A strong link has been found between the bacterium Helicobacter pylori and cot death. H. pylori is a bacterium of the gut that can cause stomach infections and peptic ulcers. It is common in adults but rare in babies in the UK, yet evidence of its presence has been found in the windpipe of a proportion of babies who have died from sudden infant death syndrome (SIDS).
Researchers from Manchester Royal Infirmary examined tissue samples taken from the stomach, windpipe and lung of 32 infants aged between two and 28 weeks who had died from SIDS. They extracted DNA from the tissue samples and looked for sequences of two genes (H. pylori ureC and cagA) that are characteristically left behind by H. pylori infection. One or both of the genes were found in 28 of the 32 babies, compared with only one of eight babies who died of a known cause.
Dr Jonathan Kerr reports in the November issue of Archives of Disease in Childhood: "We have identified a possible bacterial cause of SIDS, but emphasise that our findings must be independently confirmed." Although it is difficult to determine how the bacterium causes SIDS, because there are no obvious signs of SIDS before death, Dr Kerr postulates that the bacterium causes the release of an immune molecule that causes vomiting in babies. Death could occur because babies inhale their own vomit while sleeping. Alternatively, the vomit produced is also rich in ammonia, which could be fatally poisonous if it got into the blood stream of the baby via the lungs. These theories would also support existing risk factors, including babies sleeping on their fronts, children of mothers who smoke, and babies being overwrapped and getting hot.
Dr Kerr recommended that parents and carers should avoid passing saliva to the mouths of babies to avoid transmission, "In practical terms this means good hand hygiene and that feeding bottles and pacifiers should not be sucked by carers before being given to babies."