The PlagueY. pestis

Matt CowperKatie Pazur

https://publicaffairs.llnl.gov/Images/pestis_big.jpg

Yersinia pestis• Yersinia originally classified in Pasteurellaceae

family– Based on DNA similarities with E. coli, Y. pestis is

now part of Enterobacteriaceae family• 11 named species in genus 3 are human

pathogens– Y. pestis, Y. pseudotuberculosis, Y. enterocolitica– Y. pestis and Y. pseudotuberculosis rarely infect

humans– Y. enterocolitica is the cause of 1 – 3% of diarrhea

cases caused by bacteria

Yersinia pestis

• Gram-negative bacteria• Can grow with or without oxygen• Most commonly found in rats but also found

in:– Mice, squirrels, fleas, cats, dogs, lice, prairie dogs,

wood rats, chipmunks

Types of Plague• Bubonic Plague– Most common– Infection of the lymph system (attacks immune

system)• Pneumonic Plague– Most serious type of plague– Infection of the lungs leading to pneumonia– Primary and Secondary

• Septicemic Plague – Bacteria reproduces in the blood– Can be contracted like bubonic plague but is most

often seen as a complication of untreated bubonic or pneumonic plague

• Symptoms– Bubonic

• Fever, headache, chills, weakness, swollen and tender lymph glands

– Pneumonic• Fever, headache,

weakness, rapid onset of pneumonia (usually accompanied by: shortness of breath, chest pain, cough, bloody or watery sputum)

– Septicemic• Fever, chills, weakness,

abdominal pain, shock, bleeding underneath skin or other organs

• Diagnosis and Treatment– Most cases of plague are

diagnosed initially from presented symptoms, especially Bubonic plague. If plague is suspected, blood work is completed to determine how far the plague has progressed and to determine antibiotic resistances.

– Since no major antibiotic resistances have developed, plague is usually treated with Streptomycin. Other antibiotics that can be used are: tetracyclines, fluoroquinolones and other aminoglycosides.

– Antibiotics are administered to the patient as well as to those who are believed to have been exposed.

http://rarediseases.about.com/od/infectiousdiseases/ig/Pictures-of-Bubonic-Plague/hand-gangrene.htm

Transmission

• Bubonic and Septicemic can not be transferred human to human. They can only be contracted if bitten by an infected rodent or flea.

• Pneumonic can be transferred through exposure to infected particles. This usually occurs when in close contact with someone who is infected and is exposed to sputum that is coughed up.

http://www.unbc.ca/nlui/wildlife_diseases_bc/plague_cycles.gif

History

• There have been three major pandemics of the plague.– Mid 6th century, mid 14th century, early 20th century

• The most well known plague pandemic was in the mid 14th century in Europe known as the Black Death– The plague came from Asia and spread through Europe in

two years. – In the two years, it killed more than half of the population. – People didn’t understand how the plague worked which

allowed it to spread .– Benefits.

http://neatorama.cachefly.net/images/2005-12/sedlec-ossuary.jpg

Sedlec Ossuary in Kutna Hora

http://www.earth-photography.com/photos/Countries/CzechRepublic/Czech_KutnaHora_Ossuary1.jpg

http://z.about.com/d/goeasteurope/1/0/o/5/-/-/SedlicOssuary11.JPG

Incidence• Considered a re-emerging disease.– Incidence is on the rise: 2,000 to 3,000 cases a

year worldwide.

http://www.cdc.gov/ncidod/dvbid/plague/world98.htm

Current Research at UNC

• While the plague isn’t causing major problems amongst humans and it is easily treatable, scientists are beginning to consider its potential use as a bioweapon.

• Here at UNC, Dr. William Goldman is studying the mechanisms of plague.– Using a mouse model, they are studying the progression

of Pneumonic Plague and are working on determining how to slow its progression so it can be more effectively treated.

To Review:

The Plague Rap

Works Referenced"CDC Plague Home Page - CDC Division of Vector-Borne Infectious Diseases

(DVBID)." Centers for Disease Control and Prevention. Centers for Disease Control, June 2009. Web. 14 Apr. 2010. <http://www.cdc.gov/ncidod/dvbid/plague/index.htm>.

Crawford, Dorothy H. Deadly Companions: How Microbes Shaped Our History. Oxford: Oxford UP, 2007. Print.

Dell, Helen. "Microbiology: Perspectives on Plague." Nature Dec. 2005: 926. Web. 12 Apr. 2010.

Dunham, Will. "Scientists Find Potential Weakness in Plague Germ." abc News 26 Jan. 2007. Web. 12 Apr. 2010.

History Channel. "History Channel - The Plague." YouTube - Broadcast Yourself. 21 Nov. 2008. Web. 3 Apr. 2010. <http://www.youtube.com/watch?v=9IjhQDnoCcY&feature=related>.

"Yersinia Pestis." Plague Home Page. Web. 4 Apr. 2010. <http://plague.emedtv.com/yersinia-pestis/yersinia-pestis.html>.