Re-Emerging Disease: Cholera

The disease, cholera, is an infection of the intestines, caused by the bacterium Vibrio cholerae. As stated in Microbes and Infections of the Gut, the bacterium is "a Gram-negative, comma- shaped, highly motile organism with a single terminal flagellum" (105). Cholera is characterized by the most significant symptom that presents with the disease, diarrhea, and victims can lose up to twenty liters of body fluids in a day. Cholera can be a serious disease, due to the serious dehydration that can occur, but it is only fatal if treatment is not administered as soon as possible. This research paper includes information on the causes of cholera, symptoms, ways of treatment, studies of treatments, complications that may occur, the tests and diagnosis for cholera, and finally, the ways the cholera bacterium may be transmitted.

Introduction

Cholera is a disease caused by the cholera bacterium Vibrio cholerae infecting the intestines. Usually, the illness is mild, and for some, symptoms of cholera never even present, but sometimes, the disease can also be severe. A severe case of cholera is "characterized by profuse watery diarrhea, vomiting, and leg cramps. In these persons, rapid loss of body fluids leads to dehydration and shock. Without treatment, death can occur within hours" ("Cholera vaccine, symptoms,," 2011) . Normally, in a gentler case of cholera, the infected person only has mild diarrhea. "In 5-10% of cases, however, patients develop very severe watery diarrhea and vomiting from 6 hours to 5 days after exposure to the bacterium. In these cases, the loss of large amounts of fluids can rapidly lead to severe dehydration. In the absence of adequate treatment, death can occur within hours" ("Cholera vaccine, symptoms," 2011) .

Causes

The main source of cholera contamination is the cholera bacteria present in the stool of an infected person. However, "although V. cholerae is the source of the cholera infection, the deadly effects of the disease is the result of a potent toxin, called CTX, which the bacteria produce in the small intestine. CTX binds to the intestinal walls, where it interferes with the normal flow of sodium and chloride. This causes the body to secrete enormous amounts of water, leading to diarrhea and a rapid loss of fluids and salts (electrolytes)" ("Cholera: causes," 2011)

There are other common sources of cholera bacterium are surface or well water, seafood, raw fruits and vegetables, and grains. In water, Vibrio cholerae can survive for long periods of time, staying dormant. People in areas with poor sanitation, like crowded refugee camps, are at risk of cholera, due to the fact that water provided for said community could be a source of contamination of cholera bacteria. Seafood, when raw or undercooked, can be contaminated by cholera bacteria, if the seafood came from certain areas with contaminated waters.

Since the 1970s, cholera outbreaks in the U.S. have been caused by smuggled seafood from cholera-infected areas, and from the Gulf of Mexico. Shellfish are especially contaminated, due to the fact that "they filter large amounts of water, concentrating the levels of cholera bacteria". Raw fruits--especially unpeeled--and vegetables coming from an area with a source of cholera are another frequent source of the cholera bacteria. Inoculation of the fruits and vegetables could occur at fertilization of the plant with infected manure, or watering the plants with infected water, or even during the harvesting and processing of the fruits and vegetables. Another source of cholera bacteria are grains. "In regions where cholera is widespread, grains such as rice and millet that are contaminated after cooking and allowed to remain at room temperature for several hours become a medium for the growth of cholera bacteria". ("Cholera: causes," 2011)

As stated in MayoClinic.com's informative article on the causes of cholera, Vibrio cholerae, the bacterium that causes cholera, has two different life cycles. The life cycles these bacterium go through depend upon where they reside, be it in the environment, or in a human host. In the environment, Vibrio cholerae usually is found in coastal waters, although "the bacterium can also live in the environment in brackish rivers" as well ("Frequently asked questions," 2011). They are attached to their hosts, which are "tiny crustaceans called copepods. As many as 10,000 bacteria may adhere to a single crustacean" ("Cholera: causes," 2011)

The cholera bacterium is spread throughout the world via said crustaceans, who migrate in search of food--certain kinds of algae and plankton which grow better in warmer water temperatures. This explains why there are more cholera outbreaks in the spring and fall "when ocean surface temperatures and algae blooms are at their height. More algae mean more copepods, and more copepods mean more cholera bacteria" ("Cholera: causes," 2011).

The second possible life cycle of Vibrio cholerae included in the previously mentioned article is that of the life cycle that takes place when the cholera bacterium infects a human. When it is taken in, the human as a host won't necessarily show symptoms of the disease, but they still will have viable Vibrio cholerae in their stool. The infectious dose for cholera is over a million cholera bacteria, which is why cholera isn't contagious when it comes to "casual person-to-person contact". However, cholera is contagious when food or water, contaminated by the feces of an infected person, is consumed.

Symptoms

Cholera is caused by Vibrio cholerae, a bacterium which affects the intestines, which causes the diarrhea associated with this disease. Oftentimes, the illness is gentle and shows little symptoms, sometimes presenting with no symptoms whatsoever, but at times, the infection can be severe and potentially fatal. "Approximately 1 in 20 infected persons has severe disease characterized by profuse watery diarrhea, vomiting, and leg cramps. In these persons, rapid loss of body fluids leads to dehydration and shock. Without treatment, death can occur within hours" ("Cholera vaccine, symptoms,," 2011).

The possible symptoms of cholera are the sudden onset of watery diarrhea (up to one liter per hour), bloody feces towards the beginning of the infection, a "rice water" diarrhea appearance--as well as "flecked with mucus and dead cells" ("Cholera: symptoms," 2011) --towards the late stages of the infection, rapid dehydration, rapid or irregular pulse, dry skin, dry mucous membranes, dry mouth, excessive

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