The new Omicron variant is believed to be behind the spate of Covid-19 infections which forced a Portuguese football team to field just nine men in a match – with a player who had returned to South Africa linked to the outbreak.
An announcement from the Directorate-General for Health (DGS) early on Monday has indicated that the first 13 cases of the newly-emerged strain of Covid-19 recorded in Portugal are all believed to be players from Primera Liga outfit Belenenses, who drew international headlines at the weekend after their match at home to league leaders Benfica was abandoned after half-time.
A Covid infection within the camp led to them starting the game with just nine men and emerging for the second half with seven players.
The game was called off when they went down to six players after a goalkeeper playing in an outfield position was injured while Benfica led 7-0 – scenes which were described as a "dark chapter for Portuguese football and the country itself".
An analysis of the cases by the National Institute of Health says that the samples "associated with cases of infection of Belenenses SAD players, given that one of the positive cases will have had a recent trip to South Africa," according to local media.
The strain, which scientists fear might be the most transmissible yet, was first discovered in southern Africa and has prompted various governments to impose travel restrictions on several countries in the region.
Belenenses' South African defender Thibang Phete had recently returned from his home country.
According to the DGS, the initial tests makes it likely that "all 13 cases associated with Belenenses SAD players are related to the Omicron variant."
The country's health chiefs have subsequently announced mandatory isolation rules for anyone who may have come into even brief contact with a suspected Omicron case, regardless of a person's vaccination status.
Primera Liga bosses, meanwhile, have announced that they will launch an investigation into the circumstances surrounding the chaotic fixture between Belenenses and Benfica after both teams had petitioned league authorities to postpone the fixture.
Other teams, such as rival side Sporting Lisbon, have said that the fixture going ahead despite Belenenses being unable to field a full complement of players undermined the league system as a whole.
The DGS does not consider the Benfica players 'risky contacts' but intends to test them, according to the report.
An emergency league meeting about the game is also said to be scheduled for Monday, as well as urgent talks with health authorities to clarify protocols.