A 75-YEAR-old Preston woman died of a rare strain of the human form of mad cow disease which strikes one person in a million.

An inquest in Blackburn heard that the sporadic form of Creutzfeldt-Jacob disease (CJD) has nothing to do with eating infected beef and is a naturally occurring disease which can strike anybody at any time.

The inquest was told that Betty Riding, who lived in Walton-le-Dale died in Queen's Park Hospital, Blackburn, after being brought back from her home in Cyprus by close friends Ena and Edward Shaw, of Blackburn.

Mrs Riding, who moved to the island 12 years ago, insisted on returning there following the death of her husband Horace last year.

Immediately after a cataract operation Mrs Riding seemed fine but days later Mrs Shaw spoke to her on the telephone and noticed a change.

"She seemed frail and distressed," said Mrs Shaw. "By the end of the week, when I spoke to her again, there was a marked deterioration."

Doctors in Cyprus said there was something drastically wrong and Mrs Shaw and her husband immediately flew to Cyprus to bring their friend home.

"When we arrived she didn't really recognise us," said Mrs Shaw. "She was like a child and could not feed herself."

Mrs Riding was flown home, accompanied by her doctor, and admitted to Queen's Park Hospital where her condition deteriorated daily until she died on March 31.

Royal Preston Hospital's Consultant neuro pathologist, Dr Timothy Dawson, said the post-mortem examination had been extremely limited because of the potential risks of CJD.

The CJD Observation Unit in Edinburgh was involved and a report by Professor Ironside confirmed that there was a degenerative change of the grey matter of the brain.

Dr Dawson told the inquest that there are several variations of CJD but the one that had caught the public imagination was Variant CJD. He said there is good evidence that Variant CJD is contracted through the food chain or through that and a genetic factor.

"Sporadic CJD occurs by pure chance," said Dr Dawson. "It affects one person in a million each year and is not affected by genetic or environmental factors."

Dr Dawson said the disease resulted in rapid degeneration but the operation on Mrs Riding's eye would have had no bearing on her developing CJD.

"The risk is more to people who followed because it is very difficult to clean the instruments," said Dr Dawson. "I understand the clinicians at Blackburn have warned the hospital authorities in Pathos."

Deputy coroner Carolyn Singleton recorded a verdict of death by natural causes.