Hopkins, S. America scientists to test vaccine South America fighting a cholera epidemic that has killed more than 1,200 people.

April 30, 1991|By Frank D. Roylance | Frank D. Roylance,Evening Sun Staff

Scientists at the Johns Hopkins School of Hygiene and Public Health are working with health officials in South America to develop new ways to combat a deadly cholera epidemic.

Dr. David A. Sack, an associate professor and director of the school's Travel Clinic, will fly to Brazil and Peru next month to help authorities there establish studies of an oral cholera vaccine and a simple new test for diagnosing cholera cases.

In a separate effort, the Baltimore-based Catholic Relief Services is providing Peru with $41,723 for medical supplies and training in preventive education.

"It's a tragic situation," said Sack. "They're predicting terrible things for Brazil and other countries, and, if they have the same sort of sanitation problems as Peru, that'll happen. Central America is getting prepared also."

Peru has reported nearly 160,000 cases since January, but the epidemic also has spread to Ecuador, Colombia, Chile and Brazil. More than 1,200 deaths have been reported from the five countries, and the World Health Organization says up to 120 million people in Latin America are threatened.

Cholera is a severe, dehydrating form of diarrhea, spread by fecal contamination of untreated drinking water and inadequately cooked food. Treatment is simple and relatively cheap, but in its absence cholera can kill a healthy person in as little as four hours.

So far, Sack said, South American health officials have responded well to the outbreak, holding fatalities well below 1 percent. The disease commonly kills 10 to 20 percent of its victims in other parts of the world.

"What tends to happen is that the first few cases are at the highest risk as the cholera moves in and physicians and nurses haven't seen the disease before," Sack said. "But they learn quickly and after the first few cases. They can handle it. If they do a good job, nobody should die of cholera."

Treatment consists mainly of oral rehydration -- the rapid replacement of fluids and salts lost to the diarrhea -- plus antibiotics to kill the cholera bacteria and shorten the illness.

Hopkins scientists for years have been studying and promoting oral rehydration therapy as the simplest, most inexpensive way to combat diarrheal diseases.

Diarrhea is thought to be the world's greatest killer, taking an estimated 5 million lives every year. Of those, perhaps 100,000 are lives lost to cholera, mostly in Africa and Asia.

Cholera has been rare in the United States since the 19th century, when deadly outbreaks were common in Baltimore, New York and other cities and among wagon train travelers heading west.

But Sack said a few cases are still reported each year in Louisiana, where the bacteria reside in the waters of the Mississippi Delta and some shellfish. Proper cooking and municipal water treatment can kill the bacteria.

Latin America had somehow remained free of cholera until late January, when cases began turning up in a northern Peru port town.

Sack said health officials theorize the cholera bacteria may have been introduced into Peru by a sailor, who probably picked up the Vibria cholerae bacteria in Asia without showing any symptoms.

He may then have excreted the organism in his feces, which were dumped from the ship's toilets into the sea, where it was picked up by shellfish.

The shellfish were then caught and eaten, either raw or with inadequate cooking, by Peruvians. Given the poor sanitation and lack of water treatment in much of Latin America, the illness has spread quickly.

"I'm not a prophet, and I certainly didn't see it coming," Sack said. But he believes the disease will now become endemic to Latin America, as it is in Africa and Asia.

"Until now, they didn't have the right combination of conditions, plus the introduction of the bacteria," he said.

But the deterioration of social, economic and sanitary conditions in Peru, and similar conditions in parts of some other Latin American countries, will aid the disease's spread.

Hopkins scientists have been working with Peruvian authorities for 15 years to study and combat other diarrheal disease. That has left them in an ideal position to help with the current outbreak of cholera.

Working in cooperation with the Universidad Peruana de Cayetano Heredia, Sack and his colleagues plan to study the effectiveness of an oral vaccine for cholera that has been under development for 12 years.

The oral drug may one day replace the current vaccine, which requires two injections, each accompanied by significant side effects.

The scientists also hope to try out a new diagnostic test under real-life conditions.

"One of the problems is that they [Latin American health officials] don't have the facilities to track the disease," he said.

The current diagnostic test takes 24 to 48 hours to yield results, requires special incubators, and costs $5 to $10 to complete.

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