A federally sponsored study of AIDS patients in Africa has found evidence that not only spouses but also other members of their households are more likely to be infected with the deadly AIDS virus than are individuals living in other households.
Preliminary findings from a new study in Zaire by scientists from the federal Centers for Disease Control and the National Institute of Allergy and Infectious Diseases are the first to suggest that the virus thought to cause the disease may be spread through ordinary contact between individuals in the same household.
But federal health officials said yesterday that the data was still being analyzed and cautioned that it was too early to say what the implications might be.
CDC spokesman Donald Berreth said the Zaire study is to be presented in detail next week in Atlanta at an international AIDS conference by investigators who were en route from Africa yesterday. "Interpretation of the data is incomplete and it is not clear that it will demonstrate household transmission," Berreth said.
He and others emphasized that "there have been no cases of household transmission in the United States. Specific studies have been done to test for antibodies to the AIDS virus in household contacts and all those tests have been negative."
To date, available scientific evidence in the United States has suggested that acquired immune deficiency syndrome seems to be spread only through intimate sexual contacts, injections with contaminated needles and blood products, and occasionally from mother to unborn or newborn child.
But in a lecture Wednesday at the University of California at Berkeley, a CDC investigator who recently visited Africa presented preliminary data about the Zaire household study.
A Knight-Ridder news service report quoted Dr. Joseph McCormick as saying, "We think our study suggests that living with a confirmed AIDS patient significantly increases the risk of infection."
McCormick could not be reached for comment yesterday.
The Knight-Ridder story said McCormick reported that 17 percent of household members of AIDS patients showed signs of exposure to the AIDS virus in their blood, as compared to 4 percent of people who did not live with AIDS patients.
When spouses of AIDS patients were excluded, it said, the researchers found that about 10 percent of those living in the same dwelling, both relatives and nonrelated adults and children, showed signs of antibodies to the virus.
There is no way to know how many of those exposed might eventually become ill with AIDS.
Another CDC official familiar with the preliminary data said the numbers are still subject to change and stressed that "the implications of the study are unclear."
He said it was important to investigate "other risk factors as yet unexplained that might be shared among household members," such as the use of the same needles for medicinal purposes or other routes of exposure.
Another researcher acknowledged that the Africa study "is going to raise a lot of concern." But he said studies in the United States -- including new ones to be presented at next week's AIDS conference -- have found no unexpected evidence of household transmission among families of AIDS patients, including intravenous drug abusers, hemophiliacs or patients who received blood transfusions. The only positive evidence of spread of infection was through already recognized exposure of sex partners or infants of mothers with AIDS.
While health experts here believe that the spread of AIDS in Zaire may be different from that in this country, they say there is a possibility that it could be a harbinger of things to come. Earlier reports have indicated that AIDS seems to be spread in Zaire and other central African countries primarily by heterosexual contact, with the AIDS cases almost evenly divided between men and women.
In contrast, American AIDS cases first appeared among homosexual men, who still make up three-fourths of the 9,405 American cases to date (as of Monday, 4,533 of them had died).
The disease also has been found here predominantly in intravenous drug abusers, hemophiliacs who receive blood products, blood transfusion patients and a smaller group of heterosexual contacts of those in high-risk groups. But there is growing belief that the heterosexual spread of AIDS is likely to become more common in this country unless a treatment or vaccine is found.