CHOLERA

Cholera is a Greek word which means the gutter of the roof. It is an acute illness caused by the bacteria: Vibrio cholerae, which was discovered during a diarrheal outbreak in Egypt in 1883 by Robert Koch.

Cholera is a diarrheal illness caused by infection of the intestine with the toxigenic bacterium Vibrio cholerae, which secretes a toxin that causes the body to lose a large amount of fluid via the intestine by continuous passage of copious watery stool commonly described as a rice-water stool, this leads to dehydration, reduce urine output and circulatory collapse. Cholera runs a rapid, short course and is highly treatable but can be lethal and result in death if severe enough and not promptly treated.

V. cholerae has two major biotypes: classical and El Tor, Currently, El Tor is the predominant cholera pathogen worldwide.

People who get cholera often have mild or no symptoms, but cholera can be severe. Approximately 1 in 10 people who get sick with cholera will develop severe symptoms such as watery diarrhea, vomiting, and leg cramps. In these people, rapid loss of body fluids leads to dehydration and shock. Without treatment, death can occur within hours.

Cholera is prevalent in portions of Asia, the Middle East, Africa, South and Central America, and the Gulf Coast of the US. In 2010, an outbreak occurred in Haiti and later spread to the Dominican Republic and Cuba. Cases transported into Europe, Japan, and Australia have caused localized outbreaks.

In endemic areas, outbreaks usually occur during warm months. The incidence is highest in children. In newly affected areas, epidemics may occur during any season, and all ages are equally susceptible.

TRANSMISSION

Cholera is spread by ingestion of water, seafood, or other foods contaminated by the stool of people with symptomatic or asymptomatic infection. Household contacts of patients with cholera are at high risk of infection, which probably occurs through shared sources of contaminated food and water. Person-to-person transmission is less likely to occur because a large inoculum of the organism is needed to transmit the infection.

SYMPTOMS AND SIGNS

The incubation period for cholera is 1 to 3 days. Therefore, it may take 2-3 days after a person consumes a contaminated meal for symptoms to appear; however, symptoms may appear after a few hours in some people. Cholera can be subclinical, a mild and uncomplicated episode of diarrhea, or a fulminant, potentially lethal disease. Abrupt, painless, watery diarrhea and vomiting without nausea are usually the initial symptoms. Often, stools consist of a white liquid void of fecal material (rice-water stool).

The resultant severe water and electrolyte depletion leads to intense thirst, reduced urine output, muscle cramps, weakness, marked loss of skin turgor, sunken eyes, wrinkling of the skin on the fingers, and reduce circulating blood volume. Hypovolemia, hemoconcentration, oliguria and anuria, and severe metabolic acidosis with potassium depletion (but normal serum sodium concentration) occur. If cholera is untreated, circulatory collapse with cyanosis and stupor may follow. Prolonged hypovolemia can cause renal tubular necrosis.

Most patients are free of V. cholerae within two weeks after cessation of diarrhea.

TREATMENT

If you develop severe watery diarrhea and vomiting, particularly after eating undercooked shellfish, or you live in or travel to endemic areas- seek medical help immediately. Fluid replacement is the mainstay of the treatment of cholera; depending on the severity of diarrhea, fluid replacement may be through the oral or intravenous solution to replace lost fluid.

Mild cases can be treated with standard oral rehydration formula, which consists of a prepackaged mixture of salt and sugar that is mixed with one litre of water and drunk in large quantities. For hypovolemic and severely dehydrated patients, intravenous replacement with isotonic fluids should be used, rapid correction of severe hypovolemia is lifesaving. Prevention or correction of metabolic acidosis and hypokalemia is important.

Early treatment with an effective oral antimicrobial eradicates vibrios, reduces stool volume by 50%, and stops diarrhea within 48 hours. The choice of antimicrobial should be based on the susceptibility of V. cholerae isolated from the community.

PREVENTION

For effective control of cholera, human excrement must be correctly disposed of and water supplies purified. In endemic regions, drinking water should be boiled or chemically disinfected, and vegetables and fish cooked thoroughly. You can protect yourself and your family by using only water that has been boiled, water that has been chemically disinfected, or bottled water. Be sure to use bottled, boiled, or chemically disinfected water for the following purposes.

Drinking, Preparing food or drinks, Making ice, Brushing your teeth, washing your face and hands, Washing dishes and utensils that you use to eat or prepare food.

To disinfect your own water, boil it for one minute (or 3 minutes at higher elevations) or filter it and use a commercial chemical disinfectant. You should also avoid raw foods, including the following: Unpeeled fruits and vegetables, Unpasteurized milk, and milk products, raw or undercooked meat or shellfish, and fish caught in tropical reefs, which may be contaminated.

Moreso several cholera vaccines are available and should be used according to international guidelines.

DIAGNOSIS

When cholera is suspected, the health care provider will make a diagnosis based on laboratory investigation using Stool culture and serogrouping/subtyping.

A Stool sample is taken from your feces to test for the bacteria v.cholerea in the laboratory.

Tests for V. cholerae are available in reference laboratories; polymerase chain reaction (PCR) testing is also an option. Rapid dipstick testing for cholera is available for public health use in areas with limited access to laboratory testing. Still, the specificity of this test is suboptimal, so dipstick-positive specimens should be confirmed by culture if possible.

Cholera should be distinguished from clinically similar diseases caused by enterotoxin-producing strains of Escherichia coli and occasionally by Salmonella and Shigella.

OUTLOOK

Cholerae is highly treatable; with prompt and appropriate rehydration, very few cholerae patients should die if appropriate treatment course is undertaken immediately.

MKO Abimbola holds a doctoral degree in physician associate studies from the United States of America. He is a Harvard Medical School scholar, who specializes in Internal medicine, Acute care, Emergency Medicine, Geriatrics, Psychiatry, and Surgi­cal services.