Letters have been sent out to parents with children at Whitehills Primary School after it was confirmed a pupil had contracted scarlet fever.
Forfar is the latest town to be affected by the growing spread of the outbreak, which is the worst in the Uk for 24 years.
Pupils at Northmuir Primary school in kirriemuir and at two Carnoustie primary schools were reported to have contracted the contagious disease. A number of schools in Dundee have also reported cases amongst pupils.
At the time of going to press on Tuesday (yesterday) a spokeswoman for Angus Council said: “We can confirm that there has been scarlet fever at Whitehills Primary School and we have written to parents.”
Local mum Angie Burgoyne contacted the Dispatch via Facebook in an attempt to raise awareness of the incident as she was aware some parents had not received the letter.
The bacterial illness causes a distinctive rash, high temperature and sore throat as well as a white coating on the tongue.
It can be successfully treated with antibiotics but is highly contagious. The disease is most common among children aged between two and eight.
The number of scarlet fever cases normally increases during the winter.