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Course: Health and medicine > Unit 10
Lesson 2: GastroenteritisWhat is cholera?
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- 2:05why does cholera bacteria produces toxins which make epithelial cells to dehydrate and release ions? Does the bacteria uses these ions or gain any other benefit?(6 votes)
- Cholera enterotoxin poisons the cells, causing them to burst. The disruption of cellular function provides the bacteria with some nutritional components that are no longer sequestered in cells, and also prevents the bacteria from being targeted effectively by the immune system due to the disruption.(5 votes)
- why can't we call gastroenteritis one name and not stomach flu or stomach bug or stomach virus.(3 votes)
- Why are there multiple names for poo or stools or faeces? One name may be more scientific, but people have a lot of different ways of referring to the same thing, depending on your level of understanding/personal preference/the social context. This is why a person might say they have a 'tummy bug' while the doctor may refer to it as gastroenteritis.(3 votes)
- is it co-lur-a or cah-lair-a?(1 vote)
Video transcript
- [Voiceover] Here, I have
a picture of Dr. John Snow, and this isn't the popular
Game of Thrones character, but a doctor from the 1800s
who discovered the source of the cholera outbreak in London. He traced it to the poor sewer, waste, and water management of the city. And in doing so, his discovery
allowed for the improvement of water sanitation and waste management. So, cholera is caused by the
Vibrio cholerae bacteria, and is the most common cause
of bacterial gastroenteritis in the developing world. A lot of the symptoms of cholera overlap with the symptoms of the other
forms of gastroenteritis, like vomiting and nausea
and abdominal pain. But what really sets
cholera apart is the severe dehydration and diarrhea. Unlike other forms of
bacterial gastroenteritis, the diarrhea is not bloody. In fact, it's watery. It kind of has this rice-y,
watery-like consistency. In addition, you're
producing a lot of diarrhea over the course of a few days. It's thought to be about
anywhere between 10 to 20 liters. That's the equivalent of
about 10 bottles of soda. But because you're losing so
much water through diarrhea, you're going to experience some really bad dehydration as well. Now, you're more likely to
contract cholera if you live in areas of poor sanitation,
and that's because in areas of poor sanitation, the food
and water is more likely to be contaminated. If you eat this
contaminated food and drink this contaminated water,
you're very likely to contract the infection. So, once you contract the
infection, it first needs to make its way past the acidic
environment of the stomach and into your small intestine. So, here, I have a structure of the wall of the small intestine,
and I want to focus on this green layer over here
known as the epithelium. These green blocks are all
of the epithelial cells. And I want to actually
zoom in one of those. So, this is our epithelial cell. Over here, we have the
Vibrio cholerae bacteria. And you'll notice this kind of
structure that sort of looks like a tail, and this
is called the flagellum. That flagellum will actually
propel the bacteria towards the epithelial cell. So, now that it's in close
contact with the epithelial cell, what it'll do is it'll start
producing what's called a cholera toxin. That cholera toxin will then
enter the epithelial cell. As it enters the epithelial
cell, it'll induce a whole bunch of different biochemical reactions in signal transduction cascades. And in doing so, it'll lead
to the ultimate secretion of a whole bunch of things
from within the cell into the lumen. Remember that the lumen
is really just the space through which the food
and water passes through the small intestine. Now, what gets secreted out? Well, it's mostly ions,
things like sodium, potassium, bicarbonate, and chloride. With these ions, water
is also going to leave. So, what you're doing is
it's almost like you're kind of squeezing that cell. You're not of course
physically squeezing it, but you're removing all
the contents from the cell. And that's really where the
source of the dehydration and the diarrhea comes from. So, not only are you preventing the cell from absorbing water, you're
actually removing water from your body. Now, if you have these kinds
of symptoms of dehydration and diarrhea, you may want
to go to the doctor to see if you have cholera. What they'll do is they'll
order a stool sample. They'll send that sample
off to a lab to evaluate its contents. And that lab will check
to see if you have either the bacteria or an
antigen of the bacteria. And an antigen is really
just kind of like a marker of the bacteria itself. If it does, then we can
confirm that the person has cholera. And the doctor can then
give the recommendations for what the person
must do, the most common recommendation being to
drink a lot of fluids. Now, this is really
important for all forms of gastroenteritis, but it's
actually critical in cholera, because remember that you're
losing about 10 to 20 liters of water through diarrhea. So, you're going to be severely
dehydrated, and you really need to drink as many
fluids as you possibly can. If it gets severe, you may
have to be put on an IV fluid. And in some cases, right,
depending on the patient, the doctor may also prescribe
them some antibiotics. This will try to help
fight off the infection. But, again, it really depends
on the individual person and what the doctor
thinks is best for them. Now, like all forms of
gastroenteritis, the best thing to do to prevent it is by eating
clean food and drinking clean water. But for cholera, there's
actually a vaccination available. When we give vaccinations,
you're essentially injecting a dead or almost dead form of the bacteria into the person's body. In doing so, that will actually
stimulate the immune system to make antibodies for that bacteria. That way, when you contract
the real, live infection, your body will be
well-prepared to fight it off so that you don't have to
experience any of those nasty symptoms.