A drug user has died after being infected with anthrax, health experts said.
The Health Protection Agency (HPA) said a person who injected heroin died in Suffolk.
There has been a small outbreak of cases in Europe, with 13 cases identified by health officials since June last year.
Seven of the cases have occurred in the UK, including one in Scotland and one in Wales.
Four of the five people who contracted the bacterial infection in England have died, experts said.
The HPA said the source of the infection is presumed to be contaminated heroin.
Two of the deaths occurred in Blackpool and the other death was a drug user in Medway, Kent.
The HPA said it is “unclear” whether the British cases are linked to the European outbreak which has affected drug users in Denmark, Germany and France.
Anthrax is a bacterial infection and is primarily a disease of herbivorous mammals, though other animals and some birds can also become infected. Drug users can be exposed when heroin is contaminated with anthrax spores.
Dr Chris Williams, consultant in communicable disease control at the HPA in Norfolk, Suffolk and Cambridgeshire, said: “Anthrax can be cured with antibiotics, if treatment is started early.
“It is therefore important for medical professionals to be alert to the possibility of anthrax infection in heroin users presenting with signs and symptoms – which include severe soft tissue infections or blood poisoning – to prevent any delays in providing treatment.
“It is possible that further cases may be seen in people who inject heroin.”
He added: “People who use drugs may become infected with anthrax when the heroin they use is contaminated with anthrax spores.
“This could be a source of infection if injected, smoked or snorted – there is no safe route for consuming heroin or other drugs that may be contaminated with anthrax spores.”