Scientist Warns of Threat From New AIDS Virus

A second AIDS virus, found in West Africa last year and initially thought to cause only rare cases of the disease, appears to be just as deadly as the original AIDS virus and may pose a significant international health threat, a leading French researcher said here Thursday.

The virus, called LAV-II, seems to be a major cause of AIDS in West Africa and has spread to several countries in Western Europe. It appears to have been transmitted by blood transfusion to at least one patient in Paris, said Dr. Luc Montagnier of the Pasteur Institute in Paris.

The virus has not been found in the United States.

“We are just at the beginning of the spread of a new virus,” Montagnier told the annual meeting of the American Assn. of Blood Banks. “It is unavoidable at some time that LAV-II will reach the United States.”

A leading American AIDS researcher, however, cautioned that Montagnier’s conclusions, based on discovery of the new virus in fewer than 100 patients, may be premature.

“I would be more conservative,” said Phyllis Kanki, a Harvard University scientist, in a telephone interview. Kanki, who heard Montagnier present his data at a meeting in Paris last week, said it was too early to conclude that LAV-II infections were widespread in humans. Kanki works in the laboratory of Dr. Myron Essex, the discoverer of another variant AIDS virus.

Montagnier, whose research team discovered LAV-II, warned that the new virus is frequently not detected by the standard blood tests for the original acquired immune deficiency syndrome virus. That makes it more difficult to diagnose LAV-II infections and to protect against contaminated blood. It also complicates efforts to find a cure.

As a result, the researcher said, a new blood screening test, aimed at detecting LAV-II, is being developed. Blood screening for AIDS has been a principal concern at the meeting here. Blood bank officials entered the meeting confident that current screening procedures were working well and that cases of AIDS transmitted by blood transfusions would soon be eliminated.

“This is bad news for blood bankers,” Montagnier said. “We should require future tests to detect 100% of the donors infected with the new virus.”

Montagnier said in an interview that LAV-II had been found by other researchers in patients in Belgium, England, Germany and Sweden, as well as in France. All the patients had African contacts. None of these cases have been reported in the medical literature.

Montagnier’s data contribute to an ongoing scientific debate about the role of variant AIDS viruses in causing human disease.

The original AIDS virus was separately isolated in 1984 by Montagnier, who called it LAV-I, and by Dr. Robert C. Gallo of the National Cancer Institute, who called it HTLV-III.

The AIDS virus attacks the body’s immune system, leaving an individual vulnerable to a variety of infections and tumors. It is transmitted by sexual contact, through contaminated blood and from infected mother to child. As of the end of October, 26,875 Americans had developed AIDS and 15,070 had died, according to the federal Centers for Disease Control.

Subsequently, two variant viruses have been discovered. They are LAV-II, isolated in 1985 by Montagnier’s team in an AIDS patient from the former Portuguese colony of Guinea-Bissau, and HTLV-IV, isolated in 1985 from the blood of healthy people in the West African nation of Senegal by a research team headed by Essex.

LAV-II and HTLV-IV appear to be more similar to each other than to the original AIDS virus, but HTLV-IV infection has not been shown to make people sick. The research groups at Harvard and the Pasteur Institute have not exchanged samples of the LAV-II and HTLV-IV viruses to allow them to be directly compared.

“We believe they are most likely different viruses,” Kanki said Thursday. She said better studies of both viruses are needed throughout the world to determine any potential risk to the blood supply.

According to Montagnier, LAV-II infects both men and women. It appears to be transmitted by heterosexual contact or through the blood, although this information is preliminary.

LAV-II has not been detected in homosexual men or in intravenous drug users. “This may be why it appears to be spreading slowly,” Montagnier said.

Since LAV-II was first identified last year, the French scientists have isolated it in about 20 people from West Africa, Montagnier said. As of June, they had detected it in 43 of 1,000 other West Africans whose blood was tested for antibodies.

Like the original AIDS virus, LAV-II also appears to attack the human immune system, in particular a type of white blood cell called the T-4 cell.

Of people infected with LAV-II, 11 have AIDS and 10 have AIDS-related illnesses; seven patients have died. The others are not sick.

By contrast, HTLV-IV has been detected through blood tests in about 375 people out of several thousand tested in West African countries, according to Kanki. None had evidence of AIDS or AIDS-related disorders.

Montagnier said the original AIDS virus was the most common cause of the disease in Central Africa. But in West Africa, LAV-II may be the major cause, he said.

“This finding was really a surprise to us,” he said. “I couldn’t imagine two viruses causing the same disease.”

Of particular concern is the finding that the standard blood tests against the original AIDS virus often fail to detect LAV-II, Montagnier said. This is because of differences in the proteins coating the viruses.

His laboratory is investigating the case of a French man who received 10 units of blood in Paris in June and subsequently developed symptoms of AIDS.

Blood tests on samples taken before the transfusions were negative for both AIDS viruses. After the transfusion, they were positive for antibodies to LAV-II but negative for the presence of the original AIDS virus.