Houston, Dec 18 : Houston Mayor Sylvester Turner announced that he has tested positive for Covid-19 amid the spreading of the Omicron variant across the US. In a series of tweets late Friday night, he said: "This afternoon, I learned that I tested positive for the virus that causes Covid-19. I was not feeling well overnight and thought I was suffering from allergies or a sinus infection, so I decided to get tested before starting my daily schedule. "Before and after getting my test results, I cancelled all events for today and the weekend. My symptoms are mild, and I will spend the next several days isolating myself at home and getting some rest. " Houston is currently witnessing early signs of a new Covid wave, fuelled in part by the fast-spreading Omicron variant, as public health officials warn of a nationwide spike in cases as early as next month, Xinhua news agency quoted a report by the Houston Chronicle newspaper. The daily average of positive cases in the Texas Medical Center more than tripled last week, from 232 to 721, and Houston Methodist on Tuesday recorded nearly five times the number of positive cases in its system compared to the previous week, said the report. "We're going to have a wave. I don't doubt it at all," said Rodrigo Hasbun, professor of infectious diseases with McGovern Medical School at UTHealth Houston. "It's just the magnitude of it and the duration that's in question." Omicron has been detected in all but 17 US states. In Houston, there are signs that Omicron could usurp Delta, the country's most dominant strain nowadays, in a matter of weeks, according to the report. /IANS