Question

Medical Microbiology Tutorial: Plagues

Answer 1

\({\bf{Overview:}}\)
- three types that will be covered here: bubonic, pneuomonic, septicemic
- caused by bacteria of the genus Yersinia, most specifically Y. pestis
- both Kitasato Shibasaburō and Alexander Yersin, independently, isolated the agent responsible for bubonic plague
- Paul-Louis Simond discovered that the flea X. cheopis transmitted the plague from rats to people

Answer 2

\({\bf{Bubonic~Plague:}}\)

caused by: Y. pestis
transmitted by: mostly the rat flea, but also human flea and louse. primarily transmitted by biting the black rat R. rattus but also capable of infecting other mammal species. also spreads through contact w/ other infected people.
symptoms: usually begin w/in a week of infection
- most defining trait is the formation of buboes, swollen lymph nodes in the underarm, neck, groin regions
- formation of petechiae, skin patches that result from bleeding under the skin
- fever, chills, headaches, vomiting
- has ~60% mortality rate can kill the infected person within a week

Answer 3

\({\bf{Pneumonic~Plague:}}\)
caused by: Y. pestis, more specifically, the movement of the bacteria into lungs. most deadly form of the plague
transmitted by: either directly breathing in the bacteria, or as a secondary infection from the bubonic plague
symptoms:
- coughing or other respiratory problems
- sputum (mucus mixed w/ saliva)
- vomiting, nausea

has 99% mortality rate if not treated

Answer 4

\({\bf{Septicemic~Plague:}}\)
same transmission method as bubonic
- occurs when Y. pestis moves into blood.
symptoms:
- bleeding from underneath skin, or from mouth/nose
- blackened skin, esp. on nose, fingers, and toes
- fevers, stomach pains, diarrhea, vomiting, septic shock, clotting disorders
- formation of petechiae, but often not buboes

has 99% mortality rate if not treated

Answer 5

\({\bf{Bacterial~Features:}}\)
Pla: plasminogen activator. makes it easier to attach to ECM of host. converts plasminogen to plasmin, which breaks down plasma proteins in host.
Ybt: Yersiniabactin. chelates host iron for bacterial to utilize.
T3SS: Type 3 Secretion System. secretes yops (yersinia outer proteins) that decrease the inflammatory response of the host.
F1: Factor 1. increases resistance to phagocytosis by host macrophages.
LcrV: V antigen. down-regulates inflammatory response.



honestlyi'mmostlypostingthispicbecauseit'ssuperphallicbutshhh

Answer 6

\({\bf{Diagnosis~Methods:}}\)
- lymph node aspirates (inserting a biopsy needle into affected tissue, and removing a sample)
- blood smears
- sputum samples
- bronchial/throat samples

\({\bf{Treatment~Methods:}}\)
- no vaccine exists as of today
- typical treatment is antibiotics. there are a ton but you should probably know a few like streptomycin, gentamicin, levofloxacin, etc. antibiotics greatly reduce mortality rate.
- patient will typically be quarantined

\({\bf{Preventative~Measures:}}\)
- get symptoms checked out ASAP
- stay up to date w/ medical alerts esp. if you live in or are travelling to a typically affected area
- avoid contact w/ infected people or wild animals
- sprays/repellents against insects
- environmental considerations like cleaning areas that are likely to be inhabited by bacteria
- research and survey local populations of vectors and animal hosts
- quarantines/border closures

Answer 7

Sources:
https://www.webmd.com/a-to-z-guides/plague-faq#1
https://www.sciencedirect.com/topics/medicine-and-dentistry/yersiniabactin
https://www.sciencedirect.com/topics/neuroscience/plasminogen-activator
lecture notes