LISBON, Portugal—Portuguese health authorities on Monday identified 13 cases of omicron, the new coronavirus variant spreading fast globally, among members of a top soccer club and were investigating whether it was one of the first reported cases of local transmission of the virus outside of southern Africa. The Ricardo Jorge National Health Institute said that one of those who tested positive was a player from the Lisbon-based Belenenses SAD soccer club who had recently traveled to South Africa, where the omicron variant was first identified. The others had not reportedly traveled to southern Africa, where most of the cases have been recorded so far. Those who have been in contact with the positive cases have been ordered to isolate, regardless of their vaccination status or their exposure to possible contagion, and will be regularly tested for COVID-19, the institute said. Portugal’s health general director, Graça Freitas, said that the players …