Nasty Infectious Diseases You Want To Avoid - Cholera
Cholera is an infection of the small intestine characterized by profuse, painless, watery diarrhea has been one of the great social and political forces in history. If untreated, severe cases can cause rapid dehydration and death within a few hours. If patients are given enough fluids, most will recover. The death rate soars in pandemics when there is not enough clean water, or if so many people become ill that there are not enough healthy people to care for the sick. After one infection, resulting antibodies will protect the patient from reinfection with the same strain.
There has been a dramatic increase in cholera in the United States and its territories, and many cases may go undetected by physicians who are not familiar with the disease, according to the National Center for Infectious Diseases. The disease thrives in places without running water or treated sewage disposal. This is why in the United States and Canada, cholera does not spread from one person to the next; any cholera organisms in infected feces are killed by sewage treatment and chlorinated water.
The spread of cholera in the Western world is tied to the problems of 19th-century urbanization, with its lack of sewage control, public water supply, and burgeoning population. While tainted water supplies carry the bacillus, it is also passed in human feces. Therefore, preparing food with unwashed hands, by roaches or flies, and the location of homes and buildings near raw sewage compounds the problem. During the industrialization of the 19th century, families cases were reported. crowded together in dirty tenements and those struggling in coal mining districts were especially at high risk, as were nurses and laundresses who handled soiled linen.
Cause - Cholera is caused by the comma-shaped bacterium Vibrio cholerae, which is acquired by swallowing food or water contaminated with human feces. A person may also contract cholera from eating fruits or vegetables that are washed in tainted water and eaten raw, by eating raw or undercooked shellfish harvested from contaminated water, or by eating food prepared by someone with contaminated hands. Sometimes, flies can carry the bacteria to food. The rapid fluid loss that is the primary symptom of cholera occurs because of the action of a toxin produced by the bacterium. This boosts the passage of fluid from the blood into the large and small intestines. Still, unless there is a huge source of germs (such as contaminated water or the clothes of victims), the disease is fairly hard to acquire. Chlorination can kill the bacteria, and acids in saliva and the stomach are a natural defense.
Symptoms - Up to three fourths of all victims show no symptoms. But severe forms of the disease known for hundreds of years as "cholera morbus" usually among people who have been drinking contaminated water, can be quickly fatal. Between a few hours and five days after infection, symptoms appear suddenly, beginning with incessant diarrhea and vomiting, with severe muscular cramps and prostration. Worse yet, facial features and soft body tissues shrink because of the radical loss of fluid, and discoloration of the skin from ruptured capillaries turns the shriveled victim black and blue. Over a pint of fluid may be lost hourly, and if this is not replaced, death will occur within a few hours. Because the bacteria are inhibited by stomach acid, those with high levels of gastric acid will have only a mild infection. Those who are poorly nourished and have less gastric acid, may have more severe diarrhea. Many people (especially those living in areas where cholera is common) may have no symptoms; but they can still spread the disease to others. If the diarrhea is very bloody, the cause is probably not cholera but may be shigella, E. coli, or campylobacter.
Treatment - Cholera is treated by quickly replacing the lost fluids with water containing salts and sugar, together with intravenous fluids (if needed). Antibiotics (such as tetracycline) may shorten both the period of diarrhea and the infectiousness. While it is usually taken by mouth, IV tetracycline may be needed for very sick patients. Antidiarrheal medicines should not be taken. As soon as vomiting stops, the patient should eat a bland diet rich in carbohydrates and low in protein and fats. Airlines are required to carry onboard packets of oral rehydration solution if they carry passengers to and from cholera-infected areas so that anyone developing severe diarrhea on a long flight won't get dehydrated. With proper treatment, most patients will recover with no permanent damage.
Diagnosis - A positive stool culture will confirm the diagnosis. Stool specimens must be cultured on special culture media designed to find cholera. A blood test taken a few weeks after the illness begins will show antibodies to cholera.
Complications - Patients experience profuse watery diarrhea and without prompt treatment, half the people with severe cholera will die from profound dehydration within a few hours. Symptoms include extreme thirst, lack of urination, cramps, wrinkled skin, sunken eyes, and weakness. Because there will not be enough fluid in the body to maintain circulation, shock, coma, and death can follow.
Prevention - A vaccine is available for those traveling to cholera-infested areas but is no longer recommended because it is only 50 percent effective and protects for only three to six months. The vaccine is no help against controlling epidemics. A new, more effective oral vaccine is being tested. The new vaccine is produced in Vietnam, where cholera afflicts more than 3,000 people each year; about 30 of whom will die. Because of its low cost, the new vaccine may be within the limited health care budgets of poor countries. The bacteria are killed by chlorine or boiling. Contaminated shellfish must be boiled or steamed for 10 minutes to kill all bacteria. The core temperatures of cooked food should be 158 degrees F. Unless all the bacteria are killed by cooking, they will multiply rapidly at room temperature in cooked shellfish. Any traveler to areas where the disease is common should take extensive precautions. Cholera can be controlled by improved sanitation, especially by maintaining untainted water supplies.