The global publicity about film star Rock Hudson's battle with AIDS, the Acquired Immune Deficiency Syndrome, focuses new attention on this weird and lethal newcomer to the list of scourges that plague mankind.

Some members of the particularly susceptible gay community have been vocal in their belief that AIDS research is lagging in this country, and many AIDS victims who can afford it fly to the Institut Pasteur in Paris where, they insist, research has outstripped that in the U.S. Hudson himself, whose AIDS was diagnosed a year ago, reportedly had been under treatment at Pasteur with an experimental drug, HPA-23.

However, scientists in the United States point out that drugs similar to HPA-23 -- an antiviral agent -- are well into clinical trials in this country and even Pasteur researchers reportedly concede that they have "no breakthroughs" as yet in AIDS treatment.

The fact is, though, that when AIDS broke onto the scene about 5 years ago, no one knew what it was, how it was transmitted, or why it was proving fatal. "There's never been a disease in history in which so much progress has been made in so short a time," says a spokeswoman at the National Institutes of Health's National Institute of Allergy and Infectious Diseases (NIAID).

The viral agent that causes AIDS was identified within the past two years, along with the way it infects the body's protective T-cells, thereby devastating the immune system and making its victims subject to a host of potentially fatal illnesses from pneumonia to cancer. Moreover, scientists have learned how it is spread, and, by and large, how it is not spread.

Within the past six months they have established a screening test to identify antibodies in the blood of exposed persons. The test not only targets those who are at risk for the disorder, but helps prevent contaminated blood from entering the nation's blood supplies -- for transfusions and for providing blood products, for instance, the blood factor needed by hemophiliacs to control their illness.

Until the test -- called ELISA (for enzyme link immunosorbent assay) -- was developed and made widely available, potential AIDS infection was a threat to those receiving blood transfusions and especially to hemophiliacs.

The AIDS virus, a so-called retrovirus, is identified as HTLV-III/LAV to credit both the French and American scientists who identified it almost simultaneously -- at the Institut Pasteur and at the National Institutes of Health.

The number of victims is increasing at an epidemic rate -- almost 12,000 in the U.S. with almost 6,000 deaths -- but researchers and clinicians are convinced that it is transmitted only in limited ways and within limited groups. The majority of victims -- more than 75 percent -- have been homosexual men. It is transmitted principally through sexual relations, especially oral or anal sex, whether homosexual or heterosexual. Initially it was found rampant among Haitian immigrants to the U.S., but they are no longer considered a separate risk group.

Subsequently, researchers found that AIDS could be transmitted through the contaminated needles of intravenous drug abusers, through blood transfusions and through the blood factor hemophiliacs must have to keep from bleeding to death. Small amounts of the factor are derived from blood given by thousands of donors.

AIDS also can be transmitted to unborn babies by infected mothers -- usually IV drug abusers or the partners of drug abusers. There are an estimated 600 children with AIDS or conditions considered pre-AIDS in the United States. Most of them are in New York City or Miami, Fla. It is not unusual, say experts, for parents of babies idenified as having AIDS to simply drop them off at hospitals and then disappear.

Both Dr. Anthony S. Fauci, director of NIAID and one of the top AIDS clinicians in the U.S., and spokesmen at the Centers for Disease Control in Atlanta, say AIDS cannot be caught by casually kissing someone who is infected.

It cannot be caught by swimming in a swimming pool with someone who is infected.

It cannot be caught by being in the same school, living in the same house, caring for or nursing AIDS victims or eating food handled by AIDS sufferers.

It cannot be caught by having someone with AIDS cough or sneeze at you.

Reports that it can be transmitted by mosquitoes have also been discounted by CDC scientists.

Care givers at the NIH AIDS clinic undergo blood screening every six months. Some of them work very closely with AIDS victims in late stages of the illness; some have even been accidentally pierced with needles potentially contaminated. To date, none of the NIH staff members who were not in a risk group, tested positive for the AIDS antibodies.

For the general public concerned about AIDS, Fauci recommends "avoiding sexual contact with individuals in the risk group -- bisexual men, IV drug abusers; avoiding sharing needles with others. You shouldn't be using them on yourself, but for sure you shouldn't be sharing them."

He warns against contacts with prostitutes or "with anyone you don't know much about."

"The situation with saliva," Fauci said, "is a bit more confusing because most sexual interactions among people also involve the exchange of saliva . . . One cannot say that the virus cannot be transmitted if you have the exchange of a lot of saliva in very heavy kissing. But there is no evidence whatever that it can be transmitted by coughing or sneezing."

There is also a suggestion that "something else has to be going on," Fauci said, for someone to wind up being infected by the AIDS virus. The researchers are looking into the presence of two herpes virus infections -- cytomegalovirus, which is known to have a high incidence among male homosexuals and the Epstein-Barr virus as possible co-factors for AIDS. In other words, the AIDS virus may need an agent such as one of those viruses to permit it to become active.

To be counted as an AIDS victim in the CDC tally, patients must have one of the potentially life-threatening illnesses that their AIDS-damaged immune systems cannot forestall. Many more victims, untold thousands, perhaps a million, may have been exposed to the virus or may have a condition considered "pre-AIDS," with some immune system damage that may eventually lead to a life threatening condition.

At the NIH clinic, therapy is aimed first at controlling the virus, usually with an agent that acts like HPA-23 and prevents the virus from reproducing. When the virus appears contained, different experimental therapies are used, designed to restore the damaged immune system.

Anti-viral agents being tested at NIAID or at AIDS clinics at medical centers nationwide include alpha-interferon, suramin, ribavirin and a Swedish drug called foscarnet.

To try to enhance immune system functioning, Fauci is experimenting with bone marrow transplants on three sets of identical twins in which one twin has AIDS and one is healthy. But because of the difficulty in finding compatible bone marrow tissue in other than close relatives, Fauci also is using an agent called interleukin-2 which is manufactured in the bone marrow.

Another agent, DHTG, is being used on AIDS patients with cytomegalovirus infections. In AIDS patients, this herpes virus can cause severe eye problems and encephalitis. Other researchers are working on an AIDS vaccine, but even the most optimistic estimates put that at least five years away.

Dr. Peter Hawley, volunteer physician at the Whitman-Walker Clinic in Washington, is working with the District government and George Washington University on various AIDS support projects.

The clinic is currently screening potential AIDS victims on Wednesday evenings. He urges screening for those not in high risk groups who have contact with those who are. For example, partners of drug abusers or bi-sexual men or females who are at high risk themselves or through others who are contemplating pregnancy. For Information:

Whitman-Walker Clinic, 2335 18th St. N.W. DC 20009. For screening information phone, 332-AIDS.

The Centers for Disease Control operates two hotlines, one for the general public: 1-800-342-AIDS and for health professionals, 1-800-221-7044.