Thirty years ago, India discovered the dreaded HIV virus had reached its shores when blood samples from six sex workers tested positive. It was largely due to the efforts of one young scientist - but until now, her pioneering work has been all but forgotten.
When it was first suggested she screen people for HIV/Aids, Sellappan Nirmala balked.
It was at the end of 1985 and the 32-year-old microbiology student at the medical college in Chennai (Madras), was looking for a topic for her dissertation.
The idea came from her professor and mentor, Suniti Solomon. Formal tracking of Aids cases had begun in the United States in 1982 and the medical authorities in India didn't want to be caught napping if the disease reached India.
But at the time, the idea of that happening was widely considered "unthinkable", Nirmala recalls.
The press at the time wrote that HIV was a disease of the "debauched West" where "free sex and homosexuality" were prevalent. Indians, on the other hand, were portrayed as heterosexual, monogamous and God-fearing.
Some papers even remarked smugly that by the time the disease reached India, the Americans would have found a cure for it.
Also, the city of Chennai and the surrounding Tamil Nadu region were considered especially traditional societies. Hundreds of samples, collected from the supposedly more promiscuous city of Mumbai, had already been tested at the virology institute in the western city of Pune and no positive results had turned up so far.
So, it was not surprising that Nirmala was reluctant. "I told Dr Solomon I was pretty sure the result would be negative," she says.
Solomon, however, persuaded her student to give it a shot.
It was decided that Nirmala would collect 200 blood samples from high-risk groups like sex workers, gay men and African students, but this was not an easy job - Nirmala had previously worked on leptospirosis, a bacterial disease transmitted from dogs and rodents, and she knew nothing about HIV or Aids.
What's more, she had no idea where to find her subjects - unlike the cities of Mumbai, Delhi and Calcutta which have well-known red-light districts, Chennai had no fixed address for sex workers.
So she began frequenting the Madras General Hospital where many women were treated for sexually transmitted diseases.
"There I befriended a couple of sex workers and they would point out other sex workers to me. When I looked at their forms, I saw that many had 'V home' written on them. When I asked around, I was told that it stood for "vigilance home" where prostitutes and destitute women were remanded by the authorities."
Soliciting was - and still is - illegal in India and these women would be arrested and sent to the remand home because they were too poor to pay the bail.
So every morning, before going to work, Nirmala began dropping in at the remand home to visit the sex workers.
She had been raised in a traditional family in a small village, was married, and had two small children: "I was the nervous type, I spoke in Tamil, I wanted a peaceful quiet life."
But she was encouraged by her husband, Veerappan Ramamoorthi, who supported her every step of the way. Often, he drove her to the remand home on his scooter - the couple were just starting out on their careers and didn't have any funds to spare and that way, she could save the bus fare.
Over three months, she gathered more than 80 samples. She had no gloves, no safety equipment. And the sex workers had no idea what they were being tested for.
"I didn't tell them that I was looking for Aids," she said. "They were all illiterate and even if I had told them, they wouldn't have understood what Aids was. They thought I was taking samples for venereal diseases."
Solomon, who was married to a heart-and-lung surgeon, created a small makeshift lab with equipment borrowed from her husband and others in which she and Nirmala separated the serum from the blood samples - a key part of the testing process. In the absence of a better storage facility, Nirmala kept them in her home refrigerator.
As there was no facility for Elisa testing in Chennai, Dr Solomon arranged for the samples to be tested at the Christian Medical College (CMC) in Vellore, 200km away from Chennai.
"One day in February 1986, my husband and I put the samples in an ice-box and boarded an overnight train to Katpadi. From there, we took an auto-rickshaw to reach CMC."
There, virology department director Jacob T John assigned two junior colleagues - P George Babu and Eric Simoes - to help Nirmala.
What is HIV/Aids
- HIV (human immunodeficiency virus) is a virus that attacks the immune system, and weakens ability to fight infections and disease
- Transmitted through unprotected sex, sharing infected needles, and from HIV-positive mothers to children during pregnancy, birth and breastfeeding
- No cure, but treatments can enable most people with the virus to live a long and healthy life
- AIDS is the final stage of HIV infection, when the body can no longer fight life-threatening infections
- More information from NHS Choices, Terrence Higgins Trust and UNAIDS
"We began testing at 8:30am. In the afternoon, there was a power cut so we all took a tea break. When we returned, Dr George Babu and I arrived at the lab first," recalls Nirmala.
"Dr George Babu opened the lid, and quickly shut it. 'Don't play,' he warned. But I'd seen it, six of the samples had turned yellow. I was stunned. I'd never expected anything like that."
A minute later Simoes walked in. He also checked the results. "There are some positives," he said, and hurried out to call John, who came running into the room.
There was no denying the positive result anymore - it was staring them all in the face.
"Where did you collect these samples?" John asked Nirmala.
Before they returned to Chennai, Nirmala and her husband were sworn to secrecy.
"We were told it was a very sensitive matter, so don't tell anyone," says Ramamoorthi.
After returning to Chennai, Nirmala went to Solomon's office and broke the news to her.
Soon, she returned to the vigilance home - this time, with Solomon, Babu and Simoes - and they collected samples from the six women again.
Simoes flew with the samples to the US where a Western Blot test confirmed that the deadly HIV virus had indeed arrived in India.
The grim news was conveyed to the Indian Council for Medical Research, which informed the then-prime minister Rajiv Gandhi and then-Tamil Nadu state health minister HV Hande.
When Hande announced the bad news in the state assembly in May, Nirmala and Solomon were seated in the visitors' gallery.
The initial reaction of the people was disbelief. Some questioned the tests, some said the doctors had made a mistake.
Solomon, who died last year, was particularly singled out by the critics since she was an outsider from the western state of Maharashtra.
"People were really angry, they said a north Indian woman is telling us we are dirty. But everyone was in shock, including my mother," says her son, Sunil Solomon.
The authorities began a mad scramble to come up with a response.
"The director of ICMR told me 'this is just the tip of the iceberg. We have to get down to work quickly'," says Nirmala.
Authorities launched massive screening and prevention programmes. Over the years, HIV-Aids turned into an epidemic in India, growing rapidly, pervading every corner of the country.
For years, it was believed that India had the highest number of infected people in the world with 5.2 million infections - until new estimates in 2006 nearly halved that number.
But even today, more than 2.1 million infected people live in India and the deadly disease, which still has no cure, remains a killer.
For her part, Nirmala went back to her studies. She had to still collect more than 100 of the 200 samples she had agreed to screen for her thesis.
Over the next few weeks, she continued to visit remand homes for sex workers and prisons to meet gay men.
In March 1987, she submitted her dissertation - Surveillance for Aids in Tamil Nadu - wrote her exams, passed, and joined the vaccine production programme in the King Institute of Preventive Medicine in Chennai, from which she retired in 2010.
Exactly 30 years after her groundbreaking work confirmed the presence of HIV-Aids in India, Nirmala is all but forgotten. Except for the few press reports at the time about her triumph, there's been little recognition of her sterling work.
I ask her if she ever feels that she has not received the recognition she deserves?
"I was brought up in a village. There no-one gets excited or depressed about such things. I'm happy I got this opportunity and I've done something for the society," she says.