For the last week and a half, the same plague which cut Northern Europe's population to nearly a half in the 14th century has ravaged a large India industrial center, raising questions on how apparently vanquished diseases reappear.

On September 22, the bubonic plague took its first confirmed death in Surat.

Within two days, the "black death" had claimed 24 more victims and put 137 others in the hospital. By the 24th, about 200,000 had fled Surat to New Delhi or surrounding cities. In total, the plague may have killed about 300 people.

To those living far from Surat, however, bubonic plague connotes history rather than reality. Most have heard of the Black Death which afflicted Europe in the 13th and 14th centuries. Public health officials thought the final epidemic hit in the late '60s. In fact, a prominent biologist stated with pride in 1975, "During the last 150 years the Western world has virtually eliminated death due to infectious disease."

Biologists based their optimism on the effectiveness of antibiotics. According to an article in the American Scientist, smallpox, tuberculosis, polio and all other major infectious diseases were considered nearly eradicated by 1975.

That same year, however, saw the first of the diseases to come--with the outbreak of Lyme disease. Legionnaire's disease emerged in 1978, toxic-shock syndrome in 1978, AIDS in 1983, and chronic-fatigue syndrome in 1985, to name a few. Malaria re-emerged. Today, dengue and yellow are spreading. Instead of improving, the virulence of disease seems only to have entered a new stage.

Public health officials in the '90s are looking to understand low these new diseases emerge, and how long-deal pestilences like the plague come back.

They find a complex picture. On the one hand, the modern world fights disease with better treatment than ever before. On the other, byproducts of modernization, like rapid transportation, can spread epidemics world-wide.

The current outbreak in India demonstrates a combination of old and new factors. Surat shares at least one condition with Medieval Europe--lots of garbage.

The proper method of garbage disposal in the Middle Ages was throwing it out of the open window. Outside, the communal pigs fed in the streets. In fact, the tradition of a male accompanying a female arm in arm down the street was to protect her from flying bones and slops.

In Surat roughly one half of the 12.5 million population lives in shantytowns outside city sanitation control. In addition, a ten foot monsoon flood in August strew sewage everywhere.

The bubonic plague comes from a bacterium called yersinia pestis which lives in rats. In a dense population of humans and rats, fleas can transfer the bacteria through their bites between the species.

It was this type of plague that initially broke out in India. Sufferers experienced the same swollen lymph nodes from which bubonic plague derives its name in Medieval French.

The disease soon changed to the pneumonic variety, by far the deadlier of the two. The bacteria which carry pneumonic plague can be transmitted through water droplets from the lungs of humans--that is, whenever people sneeze. This can bring the disease to epidemic proportions as the bacteria travel from person to person through the air, as happened in Surat.

These conditions can be improved with modern technology. The Indian government has sent hundreds of tons of DDT to kill the fleas. Workers are clearing the piles of garbage. The hospitals order by e-mail millions of tablets of antibiotics. Under treatment, the 50% survival rate of the plague increases to almost 100%.