Almost 500 employees at a factory in Cornwall have now been tested for coronavirus after a single alert to the Track and Trace service identified more than 170 cases - many of which had no symptoms.

Cornwall Council has given an update on the outbreak at the Pilgrim's Pride Ltd food factory in Pool, where earlier this month it was confirmed that there had been "a small number of confirmed cases of Covid-19".

It has now said that it was a single alert to council's Public Health team from the national Test and Trace service that resulted in more than 170 cases of people who were unaware that they had Covid-19 and were not displaying symptoms.

In total, almost 500 employees at the factory have now been tested and the council said the "vast majority of the cases" who tested positive were not displaying symptoms.

The council said: "Swift identification of the initial case has therefore helped to limit the transmission of Covid-19 in the local community.

"All employees who have tested positive are isolating in line with government guidelines, as are those found to have been in close contact with them."

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Cornwall’s public health team provided the update at a meeting of the Covid-19 Local Outbreak Engagement Board yesterday and outlined the intensive testing they are carrying out to help limit the transmission of the virus, working closely with the factory, Public Health England South West and the NHS.

The council added: "The public health team provides an enhanced contract tracing service where they contact the individual identified to us by NHS Test and Trace and interview them about their recent activities.

"In this case the individual revealed to us that they worked at the factory, and so further investigations were carried out and testing procedures put in place."

The information on cases of coronavirus in Cornwall is updated weekly and can be found