Podcast
Questions and Answers
Which bacterium is responsible for causing cholera?
Which bacterium is responsible for causing cholera?
When was the El Tor biotype of V cholerae first isolated?
When was the El Tor biotype of V cholerae first isolated?
How many cholera pandemics have occurred since 1817?
How many cholera pandemics have occurred since 1817?
Which serogroup caused the epidemic of cholera in Madras, India in October 1992?
Which serogroup caused the epidemic of cholera in Madras, India in October 1992?
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Where did the seventh pandemic of cholera begin in 1961?
Where did the seventh pandemic of cholera begin in 1961?
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Why is the number of cholera patients worldwide uncertain?
Why is the number of cholera patients worldwide uncertain?
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What is the size range of the V. cholerae organism?
What is the size range of the V. cholerae organism?
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What is the antigenic structure of the V. cholerae organism?
What is the antigenic structure of the V. cholerae organism?
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What causes the dramatic increase in cAMP levels within the cell in V. cholerae infection?
What causes the dramatic increase in cAMP levels within the cell in V. cholerae infection?
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What is the consequence of the sustained activation of adenylate cyclase in V. cholerae infection?
What is the consequence of the sustained activation of adenylate cyclase in V. cholerae infection?
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What is the role of cAMP in V. cholerae infection?
What is the role of cAMP in V. cholerae infection?
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Which receptor do the B subunits of the toxin bind to on the epithelial cells lining the gut?
Which receptor do the B subunits of the toxin bind to on the epithelial cells lining the gut?
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What is responsible for separating V. cholerae into pathogenic and nonpathogenic strains?
What is responsible for separating V. cholerae into pathogenic and nonpathogenic strains?
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What causes net fluid loss leading to watery diarrhea in V. cholerae infection?
What causes net fluid loss leading to watery diarrhea in V. cholerae infection?
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What causes a decrease in sodium influx into the cell during V. cholerae infection?
What causes a decrease in sodium influx into the cell during V. cholerae infection?
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What is secreted by V. cholerae in the small intestine of affected individuals?
What is secreted by V. cholerae in the small intestine of affected individuals?
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Study Notes
Cholera
- Caused by the bacterium Vibrio cholerae
History of Cholera
- El Tor biotype of V. cholerae first isolated in 1905
- Seven cholera pandemics have occurred since 1817
Epidemics
- 1992 epidemic in Madras, India caused by serogroup O1
- Seventh pandemic of cholera began in 1961 in Indonesia, Sulawesi
Characteristics of V. cholerae
- Size range: 1-3 μm x 0.2-0.5 μm
- Antigenic structure: lipopolysaccharide (LPS) and polysaccharide capsule
Pathogenesis of V. cholerae Infection
- Dramatic increase in cAMP levels within the cell caused by ADP-ribosylation of Gsα
- Sustained activation of adenylate cyclase leads to increased cAMP production
- cAMP enhances Cl- secretion and inhibits Na+ absorption, leading to secretory diarrhea
- B subunits of the toxin bind to GM1 receptor on epithelial cells lining the gut
Pathogenicity
- Presence of ctx and zot genes responsible for separating V. cholerae into pathogenic and nonpathogenic strains
Clinical Manifestations
- Net fluid loss leading to watery diarrhea caused by increased Cl- secretion and inhibited Na+ absorption
- Decreased sodium influx into the cell due to inhibition of NHE by cAMP
- V. cholerae secretes cholera toxin in the small intestine of affected individuals
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Description
This quiz covers the biochemistry of cholera, including its etymology, causative agent V. cholerae, major biotypes, and epidemiology. It also includes background information about the discovery of V. cholerae and the history of cholera pandemics. Additionally, the quiz delves into the biochemistry of HIV.
