An entire plane-load of passengers and crew were put into quarantine in the UK when a widespread sickness broke out on board.
More than 440 holidaymakers were returning to London's Gatwick Airport from a cruise in the Caribbean when the bug struck.
Emergency service staff met the Virgin Atlantic plane and treated around 30 people, with a further three taken to hospital.
Passenger Trevor Wilson wrote on Twitter: "The illness seems to have originated on board the ship not the plane.
"Five members of cabin crew became sick on the flight."
He added that the sickness was "mainly a bad chesty cough, possibly chest infection" with "flu-like symptoms".
— Trevor Wilson (@trevwilson19) March 6, 2019
A Virgin Atlantic spokesperson said it had launched a "full investigation" into the circumstances.
They added: "The safety and well-being of our customers and crew is always our absolute priority."
A Hazardous Response Team and specialist paramedics were sent to the scene when the call came in at 5.00am on Wednesday morning.
The cruise company has also launched its own investigation.
It said there had been "no cases of acute gastroenteritis" reported in the last two weeks on board its ship, the MSC Preziosa.
A Gatwick Airport spokesperson said: "In keeping with health and safety procedures, the relevant authorities were informed and an assessment was taken on board."