Cholera may not be a serious health concern in the United States but ever year this diarrheal disease affects about 3 to 5 million people and lead to around 130,000 deaths globally. Infants and the elderly are often at the greatest risk. Death from diarrheal illnesses as cholera is the leading cause of infant death globally. It is due to dehydration that arises with the fluid and electrolyte loss, which can be severe and rapid in cholera.
What is cholera?
Cholera is bacterial infection that affects mainly the intestines and leads to severe diarrhea. These bacteria, known as Vibrio cholerae, produces toxins that irritate and damage the intestinal wall. It mainly affects the small intestine where it causes the intestinal wall to release large amounts of water from the body into the lumen of the intestine. The excessive water within the bowels cannot be reabsorbed by the colon of the large intestine. Profuse watery diarrhea is a result of this water disturbance within the bowels.
Read more on cholera.
Although cholera is usually associated with consuming water of poor quality, it can also be contracted by eating foods washed or prepared with contaminated water. Other Vibrio species of bacteria can also cause gastrointestinal infections and diarrheal illnesses. These non-cholera Vibrio infections are collectively referred to as vibriosis. However, it should not be confused with cholera despite the similarity of symptoms and species of bacteria. Vibriosis has become a particular concern recently due to the spread of this disease by consuming contaminated seafood.
Read more on vibriosis.
Signs and Symptoms of Cholera
Not every person who come into contact with the cholera bacteria will develop cholera. In fact most pople will not develop any disease. Even when an infection arises the symptoms do not develop immediately after exposure. The incubation period can vary from a 24 to 48 hours with symptoms only arising after this period. Usually cholera presents as a mild diarrheal illness but sometimes it can be severe and even life-threatening. This severe form of cholera is known as cholera gravis.
Cholera diarrhea is profuse and watery in consistency. In severe cases the diarrhea can result in about 1 liter of water loss per hour which rapidly leads to dehydration. The diarrhea is typically described as a ‘rice water’ type of diarrheal stool due to the pale to milky appearances of the feces.
The extent of the watery diarrhea coupled with the white appearance of the diarrheal stool are some of the only differentiating symptoms between cholera and other infectious diarrheal illnesses. In mild to moderate cases of cholera, this white diarrhea may not be apparent.
Little to No Abodminal Pain or Fever
Most diarrheal illnesses are accompanied abdominal cramps and pain which are typically severe and debilitating. However, with cholera the diarrhea is usually painless. There may be some degree of abdominal cramping as the disease continues, largely due to the excessive water content within the small intestine. There is also no fever present in cholera, unlike with many other diarrheal infections.
Nausea and Vomiting
Nausea and vomiting are other major symptoms of cholera. The vomiting may occur both early and late in cholera. In the early stage of cholera, the vomiting is due to the gastrointestinal disturbances caused by the bacterial infection. It may be severe and persist for hours leading to additional fluid loss in conjunction with the watery stool.
When vomiting occurs in the late stages of cholera, it may instead be due to a drop in blood pH (acidemia). This acidity of the blood is usually due to the dehydration as a result of vomiting and diarrhea in cholera. However, it is important to note that vomiting sometimes does not occur in cholera despite the profuse diarrhea.
Dehydration is a common complication of most diarrheal illnesses. It tends to arise faster and is often more severe in cholera gravis. In fact the first signs of dehydration may be evident within hours of diarrhea arising in cholera. These signs and symptoms include:
- Excessive thirst
- Dry mouth
- Sunken eyes
- Dry and wrinkled skin
- Little to no urine
- Weakness and fatigue
- Muscle cramps
- Weight loss (sometimes exceeding 10% of body weight)
As the dehydration progresses there may be cardiovascular consequences since the blood volume decreases. The heart rate rises (tachycardia), blood pressure drops (hypotension), the pulse may become thready or even absent and the heart rate becomes irregular (arrhythmia). Oxygen distribution throughout the body is affected and this can even lead to a loss of consciousness. Depending on the availability of medical treatment, shock may result in death.
How to Prevent Cholera?
Cholera is not contagious in that it is unlikely to be spread from one person to another through direct contact. This is in contract to many other diarrheal infections. However, cholera is nevertheless a very serious and potentially life-threatening diarrheal illness. Therefore preventing this infection is of utmost importance. Although not common in the United States, travelers to endemic regions need to be cautious particularly with water sports as well as food and water sources.
In order to understand how to avoid cholera, it is first important to understand where the bacteria may be found and how it is spread. Cholera is mainly found in saltwater environments but may also be found in freshwater sources. Water is the main reservoir of cholera bacteria along with humans. Animals are rarely involved in human infections. Person-to-person transmission mainly occurs when fecal particles from an infected person is ingested by another person through contaminated food or water.
The following measures may therefore be helpful in preventing cholera:
- Avoid swimming in water that may have high levels of cholera bacteria.
- Do not drink water from sources where the water has not been treated.
- Be cautious about bottled water from unknown or questionable manufacturers.
- Avoid eating raw or undercooked seafood, especially shellfish.
- Maintain good hygiene, especially with food preparation, when a person in the home has cholera.
- Beware of antacids and acid-suppressing drugs that lower the stomach acid which can help protect against cholera infections.