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What is traveler's diarrhea?

Visit us (http://www.khanacademy.org/science/healthcare-and-medicine) for health and medicine content or (http://www.khanacademy.org/test-prep/mcat) for MCAT related content. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video. Created by Jaffer Naqvi.

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  • blobby green style avatar for user Samiullah Khan
    Why is it called traveler's diarrhea?
    (3 votes)
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    • female robot grace style avatar for user Mehrunisa
      Traveler's diarrhea can happen anytime. It's just called that because people mostly get it when they are not in a familiar environment. When you visit a place that's climate and sanitary practices are different then the one you are used to, you have an increased risk of traveler's diarrhea.
      (6 votes)
  • blobby green style avatar for user MLGRIFFITH7
    what is the disease causing agent for mahi mahi fish poisoning?
    (1 vote)
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  • duskpin ultimate style avatar for user shanzi11
    Can this disease be contracted anywhere or are there certain standards like the heat or cold, the humidity or the amount of sweat the body lets out?
    (0 votes)
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    • starky sapling style avatar for user Camilla
      It can be contracted anywhere, what makes you sick is ingesting contaminated food or water. However, as you indicated there are some risk factors that make it more or less likely. First of all, the temperature is important, bacteria normally like it warm and multiply better at higher temperatures. So a hotter climate makes it easier for the bacteria to multiply and get you sick. So say you put a salad out on the counter in a place with 30C and another at 10C the one in 30C will go bad (bacteria multiply) quicker. However, hygiene in food preparation is more important. The humidity or sweating isn't going to affect the likelihood of getting infected.
      (1 vote)

Video transcript

- [Voiceover] Traveler's diarrhea is caused by a bacteria known as enterotoxigenic E. coli. It's often referred to as Montezuma's Revenge if contracted in Mexico and as Delhi Belly if contracted in India. The bacteria itself is usually transmitted via the fecal to oral route. That is, you may eat some kind of food or drink some water that's been contaminated with feces and that feces was contaminated with the pathogen. Once you ingest this pathogen, it'll make its way past the stomach and into the small intestine. So like always, we're gonna focus on this green layer over here, known as the epithelium. We'll focus in on one of those epithelial cells. The bacteria will look something like this and it'll actually try to physically associate with the epithelial cell using the structures known as pili, which is just plural for pilus. Once it's associated with the epithelial cell, it'll release two different types of toxins to help it enter that cell. The first is known as heat-labile enterotoxin and the second is known as heat-stable enterotoxin. Heat-labile just basically means that this enterotoxin is going to be inactivated at high temperatures. Heat-stable means that this enterotoxin will be stable at high temperatures. So eventually these enterotoxins will help the bacteria enter the epithelial cell. Once the bacteria is in the epithelial cell however, it'll continue to release those enterotoxins. These enterotoxins will then act on different enzymatic pathways and biochemical signaling pathways. But they'll have the same end result. They'll cause the secretion of water and chloride, and in addition, they'll prevent the reabsorption of sodium. So what you're doing is you're actually squeezing the contents of the epithelial cell out into the lumen of the small intestine. Notice this is actually a pretty similar mechanism to the way that the cholera toxin works. In fact the heat-labile enterotoxin acts on the same enzymatic pathway that the cholera toxin does. When this bacteria enters your system, it'll cause all sorts of different symptoms, much like the other forms of gastroenteritis. Usually the symptoms start within hours after exposure and it lasts for about a few days. Given that the bacteria operates similarly to cholera, a lot of the symptoms will be similar. This includes profuse watery diarrhea, dehydration, and like all other forms of gastroenteritis you may experience some nausea and vomiting. You may also experience some cramps in your abdomen. If you go to the doctor, like always, they're going to order a stool sample. That stool sample will be evaluated for its contents and if they see that you have the enterotoxigenic E. coli, then there's a good chance that you have traveler's diarrhea. There aren't really that many treatments explicitly for traveler's diarrhea, except to drink a lot of water. Remember that your small intestine is actually expelling the water from its own system, so you're going to be experiencing a lot of dehydration. If you want to prevent getting traveler's diarrhea while you're traveling, the best thing to do is to drink bottled water or really just any water that you know for sure is clean because in doing so you could avoid the risk of drinking some water that's been contaminated with the pathogen.