Beginning Nov. 2014, a cluster of E. coli O55 cases was identified in Dorset followed by another cluster in May 2015: no common source was found.

Now, a new case of E. coli O55 has been identified, along with a case in a pet cat.

To date, 26 cases of E. O55 coli have been confirmed in the county, and it is now believed that pets might be carrying the disease.

Health protection consultant Noëleen McFarland said: “Public Health England would like to reassure the public that the investigation into this unusual strain is ongoing.

“What we now know is that cats and other pets could be spreading this bacteria but they are not the source.

“E.coli is a type of bacteria that is found in the guts of cattle and other ruminants, whilst cats and other pets can act as carriers passing this on to humans in their faeces.”

Both the person and cat affected were from the same household, but however the agency will not reveal the locations of cases, citing patient confidentiality.

No common source has yet been identified for the outbreak, which is only in Dorset.