Alarmed by the fast spread of AIDS in the country, Mexican authorities have begun a campaign called Cascade Education, a novel approach that enlists those most likely to be afflicted to spread the word. The campaign is aimed directly at male and female prostitutes, the homosexual community, street gangs and the poor in the hope that what they learn about AIDS prevention will ``cascade'' down to others in their own vernacular. Most of the effort is concentrated in Mexico City, a metropolis of 18 million people, where high-risk people are hard to reach through newspapers and other standard means. ``We are teaching them to become health care promoters and sending them into their communities,'' said Dr. Glorias Ornellas Hall, director of the National Center for AIDS Information, an arm of the federal Public Health Department. ``We believe that using the media to give information is not enough to change behavior patterns. Only face-to-face contact can do that,'' she said. ``The best way is for them to reach their own communities in their own language. That includes prostitutes reaching out to prostitutes, homosexuals to homosexuals, even deaf-mutes to deaf-mutes.'' According to the center, Mexico had 1,126 confirmed AIDS cases as of Feb. 1, and the number is doubling every seven months. For every confirmed case, an additional 50 to 100 people are becoming exposed to the virus, said Dr. Jaime Sepulveda Amor, the department's director of epidemiology. Sepulveda, who is also president of the government's National Commission on AIDS Prevention, estimated during a recent interview the number of people confirmed to have AIDS will reach over 25,000 by 1991, making it the second or third leading cause of death for people in the 25 to 44 age group in Mexico, which has a population estimated at 81.7 million. In the United States the number of AIDs cases reported since June, 1981, has reached 57,024. Since it was founded last year, the information center has broadcast its services on radio and television and through bumper stickers, posters, keychains and matchbooks with condoms attached. Mexico recently received a donation of 10 million condoms from the U.S. Agency for International Development. The center also has trained dozens of Mexico City residents in its Cascade Education program, offering instructional rclasses but leaving the actual teaching process to each individual. ``We give them the basics, then leave the style of presentation in their own hands,'' Ornellas said. The center's staff also trains street-gang leaders and visits jails to teach police officials and prisoners. Ornellas said many of the Cascade volunteers from the streets originally visited the center to be tested for the AIDS virus and, with counselling and support, have joined the program. She said the best of them are those who have tested positive. One male prostitute in the program, only known by his nickname of Jaimito, regularly visits Mexico City markets to sing a ``ranchero'' song he wrote and recorded called, ``What is AIDS?'' Ornellas called Jaimito ``one of our great promoters.'' A deaf mute who also is a male prostitute is another is Cascade promoter. ``He uncovered a whole sub-culture of deaf mutes who prostitute themselves off to make a living,'' Ornellas said. ``We found that many feel they have no other way to earn money.'' An initial Health Department survey indicated that about 30 percent of the male homosexual community in Mexico City has been exposed to the AIDS virus. Gerardo Ortega Zurita, a Cascade volunteer leader, said cultural prejudices have made it very difficult for homosexual men to seek help. ``There's incredible discrimination against homosexuals, who are isolated from the centers of the country,'' Ortega said. ``Teaching them about AIDS is difficult. They are forced to hide from the police and other government authorities.'' Ortega brings youths from what he calls ``controlled groups'' of prostitutes to the center to be examined and learn about AIDS prevention. ``But there are others we can't get to, who are more preoccupied with making a living than with taking care of their lives,'' he said. Ornellas and other health officials say the Cascade approach is essential not only in reaching previously hidden subcultures but in confronting many myths about AIDS. ``We've come across many beliefs,'' Ornellas said. ``Some say AIDS is punishment from God, and others, that witchcraft can ward it off. In a country with cultural setbacks that include religious beliefs, ignorance and cultural taboos that do not allow the use of condoms, we found that this program has worked.'' Currently, Ornellas said the center is receiving 50 visits and 100 telephone queries a day from people wanting to find out about AIDS. ``It's new that they should come out at all,'' she said. ``The very lowest class is the most at risk, and the hardest to get to. There's a disrespect for life (among them); they don't care if they die.'' As in other countries in Latin America, the center had to overcome initial resistance from the Roman Catholic Church in distributing literature and promoting the use of condoms. Clerics are one way of reaching rural areas, Ornellas said. ``We haven't even started with rural people, where you have whole families living in a single room. Children learn about sex in one room. What's going to happen when AIDS reaches these rural areas?''