TORONTO, Nov 28 (Reuters) - Two cases of the Omicron variant of the coronavirus, first detected in Southern Africa last week, have been confirmed in Canada, provincial health officials said on Sunday. The cases were reported in two people who recently travelled to Nigeria, the Ontario government said in a statement.The detection of Omicron has triggered global alarm as governments around the world scramble to impose new travel restrictions and markets sold off, fearing the variant could be resistant to vaccinations and upend a nascent economic reopening after a two-year global pandemic. On Friday, Canada closed its borders to foreign travelers who have recently been to seven Southern African nations in the preceding two weeks to help stop the spread of the newly identified variant of COVID-19. "Today, the province of Ontario has confirmed two cases of the Omicron variant of COVID-19 in Ottawa, both of which were reported in individuals with recent travel from Nigeria. Ottawa Public Health is conducting case and contact management and the patients are in isolation," the statement said. The World Health Organization (WHO) said it is not yet clear whether Omicron is more transmissible than other variants, or if it causes more severe disease. read more