Yersinia pestis

Yersinia pestis (Y. pestis; formerly <a href="/facts/Pasteurella/tQ9fCtEV">Pasteurella</a> pestis) is a <a href="/facts/Gram-negative_bacteria/S1PbVtp4">gram-negative</a>, <a href="/facts/Non-motile_bacteria/Al56Rtb6">non-motile</a>, <a href="/facts/Coccobacillus/UxyvxW4p">coccobacillus</a> <a href="/facts/Bacteria/wC8xSCsU">bacterium</a> without <a href="/facts/Endospore/UKWvt6Qu">spores</a>. It is related to pathogens <a href="/facts/Yersinia_enterocolitica/lP14KXUY">Yersinia enterocolitica</a>, and <a href="/facts/Yersinia_pseudotuberculosis/T3JJxwJK">Yersinia pseudotuberculosis</a>, from which it evolved. Yersinia pestis is responsible for the <a href="/facts/Far_East_scarlet-like_fever/RHNMuG2f">Far East scarlet-like fever</a>, and the disease <a href="/facts/Plague_(disease)/4r7oe5lC">plague</a>, which caused the <a href="/facts/Plague_of_Justinian/srTzssYm">Plague of Justinian</a> and the <a href="/facts/Black_Death/fztxlxgl">Black Death</a>, one of the deadliest <a href="/facts/Pandemic/KaJe9rTu">pandemics</a> in recorded history. Plague takes three main forms: <a href="/facts/Pneumonic_plague/qLKr0Xsq">pneumonic</a>, <a href="/facts/Septicemic_plague/X33kMnU6">septicemic</a>, and <a href="/facts/Bubonic_plague/N9dCQ3EP">bubonic</a>. Y. pestis is a <a href="/facts/Facultative_anaerobic_organism/YS9tdh8N">facultative anaerobic</a> <a href="/facts/Parasitism/HWPcgky7">parasitic bacterium</a> that can infect humans primarily via its host the <a href="/facts/Oriental_rat_flea/XK8dvE9B">Oriental rat flea</a> (Xenopsylla cheopis), but also through <a href="/facts/Airborne_transmission/hpm1oR83">aerosols and airborne droplets</a> for its pneumonic form. As a parasite of its host, the <a href="/facts/Rat_flea/7uWjTHPI">rat flea</a>, which is also a parasite of <a href="/facts/Rat/5rn6uEKM">rats</a>, Y. pestis is a <a href="/facts/Hyperparasite/8eGG61Er">hyperparasite</a>.
Y. pestis was discovered in 1894 by <a href="/facts/Alexandre_Yersin/V2FTfStY">Alexandre Yersin</a>, a Swiss/French <a href="/facts/Physician/qJ3woFvG">physician</a> and <a href="/facts/Bacteriologist/Xk70D2YU">bacteriologist</a> from the <a href="/facts/Pasteur_Institute/2wW6k7hf">Pasteur Institute</a>, during <a href="/facts/1894_Hong_Kong_plague/xtqs0IwI">an epidemic of the plague</a> in <a href="/facts/Hong_Kong/4nAf3mqQ">Hong Kong</a>. Yersin was a member of the <a href="/facts/Louis_Pasteur/lboGfpy0">Pasteur</a> school of thought. <a href="/facts/Kitasato_Shibasabur%25C5%258D/LeC09mc1">Kitasato Shibasaburō</a>, a Japanese bacteriologist who practised <a href="/facts/Robert_Koch/cUDapauh">Koch's methodology</a>, was also engaged at the time in finding the causative agent of the plague. However, Yersin actually linked plague with a <a href="/facts/Bacillus/RJNLPx5q">bacillus</a>, initially named Pasteurella pestis; it was renamed Yersinia pestis in 1944.
Between one thousand and two thousand cases of the plague are still reported to the <a href="/facts/World_Health_Organization/YNN3bgug">World Health Organization</a> every year. With proper <a href="/facts/Antibiotic/sF1kIfxg">antibiotic</a> treatment, the <a href="/facts/Prognosis/3DEGwPag">prognosis</a> for victims is much better than before antibiotics were developed. Cases in Asia increased five- to six-fold during the time of the <a href="/facts/Vietnam_War/W0gfbGTE">Vietnam War</a>, possibly due to the disruption of ecosystems and closer proximity between people and animals. The plague is now most commonly found in the <a href="/facts/Democratic_Republic_of_the_Congo/E2KmHDdv">Democratic Republic of the Congo</a>, <a href="/facts/Madagascar/ez12IAcY">Madagascar</a>, and <a href="/facts/Peru/dBt7XrYD">Peru</a>. The plague also has a detrimental effect on non-human mammals; in the United States, these include the <a href="/facts/Black-tailed_prairie_dog/cjIhyy88">black-tailed prairie dog</a> and the endangered <a href="/facts/Black-footed_ferret/Lxlywgv8">black-footed ferret</a>.

Yersinia pestis open-in-new

Yersinia pestis