Until today, officials in the former Soviet Union could claim that a 1979 anthrax epidemic in Russia which killed 68 people was caused by tainted meat.

But according to Cabot Professor of the Natural Sciences Matthew S. Meselson, who led a trip last year to the region most affected by the epidemic, the outbreak may have been caused instead by airborne spores.

And if a military base near the site of the epidemic was the source, then the Soviets may be guilty of violating the Biological Weapons Convention of 1972, banning biological weapons, signed by both the U.S. and U.S.S.R.

According to Boston College professor of sociology Jeanne Guillemin '68, a member of the team, the epidemic was the largest outbreak in recent memory.

The results of the trip, reported in today's Proceedings of the National Academy of Sciences, aim to present the findings of two Russian pathologists to the English speaking public.

Meselson's team traveled to Ekaterinburg, a city 900 miles east of Moscow. There, they met with the two Russian pathologists who performed autopsies on the affected people in 1979.

The anthrax bacteria, which most commonly affects cattle, were found in lymph nodes which drain the lungs. This suggests that victims inhaled the anthrax spores. From there, the bacteria spread through the body.

"We're pretty confident that it was airborne [as opposed to being from meat]," Meselson said in a phone interview Saturday. "The most plausible source is the military base, and they do say they were working with [the anthrax bacteria] for a vaccine."

Meselson, who first became involved with the epidemic when the CIA contacted him in 1980, tried to visit the Soviet Union for several years but was not granted permission until 1986, when he was invited to speak with four doctors who treated patients in the epidemic.

But with an invitation from the director of the local university last year to study the epidemic, Meselson's team of experts began their own independent research.

The team interviewed families of 50 of the victims, but the chief veterinarian, local public health official, and the commander of the military base were "unable" to speak with the team, Meselson said. Government rules also hampered their study of the deaths of the animals.

On their request to visit the surrounding farmland, "The secret service said that 'It is forbidden and if you do, you will be out of the country in 24 hours,'" Meselson said.

According to Guillemin, interviews with local farmers would have greatly improved their ability to determine events at the time of the outbreak.

To pinpoint the source of the bacteria, the victim's DNA will be sequenced at Louisiana State University, and researchers will attempt to correlate the locations of victims.

The DNA could be used to match the strain of anthrax found with a sample from the military base, if the Russian government is willing to provide it.

Summing up the team's work, Guillemin said, "It was very much an effort of a private individual getting to the bottom of a mystery.