They found two genes which indicated the presence of H Pylori infection in 28 out of the 32 tissue samples.

These are interesting findings that may help explain why overwrapping, front sleeping and minor infections may create difficulties for babies

Joyce Epstein, FSID Director

The same gene types were found in only one of eight tissue samples taken from babies who died from other causes.

Writing in the Archives of Disease in Childhood, the researchers say that, as well as causing inflammation, H pylori can lead to production of ammonia which has been associated with SIDS in earlier research.

The research team suggest that, as H pylroi is found in saliva, it may be passed to the baby from an infected adult.

Ammonia

SIDS may result when the baby inhales a small amount of vomit containing H pylori, which releases ammonia into its bloodstream.

Cot death is the unexplained sudden death of a baby aged under one year and, despite much research, eight babies a week still die from it in the UK.

Joyce Epstein, director of the Foundation orr the Study of Infant Deaths said: "These are interesting findings that may help explain why overwrapping, front sleeping and minor infections may create difficulties for babies.

"It is only a hypothesis at this stage and it is uncertain whether this study has any practical implications."

She reminded parents to take steps which are known to reduce the risk of cot death including putting the baby to sleep on its back, not letting anyone smoke around the baby and not letting it get too hot.