cholera

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powerpoint presentation what is cholera? cholera a life-threatening secretory diarrhea induced by enterotoxin secreted by v. cholerae water-borne illness caused by ingesting water/food contaminated by copepods infected by v. cholerae an enterotoxic enteropathy (a non-invasive diarrheal disease) a major epidemic disease recent cholera pandemics 1-6th pandemic: v. cholerae o1 biotype classical 1817-1923, asia, africa, europe, america and australia 7th pandemic: v. cholerae o1 biotype el tor began in asia in 1961 spread to other continents in 1970s and 1980s spread to peru in 1991 and then to most of south & central america and to u.s. & canada by 1995 in the americas, >106 cases; 104 dead 1993: cholera in bengal caused by o139 may be cause of 8th pandemic 1)in industrialized with reported cases cholera--imported vibrio vibrio cholerae --gastroenteritis vibrio parahaemolyticus -- gastroenteritis, wound infection, bacteremia vibrio vulnificus -- wound infection, bacteremia v. cholerae grows in salt and fresh …
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on syntehtic media with glucose as sole source of crabon and energy 2)summers-water temps exceed 20 c a)summers—illnesses inc 3)zoo plankton? similarities to enterobacteriaceae g-, facultative anaerobes fermentative bacilli differences from enterobacteriaceae polar flagella oxidase positive formerly classified together as vibrionaceae primarily found in water sources cause gastrointestinal disease shown not closely related by molecular methods profile of vibrio cholerae broad temperature & ph range for growth on media 18-37c ph 7.0 - 9.0 (useful for enrichment) grow on variety of simple media including: macconkey’s agar tcbs (thiosulfate citrate bile salts sucrose) agar v. cholerae grow without salt most other vibrios are halophilic physiology of vibrio people most at risk people with low gastric acid levels (103 -105 cfu ) children: 10 × more susceptible than adults elderly blood types o>> b > a > ab not sure why o more susceptible—allows bacteria to adhere to gut lining—guess a)e1tor and …
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oxin (exotoxin [cholera toxin ct]) ct is antigenically and pharmacologically identical in all sero and bio types pathogenesis of v. cholerae cholera toxin (ct) structure the a subunit contains an intracellular adp-ribosyltransferase activity. the mature a subunit is proteolytically cleaved to produce an a1 polypeptide, which contains the intracellular enzymatic activity, and an a2 polypeptide. ct is a prototype a/b subunit toxin, 1a+5b the b subunit form a pentameric ring, which binds the holotoxin to a eukaryotic cell surface receptor. cholera toxin (ct) structure after cleavage, the a1 and a2 polypeptides remain linked by a disulphide bond. a and b subunits are connected through the c-terminus of the a2 subunit, which is inserted through the central pore of the b pentamer. how does cholera toxin work? the biological activity of ct is dependent on binding of b pentamer to specific receptors gm1 ganglioside. internalization is initiated once ct-gm1 complexes cluster …
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mally high rate which stimulates mucosal cells to pump large amounts of cl- into the intestinal contents. how does cholera toxin work? h2o, na+ and other electrolytes follow due to the osmotic and electrical gradients caused by the loss of cl-. the lost h2o and electrolytes in mucosal cells are replaced from the blood. thus, the toxin-damaged cells become pumps for water and electrolytes causing the diarrhea, loss of electrolytes, and dehydration that are characteristic of cholera. how does cholera toxin work? inactivates gtpase function of g-protein coupled receptors in intestinal cells g proteins stuck in “on” position 100 fold increase in camp activation of ion channels ions flow out and water follows 1)bact prod toxin that…. 2)prevents hydrolysis of gtp to gdp diagnosis cholera should be suspected when patients present with watery diarrhea, severe dehydration based on clinical presentation and confirmed by isolation of vibrio cholera from stool no …
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st); cause food poisoning in human beings. raw sea-food vibrio parahemolyticus clinical manifestations self-limiting diarrhea to mild cholera-like illness 24 hours after ingestion-explosive water diarrhea headache, abdominal cramps, nausea, vomiting, low grade fever for 72 hours or more uneventful recovery wound infections in people exposed to seawater-containing vibrios helicobacter pylori helicobacter pylori g- with s or spiral-shaped very motile ---corkscrew motion 2~6 flagella at one end of hp 5% o2+10% co2 at 37 oc reaction of urea hydrolysis and creates an ammonia cloud pathogenesis of hp caga (cytotoxin associated) vaca (vacuolationg associated) lps also play great importance flagellum and urease is necessary for its adhesion and inhabitation adhesin duodenal ulcer (du) gastric ulcer (gu) campylobacter jejuni g- rods with comma, s, or “gull-wing” shapes. motive, with a single polar flagellum no spore & no capsule 5% o2+10% co2 two types of colonies:  watery and spreading round and convex produces …

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powerpoint presentation what is cholera? cholera a life-threatening secretory diarrhea induced by enterotoxin secreted by v. cholerae water-borne illness caused by ingesting water/food contaminated by copepods infected by v. cholerae an enterotoxic enteropathy (a non-invasive diarrheal disease) a major epidemic disease recent cholera pandemics 1-6th pandemic: v. cholerae o1 biotype classical 1817-1923, asia, africa, europe, america and australia 7th pandemic: v. cholerae o1 biotype el tor began in asia in 1961 spread to other continents in 1970s and 1980s spread to peru in 1991 and then to most of south & central america and to u.s. & canada by 1995 in the americas, >106 cases; 104 dead 1993: cholera in bengal caused by o139 may be cause of 8th pandemic …

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