Editing Plague (disease) (section)

==Signs and symptoms==
There are several different clinical manifestations of plague. The most common form is bubonic plague, followed by septicemic and pneumonic plague.<ref name=":2">{{Cite journal|last1=Nelson|first1=Christina A|last2=Fleck-Derderian|first2=Shannon|last3=Cooley|first3=Katharine M|last4=Meaney-Delman|first4=Dana|last5=Becksted|first5=Heidi A|last6=Russell|first6=Zachary|last7=Renaud|first7=Bertrand|last8=Bertherat|first8=Eric|last9=Mead|first9=Paul S|date=2020-05-21|title=Antimicrobial Treatment of Human Plague: A Systematic Review of the Literature on Individual Cases, 1937–2019|journal=Clinical Infectious Diseases|volume=70|issue=Supplement_1|pages=S3–S10|doi=10.1093/cid/ciz1226|pmid=32435802|issn=1058-4838|doi-access=free}}</ref> Other clinical manifestations include plague meningitis, plague pharyngitis, and ocular plague.<ref name=":2" /><ref name=":3">{{citation-attribution|1={{Cite journal|last=Nelson|first=Christina A.|date=2021|title=Antimicrobial Treatment and Prophylaxis of Plague: Recommendations for Naturally Acquired Infections and Bioterrorism Response|journal=MMWR. Recommendations and Reports|language=en-us|volume=70|issue=3|pages=1–27|doi=10.15585/mmwr.rr7003a1|pmid=34264565|pmc=8312557|issn=1057-5987|doi-access=free}} }}</ref> General symptoms of plague include fever, chills, headaches, and nausea.<ref name="CDC2015Sym" /> Many people experience swelling in their lymph nodes if they have bubonic plague.<ref name="CDC2015Sym" /> For those with pneumonic plague, symptoms may (or may not) include a cough, pain in the chest, and haemoptysis.<ref name="CDC2015Sym" />

===Bubonic plague===
{{Main|Bubonic plague}}

[[File:Plague -buboes.jpg|thumb|Swollen inguinal lymph glands on a person infected with the bubonic plague. The swollen lymph glands are termed ''buboes'' from the Greek word for groin, swollen gland: ''bubo''.]]

When a flea bites a human and contaminates the wound with regurgitated blood, the plague-causing bacteria are passed into the tissue. ''Y. pestis'' can reproduce inside cells, so even if [[phagocytosis|phagocytosed]], they can still survive. Once in the body, the bacteria can enter the [[lymphatic system]], which drains [[interstitial fluid]]. Plague bacteria secrete several [[toxin]]s, one of which is known to cause [[beta blocker|beta-adrenergic blockade]].<ref>{{cite journal |last1=Brown |first1=SD |last2=Montie |first2=TC |title=Beta-adrenergic blocking activity of Yersinia pestis murine toxin |journal=[[Infection and Immunity]] |volume=18 |issue=1 |pages=85–93 |year=1977 |doi=10.1128/IAI.18.1.85-93.1977 |pmid=198377 |pmc=421197 |url=}}</ref>

''Y. pestis'' spreads through the [[lymphatic vessels]] of the infected human until it reaches a [[lymph node]], where it causes acute [[lymphadenopathy|lymphadenitis]].<ref>{{cite journal|last1=Sebbane|first1=F|last2=Jarret|first2=C.O.|last3=Gardner|first3=D|last4=Long|first4=D|last5=Hinnebusch|first5=B.J.|title=Role of ''Yersinia pestis'' plasminogen activator in the incidence of distinct septicemic and bubonic forms of flea-borne plague|journal=Proc Natl Acad Sci U S A|volume=103|issue=14|pages=5526–5530|doi=10.1073/pnas.0509544103|pmid=16567636|pmc=1414629|year=2006|bibcode=2006PNAS..103.5526S|doi-access=free}}</ref> The swollen lymph nodes form the characteristic [[bubo]]es associated with the disease,<ref>{{cite web|title=Symptoms &#124; Plague|url=https://www.cdc.gov/plague/symptoms/|website=Centers for Disease Control and Prevention|access-date=18 April 2017|date=14 September 2015}}</ref> and autopsies of these buboes have revealed them to be mostly [[bleeding|hemorrhagic]] or [[necrosis|necrotic]].<ref>{{cite journal|last1=Sebbane|first1=F|last2=Gardner|first2=D|last3=Long|first3=D|last4=Gowen|first4=B.B.|last5=Hinnebusch|first5=B.J.|title=Kinetics of Disease Progression and Host Response in a Rat Model of Bubonic Plague|journal=Am J Pathol|volume=166|issue=5|pages=1427–1439|doi=10.1016/S0002-9440(10)62360-7|pmid=15855643|pmc=1606397|year=2005}}</ref>

