Test Two: Module 5 The Plague Flashcards
(34 cards)
Define zoonotic disease:
disease originated in and transmitted from animals to other animals… in this case… the human animal
Define epizootic disease:
Relating to a rapidly spreading disease that affects a large number of animals at the same time within a particular area.
Name the etiological agent associated with The Plague:
Yersinia Pestis bacterium
Name the three forms of the plague:
bubonic, pneumonic, septacemic
What was the vector for the plague and what forms are associated with this vector?
Flea; bubonic, septacemic
How was the pneumonic form of the plague spread?
Air-borne water droplets from coughing
What is an animal reservoir for the plague?
The animal reservoir for plague includes mice, camels, chipmunks, prairie dogs, rabbits, and squirrels, but the historcially most dangerous for humans are rats,
Name the three varieties of Yersinia Pestis:
Orientalis, medievalis, and antiqua
What plague pandemic is associated with antiqua?
probably caused the plagues of antiquity, Plague of Justinian 6th-8th century. Still exists around the Great lakes of central Africa.
What plague pandemic is associated with medievalis?
Probably caused the Black Death 14th-19th century.
What plague pandemic is associated with Orientalis?
Variety that exists most often today, responsible for most recent pandemic of the Far East 19th-20th century
How does Yersinia Pestis cause illness(infection)?
1) Produces toxin lethal to host cells
2) When ingested by white blood cells they (bacteria) continue to multiply
3) Progeny disseminate throughout the body
4) Bacilli accumulate in the blood stream and clog capillaries, causing them to burst.
5) Blood filled fluid swells lymph nodes ( causing pain)
6) Secondary infections cause abscesses
How does Yersinia Pestis cause death?
1) Cuts off immune cell’s ability to communicate with other immune system cells needed of fight off bacterial invasion
2) Attacks family of molecules used by mammalian cell to transmit signals involved in immune response and cell death
How does Yersinia Pestis bypass immune response?
1) Invades directly through skin and engages host macrophages and neutrophils at site of invasion (most Y. pestis killed by neutrophils).
2) Survives in macrophages during early stages of infection ( wax-like structure of the cell wall resists phagocytosis).
3) temperature transition to human host (98.60F) produces non-stimulatory proteins containing CCR5
How does the temperature change from flea to host help the bacterium become more virulent?
make bacteria resistant to serum-mediated cellular destruction and inhibits production of pro-inflammatory cytokines
What is the effect of Yersinia pestis on the specific cells of the immune system?
1) Produces thick, anti-phagocytic trail as it moves thoughout the body.
2) Causes depletion of natural killer cells
3) paralyzes phagocytes‘ expression of antigen markers; inhibits maturation of dendritic cells and destroys antigen presentation by dendritic cells
4) suppresses T-lymphocyte activation… inhibits ability to produce cytokines (messenger cells)
Contrast Sylvatic and Urban Cylcles of the plague:
Sylvatic (forest) and Urban based on different reservoirs…
Sylvatic (wild, forest) cycle:Sylvatic: fraction of the pathogen population’s lifespan spent cycling between wild animals and vectors
“domestic”, or “urban”, cycle, in which the pathogen cycles between vectors and non-wild, urban, or domestic animals;
Describe the characteristics of the bubonic form of plague infection:
1) Enters body through the skin, incubation period 2-6 days,
* if untreated death occurs within 5-8 days with a mortality rate of 40-70% (untreated).
2) Lymph node swelling and abscess formation associated with this form.
Describe the characteristics of the pneumonic form of the plague:
1) Y. Pestis enters the body through the lungs, 2) if untreated death occurs within 1-3 days of onset, mortality rate among untreated around 100%.
3) Can be contracted from airborne flea feces or airborne victim’s cough droplets.
Describe the characteristics of septicemic plague:
1) if untreated, death occurs hours after onset, 2) mortality 100% (untreated), 30-50% treated
3) virtually no incubation period
What is the oldest record of a plague type epidemic?
Amulet dating from 800 BCE-612 BCE for warding off plague. Found in the city of Ashur, Neo-Assyrian period
What evidence is presented in the Bible of a possible plague?
I Samual 5:6 Philstines stricken with a plague
What was the first instance of a widespread plague pandemic?
Justinian Plague; occurred from the Middle East to the Mediterranean basin during the 6th-8th CE killing approximately 50% of the population in these areas
What was the second plague pandemic?
The Black Death; (14th – 19th CE) Origin in early 14th C, destroying nearly 40% of the population in Europe
