AIDS Virus Infects U.S. Researcher : Lab Worker Had No Known Direct Contact With Disease

Federal health officials said Friday that they are investigating the case of a government AIDS researcher who became infected with the virus despite apparently having no known direct contact with it--representing what may be the first instance of an AIDS infection that cannot be explained by recognized routes of transmission.

The researcher, who has not been identified, was processing highly concentrated amounts of the AIDS virus in the laboratory and claims to have no risk factors, such as homosexuality, intravenous drug use or blood transfusions, National Cancer Institute officials said Friday, confirming information that had been obtained by the press.

Dr. Peter Fischinger, the institute’s deputy director, said the investigation will concentrate on a centrifuge that the researcher was using. He said officials hope to determine whether a broken seal might have allowed the virus to escape.

Search for Explanation

“In many labs when you work with viruses and use a centrifuge, a seal will leak,” Fischinger said. “So what we really have to do is get the technical experts who know centrifugation . . . to look very carefully at whether this can be explained on a technical level.”

AIDS researchers believe that the deadly virus is communicated only by intimate sexual contact or direct entry into the bloodstream. A few medical personnel have been infected after being splashed with contaminated blood, with the virus apparently entering through breaks in their skin.

However, the officials said they have not determined that the laboratory worker came into direct contact with the virus.

Asked about the possibility of an unknown route of transmission, such as inhalation, Fischinger said: “You have to exclude everything else before you look at new modes of transmission. I would consider that far down the line. There is no implication that there is anything new happening here. It’s really not known yet.”

Same as Lab Virus

Health officials last week isolated virus from the researcher’s blood and confirmed that it was the same type as that being grown in the laboratory, Fischinger said. He said this made it unlikely that the worker was infected in some other way because there are many variants of the virus in nature.

“This one looks like the lab virus,” he said.

About 3% of all AIDS cases have been placed in the category of having no known risk factors, the federal Centers for Disease Control in Atlanta says. However, in most of these cases the patients died before they could be interviewed about risk factors or they are ultimately expected to be linked with a known route of transmission when the facts are established, the CDC has said.

Fischinger emphasized that the researcher was handling large amounts of highly concentrated virus, and said that “you don’t find this in nature.” Another source said the researcher was handling 70 liters of the virus on a daily basis, but that could not be confirmed at the institute.

Precautions Assumed

Fischinger said that “the assumption is that the individual was wearing protective clothing and taking the proper precautionary measures,” which typically include wearing gloves to prevent any skin contact with the virus.

Citing reasons of privacy, the institute would not disclose the researcher’s gender, age or other characteristics. The individual was working on a National Cancer Institute study, in which personnel directly involved have undergone random testing for more than a year, the institute said.

AIDS, or acquired immune deficiency syndrome, destroys the body’s immune system, leaving it vulnerable to opportunistic infections or rare cancers. The virus can also invade the central nervous system, causing severe neurological disorders.

In the United States, it has afflicted male homosexuals and bisexuals, intravenous drug users, their sexual partners and people who have received transfusions of infected blood. New controls have made transmission through blood transfusions slight.

AIDS is commonly transmitted through anal and vaginal sexual intercourse, the sharing of unsterilized hypodermic needles and from woman to fetus during pregnancy.

As of Aug. 31, there have been 41,366 cases in the United States; 23,884 patients have died.