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Cholera: what people need to know about the disease

Sep 4, 2012, 10:49 AM

The Ministry of Health and Social Welfare, the National Disaster Management Agency and key stakeholders has warned of a cholera outbreak in the West Africa region.

In a statement issued last Thursday, the Ministry said currently there is an outbreak of cholera in Sierra Leone and Guinea Conakry, though “there is no reported case in The Gambia.”

The ministry noted that in view of the contagious nature of the disease, it is requesting the general public to be aware of the signs and symptoms of cholera, which are severe watery diarrhea; vomiting; and fever.

As a precautionary measure, the ministry urged all individual that must travel to neighbouring countries, especially those travelling within the sub-region to adopt strictly to preventive measures like proper washing of hands with soap and water; washing of all vegetables and fruits thoroughly before eating, and drinking water from a safe and protected source.

In out today’s Health Column, proudly sponsored by Ecobank, The Pan African Bank, we bring you facts about cholera, signs and symptoms, history about cholera and who is at risk of cholera and where does cholera outbreaks occur.

Cholera facts

Cholera is a disease caused by bacteria that produce a watery diarrhea that can rapidly lead to dehydration.

Cholera symptoms and signs include a rapid onset of copious, smelly diarrhea that resembles rice water and may lead to signs of dehydration (for example, vomiting, wrinkled skin, low blood pressure, dry mouth, rapid heart rate.

Cholera is most frequently transmitted by water sources contaminated with the causative bacterium Vibrio cholerae, although contaminated foods, especially raw shellfish, may also transmit the cholera-causing bacteria.

Cholera is presumptively diagnosed by patient history and examination of stool for rice-water appearance and presence of V. cholerae-like organisms microscopically; definitive diagnosis is done by isolation and identification of V. cholerae from stool samples, usually with immunologic tests.

The main treatment for cholera is fluid and electrolyte replacement, both oral and IV. Antibiotics usually are used in severe infections in which dehydration has occurred.

The prognosis of cholera ranges from excellent to poor. Rapid treatment with fluid and electrolytes result in better outcomes while people with other health problems beside cholera or those who are not rapidly replenished with fluid treatments tend to have a poorer prognosis.

Cholera can be prevented with appropriate measures such as safe drinking water and non-contaminated foods; some protection can be obtained from oral vaccines while avoiding areas where cholera commonly occurs or has had a recent outbreak.

What are cholera symptoms and signs?

The symptoms and signs of cholera are a watery diarrhea that often contains flecks of whitish material (mucus and some epithelial cells) that are about the size of pieces of rice. The diarrhea is termed “rice-water stool” (See figure 1) and smells “fishy.” The volume of diarrhea can be enormous; high levels of diarrheal fluid such as 250 cc per kg or about 10 to 18 liters over 24 hours for a 70 kg adult can occur.

What is the history of cholera?

Cholera has likely been with humans for many centuries. Reports of cholera-like disease have been found in India as early as 1000 AD. Cholera is a term derived from Greek khole (illness from bile) and later in the 14th century to colere (French) and choler (English). In the 17th century, cholera was a term used to describe a severe gastrointestinal disorder involving diarrhea and vomiting. There were many outbreaks of cholera, and by the 16th century, some were being noted in history. England had several in the 18th century, most notable being in 1854, when Dr. John Snow did a classic study in London that showed a main source of the disease (resulting in about 500 deaths in 10 days) came from at least one of the major water sources for London residents termed the “Broad Street pump.” The pump handle was removed, and the cholera deaths slowed and stopped. The pump is still present as a landmark in London. Although Dr. Snow did not discover the cause of cholera, he did show how the disease could be spread and how to stop a local outbreak. This was the beginning of modern epidemiologic studies. The last reference shows the map Dr. Snow used to identify the pump site.

V. cholerae was first isolated as the cause of cholera by Filippo Pacini in 1854, but his discovery was not widely known until Robert Koch (who also discovered the cause of tuberculosis), working independently 30 years later, publicized the knowledge and the means of fighting the disease. The history of cholera repeats itself. The U.S. National Library of Medicine houses original documents about multiple cholera outbreaks in the U.S. from the 1820s to the 1900s, with the last large outbreak in 1910-1911. Since the 1800s, there have been seven cholera pandemics (worldwide outbreaks).

Cholera riots occurred in Russia and England (1831) and in Germany (1893) when the people rebelled against strict government isolation (quarantines) and burial rules. In 2008, cholera riots broke out in Zimbabwe as police tried to disperse people who tried to withdraw funds from banks and were protesting because of the collapse of the health system that began with a cholera outbreak. Similar but less violent public protests have occurred when yellow fever, typhoid fever, and tuberculosis quarantines have been enforced by health authorities.

Multiple outbreaks worldwide continue into the 21st century with outbreaks in India, Iran, Vietnam, and several African countries occurring over the last 10 years (most recent outbreaks occurred in Haiti and Nigeria in 2010-2011). Why is cholera history repeating itself? The answer can be traced back to Dr. Snow’s studies that show a source (water or occasionally food) contaminated with V. cholerae can easily and rapidly transmit the cholera-causing bacteria to many people. Until safe water and food is available to all humans, it is likely that cholera outbreaks will continue to happen.

Who is at risk for cholera, and where do cholera outbreaks occur?

Everyone who drinks or eats food that has not been treated to eliminate V. cholerae (liquids need to be chemically treated, boiled, or pasteurized, and foods need to be cleaned and cooked), especially in areas of the world where cholera is present, is at risk for cholera.

Everyone who drinks or eats food that has not been treated to eliminate V. cholerae (liquids need to be chemically treated, boiled, or pasteurized, and foods need to be cleaned and cooked), especially in areas of the world where cholera is present, is at risk for cholera.

Outbreaks occur when there are disasters or other reasons for a loss of sanitary human waste disposal and the lack of safe fluids and foods for people to ingest. Haiti, a country that had not seen a cholera outbreak in over 50 years, had such circumstances develop in 2010 after a massive earthquake destroyed sanitary facilities and water and food treatment facilities for many Haitians. V. cholerae bacteria eventually contaminated primary water sources, resulting in over 530,000 people diagnosed with cholera that resulted in over 7,000 deaths. This cholera outbreak spread to Haiti’s neighbor, the Dominican Republic. The Vibrio cholerae strain was closely related to a strain found in Nepal and leads some individuals to blame Nepalese troops that helped with the earthquake disaster as the source of the Haiti cholera outbreak.

Some individuals are at higher risk to become infected than others. People who are malnourished or immune-compromised are more likely to get the disease. Children ages 2-4 seem more susceptible than older children, according to some investigators. In addition, researchers have noted that patients with blood type O are twice more likely to develop cholera than others. The reason for this blood type susceptibility is not completely understood. People with achlorhydria (reduced acid secretion in the stomach) and people taking medicines to reduce stomach acid (H2 blockers and others) are also more likely to develop cholera because stomach acid kills many types of bacteria, including V. cholera.