Diseases Flashcards
(30 cards)
The infectious agent causing cholera
Vibrio cholerae
What type of pathogenic organism causes cholera?
A bacterium - Vibrio cholerae
What are the 4 main types of pathogenic organisms?
Bacteria, viruses, fungi, parasites
What are the 3 mains types of pathogenic parasites?
Protozoa, helminths, ectoparasites
Which part of the body does Vibrio cholerae mainly colonise?
The small intestine
How does Vibrio cholerae move?
It has a flagellum, and responds to chemotaxis
Once inside the small intestine, what does Vibrio cholerae try to do?
Reach the epithelial cells lining the small intestine
What barriers are presented to Vibrio cholerae infecting the small intestine?
Stomach acid kills Vibrio cholerae, peristalsis moves it through the small intestine before it can adhere, and the small intestine is lined with a mucous net
What kind of cells make up the mucous net lining the small intestine?
Goblet cells
What kind of Vibrio cholerae tends to be hyper-infectious?
Bacteria that have passed through another human host
True or false - in order to be affected by cholera disease, a human usually only needs to ingest a small number of Vibrio cholerae bacteria?
False - usually a large number of Vibrio cholerae bacteria need to be ingested in order for some to survive passage through stomach acid and other barriers
What type of cells line the intestinal tract?
Epithelial cells
What does Vibrio cholerae use to get past the mucous net lining the small intestine?
It produces enzymes to digest the mucous
How does Vibrio cholerae adhere to epithelial cells?
It uses thread-like appendages called pili or fimbriae
What is this?
Vibrio cholerae
Vibrio cholerae - gram positive or negative?
Gram-negative
What kind of natural environment does Vibrio cholerae survive in (outside of humans)?
Brackish or salty water
What cells in the human body are primarily affected by Vibrio cholerae?
The epithelial cells of the small intestine
What does Vibrio cholerae use to disturb the function of epithelial cells in the small intestine?
It secretes a toxin which is then engulfed by the epithelial cell
What channels in the epithelial cell are affected by the cholera toxin?
The toxin affects the choride channels, meaning that first large amounts of chloride ion leaves the cell, followed by large amounts of sodium ion
Why does cholera cause rapid dehydration?
The disruption of chloride channels in the epithelial cells of the small intestine means that a) these cells lose water and b) water in the intestine is no longer able to be absorbed by the body, and is excreted as diarrhoea
What is the first-line therapy for cholera?
Oral rehydration salts (or intravenous hydration)
True or false - Vibrio cholerae is considered a highly virulent pathogen
True - the degree of disease it causes is severe, and can cause death in a previously healthy individual within hours
True or false - most people infected with Vibrio cholerae become acutely ill
False - most people infected with Vibrio cholerae do not show any symptoms
