An 18-year-old, who recently returned from England, tested positive for the novel coronavirus on Tuesday making it the first case in the state.
The man was admitted to Beleghata ID Hospital after he showed symptoms of Covid-19, NDTV reported.
Doctors say the young man is in stable condition. He was apparently asymptomatic and not detected during screening at the Kolkata Airport when he arrived on March 15.
It was only after his friends in England told him over phone that three people with whom he had attended a party had tested positive for COVID-19, he admitted himself to Kolkata's state-run Infectious Diseases Hospital.
According to some reports, the teenager's parents and driver may also be quarantined separately but this could not be independently confirmed.
"As of today total 74,978 travellers/persons have been screened at Kolkata and Bagdogra Airports and 280,362 persons have been screened at seven Land Border Check Points along Nepal and Bangladesh. Also 3,989 crew members of ships have been screened in three ports. Till date 12,244 travellers from Covid-19 affected countries have been identified and placed under surveillance," an official release from West Bengal's health department said.
"Eighteen are admitted in isolation facility and rest 11,978 are under home surveillance till date", it said.
However, a 64-year-old man died in Mumbai on Tuesday, taking the number of coronavirus-linked deaths in the country to three.
As the total number of infected people in India reached 137 so far, according to the Ministry of Health and Family Welfare. Maharashtra is still the state which has the highest number of patients - the figure is still 39.
The Indian government has stopped incoming travel from a number of nations, including the European Union, Malaysia, Philippines and Afghanistan.