Two members of the England touring party in South Africa returned "unconfirmed positive tests" for COVID-19 since the first one-day international was postponed at the hotel where both teams are staying due to a virus outbreak.
No names were released by the England and Wales Cricket Board and they didn't mention whether the two members were players or officials.
It said that after an additional round of testing on players and officials prompted by the news that two staff members at the Cape Town hotel used by both teams for the series tested positive for COVID-19, the two positive tests came after a further round of testing.
Before further guidance from the medical staff, the players and management are now self-isolating in their offices, the ECB said.
After the first of three ODIs was already postponed to Friday after a South African player tested positive for COVID-19, the remainder of the tour is still in question.
The South African, who was also not called, is the third player from South Africa to test positive during the tour of England.
The news that the two hotel staff members tested positive initially caused a pause in the nearby town of Paarl at the start of Sunday's game.
With news concerning the two representatives of England's faction, it was later abandoned. The ECB stressed, however, that their tests were positive, "unconfirmed."
In a joint statement, the ECB and Cricket South Africa said that medical advice had been issued to cancel the match.
"A decision will be made on the remaining matches in the series once the findings of the tests have been independently ratified by medical experts," the two cricket bodies said.
"We regret that we are unable to play in today's ODI, but our main concern is the welfare of the players and support staff, and while we await the results of further tests, the medical advice from both teams was that this game should not take place," said Ashley Giles, managing director of England's men's cricket.
"Together with Cricket South Africa, we remain in constant dialogue and will continue to work closely with them to determine how best to move forward."
Before the three-game Twenty20 series, which went ahead and England won 3-0, two of the South African players who tested positive on the tour returned their positive samples.
Three ODIs are due to be played by the teams, but it is unclear whether they are going to go ahead now. On Thursday, England is due to return home.
Before they are reunited with their families before Christmas, all the England players and officials now face potential extra quarantine requirements.
At short notice, England's six-game limited-overs tour was arranged to fill holes in the schedules created by the coronavirus pandemic in both teams.
But it coincided with South Africa, once one of the world's worst-affected nations, seeing signs of a second virus surge.
To restrict travel for players and officials, all six games were to be played in Cape Town and nearby Paarl, but it's one of the regions in South Africa that is now seeing a rise in cases of viruses.