Christine Maggiore, who was diagnosed with HIV in 1992 and for years denied that HIV causes AIDS, died December 27 in Southern California. She was 52.

A spokesman for the Los Angeles County Coroner's office did not have a cause of death because the case is not being handled by the office. He did not know if Ms. Maggiore had been hospitalized at the time of her death.

The Los Angeles Times reported Tuesday that Ms. Maggiore died at her Van Nuys home and that the coroner's office said that she had been treated for pneumonia in the last six months.

Ms. Maggiore died three years after the death of her 3-year-old daughter, Eliza Jane Scovill. Eliza Jane's death prompted investigations by Los Angeles county authorities after a coroner's report ruled that her death was the result of AIDS-related pneumonia. The district attorney's office, however, declined to file criminal charges against Ms. Maggiore.

During her pregnancy, Ms. Maggiore said that she did not take antiretroviral medications and she did not have her daughter tested after birth. She also breast-fed her daughter and her son, Charlie.

Medical research indicates that breast-feeding by HIV-infected mothers increases the risk of HIV transmission to a child by up to 15 percent.

Ms. Maggiore founded the HIV denialist group Alive & Well AIDS Alternatives, which challenges the "common assumptions" about AIDS. She also wrote a book, What if Everything You Thought You Knew About AIDS Was Wrong?

Mainstream AIDS activists were sharply critical of Ms. Maggiore's beliefs and activities over the years, with many saying that she was responsible for much of the misinformation that led some people to reject medical treatment.

"Of course it is a personal decision to choose not to take medical treatment for life threatening conditions but for a person with HIV to go on a personal crusade to brainwash people into believing HIV does not cause AIDS and fooling them to disbelieve life saving treatment is pure insanity," Matthew Sharp, a longtime AIDS activist and former member of the now-defunct ACT UP/Golden Gate and its later incarnation, Survive AIDS, told the Bay Area Reporter. "However, Maggiore, like several other well-known HIV-positive denialists, made their own choices and consequently dug their own graves."

In a 2005 Times article about Eliza Jane's death, Ms. Maggiore said, "I am not second-guessing or questioning my understanding of the issue" of her beliefs. She came to believe that flu shots, pregnancy, and common viral infections could lead to a positive HIV test result.

Ms. Maggiore is survived by her husband, filmmaker Robin Scovill, and their son Charlie.