SCIENTISTS and health officials have confirmed they are developing ground-breaking new tests as they continue to investigate an outbreak of E. coli 055 in Dorset.

Thirty people in the county have contracted the disease since July 2014, with some hospitalised in a life-threatening condition after developing symptoms.

Now, Public Health England (PHE), the Government agency responsible for investigating the outbreak of the disease, has confirmed that although it is no closer to finding the cause of the outbreak, it is working alongside scientists from the Animal and Plant Health Agency to develop new tests for cattle and sheep, and will also review the results of its questionnaires and re-interview people who have contracted the disease to see if they have missed anything.

Noeleen McFarland, consultant in health protection at PHE, said: "It's an ongoing investigation, we are still trying to track down the source.

"As well as the new tests and re-interviewing people, we are carrying out more tests on sampling in the laboratories in Dorset for E. coli 055 to see how widespread it is in the community of Dorset because what we do know is that people can carry the strain without showing symptoms or only mild symptoms, so we need to find if there are more cases.

It is expected that the new tests will be ready to test on animals by 2016, and the announcement follows criticism of PHE from Healthwatch Dorset, which called on the agency to redouble its efforts to find the source of the strain.

E. coli O55 is a rare strain of the E. coli disease, and the outbreak in Dorset is the first time it has been recorded in the United Kingdom.

The outbreak has spanned 15 months, affecting families across Dorset, including an outbreak in Weymouth. Four people were diagnosed with the disease as recently as September this year.

Two cats have also been confirmed as having the disease

Mrs McFarland added: "The APHA is developing a new test for cattle to detect O55 because although we can test for the 0157 strain in cattle, the O55 strain is new.

"We know that the disease lives in the gut of cattle and sheep, and although cats have been tested they are just vectors and not the source of it, and these new tests might help us find it.

"We are committed to finding the source of this strain, but in the meantime we urge people to practice good food and hand hygiene to stop the bacteria entering the body."