The parasite that entered Arthur Ashe's brain in 1988 causes one of the infections that doctors consider a hallmark of full-blown AIDS, experts in infectious diseases said yesterday.
The retired tennis star said he probably contracted the AIDS virus from the blood transfusion he received a few days after a heart bypass operation in 1983. If so, the virus quietly damaged his immune system until the day in September 1988 when his right hand suddenly "went dead" and "stopped working."
A biopsy of brain tissue revealed toxoplasmosis, a parasite that was impairing the neural pathways to his right hand.
"Toxoplasmosis is an AIDS-defining illness," said Dr. Alfred J. Saah, an infectious-disease epidemiologist at the Johns Hopkins School of Hygiene and Public Health. This means it is one of the "opportunistic infections" that do not cause serious illness in people with healthy immune systems but can kill people who lack normal defenses.
Dr. John Bartlett, chief of infectious diseases at the Johns Hopkins School of Medicine, said only 3 percent of all AIDS patients have toxoplasmosis as their "defining illness." Much more common is an initial diagnosis of pneumocystis pneumonia, a respiratory infection.
Sometime during their illness, 8 percent to 12 percent of all AIDS patients develop toxoplasmosis, he said, adding that it is usually "something that happens in the relatively late stage of their disease."
People can acquire toxoplasmosis from cat feces that collect in kitty litter. In otherwise healthy people, the parasite can produce a low-grade illness that causes fever and aches but usually clears without medication. Pregnant women are often warned to avoid cat boxes, however, because the parasite can cause BTC serious neurologic impairment in babies.
Mr. Ashe told the nation yesterday, "I have AIDS." In comparison, basketball star Magic Johnson says he is still in the incubation phase, meaning the virus has yet to damage his immune system so severely that he cannot resist life-threatening infections.
Mr. Ashe said he probably acquired the virus a few days after a heart bypass operation in New York in 1983, when a doctor gave him two units of blood to help him through an "awful" period of recovery. He lamented that he received the transfusions about 18 months before blood banks started screening all units of donated blood for the human immunodeficiency virus, which causes AIDS.
In the wake of Mr. Ashe's announcement, leaders of blood banks across the country tried to allay concerns about the safety of the blood supply. Dr. Paul Ness, medical director for the American Red Cross chapter in Baltimore, said the risk of contracting the AIDS virus from a unit of blood is about 1 in 60,000 -- a low rate that he attributed largely to laboratory testing.
Mr. Ashe's announcement is also likely to produce concern among patients who received transfusions prior to May 1985, when blood screening began.
"People who are worried about it ought to go ahead and get tested, but they ought to know ahead of time that the likelihood [that they have the infection without already knowing about it] is very low," Dr. Bartlett said.
He said most people who acquired the virus between 1978, when the virus is thought to have entered the blood supply, and May 1985 probably have already suffered some early symptoms of infection -- such as fatigue, swollen glands, or a fungal infection of the mouth.
Also, he estimated that the risk of contracting the AIDS virus from ablood transfusion in New York, San Francisco or Los Angeles before 1985 was probably about "a hundred times higher than if you were in Baltimore." This is because the epidemic first surfaced in those cities, so many more infected people were donating blood.
In Maryland, 12 cases of AIDS had been traced to blood transfusions through February 1992, while about 30 had been attributed to the clotting factor given to hemophilia patients. Other patients, however,may be infected without knowing it because they are still in the incubation stage.
Nationally, about 4,700 AIDS cases have been attributed to tainted blood transfusions, accounting for about 2 percent of 215,000 total cases. The first well-documented case of transfusion-related AIDS occurred in 1982, involving an infant who received 18 units of blood in San Francisco.
A short time later, one of the donors was diagnosed with AIDS.