Six people have contracted an infection from Countryfile TV presenter Adam Henson's Cotswold farm.
Five visitors and a member of staff are being treated for a bug which affects the intestine called cryptosporidium.
Public Heath officals are investigating the outbreak at Cotswold Farm Park near Bourton-on-the-Water.
They say those affected are recovering well.
The farm says it has taken extra precautions to reduce any risk for visitors over the Bank Holiday.