بسم الله الرحمن الرحيم GENUS: YERSINIA Prof. Khalifa Sifaw Ghenghesh

Yersinia pestis  Plague  Infected Fleas ( Xenopsylla cheopis ) are the Major Mechanism of are the Major Mechanism of Transmission. Transmission.  Rodents >>

Clinical Syndromes i. Bubonic Plague:  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:  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.  Transport Media >>

Yersinia pestis on Sheep Blood Agar (72hrs)

TREATMENT – Streptomycin CONTROL – –A Quarantinable Disease. – – Control of Urban Plague: – – Garbage Disposal.

  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