A drug user has become the first person to die in England from a batch of anthrax-contaminated heroin which has now killed 11 addicts in the UK and Germany.

The unnamed user from Blackpool is the second case in England to emerge in the last week after it emerged five days ago that a female addict from London was being treated in hospital.

The death in Blackpool follows nine fatalities across central Scotland since the contaminated heroin emerged in early December in Glasgow. There have been 19 confirmed cases in Scotland, with deaths in Glasgow, Lanarkshire, Dundee, Fife and Stirling.

The German victim died in Aachen in December but the death was only officially linked to the batch found in the UK last week, after the strain was found to be "indistinguishable" from the type of anthrax found in Scotland.

The surge of cases – the most serious anthrax outbreak in the UK in recent times – has puzzled police and health experts, who remain uncertain how or where the heroin became infected. The frequently lethal bacteria is mostly found in animals in Asia and Africa, and very rarely occurs in Europe.

They are investigating whether the heroin was contaminated at its likely source in Afghanistan, perhaps from contaminated soils or contact with infected animal skins, or was infected by a cutting agent used by drugs dealers or traffickers closer to Europe.

The cases in London and Germany have no known link to the Scottish outbreak, increasing anxieties that the contamination could be widespread. There has been only one previous case of a heroin user dying from anthrax, in Norway in 2000.

Professor Qutub Syed, director of the Health Protection Agency in north-west England, said the risk to non-heroin users, including the close relatives of addicts, was "negligible". He added: "It is extremely rare for anthrax to be spread from person to person and there has been no evidence of a significant risk of infection being passed on in the current situation in Scotland."

Dr Arif Rajpura, the director of public health with NHS Blackpool, repeated warnings to heroin users to stop taking the drug or watch closely for unusual symptoms, including rashes, swelling, severe headaches or high temperatures.

"Heroin users are strongly advised to cease taking heroin by any route, if at all possible, and to seek help from their local drug treatment services. This is a very serious infection for drug users and prompt treatment is crucial," he said.