LIMA, PERU, FEB. 16 -- At Maria Auxiliadora Hospital just south of the city, the faces are shocking -- gaunt, wan, with sunken cheeks and vacant, uncomprehending eyes. They are the faces of cholera, and they are likely to be with Peru for some time.

Health officials here say that an epidemic of some 14,000 cases of cholera has begun to slow its spread. But they warn that even after the outbreak has been brought under control, the disease will almost certainly remain in Peru. Only massive improvements in sewage treatment and hygienic standards -- changes that are unlikely given Peru's critical economic straits -- offer a chance of eradicating cholera.

Dr. Marlo Libel, an epidemiologist from the Pan American Health Organization, predicted that after the epidemic is controlled, Peru will see a "low, constant level of cases" of cholera.

"We are seeing a possible conversion of Peru into a zone where cholera is endemic," said Dr. Carlos Carillo, technical director of the Peruvian National Institute of Health.

Cholera causes violent diarrhea, which leads to rapid and near-complete dehydration. Death can follow within days or even hours. But if caught in time, cholera is easily treated -- there have been fewer than 100 deaths in the current outbreak, and Peruvian health officials have been praised for their quick response.

The appearance of cholera here is believed to be part of a worldwide outbreak, or pandemic, that began in 1961. This is the pandemic's first firm foothold in the Western Hemisphere, and while its spread to other countries can be controlled, experts say, it probably cannot be prevented.

"We have no effective way of keeping cholera from appearing in other countries," said Dr. Horacio Lores, an epidemiologist based here. "Quarantine is totally ineffective."

Libel said that three-fourths of those infected with the bacteria that causes cholera do not get sick, and in fact show no symptoms at all. For this reason, he said, it makes no sense to quarantine the sick, since for each hospitalized patient there are at least three others unknowingly carrying and spreading the disease.

This means that there is little that can be done to prevent apparently healthy travelers from carrying cholera to other countries. However, the disease is easily contained with adequate sanitation, particularly in the treatment of human wastes.

Lores said cholera "has a social aspect, linked to poverty and poor environmental conditions. The permanence of cholera will depend on the improvement of conditions."

Health officials in other South American countries have been alarmed at the prospect that they, too, might soon see cholera outbreaks. Three cases already have been reported in Ecuador. But neighboring Chile, for example, has much better sanitation than Peru. Bolivia, on the other hand, has conditions that might be even worse.

Cholera is spread when fecal matter from an infected person finds its way into the water supply. Healthy people contract the microbe vibrio cholerae by eating fish or shellfish taken from contaminated waters or by eating other foods that came into contact with contaminated water during their preparation.

Millions of Peruvians live in conditions ideal for the spread of cholera.

"There is very little treatment of sewage here," said Carlos Cuneo, the Pan American Health Organization's representative in Peru. "Generally, sewage is sent directly into the rivers or the sea."

Officials maintain that the water supply for metropolitan Lima is safe. But more than 2 million Lima residents live in shantytowns that generally do not have running water. They must get their water from rivers or from delivery trucks -- and then store it for days at a time in unsanitary cisterns and tanks.

There is no cholera to speak of, by contrast, in the upscale districts of Miraflores and San Isidro, and no tourists have been reported to have come down with the disease.

The cholera microbe cannot live in high temperatures, so officials have recommended boiling water before using it and cooking all food thoroughly. Officials in various parts of Lima have also tried to crack down on vendors who sell fast food from curbside carts and who, according to Libel, present "a great risk" of contamination. But Friday, food carts were doing business as usual throughout the city and did not appear to want for customers.

Three weeks after the first cases were reported, epidemiologists still have not specifically identified the means by which cholera is being spread.

The first major outbreak appeared in the coastal city of Chimbote, north of Lima. Outbreaks quickly appeared in other port cities, leading researchers to suspect that coastal waters were contaminated and that people were contracting the disease by eating seafood taken from those waters.

Dr. Victor Lucero, director of Maria Auxiliadora Hospital, said that in the early days of the epidemic almost all cholera patients reported having eaten fish before becoming ill. A relatively new hospital, Maria Auxiliadora sits amid three burgeoning shantytowns with a total population of more than 800,000 and is also near the Villa Maria del Triunfo Fish Terminal, which provides local residents with their cheapest and most popular source of food.

"At first, 80 percent had eaten fish," Lucero said. "But now it's all foods, not just fish."

The hospital has treated nearly 500 patients for cholera. At any given time it has about 30 patients receiving rehydration treatment in a special ward. The number of cholera victims arriving for treatment each day -- some on an outpatient basis -- has dropped from roughly 75 to around 30, but Lucero said he believes that decline largely represents new effectiveness by smaller neighborhood health centers.

Cholera ravages its victims with startling speed. A 14-year-old boy arrived at the hospital around 6 p.m. Friday barely conscious, too weak to stand, hardly able to keep his eyes open and clearly unaware of what was happening around him. His face was desiccated and drawn.

As nurses struggled to haul him into a bed, his mother, Juana Quintana, explained that the boy had experienced his first attack of diarrhea at 10 that morning. Within eight hours he had been reduced to a state of utter collapse.

Quintana said that the family had been taking precautions, but added that her husband works at the nearby fish market. The government ordered the market closed last week, but now appears ready to reopen it amid protests by fishermen and market workers who have suddenly lost their livelihood.

On the other side of the cholera ward are recovering patients. The basic treatment for cholera is rehydration with a solution of water and salts, and it works: Maria Auxiliadora has seen just two deaths.

"We have prepared ourselves for the epidemic to last 12 weeks, and then will come the endemic phase where we see the disease constantly," said Lucero. "We didn't study cholera in university; we have all had to go back to the books.

"The conditions in Peru are such that we should have had cholera long ago. We were lucky."