Wu identified epidemiology of the pneumonic
    plague

11
Yersinia enterocolitica
  • Infection from eating raw or undercooked pork
  • Disease most often seen in small children
  • Fever, abdominal pain, diarrhea
  • In older children and adults can be confused with
    appendicitis

   
12
Yersinia pseudotuberculosis
 
  • An intestinal pathogen of rodents and birds
    sometimes infecting humans - survives in soil and
    water
  • Causes septicemia, acute gastritis and
    pseudoappendicitis with lesions similar to
    intestinal tuberculosis
  • 90 DNA homology with Y. pestis

13
Yersinia pestis
  • Evolved from Y. pseudotuberculosis between 1,500
    and 20,000 years ago
  • Has lost function of 13 of Y.
    pseudotuberculosis genes
  • Has gained virulence plasmids, ability to infect
    fleas

14
Plague in Fleas
  • Xenopsylla cheopis
  • Acquires Yersinia in blood meal
  • Yersinia infection confined to digestive tract
  • Not transmitted transovarially
  • Artificially infected larvae clear infection in
    24 hours

15
Flea life cycle
60 days
Xenopsylla cheopis female
Xenopsylla cheopis male
4 days
7 days
24 days
16
Plague in Fleas
  • Yersinia multiplies in midgut
  • Forms large mass of bacteria and a fibrinoid
    material biofilm
  • Blocks proventriculus and prevents blood meals
    from getting to stomach - flea repeatedly
    attempts to feed
  • Yersinia regurgitated into host

17
Plague Vector Xenopsylla cheopsis
18
Yersinia in Host
  • Initially phagocytosed by PMNs and monocytes
  • Grows intracellularly in monocytes and becomes
    resistant to phagocytosis
  • Spreads from bite to regional lymph nodes -- bubo

19
Plague Bubo
20
Plague Virulence Determinants
21
Yersinia in Host
  • Spreads into bloodstream
  • Removed by liver and spleen
  • Eventually spreads to other organs
  • Bacteremia allows for uptake by another feeding
    flea

22
Lethality of Plague?
  • Killing host generally thought to be
    counterproductive for a pathogen
  • Killing host causes fleas to seek new host and
    spread disease
  • Differential susceptibility of mammalian hosts
  • Reversion to chronic disease

23
Plague is a Zoonosis
  • Plague arrived in North America (San Francisco)
    about 1900
  • Many North American rodents experience massive
    die-offs (epizootics) after exposure
  • Long term maintenance of plague is in enzootic
    (reservoir) hosts - kangaroo rats, deer mice,
    grasshopper mice

24
Enzootic and Epizootic Reservoirs - US
Deer mouse
California ground squirrel
13-lined ground squirrel
Black-footed ferret
Prairie dog
25
Animal Reservoirs United States
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Plague Epidemiology
Enzootic and Epizootic
27
High Risk Groups in US
  • Native Americans, especially Navajos
  • Hunters
  • Veterinarians and pet owners
  • Campers and hikers

28
Environmental Factors
  • Increased rainfall
  • Displacement of wildlife
  • Deforestation
  • Homes from which rodents cannot be excluded
  • Human movement into endemic areas

29
Bubonic Plague
  • Acquired from flea bite
  • Incubation period 2-6 days
  • Fever, headache, tender lymph nodes, prostration
  • Swollen lymph node(s) buboes
  • 40-60 mortality if untreated

30
Size of Flea
31
Ulcerated Flea Bite
32
Bubonic Plague
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Septicemic Plague
  • Septicemia (bacteria in blood) in absence of
    swollen LN
  • May be spread from bubonic plague
  • Fever, prostration, abdominal pain, shock and
    bleeding into skin
  • Disseminated intravascular coagulopathy
  • Multiple organ failure

34
Septicemic Plague
100 fatality if untreated
35
Pneumonic Plague
  • Spread from bubonic or acquired from domestic cat
  • Incubation period 1-3 days
  • Fever, cough, bloody sputum, difficulty in
    breathing, rapid shock and death
  • Person-to-person spread
  • 100 fatal if not treated immediately

