Researchers studying the AIDS virus among prostitutes in Nairobi, Kenya, have found that those who took birth control pills were infected at a rate nearly one-third higher than were those who did not. But they said yesterday that it was too soon to conclude that all women who use oral contraceptives are at greater risk than non-users.

Dr. Francis A. Plummer, speaking at the Third International Conference on AIDS here, said that of 115 prostitutes that were not infected with the AIDS virus two years ago, 74 members of the group, or 65 percent, now carry the virus. For 23 of them, oral contraceptives were found to be the major factor that increased their susceptibility to the virus, he said.

He stressed that the findings "urgently needed confirmation" and do not prove that women who use birth control pills are at greater risk of contracting AIDS.

"The message to the public is it really doesn't matter what contraception you use," Plummer said. "If you live a life that puts you at risk, you have to use condoms."

He said the 500 prostitutes in his study, which was directed by the Kenya Medical Research Institute, were 10 times more likely to contract the infection if they did not use condoms.

The paper, presented at a session on acquired immune deficiency syndrome in the developing world, brought sharp reactions from the audience of AIDS experts. "It's hard to imply that 32 percent of HIV {AIDS virus} infection can be attributed to oral contraception," said Dr. James Curran, director of AIDS activities at the federal Centers for Disease Control.

Plummer said that oral contraceptives might somehow alter the female genital tract, making it more susceptible to HIV infection. Alternately, he suggested that birth control pills could increase the risk of chlamydia, a venereal disease that in turn could increase chances of HIV infection.

The study was an attempt to assess the most common risk factors for transmitting the AIDS virus in Africa.

All the women were from one extremely poor part of Nairobi and were examined regularly at a clinic where they lived. Plummer said they had no blood transfusions, were not intravenous drug users and reported that they did not engage in anal intercourse.

Plummer attributed more than half of the new cases -- 40 of the 74 -- of HIV infection among the prostitutes to genital ulcers, which make it much easier for the virus to be absorbed in the blood system. Chancroid, a common bacterial infection among women in eastern and southern Africa, causes genital ulcers that can last up to six weeks.

The papers presented later yesterday portrayed a developing world having trouble accepting the profound social, political and economic burdens of a disease that is epidemic there.

"I'm feeling pretty pessimistic," said Dr. Brian Brink, of the South African Chamber of Mines. "There are incredible hurdles."

Brink reported a study of AIDS infection among seasonal mine workers who migrate to South Africa. South Africa tested more than 510,000 mine workers and selected 30,000 at random to test for HIV infection.

Brink reported that almost one in 10 mine workers contracted a sexually transmitted disease each year and that the connection between sexually transmitted diseases and HIV infection was high.

The study indicated that the closer workers were to Central Africa, where AIDS has hit hardest, the greater the incidence of infection. Four percent of all Malawi mine workers tested positive for the virus, and more than 15 percent of Malawi workers with other sexually transmitted diseases tested positive.

Reports from Central Africa, Brazil and Mozambique all suggested that the virus was spreading much more quickly in underdeveloped regions than in the developed world. Brazil, which has the second largest number of reported AIDS patients in the world, has had to reorder its health priorities dramatically to fight the disease, according to a paper presented.