A heroin user who died in hospital has tested positive for anthrax. Blood tests showed the presence of the deadly bacteria in the unidentified patient, who died at the Victoria Infirmary in Glasgow yesterday.
Health officials said another heroin user being treated at the same hospital has also tested positive for anthrax.
A third patient, who is being treated at Glasgow Royal Infirmary, is being tested for anthrax. All three had infections in areas of the body they injected with heroin.
NHS Greater Glasgow and Clyde said its Public Health Protection Unit was now working with the Procurator Fiscal and Strathclyde Police to identify the source. Anthrax was suspected of being responsible for a spate of deaths among Scottish heroin addicts in 2000.
One possibility being investigated is that contaminated heroin, or an agent used to cut the drug, may be to blame.
Dr Syed Ahmed, consultant in public health medicine, said the risk to the general public was "negligible".
He added: "I urge all drug-injecting heroin users to seek urgent medical advice if they experience an infection."