This image released by the University of Mississippi Medical Center shows Hannah Berry Gay, a pediatrician at the University of Mississippi. “I just felt like this baby was at higher-than-normal risk, and deserved our best shot,” she said. (Jay Ferchaud/AP)

The Mississippi doctor who treated a baby girl born with the AIDS virus and apparently cured her of the infection is a former missionary who lived for several years in Ethi­o­pia and a no-nonsense mother of four who dislikes the limelight, according to her family, colleagues and former pastor.

But Hannah Berry Gay, 58, a pediatrician at the University of Mississippi Medical Center in Jackson, is now the focus of intense international interest. By aggressively treating the newborn with antiretroviral drugs, she achieved what researchers described as a “functional cure.”

A report on the case, which also included researchers from the Johns Hopkins Children’s Center and the University of Massachusetts Medical School, was officially presented Monday at a conference in Atlanta. If confirmed, the results would offer hope for hundreds of thousands of babies born with HIV infection around the world each year.

Gay, a Jackson native, has spent nearly two decades at the medical center working on pediatric HIV cases. For years, she has advocated for aggressive early treatment of infants and children.

“She is very diligent and wants to make sure the babies born to HIV-infected mothers get the best care possible,” said her boss, April Palmer, chief of the medical center’s pediatric infectious disease division. “She’s fairly soft-spoken but very intense when it comes to taking care of her patients.”

In the case of the baby girl, who has not been identified, the baby’s mother arrived at the hospital without having had any prenatal care. When a screening test for HIV came back positive, “she was too near delivery to give even the dose of medicine that we routinely use during labor,” Gay wrote in a short narrative of the events.

Because of the baby’s unusually high risk of having been infected, Gay and her colleagues started full treatment with a combination of drugs known as “triple therapy” 30 hours after birth, she said.

Currently, high-risk newborns — those born to mothers with poorly controlled infections or whose mothers’ HIV status is discovered around the time of delivery — receive a combination of antivirals at prophylactic doses to prevent infection for six weeks and are started on higher therapeutic doses if and when an infection is diagnosed.

Gay’s work in preventing and treating HIV in children stretches back years. It includes projects funded by the federal Ryan White program, aimed at providing early intervention and treatment for HIV patients throughout the country, especially in low-income and rural areas.

In a 2008 paper in which Gay was the lead author, Gay advocated for “aggressive” antiretroviral treatments in children, noting that both published studies and “unpublished experience within the University of Mississippi pediatric HIV clinic” suggested that such an approach could lead to significantly better outcomes.

She acknowledged that early therapy in infected infants carries “significant risks,” including possible medication side effects on an infant’s developing organ systems and the potential of creating drug resistance early in life. But treating children as early as possible, including with a combination of three drugs, could also allow them to develop normal immunity and help fight off HIV infection, she wrote.

Since the news broke Sunday, her family and friends say Gay, who is married and has four grown children and a grandson, has been overwhelmed by the attention.

“She’s shocked and excited,” said her daughter, Ruth Gay Thomas, 24. “She does not like being in the spotlight.”

She described her mother as someone who put her faith first, followed by her family and her career. She typically juggled all three, her daughter said.

In recent weeks, Hannah Gay would rush home from work on Wednesday nights so she and her husband could lead the weekly “Bible drill” at church, helping third- and fourth-graders learn passages in the Bible through memorization and competition. During this time, she also helped plan her daughter’s Feb. 23 wedding while working on the HIV presentation for the Atlanta conference.

Born and raised in Jackson, Gay graduated from the University of Mississippi, where she met her future husband, Paul. She also attended medical school there, and completed her residency training at the medical center where she now works.

For several years in the 1980s, the Gays worked as missionaries in the Ethio­pian capital of Addis Ababa. The Gays and their children were there when rebel troops launched attacks on a main supply route to the capital, according to an October 1989 article in the Baptist Press, the news service of the Southern Baptist Convention.