A mystery illness killed a boy in 1969. Years later, doctors learned what it was: AIDS.

FILE — Eric Ciasullo speaks in front of a large AIDS memorial quilt during an observance of World Aids Day held at the National Aids Memorial Grove at Golden Gate Park in San Francisco, Calif. Saturday, Dec. 1, 2018. less FILE — Eric Ciasullo speaks in front of a large AIDS memorial quilt during an observance of World Aids Day held at the National Aids Memorial Grove at Golden Gate Park in San Francisco, Calif. Saturday, Dec. ... more Photo: Jessica Christian / The Chronicle Buy photo Photo: Jessica Christian / The Chronicle Image 1 of / 14 Caption Close A mystery illness killed a boy in 1969. Years later, doctors learned what it was: AIDS. 1 / 14 Back to Gallery

The 16-year-old boy had the kind of illness that wouldn't be familiar to doctors for years: He was weak and emaciated, rife with stubborn infections and riddled with rare cancerous lesions known as Kaposi's sarcoma, a skin disease found in elderly men of Mediterranean descent.

The boy, Robert Rayford, died on May 15, 1969, in St. Louis. It would be more than a decade before doctors started seeing similar cases among gay men in New York and California. In 1982, with the numbers of sick surging, the disease got a name: Acquired Immune Deficiency Syndrome. The AIDS epidemic had begun.

But the mystery of Robert R. - as he was long known to researchers - would linger in the minds of the physicians who had cared for him. With a sense that something important could someday be learned, two doctors collected tissue samples after his death and froze them for almost 20 years.

In time, the case of a poor young African American who apparently never left the Midwest would add a surprising twist to the understanding of a disease many connected with gay white men in cosmopolitan coastal cities. Researchers would come to see Rayford as the country's first known death from a strain of the human immunodeficiency virus, HIV, the virus that causes AIDS.

"Every time this date comes around, I think about this young man and the hell he went through," said Memory Elvin-Lewis, a microbiologist who was central to the case. "It's burned in my brain."

For some, the assertion that Rayford died of AIDS may never be fully proved. Anthony Fauci, a renowned AIDS expert and head of infectious-disease research at the National Institutes of Health, said the inferior state of antibody tests at the time make the case of Robert R. both fascinating and frustrating.

"It certainly could be true, and may even be likely that it's true," Fauci said, "but the absolute nailed-down proof isn't there."

Robert was already struggling when he arrived at St. Louis's City Hospital in late 1968. Then 15, the boy was suffering from swollen legs and genitals, fatigue and hemorrhoids. But according to doctors at the time and journalists who went back over the case years later, neither Rayford nor his family were very forthcoming with information.

"He would never say a word to me," said Elvin-Lewis, now 85 and still working.

The uncommunicative Rayford might have had a mental disability, doctors said later. When they found he had chlamydia, a sexually transmitted bacterial infection, he dodged questions about his sexual activity or would say only that he had been with a neighborhood girl. But there was physical evidence he had engaged in homosexual activity, willingly or not.

More frustrating, his doctors couldn't come up with a clear diagnosis, and none of their treatments worked. Over 15 months, he was moved twice to other hospitals and his case attracted several specialists. One of them was Elvin-Lewis, a newly hired microbiologist at Washington University Dental School with an expertise in chlamydia. She was surprised to find the infection spread through Rayford's body in a way she had never seen. And yet, the boy's own defenses were barely fighting the bacteria. His immune system seemed strangely inert.

Three months after turning 16, Rayford died of pneumonia.

The mystery only grew when the autopsy revealed numerous internal lesions known as Kaposi's sarcoma, which were almost unheard of in a black teenager. Elvin-Lewis and a lymphologist named Marlys Witte, who didn't respond to a request for an interview, had tissue samples gathered and preserved in sucrose-potassium glutamate in the hopes that medical science would someday be able to unlock some of their secrets.

"We knew there had to be another virus or something that was causing his immune deficiency," Elvin-Lewis said.

There would be no answers for years. Elvin-Lewis and Witte did present a paper highlighting some of the perplexities of the case, but the world moved on. The Vietnam War flared up and wound down. Richard Nixon won election to a second term, vowed he wasn't a crook and then resigned. Disco arrived, amid a wave of "Saturday Night Fever." Cocaine coursed through the night life of big cities.

And gay men started getting sick in noticeable numbers.

In June of 1981, the Center for Disease Control noted in its Morbidity and Mortality Weekly Report the appearance of a rare pneumonia in five young gay men in Los Angeles. Additionally, the men, all of whom would die, showed compromised immune systems. The same day, a New York dermatologist tipped the CDC to a baffling spate of Kaposi's sarcoma cases among gay men. Newspapers began writing about "gay-men's pneumonia" and "gay cancer" and, eventually, of AIDS.

Researchers slowly traced HIV's likely origins to chimpanzee populations in central Africa, where it probably jumped to human hunters through contact with animal blood. They believed the virus crossed the globe with infected travelers in the 1970s. Multiple vectors of infection were identified, including homosexual and heterosexual contact, blood transfusions and sharing contaminated needles.

Little of that seemed to point to an obscure Midwestern medical mystery almost 15 years earlier. But for Rayford's doctors, the descriptions of AIDS rang a bell. In 1984, Witte published a letter in a journal noting the similarities with Rayford's history. In 1985, when a test became available that could detect HIV antibodies, Elvin-Lewis packed some of her long-held samples in dry ice and shipped them to Witte, who had them tested by Robert Garry, a Tulane virologist. Garry tested for nine distinct HIV proteins. Rayford's blood showed evidence of all nine.

"Case Shakes Theories of AIDS Origin," read a Chicago Tribune story that broke news of the results in October 1987. "Area Teen May Have Died from AIDS-In 1969," said a banner headline in the St. Louis Post-Dispatch.

The tests on Rayford's tissues astonished researchers. The finding wouldn't change how the disease was treated, but it challenged the conventional wisdom of how it arrived.

"If the findings are factual, it would be the earliest case of the AIDS in the United States," epidemiologist Peter Selwyn told the Post-Dispatch at the time. "St. Louis doesn't stand out as a hot spot for the AIDS virus."

Researchers were skeptical. But as the testing grew more refined, Garry did further analysis that more conclusively pegged Rayford's infection as an early strain of HIV that was distinct from the strain that led to the epidemic in the early 1980s.

Those tests haven't erased all doubts, Fauci said. For him, "nailed-down proof" would require more testing on Rayford's tissue samples. But that's no longer possible. The last known tissue samples to survive were in Garry's lab in New Orleans. They were wiped out by Hurricane Katrina in 2005.