Download Lecture 18-Yersinia

‫بسم هللا الرحمن الرحيم‬
GENUS: YERSINIA
Prof. Khalifa Sifaw Ghenghesh
Yersinia pestis
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Plague
Infected Fleas (Xenopsylla cheopis)
are the Major Mechanism of
Transmission.
Rodents >>
Clinical Syndromes
i. Bubonic Plague:
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Incubation period:
– < 7 days after flea bite.
High fever and painful bubo in the groin and
axilla.
Untreated
Bacteremia > 75% mortality
rate
ii. Pneumonic Plague:
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Bubonic Disease >Pneumonic Plague >
Exhales the Organism in Droplets.
Highly infectious
Incubation period:
– 2 to 3 days, with fever and malaise
– pulmonary signs within one day
Untreated
> 90% mortality rate
Yersinia pestis
Puss from bubo/Gram-negative rods
LABORATORY DIAGNOSIS

Aspirate from Buboes,
Pus from the Area of Flea Bite,
Sputum, Throat Swab or Blood.
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Transport Media >>
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Yersinia pestis on Sheep Blood Agar (72hrs)
TREATMENT
– Streptomycin
CONTROL
–A Quarantinable Disease.
– Control of Urban Plague:
– Garbage Disposal.
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Y. enterocolitica
Y. pseudotuberculosis
– Enterocolitis:
 Diarrhea,
fever and abdominal pain
 Infection can mimic acute appendicitis
 More common in children
– Other infections:
 Septicemia,
arthritis, hepatitis, and
osteomyelitis
– Epidemic outbreaks due to Y. enterocolitica:
 Contaminated meat and milk