If a trip abroad always sees you laid low with a stomach bug, your blood type could be to blame. Picture: File

If a trip abroad always sees you laid low with a stomach bug, your blood type could be to blame.

A study found those in blood group A were likely to be struck down sooner and more severely. Nearly half of Britons have type A or AB blood, raising the chance of ‘travellers’ diarrhoea’.

US researchers gave more than 100 volunteers water containing enterotoxigenic E. coli. Some 81 per cent of those with type A blood needed medical treatment for diarrhoea, compared with 56 per cent of others.

The study, in The Journal of Clinical Investigation, found E. coli releases a protein that latches on to intestinal cells of those with blood type A.

Author Dr James Fleckenstein, of Washington University, said a vaccine targeting the protein could protect sufferers. Up to 60 per cent of travellers are hit by stomach bugs, with several types of bacteria, including E.coli, to blame.

Daily Mail