It is not likely that cholera is spread directly from one person to another. The symptoms may appear from a few hours to five days after eating or drinking contaminated food or water. Cholera is diagnosed when the cholera bacteria, Vibrio cholerae , is found in a stool sample or rectal swab.
Patients can be treated with an oral rehydration solution, a prepackaged mixture of sugar and salts mixed with water in large amounts.
This solution is used throughout the world to treat diarrhea. Severe cases also require intravenous fluid replacement. Antibiotics shorten the course and diminish the severity of the illness, but they are not as important as receiving rehydration. Persons who develop severe diarrhea and vomiting in countries where cholera occurs should seek medical attention promptly. Severe dehydration is a medical emergency that requires immediate care. A bacterium called Vibrio cholerae causes cholera infection.
The deadly effects of the disease are the result of a toxin the bacteria produces in the small intestine. The toxin causes the body to secrete enormous amounts of water, leading to diarrhea and a rapid loss of fluids and salts electrolytes. Cholera bacteria might not cause illness in all people who are exposed to them, but they still pass the bacteria in their stool, which can contaminate food and water supplies. Contaminated water supplies are the main source of cholera infection.
The bacterium can be found in:. Everyone is susceptible to cholera, with the exception of infants who get immunity from nursing mothers who have previously had cholera. Still, certain factors can make you more vulnerable to the disease or more likely to have severe signs and symptoms.
Cholera can quickly become fatal. In the most severe cases, the rapid loss of large amounts of fluids and electrolytes can lead to death within hours. In less extreme situations, people who don't receive treatment can die of dehydration and shock hours to days after cholera symptoms first appear. Although shock and severe dehydration are the worst complications of cholera, other problems can occur, such as:.
Cholera is rare in the United States with the few cases related to travel outside the U. If you're traveling to areas known to have cholera, your risk of contracting the disease is extremely low if you follow these precautions:. Drink only safe water, including bottled water or water you've boiled or disinfected yourself.
But exactly what environmental conditions lead to cholera outbreaks? If researchers knew what caused the cholera bacteria to flourish and spread, they might be able to prevent many deaths. Antarpreet Jutla, a Tufts graduate student, is working on cholera research with Islam. But we still cannot predict it.
The researchers decided to start their project in Bangladesh, because it is home to the longest time series of cholera data. Hospital records there follow the twice-annual outbreaks back to , providing some of the most detailed data on cholera in the world. But despite the wealth of data on outbreaks, nobody knows when exactly they will happen. Earlier studies had found potential connections between cholera outbreaks and a number of environmental factors, but most of those studies had focused on specific locations and short time periods.
For example, researchers would sample water from only one village, or record water temperatures in just a few locations surrounding an outbreak. The researchers wanted to explore those environmental factors from a broader perspective.
While the link between copepods and cholera was clear, they did not know what factors allowed copepods to multiply and spread the disease from ocean waters into drinking water. Copepods cannot be measured directly over a large area; the tiny animals are invisible to the human eye. But the brilliant green phytoplankton, which copepods rely on for food, gives them away.
The SeaWiFS data indicated the amount of copepod-supporting phytoplankton in the water. In the spring, when hot temperatures and arid weather dry up the Bengal delta region, cholera outbreaks were strongly linked to both chlorophyll levels and salinity in the river waters, two factors that help support the copepods that carry cholera.
So there is a lot of salt water intrusion in coastal areas. In contrast, during the rainy fall season, the team discovered, cholera outbreaks were instead linked to flooding and rainfall, which spread dirty water and contaminated wells. In places like Bangladesh, cholera is not going away.
But the very persistence of the disease has actually helped efforts to fight it. In severe cases, dehydration from cholera can lead to a loss of body weight of 10 percent or more. If untreated, shock accompanied by an electrolyte imbalance can lead to death.
Other complications can include low blood sugar and kidney failure. See Complications, below. Cholera is caused by a bacterial infection. There are two serotypes, or strains, of Vibrio cholerae that cause outbreaks of cholera: O1 and O Of the two, O1 is more common. This in turn causes the cells that line your intestine to release increased amounts of water, which can lead to dehydration. Drinking contaminated water or consuming contaminated food is the most common way you can be exposed to the O1 or O bacteria.
O1 and O bacteria are most common in places with poor water treatment, sanitation, and hygiene practices, according to the CDC. In addition, although there are no other animals besides humans in which the bacteria can reproduce and spread, Vibrio cholerae frequently attach to the shells of crabs, shrimps, and other shellfish.
As a result, raw and undercooked shellfish have been sources of cholera infections in the United States. Raw fruits and vegetables are also a common source of cholera in areas where the disease is found, because crops may be treated with contaminated water or manure fertilizers. Similarly, in regions where cholera is common, grains such as rice that are contaminated after cooking and kept at room temperature for several hours can also contain cholera bacteria.
Everyone is at risk for cholera though infants can get immunity from a nursing mother who has previously had the infection. In general, cholera is common in areas where a safe supply of drinking water is difficult to maintain, including refugee camps, impoverished countries, and areas impacted by famine, war, or natural disasters.
In addition, research indicates that people with type O blood are twice as likely to develop cholera compared with people with other blood types — though it's unclear why. Cholera also spreads easily. A person infected with the bacteria can cause a one-million-fold increase in Vibrio cholerae numbers in the environment through a single diarrheal episode, according to the National Institute of Allergy and Infectious Diseases.
In addition, because people with cholera shed bacteria in their stool for 7 to 14 days, they can infect anyone who comes in contact with their feces, or water contaminated by it. In areas where the infection is common, cholera may be recognized by its symptoms, but the only way to confirm the diagnosis of cholera is to identify the O1 or O bacteria in a stool sample.
Without treatment — usually rehydration — up to half of those infected with cholera will die. Risk of death is higher in children, pregnant women, and the elderly. Generally, the risk for death from cholera has declined globally in recent years because of enhanced access to healthcare, and improved sanitation and education. With effective rehydration, less than 1 percent of those infected with cholera die from it.
As noted above, symptoms usually appear within two or three days of exposure to the bacteria. In mild or uncomplicated cases of cholera, symptoms subside on their own within three to six days of onset and the bacteria disappear from your system within two weeks.
0コメント