Miscellaneous
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STEM : Stop the Spread

Investigate a communicable disease

Diseases linked to limited access to clean water

Image of a cholera baterium

A false color transmission electron micrograph (TEM) of Vibrio cholerae magnified 6,000 times its original size.

Cholera [Photograph]. (2010). World of Scientific Discovery. Gale, a Cengage Company. https://link.gale.com/apps/doc/CV2210049472/SUIC?u=61_alls&sid=SUIC&xid=70dae6a2


 

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Search term - cholera

Although the illness called cholera is usually not life-threatening, the symptoms it produces can be extremely uncomfortable. Cholera is caused by a organism called Vibrio cholerae. This organism is a kind of bacteria that lives in some rivers and along the coasts of oceans.

How Cholera Is Spread
Cholera is spread by eating food or drinking water that has been contaminated with the cholera bacterium. Foods such as raw shellfish are a frequent culprit in this illness. Sometimes foods such as raw fruits and vegetables are to blame. Although these foods do not live in water, as shellfish do, they can become contaminated with cholera if they are washed in water that contains the bacteria. Cholera is frequently found in countries that do not have modern facilities for cleaning water before people can drink it or wash with it. Because cholera is spread by eating contaminated food or drinking contaminated water, it is called a food-borne illness.

Symptoms
The most common symptom of cholera is diarrhoea. In many cases, the person only suffers mild symptoms that disappear within a short period of time. In some people, the symptoms are quite severe. The person will suffer frequent bouts of vomiting, along with severe, very watery diarrhoea. This leads to dehydration, a condition in which the body loses fluids very rapidly. If the dehydration is not corrected within a short time, the patient can go into shock. In some cases, this can lead to death within only a few hours.

Treatment
Treatment for cholera consists mainly of rehydration. This means that the patient is given fluids through an intravenous tube in a hospital. If vomiting is not too severe, the patient may also be given certain types of liquid to drink. These liquids contain not only water but also a mixture of salts and sugars that help restore the important nutrients lost from vomiting and diarrhoea. In some cases, antibiotics are given to the patient.

The best treatment for cholera is prevention. It is always very important to drink only water that has been properly cleaned and treated to destroy bacteria and other germs. In some developing countries, where water treatment methods have not been modernised, only bottled water should be consumed. It is also important in these countries to avoid raw or undercooked foods. In the United Kingdom, modern water treatment methods are used to keep water clean. This has greatly helped to control outbreaks of cholera. However, it is important even in the United Kingdom to never drink water directly from a stream or river or lake. Although it is safe to eat raw fruits and vegetables in the UK – provided they have been washed first – it is not safe to eat raw or undercooked shellfish.

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Cholera. (2021). In Encyclopædia Britannica. Retrieved from https://school.eb.com.au/levels/middle/article/cholera/440050


 

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Level 3

"Cholera is an acute illness characterized by watery diarrhea that is caused by the bacterium Vibro cholerae. Cholera is spread by eating food or drinking water contaminated with the bacteria."

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Cholera. (2010). In World of Health. Gale. https://link.gale.com/apps/doc/CV2191500267/SUIC?u=61_alls&sid=SUIC&xid=2b615a65

image of shigella bacterium

"Photomicrograph of rod-shaped Shigella", the bacterium that causes dysentery.

Shigella. [image]. In Encyclopædia Britannica. Retrieved from https://school.eb.com.au/levels/high/assembly/view/116864#

Encyclopedia Britannica logo

Click the link above to be taken to Encyclopedia Britannica and choose Middle School.

Search term - dysentery

Level 3

"Dysentery, infectious disease characterized by inflammation of the intestine, abdominal pain, and diarrhea with stools that often contain blood and mucus. Dysentery is a significant cause of illness and death in young children, particularly those who live in less-developed countries. There are two major types: bacillary dysentery and amebic dysentery, caused respectively by bacteria and by amoebas."

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Dysentery. (2021). In Encyclopædia Britannica. Retrieved from https://school.eb.com.au/levels/middle/article/dysentery/31677

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Level 3

"Dysentery, which was historically called bloody flux or flux, is an infectious disease that involves severe diarrhea along with blood within the feces...The disease still is a major problem in tropical countries with primitive sanitary facilities."

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Blaser, L. (2014). Dysentery. In K. L. Lerner & B. W. Lerner (Eds.), The Gale Encyclopedia of Science (5th ed.). Gale. https://link.gale.com/apps/doc/CV2644030729/SUIC?u=61_alls&sid=SUIC&xid=a252e9fc

virus: gastroenteritis viruses

"Gastroenteritis viruses in humans can be seen in electron micrographs"

Shigella. [image]. In Encyclopædia Britannica. Retrieved from https://school.eb.com.au/levels/middle/article/gastroenteritis/324341

Encyclopedia Britannica logo

Click the link above to be taken to Encyclopedia Britannica and choose Middle School.

