Around 200 workers at a farm in Herefordshire, England have been put into lockdown following an outbreak of Covid-19.
Some 73 positive cases of the virus have been confirmed among workers at vegetable producer AS Green & Co, which is based in the village of Mathon, near Worcester.
A joint statement from Public Health England (PHE) Midlands and Herefordshire Council said employees were being asked to remain on the farm during the period of isolation.
The council said it is arranging food and essential supplies for residents on the site - who stay in mobile homes there during the harvesting season - while they self-isolate.
Katie Spence, PHE Midlands health protection director, said that to support the workforce of around 200 key workers, the company had put a range of infection control measures in place.
"Despite these measures, a small number of workers became symptomatic earlier this week and they and a few close contacts among the workforce were tested initially and found to be positive," she said in a statement.
"In line with NHS guidance, affected individuals were asked to self-isolate for seven days, with their households and close contacts asked to isolate for 14 days.
"As we have seen a global trend of large food producers being subject to outbreaks, as a precautionary measure, the decision was made to test the entire workforce.
"The initial batch of results showed a significant percentage of positive cases, despite these individuals being asymptomatic.
"We are still awaiting a few final results, but currently we have 73 positive cases of Covid-19 among the workforce."
A statement on the farm's website said the site has been closed to all visitors, while no workers are permitted to leave.