Microbiology and Immunology 2500A/B : Lec 3( The Plague) - summary.docx
6 Jan 2013
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Yerisnia pestis- sequenced genome from teeth from mass graves. Continued in cycles = total 100 mill ppl killed. Originated in asia, reached europe in 1340s. The feudal system destroyed- bc new opening of positions- doctors, gravediggers, etc. Started in china in 1850s- active for 100yrs. Reached sanfran in 1900 now established in sw usa. Gram negative rods, facultative anaerobes (use o but don"t need it) Very very vey virulent- not efficient colonizer, bc just kills. Death (2-4 dy) by sepsis, pneumonia, respiratory failure. Live in rodents, transmitted by fleas (zoonotic path- animals to humans) Biofilm blocks flea"s proventriculus starve fleas bite around & regurgitate y. pestis in host. Survives & grows in macrophages go to lymph nodes swelling buboes. Terminal stage- high conc of bacteria in blood easy for fleas to transmit. Vf plasmids biofilm formation, flea toxin phospholipase d- tosurvive in fleas plasminogen activator- dissemination. Lost ability to live in intestine (y pseudotb can live in intestines)
