A sergeant of the Kolkata trafficpolice has tested positive for COVID-19 and is currently undergoing treatment at a private hospital here, sources said.The sergeant, posted at Jorabagan traffic guard here, was taken to MR Bangur Hospital and then moved to a private facility, after he showed symptoms of COVID-19, the police sources said.The traffic police department is trying to trace all officers who came in touch with him, a senior officer said."Once they are traced, we will conduct swab tests on them and, if required, place them under home quarantine," the officer said.Last month, too, a few senior officers of the Kolkata Police were diagnosed with COVID-19.West Bengal has so far reported 1,259 coronavirus cases.