HIV TYPE MISSED IN TESTS : L.A. WOMAN SHOWS RARE STRAIN OF VIRUS FDA SEEKS BLOOD TEST FOR RARE HIV STRAIN.

Byline: Keith Stone Daily News Staff Writer

Federal researchers say they have identified a Los Angeles woman as the first person in the United States infected with a strain of HIV that tests do not detect consistently.

Out of 10 tests performed on the woman, three failed to reveal her HIV-1 group O infection, including her first confirmed test in February 1995, according to the federal Centers for Disease Control and Prevention in Atlanta.

``There may be other cases, but the evidence is that this is extremely rare,'' said Patrick Sullivan, a CDC epidemiologist who chronicled the case in today's issue of Morbidity and Mortality Weekly Report.

In confirming the case, the CDC and Food and Drug Administration stressed confidence in the integrity of the U.S. blood supply, even though routine tests cannot reliably pick up the group O strain.

``It sends up a flare - that we need to do some long-range planning to continue to protect the blood supply as best as we can,'' said Dr. John Ward, chief of the CDC's HIV-AIDS Surveillance Branch.

``There has to be a reconsideration of how our HIV screening tests are structured, so they can identify these group O strains more reliably,'' Ward said.

FDA spokesman Lawrence Bachorik said his agency and manufacturers have been working since at least 1994 to find a better test and expect to have one within a year.

``It is a lot more difficult than it sounds,'' he said.

Since blood donation screening began in 1985, there have been only 35 reported cases in which someone was infected by a donation that otherwise showed no sign of the human immunodeficiency virus, according to CDC statistics. None was a result the group O strain.

A spokesman for the American Association of Blood Banks said the Los Angeles case was anticipated but should not trigger alarm because of the apparent rarity of such infections in the United States.

``This individual would not have been accepted as a blood donor,'' said Roger Dodd, a board member for the association, which represents the American Red Cross and some 2,400 other blood banks and transfusers.

The group O strain of the virus that causes AIDS is found predominantly in West Central Africa, the region the woman emigrated from in 1994, Sullivan said. Other than its ability to elude testing, the strain causes the same syndrome, AIDS, as the group M variant, he said.

Blood donation regulations require people from regions where malaria exists - such as West Central Africa - to wait three years before making a contribution. Prospective donors also are quizzed about risky behavior and their health.

The CDC found this woman's case in April during its search for unusual HIV strains, but only after a Los Angeles County health worker had added the woman mistakenly to a registry of people with AIDS, officials said.

The woman, whom health officials would not identify to protect her privacy, told the CDC she did not know how she was infected.

She told investigators that she has never used intravenous drugs and had three sexual partners in her life, all of whom are now living in Africa. But twice when she underwent ritual scarification in Africa, the folk healers might have used non-sterile razor blades, the CDC says.

Because people can be infected with HIV and show no outward symptoms for 10 years or more, it is possible that they could be approved for a blood donation, said Dodd, who is head of the Red Cross' Transmissible Diseases Department.

Studies show that routine blood tests catch the HIV-1 group O strain about 80 percent of the time, Dodd said.

``We couldn't exclude the possibility that an individual such as this - not necessarily this individual - might give blood,'' Dodd said.

Other researchers, including the CDC epidemiologist assigned to Los Angeles, said the accuracy of testing for the group O strain is not clear because so few cases have been found. The Los Angeles woman is among approximately 50 people worldwide with a group O infection, the CDC reports.

In the Los Angeles case, the woman became sick, with enlarged lymph glands, and sought medical help in November 1994. In February 1995, she took what authorities said they believe was her first test. It did not detect her infection.

``She may have been tested several times in that interval, but we can find only confirmation of one,'' said Dr. Paul Simon, the CDC epidemiologist in Los Angeles.

Because of prolonged menstrual bleeding, she next went to Kaiser Permanente West Los Angeles Medical Center for treatment. There, the cause of her bleeding was found to be a low count of blood platelets, said her Kaiser doctor, Leora Britvan.

Britvan said the woman's condition raised her suspicions, so she ordered an HIV test. The result showed a weak positive for the virus, and a test to confirm was inconclusive, Britvan said.

One of Los Angeles County's 10 surveillance staff members came across the woman's results and indications that her immune system had been weakened, a sign of a HIV infection.

The worker added the woman to the rolls of people with AIDS, without checking the confirmatory test, as is required, said Dr. Peter Kerndt, head of the county HIV-Epidemiology Program.

Instead, Kerndt said, the worker should have recognized that the case raised enough suspicion to be reported as a possible rare infection. ``Then we would have detected this over a year ago,'' he said.

Britvan said the case points to the need for doctors to remain alert for cases that do not fit the typical definition for an HIV infection.

``Follow your gut and take it further and report it to the CDC,'' Britvan said.

As for the woman, Britvan said, ``She is doing quite well. She is not ill.''