Outside, the seasonal winter rain fell steadily on cobblestone streets where orange peels, chicken bones and wadded paper spilled out of black plastic refuse bags torn open by frolicking children and inquistive rodents.

"There is too much garbage in the streets, so these days I am keeping the baby indoors," says Signora Godono, a mother here who like many others has been frightened by the viral respiratory epidemic that has killed 64 of the city's infants and toddlers since last June.

But in a city where unemployment, malnutrition, dirt, decay, and a high rate of infectious diseases have always prevailed, Signora Godono, 26, is one of the lucky ones. Her husband has a part-time job, and her spotless, topfloor apartment in the poor, central Montecalvario district of Naples has at least a splendid view of Naples Bay and sufficient cross ventilation and sunlight to assure the health of her 14-month-old son.

Seven flights down in the street below, however, the view -- and the accompanying sanitary conditions -- are considerably worse.

Here, children play soccer amid scattered refuse in dank courtyards and narrow, crowded alleys that -- flanked by high-buildings and adorned with cluttered clotheslines -- rarely get the sun.

Many of the children live with their parents -- and several brothers and sisters -- in the thousands of damp, one-room, windowless ground-floor apartments called bassi , which elsewhere would be used exclusively as warehouses or stores.

The bassi , like many of the higher-floor apartments, are often without running water, and only one out of four of these slum dwellings has a shower or a tub. In over half, the bathroom consists of a toilet stuck into a kitchen corner. Thus, keeping the children at home is little defense against the fast spreading virus that has killed some 30 infants in only a month and a half.

In 1974, 59 percent of the city's 323,000 dwellings were defined as "mediocre to bad" by urban housing experts. An estimated 7 million rats share the city with its 1.3 million inhabitants. An inadequate sewer system dates back at least a century, and there is a shortage of both housing and schools. At least 140,000 persons -- about one third of the city's labor force -- are currently unemployed, while another 100,000 scrape by with semilegal odd jobs that bring neither social security nor medical benefits.

Population density is staggering, with an average conglomeration of 27,000 people a square mile, reaching peaks in some downtown neighborhoods of 40,000 and 50,000.

By comparison, Washington has a population density of about 12,400 people a square mile.

"In other words," virologist Giulio Tarro said, "the slums are an ideal breeding ground for all infectious diseases." These conditions, together with the fact that almost all the infant victims were from slum-dwelling families, made it clear from the start that whatever its direct cause there is really nothing "mysterious" about the current epidemic.

"This is what's killing our children, said a 40-year-old housewife, pointing to the maze of decaying tenements and littered streets that stretched as far as the eye could see.

In fact, like the outbreak of salmonella that killed 21 Naples-area babies in 1975, like the cholera epidemic of 1973 that took 24 lives, and like the recurring cases of typhus and hepatitis, the main culprit today in Naples is urban poverty and overcrowding and the accompanying poor sanitary conditions.

Also to blame are the local and central authorities who over the last three decades have failed to make the concerted effort necessary to improve the quality of life here. Death is nothing new for the "bambini" of this bustling, chaotic port city, where children under nine years of age represent at least a third of the population.

In 1975, 1,793 babies died during their first year of life, giving the province of Naples the highest infant mortality rate (34 per thousand) both in Italy and in the rest of Western Europe.

Last week a seven-member team of foreign experts described the disease that killed the 64, all under two years of age, and has since hospitalized four others as "a normal winter epidemic." They said it is caused primarily by the syncytial virus first discovered 23 years ago by U.S. doctor Robert Chanock, and generally transmitted through the air. No vaccine is available for it.

This virus is reportedly responsible for 60 percent of the respiratory diseases that strike infants, and is often contracted by children under three in other Western European and North American cities, including Washington and Seattle, although serious epidemics are more rare.

The recent intense cluster of deaths in Naples, the experts said, partly reflects an unusually harsh and rainy winter, as well as frequent parental delay in getting medical help. But according to Dr. Antonino de Arcangelis, a well-known local pediatrician and expert on infant diseases, many Neapolitan babies are simply undernourished and unhealthly and therefore more vulnerable.

This year's epidemic represents a major embarrassement for the Communist-Socialist administration that has ruled the city for over three years. It took office promising to clean up the city and improve conditions left by decades of Christian Democrat and monarchist rule.

Communist Mayor Maurizio Valenzi admits that worker absenteeism and sabotage by the angry unemployed have left the city dirtier than it was two years ago when a Communist sanitation plan first appeared to be paying off.