Search term - gastroenteritis

Level 2

Gastroenteritis is a general term applied to a group of syndromes of the digestive system that are characterized by one or more of the following symptoms: loss of appetite, nausea, vomiting, diarrhea, and abdominal pain. The irritant responsible may be bacteria, a virus, a parasite, a toxin, or an unknown source. Treatment is usually bed rest and the intake of fluids to prevent dehydration.

Gastroenteritis, acute infectious syndrome of the stomach lining and the intestine. It is characterized by diarrhea, vomiting, and abdominal cramps. Other symptoms can include nausea, fever, and chills. The severity of gastroenteritis varies from a sudden but transient attack of diarrhea to severe dehydration.

Numerous viruses, bacteria, and parasites can cause gastroenteritis. Microorganisms cause gastroenteritis by secreting toxins that stimulate excessive water and electrolyte loss, thereby causing watery diarrhea, or by directly invading the walls of the gut, triggering inflammation that upsets the balance between the absorption of nutrients and the secretion of wastes.

Viral gastroenteritis, or viral diarrhea, is perhaps the most common type of diarrhea worldwide; rotaviruses, caliciviruses, Norwalk viruses, and adenoviruses are the most common causes. Other forms of gastroenteritis include food poisoning, cholera, and traveler’s diarrhea, which develops within a few days after traveling to a country or region that has unsanitary water or food. Traveler’s diarrhea is caused by exposure to enterotoxin-producing strains of the common intestinal bacterium Escherichia coli.

The treatment of gastroenteritis depends on the cause and the severity of symptoms and may include antibiotics or simply supportive care. Adults tend to have milder cases of the illness than do children and the very old, who run the risk of dehydration due to diarrhea and vomiting.

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Gastroenteritis. (2021). In Encyclopædia Britannica. Retrieved from https://school.eb.com.au/levels/middle/article/gastroenteritis/324341


 

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Level 2

"Gastroenteritis is a catch-all term for infection or irritation of the digestive tract, particularly the stomach and intestine...The most common cause of gastroenteritis is viral infection. Exposure often occurs by consuming materials contaminated by excrement (fecal-oral route). Viruses involved in gastroenteritis include rotavirus, adenovirus, astrovirus, and calicivirus and small round-structured viruses (SRSVs)..."

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Image of salmonella typhi bacterium

A scanning electron microscope (SEM) image displays Salmonella typhi , the bacteria that causes typhoid fever, on the surface of the Schistosoma mansoni parasite.

Salmonella typhi , the bacteria that causes typhoid fever [Photograph]. (2014). K. L. Lerner & B. W. Lerner (Eds.), The Gale Encyclopedia of Science (5th ed.). Gale. https://link.gale.com/apps/doc/PC4205138967/SUIC?u=61_alls&sid=SUIC&xid=9cc409b0


 

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Search term - typhoid fever

Level 2

Typhoid fever is a serious disease. It is rare in wealthy countries but common in poor ones. People with the disease usually have a high fever for many days. Other symptoms, or signs, of typhoid fever include headache, stomach pain and weakness. A rash of rosy spots also may appear on the body.

Tiny living things called bacteria cause typhoid fever. The type of bacteria that causes the disease lives only in humans. It travels in the blood and attacks the intestines. It passes from person to person through water or food.

Typhoid fever may be prevented by keeping water supplies clean. Washing the hands before preparing food is important, too. People also may get a typhoid fever vaccine (a substance that prevents the disease) from a doctor or a nurse. People who do get the disease need to be treated with drugs called antibiotics right away. Antibiotics kill the bacteria. People who are not treated may die.

In the early 1900s a cook called Mary Mallon spread typhoid fever to at least 51 people. She carried the bacteria but did not get the disease. She passed the bacteria to people through food that she prepared. Mallon’s actions earned her the nickname Typhoid Mary.

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Typhoid fever. (2021). In Encyclopædia Britannica. Retrieved from https://school.eb.com.au/levels/middle/article/typhoid-fever/313928


 

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Level 3

"Typhoid fever is a life-threatening disease of the intestinal system caused by the typhoid bacillus, Salmonella typhosa, which lives only in humans who carry it in their bloodstream and intestinal tract."

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Typhoid fever. (2007). In World of Health. Gale. https://link.gale.com/apps/doc/CV2191501322/SUIC?u=61_alls&sid=SUIC&xid=7fe8db0d