Plague

Question 1

What if the organism that can cause the plague

Answer 1

Yersinia pestis

Question 2

Yersinia pestis morpohlogy

Answer 2

Gram negative rods

bipolar stainging (safety pin)

capsule

Question 3

what will lead to loss of viruclance of Yersinia pestis and hom many bacteria to casues the disease

Answer 3

the capsule
ID-50 IS 1-10

Question 4

What are the properties that make Yersinia pestis highly infective 5

Answer 4

Envelop - escape phagocytosis
Endotoxin
exotoxin
W and V antiget - enhance intracellular survival and growth

Question 5

The most effective virulence factors of Yersinia pestis

Answer 5

YOPS (Yersinia outer protein)
F1 Capcular protein

Question 6

Pathogenesis

Answer 6

Virulence factor are not expressed immediately after the flea bite

Hide inside macrophage

resist macrophage - mediated killning by : secreting typer III secretion system which will dephosphorylate protein required phagocytosis induce cytotoxicity . and initiating apoptosis

the type 3 secretion suppres cytoking production

Question 7

Two plasmid that encode virulence gene what are they and what they express

Answer 7

F1 - Anti-phagocytic capsule
PLA protease - degreade complement (c3b c5a) preventing opsonizaiton and phagocytic migration,respectively

PlA also degrafe fibrin clot making the Yersinia pestis spread quickly

Question 8

Transmission of Yersinia pestis consist of two cycle

Answer 8

Enzootic cucle (sylvatic cucle ) –>transmission among wild rodents by fles
Urban cycle —–> transmission of the bacteria among urban rats )the reservoir) with the RAT FLEA as vector

Respiratory droplet transmission by patient with pneumonic plague

host _ human accidental host

Question 9

Defince urban cycle

Answer 9

The flea ingest the bacteria from an infected rodent , causing blood clot in the GIT of the flea by the action of COAGULASE which is produced by bacteria . The bacteria replacte and proliferate in the clot .because of the clot the flea REGURGITATES the organsim into the next animal . beacue of the clot in the GIT the flea become hungrier

Question 10

Yersinia pestis events in human 3

Answer 10

1-Organism spread to reginonal lympnode which will become swollen and tender which are named ;buboes; .
2-When the concentration of the organism increase in the blood , it DISSEMINATE to form abscesses in many organs
3- ENDOTOXIN will cause the including symptoms : - 1DIC : proteins that control blood clotting become overactive.
2cutaneous hemorrhages

Question 11

there is 4 plague caused by Yersinia pestis what are they

Answer 11

1-bubonic plague
2-penumionic plague
3-septicemic plague
4-pestis minor

Question 12

symptoms of bubonic plague and what is the untreated mortilty. if untreated then developes into

Answer 12

High grade Fever chills headache vomating and nausea
Regional lymphadientits (bubos) 24-48 after initian sings and symptoms
Sever systemic disease after 24-48 of the appearance of bubos

untreated mortilty is 50 - 60 percent

if untreated then developes into
-spetic shock
pneumonia

Question 13

symptoms of pneumonic plague and what is the untreated mortilty

Answer 13

Repirotory droplet infect other

FEVER COUGH CHEST PAIN
Endtoxin mediate lung damgage

100% if untreated mortality

Question 14

symptoms of spetiecemic plague and what is the untreated mortilty

Answer 14

Flea bite usually

without formoation of bubois , rapid progression to sepsis

Vascultitis purpura(BLOOD VESSLE BLEED, DOTS IN HANDS AND LEGS) , ecchymosis DIC (BRUISE)

black death
100 %

Question 15

symptoms of pestis minor and what is the untreated mortilty

Answer 15

flea bite

Infection is localazed dont not extend to lympnodes

mortility : 0

Question 16

Lap dignosis of plague 3

Answer 16

Smear & and culture of blood or pus from the bubos is diagnositc
Safety pins an gram stain
PCR for plasmid gens