A New Jersey medical worker who was the Garden State’s first coronavirus patient says every day his health is “getting worse” — and warned others to take the bug more seriously, especially since he has none of the underlying conditions that officials have warned about.

James Cai, a 32-year-old physician’s assistant, said he thinks he caught the bug while attending a medical conference last weekend at a Times Square hotel, news station WCBS reported.

“It happened so quick,” Cai told the outlet. “The virus is everything. Diarrhea, watery eyes, shortness of breath, chest pain, you name it. High fever. … Every day is getting worse.”

Cai said he first visited an urgent-care clinic, then went to the emergency room at Hackensack University Medical Center, where he’s remained since Tuesday, according to the outlet.

“People have to take the coronavirus seriously. It’s very serious,” Cai told CBS.

Mayor Bill de Blasio said Sunday that a New Jersey health care provider with Covid-19, matching Cai’s description, had visited a Westin hotel in Midtown and the King David Center nursing and rehab facility in Gravesend, Brooklyn, where the worker saw 11 patients. The worker was wearing a mask at the time, the mayor said.

King David confirmed to The Post on Monday that Cai was the worker.

Cai told WCBS he doesn’t agree with some health officials’ advice that face masks are unnecessary.

“A lot of people say, ‘It’s OK, don’t wear masks.’ I don’t believe that,” Cai said.

New Jersey Gov. Phil Murphy announced Cai’s case Wednesday, saying, “We take this situation very seriously and have been preparing for this for weeks.”

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There have since been five other cases reported in the Garden State as more than 550 people have become infected across the county, CNN reported.

Additional reporting by Reuven Fenton