Mexican food chain Wahaca has had to close nine restaurants - five in London - after a suspected outbreak of norovirus.
UPDATE: Wahaca has now reopened all its restaurants. Read more here.
Public Health England (PHE) said it had launched an investigation after 205 staff and 160 members of the public fell ill.
Most of the restaurants have since reopened though four are still shut and they're all in the capital. While White City has reopened, Soho, Oxford Circus, Covent Garden and Canary Wharf remain closed.
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Wahaca co-founders Mark Selby and Thomasina Miers said in a statement:
Last week a number of our staff and customers were struck down by what is suspected to be the winter vomiting bug, norovirus.
We assessed each case and when it became clear they were not isolated incidents, we got in touch with relevant officials at Public Health England and Environmental Health Offices.
In tandem with that, we took our own precautionary measures – voluntarily closing affected restaurants, carrying out anti-viral deep cleaning at all of our restaurants, whether affected or not, and ensuring that any staff member who had reported illness remained off site until their symptoms had ceased for at least 48 hours.
We are incredibly sorry that people have been unwell. In the nine years since we first opened Wahaca we have never had such an unprecedented incident, and we are doing everything we can to get to the bottom of how this may have happened.
Those affected by the virus tend to return to health after a few days, though the NHS advises calling a GP or the 111 helpline if symptoms continue.
Still, at least it's not Chipotle. Over in the US, a norovirus contamination in a California restaurant resulted in Chipotle getting dished up a grand jury supoena in a criminal investigation. The Mexican chain was under investigation after a highly contagious virus causing winter vomiting disease spread at a California outlet in August 2015.
It marked the first of several health scares for the chain last year. More than 50 people in nine states were affected by an E.Coli outbreak in the autumn, and then in December, 91 people in Brighton, Massachusetts were infected by norovirus at the restaurant.
Wahaca was founded in 2005 by MasterChef winner Miers, along with Selby, and has 19 branches, predominantly in London.
It opened its first branch in the West End in 2007 and opened its first restaurant in the north west based in Manchester in September 2015.