Legionnaires' disease is spread by water droplets

Health officials said it was still safe to visit the city, where work to decontaminate a cooling tower at a Bulmers cider plant is continuing.

Mike Deakin, the county's director of public health, said the latest cases were "not unexpected".

GPs were on the lookout for the disease and even those with the mildest symptoms were being diagnosed, he said.

The number of new cases on Saturday was the biggest in one day since Herefordshire Primary Care Trust revealed more than a week ago that the disease had struck.

The outbreak has so far killed one man, in his 70s.

Another patient, also a man in his 70s, was said to have taken a turn for the worse on Friday night.

These new cases may have contracted the disease from a local source but we are confident this has now been eradicated as part of extensive cleaning and disinfecting Dr Brian McCloskey, Health Protection Agency

The rest of the original 15, all middle-aged or elderly, are all stable in Hereford General Hospital except for one man, who has been discharged.

No details about the latest seven patients or their conditions were being released because relatives were still being informed, the trust said.

Mr Deakin said: "The procedures that have been put in place since the start of the outbreak mean that GPs are on increased lookout for Legionnaires' symptoms.

"We are also continuing our intensive case-finding exercise, and this is helping to identify some people who have a milder form of the disease which in normal circumstances may have passed with no ill effects.

"We would emphasise again that Legionnaires' disease cannot be transmitted person to person, and that it is safe to visit Hereford."

Cider safe

Dr Brian McCloskey, of the Health Protection Agency, said the new patients had been diagnosed within the normal incubation period of Legionnaires', which is between two days and several weeks.

Mr McCloskey said: "This means that these new cases may have contracted the disease from a local source but we are confident this has now been eradicated as part of extensive cleaning and disinfecting."

It has not been confirmed that the source of the outbreak is the Bulmers plant.

But the legionella bug was found in a sample taken by health officials from one of its evaporation towers on 7 November.

The firm has closed down the tower while it is being sterilised, but production is continuing as normal.

Officials stressed it was still safe to drink the cider.