The same strain of anthrax has been found in a drug user in Germany
The death of a drug user in Germany has been linked to the anthrax outbreak that has killed nine heroin users in Scotland.
Tests by the Health Protection Agency and German scientists show the strain of the infection is indistinguishable from cases in Scotland.
The results suggest the anthrax contamination in both countries could come from a common source.
In Scotland there have been 19 confirmed cases of anthrax infection.
The outbreak began with the identification of cases in NHS Greater Glasgow and Clyde in December.
Fourteen of the confirmed cases in Scotland had the same strain of anthrax while the others are being investigated.
Health Protection Scotland said typing on the sample isolated from the German patient, who died in mid-December, has confirmed it is also of the same strain.
A further case of anthrax in a patient living in London with a history of heroin use has also been confirmed by the agency.
This individual developed symptoms at the end of January 2010. Investigations are continuing but no obvious connections to Scotland have been identified.
Evidence suggested that contaminated heroin may still be in circulation, and drug users across Scotland have been warned to remain vigilant.
Head of the national outbreak control team, Dr Colin Ramsay, said: "Drug users are advised to cease taking heroin by any route if at all possible.
"While we appreciate that this may be extremely difficult advice to follow, it remains the only public health protection advice possible based on current evidence."
He said filters would not make heroin safe for drug users.
He added: "Users should seek urgent medical attention in the event of symptoms such as redness or swelling at or near an injection site or other symptoms of general illness such a high temperature, chills or a severe headache, as early antibiotic treatment can be lifesaving."
Anthrax is a deadly bacterial infection which occurs mostly in animals in Asia and Africa.
Humans are seldom infected and it is extremely rare for anthrax to be spread from person to person.