This is a PowerPoint presentation on the Plague, also known as the Bubonic Plague and the Black Death. The presentation includes an identification of the agent involved, who is at risk, where it is most common, modes of transmission, clinical manifestations of infection, resistance, and how it could be used in bioterrorism.

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The Plague

2. Description
The Plague, also historically referred to as the “Black Death”,
is a dangerous bacterial infection. The infection's culprit is the
bacteria called Yersinia Pestis and can be found in infected
animals and contaminated water. This bacteria has been linked
to pandemics as far back as at least 541 CE.
The Plague is infamously known as the Bubonic Plague
because of the “buboes” that characteristically appear on the
skin.
● Buboes are painful, infected swollen lymph nodes, usually in the groin or axillary regions of the body.
The Plague can also refer to septicemic plague and pneumonic plague.
● Septicemic plague is when Y. Pestis has infected the bloodstream. It can easily lead to septic shock and death if not
treated promptly.
● Pneumonic plague is when Y. Pestis infects the lungs. It generally takes over relatively quickly, so prompt treatment
is crucial in order to prevent fatalities. (Riedel, 2005)
Photo from CDC; used courtesy of the Public Health Image Library. (Riedel, 2005)

3. Occurrence
•Who
•No one is safe!!
•According to the CDC, plague has occurred in people of all ages (infants to age 96)
•Since the plague is spread by bacteria, it can affect anyone
•Seen in both men and women (slightly more common in men due to increased outdoor activities)
•Typically crowded, rodent infested areas, with fleas
•https://www.youtube.com/watch?v=SQBxTLjYRsI

4. Occurrence

5. Occurrence
•Where
•Plague epidemics have occurred Worldwide: Africa, Asia, South and North America
•Most human cases have occurred in Africa
•People living in small towns or village
•Agricultural areas
•World Health Organization reports 1,000-2,0000 cases per year from these countries

6. Occurrence
•Where
•Current outbreaks of Plague
•Colorado
•From 1959- 2014, 69 residence have contracted the disease
•10 deaths occurred
•Colorado
•In the past year (2014-2015), 12 residence have contracted the disease
•2 deaths occurred
•1 case was linked to Yosemite National Park in California
•Due to infected prairie dogs
•Other states include Arizona, California, Georgia, New Mexico, Oregon and Utah

7. Occurrence

8. Reservoir/mode of transmission
Reservoir:
• The plague bacteria often cycles between rats
and their fleas.
• Rock squirrels, wood rats, ground squirrels, prairie
dogs, chipmunks, mice, voles, and rabbits can also
carry the plague bacteria. Carnivores that eat these
rodents are susceptible to being infected.
• Scientists believe that the bacteria circulates at a
low rate within the different rodent population and
doesn’t cause a large number of rodents to die from
it. They also believe that these rodents with the
fleas that carry the bacteria serve as long-term
reservoirs. This is called an enzootic cycle.

9. Mode of Transmission
Mode of Transmission
The plague bacteria can be transmitted to humans in the following ways:
Flea bites: The plague bacteria most often infects other animals or species by getting bit by a flea that has previously been
infected. During a plague epizootic, when the animals die from the plague, the infected fleas will search for other sources of
blood to live off of, which then causes the next host to become infected. If dogs and cats are outside where the plague has
recently killed animals, the dogs and cats can spread the fleas with the bacteria to humans and other pets.
Contact with contaminated fluid or tissue: If a human come in contact with the tissue or body fluid of an animal infected with the
plague, they could become infected as well. This can happen to hunters that skin the animals that they kill.
Infectious droplets: When a person gets plague pneumonia, they are able to spread the plague by coughing droplets into the air
that can infect others by them breathing in the droplets. Often times, this only happens when there is direct and close contact
between people. This is the only way that the pneumonic plague can spread from person to person.

10. Incubation Period
The period of time between being infected with the Yersinia pestis
bacteria and when symptoms first appear.
❖ Bubonic Plague: 2-6 days
➢ Occurs within the Lymphatic System
❖ Primary Pneumonic Plague: 2-4 days
➢ Occurs within the lungs
❖ Septicemic Plague: 1-6 days
➢ Occurs within the bloodstream

11. Risk Factors
● Large rodent
populations
● Pets w/o flea treatment
● Handling dead animals
● Person to person via
respiratory droplets
Bioterrorism
● Likely to be aerosolized
for greatest
infection/mortality.
● Y. pestis quickly overwhelms
body’s defenses.
● Can be treated with antibiotics.
● Nearly 100% mortality in
pneumonic version.
● No vaccine.
Susceptability/Resistance

12. Prevention/Control:
Rat/rodent control
Informing people when plague is active in their environment
Avoid direct contact with infected tissues such as buboes
Avoid direct exposure to those with pneumonic plague (wear PPE)
Vaccinate healthcare workers who have a high likelihood of being exposed/contaminated (Not highly effective though).
Isolate patients with pneumonic plague
Locate and stop the source of the infection to prevent further exposure
Investigate animals implicated in plague cycle to limit spread

14. References
Butler, T. (2009). Plague into the 21st century. Clinical Infectious Diseases. 736-742.
Ecology and Transmission. (2012). Retrieved from Centers of Disease Control and Preventiong:
http://www.cdc.gov/plague/transmission/
Kugler, M. (2011). Bubonic plague pictures. In About Health.
Maps and statistics: Plague in the united states (2015). In Centers for Disease Control and Prevention.
Parry, W. (2011). Pictures of a killer: A plague gallery. In Live Science.
Plague (2007). In Centers for Disease Control and Prevention.
Riedel, S. (2005). Plague: from natural disease to bioterrorism. Baylor University Medical Center
Proceedings, 18(2), 116-124. Retrieved from
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1200711/