A bacterium called clostridium was the most likely cause of the deaths of eight heroin users in the State, the head of the investigation into similar deaths in Glasgow said yesterday.
Dr Laurence Gruer, consultant in public health medicine with the Greater Glasgow Health Authority, said: "Everything points to it [the cause of the infections] being one of the clostridium family."
However, the process of isolating the bacterium behind the illness could take several weeks.
Dr Joe Barry, consultant in public health medicine with the Eastern Regional Health Authority, said it was difficult to know whether clostridium was the cause, though he confirmed it was one of the "theories".
"Until we have definitively identified the cause of this illness, our approach is to say to drug users: `Regardless of the cause, something is wrong with the heroin, and anyone who is concerned about their symptoms should present for treatment'. "
The eight people have died in the Dublin, Wicklow and Kildare area since May 1st. A further seven cases of the illness have been confirmed. Five more reported cases are being investigated. The illness has killed 12 addicts in Glasgow and two in Aberdeen. The most recent Scottish death was of a young Aberdeen man last Sunday.
The investigators have looked at similar drug deaths in Switzerland and the US where clostridium was found to be the cause.
The illness, which begins with severe abscesses and sores on the skin where the addict has been injecting, develops into an infection which attacks the blood and eventually engulfs the body's major organs.
Secondary infections such as pneumonia or streptococcal illnesses can also develop.
Habitual intravenous drug users have a weakened immune system and would be particularly vulnerable to infection.
Clostridium is an anaerobic bacterium, meaning it thrives in the absence of oxygen but is killed by it.
"Clostridia, however, can survive in suspended animation as a spore for months and years in dust," said Dr Gruer. "It is perfectly feasible, therefore, that if someone mixed pure heroin with an adulterant to increase profits, it could be contaminated with clostridia."
Recent seizures of heroin in Dublin and Glasgow have been up to 65 per cent pure, according to police sources. Because of this, addicts are using up to six times the usual amount of citric acid to dissolve the powder, which burns a hole in muscle tissue, Dr Gruer said. The majority of those who died had been injecting into muscle, as habitual injection can cause veins to collapse.
According to Dr Gruer, once clostridium-contaminated heroin has been injected, the bacterium thrives and grows in the oxygen-free environment.
"It produces a toxin which can leach into the bloodstream. The difficulty is that there are more than 300 species of clostridium producing different toxins and it looks like this is not one of the common ones."
Identifying which clostridium is behind the illness involves examining blood and tissue samples from affected addicts. "The difficulty is that even the slightest whiff of oxygen kills it, so removing and examining the tissues is a very difficult and delicate procedure," Dr Gruer said. "Also, because many of these people will have been taking antibiotics, the bacterium has been killed, though the toxins remain."
Identification of the individual strain of clostridium would allow researchers to prescribe the correct treatment and begin work on an anti-toxin.