36
Pneumonic Plague
37
Plague Diagnosis
38
Treatment
  • Yersinia pestis sensitive to antibiotics
    streptomycin, gentamycin, tetracyclines
  • Isolation of patient and notification of public
    health personnel
  • Death rates 15 with antibiotic therapy
    (pneumonic plague over 50)

39
Case Studies
  • Imported Plague - New York City, 2002. MMWR
    August 8, 2003
  • Fatal Human Plague - Arizona and Colorado, 1996.
    MMWR July 11, 1997
  • Pneumonic Plague - Arizona, 1992.
  • MMWR October 9, 1992

40
Prevention
  • Monitoring of wild reservoir populations for
    plague
  • Controlling rats in urban and rural areas
  • Insecticide use to control fleas when plague is
    present
  • Flea control in pets

41
Prevention
  • Prophylactic antibiotics for people exposed to
    fleas or tissues of infected animals
  • No commercial vaccine in U. S.

42
Plague in the 20th century
  • Rats and infected fleas in the home primary
    source of disease
  • Most cases in developing countries
  • Worldwide 1,000-2,000 cases/year
  • Last urban plague epidemic in Los Angeles in
    1924-1925.

43
US Plague 1970-1997
  • Plague is endemic in Arizona above 4,000 ft
    elevation

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US Plague Cases
  • 10-20/year
  • low 1 high 40 (1984 prairie dog and rock
    squirrel epizootic)
  • 2000 6, none fatal
  • 14 (1 in 7) fatal
  • Usually acquired from wild animal via flea bite,
    contact with tissues, or contact with infected pet

46
Prairie Dog Plague, Flagstaff, 2001
  • 99 colonies observed
  • 49 colonies experienced 99 mortality
    May-September 2001
  • Y. pestis confirmed as cause of die offs at 19
    colonies

47
Prairie Dog Plague, Flagstaff, 2001
48
Plague in the Americas1994-1999
  • Highest incidence Peru 1994
  • 1,122 cases, 51 deaths
  • El Niño
  • Ecuador 1998
  • 160 cases (estimate), 14 deaths
  • Peru 1999
  • 151 cases, 5 deaths

49
World Plague Distribution
50
Plague World Data
51
Plague Case Fatality Data
52
Plague in Madagascar
  • 1983-1998 45 of plague cases in Africa have been
    in Madagascar
  • Brought to county in 1898 by steamboat from India
  • Multidrug resistant strain isolated

53
Plague Bioterrorism
  • Caffa (Feodosija, Ukraine) 1346
  • Bodies of plague victims were catapulted over the
    city walls
  • China WWII
  • Japan released plague-infected fleas over several
    Chinese cities

54
Plague Surveillance
55
Plague Surveillance
56
Plague Surveillance
  • SUSPECTED PLAGUE SHOULD BE CONSIDERED IF THE
    FOLLOWING CONDITIONS ARE MET
  • Clinical symptoms that are compatible with
    plague, i. e., fever and lymphadenopathy in a
    person who resides in or recently traveled to a
    plague-endemic area.
  • If small gram-negative and/or bipolar-staining
    coccobacilli are seen on a smear taken from
    affected tissues, e.g.
  • Bubo (bubonic plague)
  • Blood (septicemic plague)
  • Tracheal/lung aspirate (pneumonic plague)

57
Plague Surveillance
  • PRESUMPTIVE PLAGUE SHOULD BE CONSIDERED WHEN ONE
    OR BOTH OF THE FOLLOWING CONDITIONS ARE MET
  • If immunofluorescence stain of smear or material
    is positive for the presence of Yersinia pestis
    F1 antigen.
  • If only a single serum specimen is tested and the
    anti-F1 antigen titer by agglutination is 110.

58
Plague Surveillance
  • CONFIRMED PLAGUE IS DIAGNOSED IF ONE OF THE
    FOLLOWING CONDITIONS IS MET
  • If a culture isolated is lysed by specific
    bacteriophage.
  • If two serum specimens demonstrate a four fold
    anti-F1 antigen titer difference by agglutination
    testing.
  • If a single serum specimen tested by
    agglutination has a titer of 1128 and the
    patient has no known previous plague exposure or
    vaccination history.
  • Agglutination testing must be shown to be
    specific to Y. pestis F1 antigen by
    hemagglutination inhibition.
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