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. Last Updated: 07/27/2016

Putting the Anthrax Scare Into Perspective

WASHINGTON -- In April 1979, hundreds of residents of Sverdlovsk, now called Yekaterinburg, fell ill with flu-like symptoms, and 66 died. Thirteen years later, Matthew Meselson, a Harvard biologist, tracked down where the victims had worked, plotted the locations on a map and discovered that he could draw a straight line connecting all of them.

Upwind of the line was a Soviet facility that was making anthrax -- a favored bacterial bioweapon. Eventually, Meselson found villages nearly 50 kilometers from the facility -- but still on the straight line -- that reported dead animals.

As U.S. officials grapple with the reasons that one Florida man died last week from anthrax and another has tested positive for the infection, the Russian case indicates the enormous complexity involved with masterminding, investigating and predicting the course of an anthrax release -- either deliberate or accidental.

An extraordinary array of factors influences whether anthrax can be deadly. Those factors range from the scientific sophistication of the people handling the anthrax to pure chance.

In the Sverdlovsk case, Meselson calculated that as much as a gram of anthrax -- about a trillion spores -- may have been accidentally released from the bioweapons facility. A steady wind happened to blow the spores in a single direction. A shifting wind pattern could have spread the spores more widely across the city of 1.2 million people. Paradoxically, fewer people might have fallen sick and died.

That's because inhaling small numbers of anthrax spores is unlikely to cause infection and disease. When anthrax infects people through cuts in the skin and only a few spores enter the body, humans readily fight off the infection.

Scientists believe it could take thousands of inhaled spores to cause someone to fall sick. Between 1990 and 1993, when the Shinri Kyo terror cult in Japan deliberately released anthrax spores four times, no one fell sick or died. Those terrorists may have failed because they dispersed their anthrax too widely, or because they didn't mix the anthrax properly. "The bottom line is the Russians knew how to weaponize anthrax spores and these cults didn't," said Philip Hanna, a professor of microbiology and immunology at the University of Michigan and an anthrax expert. "The spores have to be weaponized, to get it to the right consistency. It takes some specialized knowledge."

Several countries are believed to be studying anthrax and may have stockpiles. Hanna said Iraq, Iran, North Korea and Russia all probably had anthrax and some had developed strains of the bacteria that were resistant to treatment with conventional antibiotics.

The strain in Florida appears to be susceptible to treatment. Doctors say that if anthrax is spotted early, or if its release is suspected in a terror attack, prophylactic treatment with antibiotics can head off death.

The reason the illness has traditionally been so deadly is that its symptoms are mistaken for the flu and patients seldom seek specialized treatment until it's too late.

Anthrax spores are essentially sheaths of armor around the bacteria that cause the disease. When the spore finds itself in a comfortable medium such as the lungs, the bacteria begin to multiply.

Infected patients complain of headaches, fever, vomiting, chills and stomach or chest pains. The anthrax bacteria eventually find their way to the bloodstream. Concentrations can rise to a hundred million bacteria per drop of blood. The bacteria release a toxin that sends the body confusing cellular messages.

"The cells that clot are told, 'clot more' and some [other cells] are told 'bleed more' so you get a hemorrhage," said Trish Perl, an associate professor of medicine at Johns Hopkins University. "You get messages that increase or drop your white cell count. You get messages that control blood pressure saying, 'dilate blood vessels."'

The immediate cause of death is often a steep fall in blood pressure. Treating patients at this stage with antibiotics is ineffective, because the medicines won't affect the toxin.

Meselson said Soviet doctors tried to treat some of the Sverdlovsk victims for both the bacteria and the toxin. "They gave them huge amounts of penicillin, tetracycline and anthrax antiserum, probably from horses," he said.

Can people protect themselves from anthrax? Doctors recommend against widespread use of antibiotics, which carry risks of their own. Cases are now unlikely to be ignored, since doctors are alert to the possible meanings of flu-like symptoms.

The public is unlikely to benefit from wearing masks, experts said.

"I don't think it makes sense for people to wear masks," said Tara O'Toole, deputy director of the Johns Hopkins Center for Civilian Biodefense Studies. "If this was a deliberate release, it was into the building. The risk even to people in the building is quite low. Only two people are sick.

"The problem with masks is stuff gets in around the edges unless they are carefully fit and tested," she said. "This has to be a public health response. This is something the government has to take care of. People would love to have individual actions but this is a situation in which we have to depend on government."

One concern is that anthrax spores are long-lived. They've been known to have an incubation period as long as two months.

In nature, anthrax is enormously resistant to destruction. During World War II, Britain tested anthrax-laden explosives at Gruinard Island off Scotland. The spores were still viable four decades later.