From the point of view of those of us who study infectious disease, it was only a matter of time before a cholera outbreak occurred amid the devastation of post-earthquake Haiti. Why? Because cholera spreads in areas where there is untreated sewage, contaminated water, and people living close together. Cholera may also spread easily among people who are ill or malnourished as is clearly the case throughout Haiti.
What is cholera? It is a species of Vibrio bacteria and it produces a deadly toxin. The toxin is the key to why cholera is so deadly -- it kills 60 percent of those who acquire it but aren't treated.
The bacteria is weak and doesn't invade the intestine, but the toxin, by activating the adenylate cyclase enzyme, causes a tremendous pumping out of salt and water into the intestine while also interfering with the absorption of sugar. The effect is almost immediate, and causes massive diarrhea. A patient may typically lose gallons of fluid and electrolytes within a day. This loss of fluid leads to severe dehydration and low blood pressure. The associated loss of potassium may lead to cardiac arrhythmias and sudden death.
What is the treatment? The primary treatment is replacement of fluids with the addition of the lost electrolytes. If sterile intravenous fluids aren't available, oral solutions that include glucose can help overcome the dehydration. This treatment is often miraculous, and reduces the mortality from cholera by a factor of ten times! Antibiotics such as tetracycline are of limited use but may shorten the duration of diarrhea and fluid loss.
Where did cholera come from? Cholera has been around for many centuries; the first descriptions of death due to severe diarrhea were recorded in the time of Hippocrates.
Epidemic cholera was described in India in 1563 by Garcia del Huerto, a Portuguese physician, and there have been many outbreaks on the Indian continent since then.
The first spread of cholera to Europe and the Americas occurred in 1817, and by the early 20th century, there had been six large waves of the disease -- known as pandemics -- across the world.
In 1849, Dr. John Snow of London demonstrated that cholera was spread by water, and in 1883, Robert Koch isolated the bacteria and showed it was the cause of the disease.
Even with the advent of modern public health measures, cholera has survived into the 20th and 21st centuries by evolving into a form, known as "El Tor," that lasts longer in the environment, and may be carried easily from one patient to another. El Tor also disrupts and destroys red blood cells, causing a more complicated disease.
In 1961, the "El Tor" type of cholera emerged in the Philippines and initiated the seventh global pandemic. It has remained the predominant subtype of cholera ever since.
In the U.S., cholera has been practically eliminated by modern sewage and water treatment facilities. It was prevalent in the 19th century, but now practically all cases are brought here by infected travelers or by contaminated seafood.
Is there an effective vaccine? Survivors of cholera have antibodies that provide long-lasting immunity, but attempts to create a durable vaccine that provides sustained immunity have been problematic.
Currently there is an oral vaccine which uses inactivated infected whole cells. This vaccine is used in Europe, Canada, Asia, Africa, and Australia but not yet in the U.S., where the last major cholera outbreak occurred in 1910. -- There are two recent studies which suggest that this vaccine could be useful in Haiti if administered early enough in the outbreak.
With the number of cases from the current cholera outbreak in Haiti in the thousands and the number of deaths in the hundreds and rising, it is only a matter of time before this treacherous disease spreads to the tent cities around the capitol city of Port-au-Prince. The major hope is a large administration of sugar water, and an increase in the number of clinics and medical facilities that offer intravenous fluids. I also believe that there is enough evidence to warrant widespread use of the oral cholera vaccine.
Before cholera spreads up here to the U.S. and around the world, we need to see this outbreak contained and controlled in Haiti. More than anything else, we need a big infusion of sugar/electrolyte drinking water and intravenous salt solution to be sent to the country along with a program to vaccinate travelers and everyone living there. Humanitarian efforts must not lapse or we could have another worldwide pandemic on our hands.
Marc Siegel M.D. is an associate professor of medicine and medical director of Doctor Radio at NYU Langone Medical Center. He is a Fox News medical contributor.