To the Editor:

The next global epidemic, which may be more devastating than AIDS, is waiting to strike, and we are pitifully unprepared to fend it off.

In recent years new diseases have been emerging and old ones reappearing in all parts of the world, spurred by environmental disruption, population movements, urban crowding and the intrusion of commerce into once-isolated corners of the earth. The constant flow of intercontinental transport provides a means for their rapid spread.

Drug-resistant tuberculosis is now a worldwide problem; a new type of cholera that eludes previously established immunity is spreading rapidly; mosquitoes carrying diseases formerly limited geographically are now extending their ranges. Lethal virus diseases for which we have no treatment have broken out in North America, Africa and Europe. The pneumonic plague episode in India is, relatively speaking, kid stuff.

For the most threatening types of diseases, vaccines are by far the most effective intervention. We need to be prepared to develop and distribute them quickly and widely when an epidemic looms. However, vaccine development and production are in a sorry state -- leaderless, fragmented, inhibited by high costs, uncertain markets and legal problems. Some kind of coordinated government-private industry partnership is desperately needed.

Even more pressing is the need for surveillance to spot new disease outbreaks early, while there is still time to stop their spread. AIDS has shown the difficulties of trying to cope with a disease once it has become established. Yet, astonishingly enough, even now no country, including the United States, and no international organization, has a system for monitoring the emergence of new or unexpected diseases.

Alarmed at the potential for worldwide disaster, prominent infectious disease experts from some 40 countries and every continent have come together to draft and seek international support for a global program to monitor emerging diseases. The World Health Organization would like to implement this proposal, but it cannot do much without resources and support from its member governments.

What is needed to spark action on monitoring disease outbreaks and developing vaccines for them? Not technological breakthroughs -- we know how to do these things -- but a readjustment of political priorities. Not big money -- prevention is relatively cheap -- but the recognition that there is no wealth but life.

The human population risks crashing as gypsy moth populations crash periodically, through the uncontrollable spread of infectious dis eases. The moths would do something to prevent it if they could. Will we? BARBARA HATCH ROSENBERG Director, Federation of American Scientists Biological Program Purchase, N.Y., Oct. 14, 1994