Week 1- Plague

Question 1

What is the infectious agent that causes the plague?

Answer 1

Gram negative bacterium Yersinia pestis

Question 2

How is the plague transmitted?

Answer 2

Through the bite of fleas that have fed on infected animals like mice, rats, rabbits. squirrels, chipmunks, and prairie dogs, or on infected humans. It also spreads through direct contact with an infected person or animal, or by eating an infected animal that hasn’t been cooked properly

Question 3

Why is the plague considered a nationally notifiable disease?

Answer 3

Because it’s very dangerous- infected people need to notify the CDC

Question 4

The plague is endemic to rural areas in (4)

Answer 4

1. Central and southern Africa (especially eastern 2. Democratic Republic of Congo, northwestern Uganda, and Madagascar)
2. Central Asia and the Indian subcontinent
3. The northeastern part of South America
4. Parts of the southwestern United States

Question 5

Endemic

Answer 5

An endemic disease is naturally occurring in that environment

Question 6

Incubation period definition

Answer 6

Time between infection and onset of symptoms

Question 7

What is the incubation period of the plague?

Answer 7

1-6 days

Question 8

Types of plague (3)

Answer 8

1. Bubonic (most common)
2. Pneumonic- spreads through aerosols
3. Septicemic- blood infection

Question 9

Bubonic plague signs and symptoms

Answer 9

Rapid onset of fever, painful and swollen lymph nodes (usually inguinal, axillary, or cervical), headache, nausea and vomiting, joint pain. The swollen lymph nodes can break and release pus that contains Yersinia pestis

Question 10

Pneumonic plague signs and symptoms

Answer 10

High fever, overwhelming pneumonia, cough, bloody sputum, chills, muscle weakness. Bloody sputum typically does not occur with regular pneumonia

Question 11

Septicemic plague signs and symptoms

Answer 11

Fever, prostration, hemorrhagic or thrombotic phenomena, progresses to acral gangrene (extremities turn black and discharge liquid)

Question 12

Why is the plague also called the black death?

Answer 12

Called black death due to dead tissue (tissue becomes necrotic)

Question 13

What is the most deadly form of plague?

Answer 13

Septicemic is the most deadly form- it takes a while to realize that you have the septicemic form and by then it’s too late

Question 14

What is the most contagious form of plague?

Answer 14

Pneumonic is most contagious because it’s airborne

Question 15

What samples are collected to diagnose plague?

Answer 15

Isolation of bacteria from bubo aspirates, blood cultures, or sputum culture (if pneumonic). Need blood cultures for septicemia, but you can do it for all forms

Question 16

How is Y. pestis identified in collected samples?

Answer 16

Culture, serologic tests for the Y. pestis F1 antigen

Question 17

Antibiotics used to treat plague (4)

Answer 17

gentamicin, doxycycline, ciprofloxacin, and levofloxacin

Question 18

Parental antibiotics (3)

Answer 18

Moxifloxacin, streptomycin (alternative), and chloramphenicol (alternative). These antibiotics are given by IV when people are very sick

Question 19

Why is plague considered a re-emerging disease?

Answer 19

The black death is re-emerging due to antibiotic resistance. Also, you would normally find Y. pestis is a wild environment, but we are starting to invade wild areas and being exposed to infected animals

Question 20

Ways to prevent plague (5)

Answer 20

1. Keep rodent population under control in your home, workplace, and recreation area
2. Keep the home free from stacks of cluttered firewood or piles of rock, brush, or other debris that could attract rodents
3. Protect pets from fleas using flea control products. Pets that roam freely outdoors may be more likely to come into contact with plague-infested fleas or animals
4. Use insect repellent products
5. Vaccines- no licensed vaccines- the ones that are available aren’t effective for a long period of time

Question 21

Types of vaccines (4)

Answer 21

1. Killed whole cell vaccine
2. Live attenuated vaccine
3. Subunit vaccines are under development
4. Monoclonal antibodies are used as a therapeutic vaccine

Question 22

Killed whole cell vaccine

Answer 22

Kill the bacteria and introduce the entire killed bacteria to the body. The body recognizes the threat and produces antibodies

Question 23

Live attenuated vaccine

Answer 23

Bacteria has been attenuated (missing certain components so it’s not infectious anymore)

Question 24

Subunit vaccine

Answer 24

Has certain products of the bacteria- difficult to develop this type of vaccine against a whole bacteria

Question 25

Monoclonal antibodies

Answer 25

Used as a therapeutic vaccine. Antibodies can be created in a lab, or plasma can be isolated from a plague patient that contains antibodies and introduce it to another patient. Allows the body to create its own antibodies for a certain period of time

Question 26

When did the medieval plague occur?

Answer 26

Over a span of 7 years in the mid 14th century. Half of Europe’s population died

Question 27

How did the plague influence European culture?

Answer 27

It drove the intensification of Christian belief and practice. It manifested as extremist cults that questioned the authority of the clergy and in Christian pogroms against European Jews. Heightened religiosity inspired the founding of new universities- this decreased the unity of medieval Christianity and enhanced the rise of stronger national identities. It also contributed to the rise of the Reformation that split Christianity in the 16th century

Question 28

How did the plague shape the medical field?

Answer 28

Doctors had firsthand experience with plague patients and began to rebel against ancient medical doctrine, like the causes of disease. People began to realize that diseases were contagious, and doctors prioritized a new empirical approach- this was the basis for the scientific revolution. In the 15th century, quarantines became routine- new outbreaks were due to breaks in the quarantine. This resulted in the emergence of state power in Europe

Question 29

How did the plague shape the European economy?

Answer 29

Wage rates rose rapidly in Europe- people were willing to pay more for scarce labor- rising autonomy of the poor contributed to peasant uprisings. The plague also ended the medieval trade system between Europe and Asia. There was a new economic globalization involving the Americas- stimulated new pandemics of other diseases like measles and smallpox

Question 30

Why are modern plague infections less severe than infections in the medieval period?

Answer 30

Modern plague infections are much less severe than medieval plague infections, but this isn’t due to differences in the genome- the genomes of the medieval strains of the plague and the modern strains are very similar. Could be due to climate changes or social changes, but also due to modern immunity since we have been exposed to different pathogens