Uncertainty hung over two international rugby tours to South Africa on Tuesday as a third wave of the coronavirus pandemic wreaked havoc.
A match between the Bulls and the British and Irish Lions in Pretoria on Saturday was postponed after four unidentified players and one official from the host franchise tested positive for Covid-19.
There are doubts whether Friday's Test between South Africa and Georgia in Johannesburg will go ahead following positive tests in both camps, according to a South African Rugby statement.
"These positive results are a setback and have underlined the danger of transmissibility of the Delta variant," said SA Rugby chief executive Jurie Roux.
"The Springboks' second Test against Georgia is now in serious doubt, but we will wait for the MAG (medical advisory group) to consider the data and we will make the final decision tomorrow (Wednesday).
"The priority is to maintain the integrity of the Test series and we will continue to focus on that."
Centre Francois Steyn, fly-half Handre Pollard, prop Francs Malherbe and lock Marvin Orie are the latest Springboks to contract the disease after another lock, Lood de Jager, tested positive on Monday.
Head coach Jacques Nienaber, five other management team members and a masseuse have also contracted the disease.
Georgia, who lost 40-9 to South Africa last Friday in the first of two Tests, have also been affected by the pandemic with four players testing positive.
South Africa wing Sibusiso Nkosi and prop Vincent Koch contracted the virus before the first international against Georgia while scrum-half Herschel Jantjies had a false positive result.
- Springboks' first outing -
It was the first outing for the world champions since defeating England 32-12 in the 2019 Rugby World Cup final in Japan on November 2, 2019.
Covid-19 has hit South Africa harder than any other major rugby nation with all 13 home and away internationals planned for last year cancelled.
The Lelos are in South Africa to help the Springboks prepare for a hugely anticipated three-Test series against the Lions, starting in Cape Town on July 24.
The tourists' match against Durban franchise the Sharks is set to go ahead on Wednesday, with the kick-off brought forward one hour to avoid a clash with the England against Denmark Euro 2020 semi-final in London.
With the Bulls match postponed, the tourists will have just two games in Cape Town against South Africa 'A' and the Stormers before the first Test, unless an alternate fixture is hastily arranged.
The Lions began the tour last Saturday by overwhelming the Johannesburg-based Lions 56-14 with Wales winger Josh Adams scoring four tries, all in the second half.
England flanker Tom Curry, who will make his debut for the Lions against the Sharks, expressed sympathy with local rugby players.
"For South African players a Lions tour is once every 12 years. It's a huge occasion for them, so massive, massive understanding for them," he said.
"It's not people's fault if they catch Covid, so huge understanding for them."
Johannesburg and Pretoria are situated in the Gauteng province, the epicentre of the third wave of coronavirus in the republic.
By late-Monday, there had been 2,075,409 recorded cases and 62,171 deaths in the African country most affected by the pandemic.