Stoke-on-Trent Legionnaires' disease cases rise to 19
Another person has been diagnosed with Legionnaires' disease in Staffordshire, bringing the total to 19 cases, health officials have said.
One patient has died and eight people are being treated in hospital.
On Monday the Health Protection Agency (HPA) said a hot tub was believed to be the "probable" source of the outbreak.
Investigations have been taking place at JTF Warehouse in Fenton, Stoke-on-Trent. The firm has said the hot tub has been withdrawn from all stores.
The HPA said samples from the hot tub were confirmed at a specialist laboratory in Colindale on Monday as being an unusual strain of legionella bacteria and matched those taken from patients.
A spokesman for the University Hospital of North Staffordshire said: "The trust is currently treating eight patients, all of whom are in a stable or improving condition.
"These eight include one new patient and one patient who required readmission."
Another person is also being treated at Glenfield Hospital in Leicester.
Details of the patient who died on Saturday have not been released but those affected by the disease, which infects the lungs, are aged between their late 40s and mid-70s.
Rob Flello, Labour MP for Stoke-on-Trent South, has criticised the handling of the outbreak.
He said: "Although understandably the agencies want to restrict the information and not cause panic, I think what they've done in some cases is actually cause panic by withholding too much information."
Prof Harsh Duggal, director of the West Midlands North Health Protection Unit, said: "We have worked very closely with our partner organisations to make sure the necessary control measures were taken quickly to find a potential source.
"Working in this way has enabled us to get the results we have and minimised the impact on the wider public."
Dr Zafar Iqbal, the director of public health for NHS in Stoke-on-Trent, said: "It's important to remember that Legionnaires' disease cannot be passed from person to person.
"The early symptoms of legionella infection include a 'flu-like' illness with muscle aches, tiredness, headaches, dry cough and fever."
He added that anyone with concerns should contact NHS Direct on 0845 46 47 or see their GP.