Wrexham lambing event probed after stomach bug outbreak
An investigation is under way into an outbreak of cryptosporidium as a group falls ill following a farm and "lamb petting" event at a Wrexham stately home.
Another three suspected cases are also being examined.
Those who became ill visited Erddig Hall, owned by the National Trust, over the last 12 months.
Public Health Wales said there was no ongoing risk and that it would continue to monitor the situation.
Dr Judy Hart, Consultant in Communicable Disease Control, said: "Cryptosporidium is generally a mild disease.
"Most people with cryptosporidium are expected to recover without treatment, but in individuals with severely weakened immune systems, a more serious illness may develop.
"We are encouraging people who have come into contact with livestock to take thorough hand hygiene precautions to limit the spread of diseases passed from animals to humans.
"Pregnant women or those with an underlying health condition are also advised not to help lamb or milk ewes.
"All people should seek medical advice if they experience diarrhoea, fever or influenza-like symptoms, if they are concerned that they could have acquired an infection from a farm environment."
Public Health Wales said people can become infected with cryptosporidium by swimming in or drinking contaminated water, from contact with an infected person, eating contaminated food, or from contact with faeces.
The incubation period ranges from one to 12 days, but usually within five to seven days.
The length of the illness can vary but people can be ill for several weeks.
Most people will recover without treatment, but in individuals with severely-weakened immune systems, a more serious illness may develop.
Symptoms include diarrhoea, often accompanied by stomach pain, nausea or vomiting, fever and sometimes dehydration and weight loss.
The 18th Century Erddig Hall is run by the National Trust.
As well as tours of the hall itself, the trust runs trips around its gardens, and organises events in the grounds, including spring lamb events for children.
Mr Champion said the National Trust was working closely with the HSE on the investigation.