If the lymph node is overwhelmed, the infection can pass into the bloodstream, causing ''secondary septicemic plague'' and if the lungs are seeded, it can cause ''secondary pneumonic plague''.<ref>{{cite web|title=Plague|publisher=Centers for Disease Control and Prevention|url=https://www.cdc.gov/plague/healthcare/clinicians.html|access-date=2014-08-05}}</ref>

===Septicemic plague===
{{Main|Septicemic plague}}
[[File:PlagueTypes.jpg|thumb|Septicemic plague resulting in necrosis]]
Lymphatics ultimately drain into the bloodstream, so the plague bacteria may enter the blood and travel to almost any part of the body. In [[septicemia|septicemic]] plague, bacterial endotoxins cause [[disseminated intravascular coagulation]] (DIC), causing tiny clots throughout the body and possibly ischemic necrosis (tissue death due to lack of circulation/perfusion to that tissue) from the clots. DIC results in depletion of the body's clotting resources so that it can no longer control bleeding. Consequently, there is bleeding into the skin and other organs, which can cause red and/or black patchy rash and hemoptysis/hematemesis (coughing up/ vomiting of blood). There are bumps on the skin that look somewhat like insect bites; these are usually red, and sometimes white in the centre. Untreated, the septicemic plague is usually fatal. Early treatment with [[antibiotics]] reduces the mortality rate to between 4 and 15 per cent.<ref name="Wagle1948">{{cite journal| author=Wagle PM| title=Recent advances in the treatment of bubonic plague| journal=Indian J Med Sci| year=1948| volume=2| pages=489–94}}</ref><ref name="Meyer1950">{{cite journal| author=Meyer KF| title=Modern therapy of plague| year=1950| journal=J Am Med Assoc| volume=144| pages=982–85| pmid=14774219| issue=12| doi=10.1001/jama.1950.02920120006003}}</ref><ref name="DattGupta1948">{{cite journal| author=Datt Gupta AK| title=A short note on plague cases treated at Campbell Hospital| journal=Ind Med Gaz| year=1948| volume=83| issue=3| pages=150–51| pmid=29014753| pmc=5190352}}</ref>

===Pneumonic plague===
{{Main|Pneumonic plague}}
The [[pneumonia|pneumonic]] form of plague arises from [[infection]] of the [[human lung|lungs]]. It causes coughing and thereby produces [[Airborne disease|airborne]] droplets that contain [[bacteria]]l cells and are likely to infect anyone inhaling them. The [[incubation period]] for pneumonic plague is short, usually two to four days, but sometimes just a few hours. The initial signs are indistinguishable from several other respiratory illnesses; they include headache, weakness, and spitting or vomiting of blood. The course of the disease is rapid; unless diagnosed and treated soon enough, typically within a few hours, death may follow in one to six days; in untreated cases, mortality is nearly 100%.<ref>{{cite book |editor-last=Ryan |editor-first=K. J. |editor2-last=Ray |editor2-first=C. G. |title=Sherris Medical Microbiology: An Introduction to Infectious Diseases |location=New York |publisher=McGraw-Hill |edition=4th |year=2004 |isbn=978-0-8385-8529-0 }}</ref><ref name="Hoffman1980">{{cite journal| author=Hoffman SL| title=Plague in the United States: the "Black Death" is still alive| journal=Annals of Emergency Medicine| year=1980| volume=9| pages=319–22| doi=10.1016/S0196-0644(80)80068-0| issue=6| pmid=7386958}}</ref>