Houston, Dec 8 (IANS): The Omicron variant of Covid-19 has been found in wastewater in Houston, the largest city in the south central US state of Texas, confirming the local spread of the new strain, city officials said on Tuesday.

The city has detected the Omicron variant in eight of its 39 wastewater treatment plants, according to multiple local media outlets.

A woman in her 40s living in Harris County, which covers much of Houston, was identified on Monday as Texas' first case of the Omicron Covid variant, according to Texas Department of State Health Services, Xinhua news agency reported.

The woman was fully vaccinated and did not report any recent travel history, local media reported.

The first Covid Omicron variant case in Chicago was identified in someone who had contact with an individual who had traveled to the city and tested positive for Omicron in another state, Chicago Tribune reported Tuesday, adding that the person was fully vaccinated with a booster dose and is not hospitalised.

First reported in South Africa on November 24, Omicron has been listed as a "variant of concern" by the World Health Organisation.