A Manhattan lawyer who was hospitalised suffering from coronavirus is in “severe condition” according to New York City health officials, as tests confirm his family have also tested positive.

On Wednesday, New York governor Andrew Cuomo announced that the man’s wife, son, daughter, and a neighbour in Westchester County have contracted the virus — none are thought to be in a serious condition. This takes the total number of cases in New York to six.

Authorities are rushing to contain the spread of coronavirus in both the state and the country’s largest city by tracking the movements of those they have identified. Governor Cuomo has appealed for calm but said that community spreading in New York City is inevitable.

“The real issue is how many people will get seriously ill. How many people, God forbid, could lose their lives,” said Governor Cuomo.

The New York Post identified the lawyer as Lawrence Garbuz of the firm Lewis & Garbuz, which he runs with his wife and where his son works as a paralegal.

The firm employs seven lawyers, specialises in family law and is located across the street from Grand Central Terminal on 42nd Street. Mr Garbuz and his wife commute to the office from their home in New Rochelle on Metro North Rail.

Initially hospitalised on Friday at Lawrence Hospital in Bronxville, Mr Garbuz was transferred to NewYork-Presbyterian Columbia University Medical Centre in Upper Manhattan on Monday when his condition worsened. He is being treated in the intensive care unit and is understood to have an underlying respiratory condition. The family is in quarantine at their home in Westchester.

Medical staff who cared for Mr Garbuz at Lawrence Hospital are also quarantined and await their test results. Employees at the firm are considered at risk, having spent a prolonged period of time in close proximity to Mr Garbuz.

New York City mayor Bill De Blasio told reporters that an intense search was underway to find anyone else who may have been in contact with the family. They will be informed as soon as a list has been compiled.

In response to the son’s diagnosis, Yeshiva University has cancelled all classes at its Washington Heights campus including both graduate courses and those at the boys’ high school. A second student who visited the law firm’s office has self-quarantined.

Mr Garbuz regularly attends the Young Israel Synagogue in New Rochelle, and those who attended services on 22 and 23 February have been told to self-isolate until 8 March.

The Garbuz’s daughter, who does not have symptoms, attends Salanter Akiba Riverdale Academy and High School in the Bronx, which along with two other schools has closed as a precautionary measure.

In addition, Mr Garbuz is believed to have travelled to Miami, where Florida officials are looking into his travel history while in the state.