LONDON (Reuters) -- Anthrax could be the deadly element in heroin which has killed 11 European drug users and may have infected many more, New Scientist magazine said on Wednesday.

Scientists at Britain's Porton Down biological defense laboratory have discovered signs of anthrax infection in two victims of a disease which killed 10 Scottish heroin users in the last month. One person in Norway also died from the same disease.

Another nine people in Scotland are ill, and one bears the black scab typical of localized anthrax infection, the report said.

The anthrax link first occurred to scientists when tests in April on the victim from Norway uncovered traces of the bacteria, the report said.

Evidence of anthrax infection in both Britain and Norway, coupled with the fact that the disease is hard to monitor among drug users, has sparked doctors' fears of widespread infection.

While the blood tests at Porton Down have not found actual anthrax bacteria in tests on the victims from Scotland, two of five samples contained the main toxin associated with anthrax.

Antibiotics can wipe out circulating anthrax bacteria, but the associated toxins can still be fatal, the magazine said.

"Nothing (but anthrax) would give that result," Phil Hanna, an anthrax expert at the University of Michigan, was quoted as saying of the Porton Down tests.

The spotlight fell on a possible link to anthrax after a Norwegian medic used the Internet to post the case history of the heroin addict who died in Oslo in April.

DNA tests confirmed that a contaminant in his spinal fluid was anthrax, a bacteria endemic in Iran, Afghanistan and Pakistan, the main exporters of heroin bound for Europe.

New Scientist cited Louisiana State University's Martin Hugh-Jones as saying gelatin or bone meal, which may have been mixed with heroin from these countries, could have been contaminated with anthrax.

The link is supported by evidence that the Scottish victims of the disease were injecting heroin directly into the muscle.

The infection spreads when anthr ax spores are devoured by white blood cells, a process which occurs far more readily in muscle than in the blood, the report said.