The Navy is preparing to send an aircraft carrier to sea after a coronavirus scare among its crew, the service’s latest challenge in dealing with a disease that has crippled another aircraft carrier now at port in Guam.

The USS Nimitz began embarking sailors at the beginning of April in an effort to segregate them from the general population, but a sailor was removed from the ship and put in isolation after showing influenza-like symptoms, according to four people familiar with the issue.

The sailor was tested for the virus at least twice, with inconclusive results, said a defense official, who like others spoke on the condition of anonymity because of the sensitivity of the issue. It is still not clear whether that sailor had the virus.

“A sailor displayed symptoms, was placed into isolation off the ship out of an abundance of caution, and subsequently had testing that was inconclusive,” said the spokesman, Cmdr. John Fage. “Sailors that had been in close contact with the individual were also removed from the ship as a precaution and placed into quarantine. That sailor remains off the ship.”

Fage said the crew of the Nimitz “has been and will continue to conduct increased cleaning stations” that follow guidance from the Centers for Disease Control and Prevention. The crew also has minimized group gatherings to the maximum extent possible, he said.

The situation on the Nimitz comes amid a political firestorm involving the USS Theodore Roosevelt, where 286 sailors had tested positive for the virus as of Wednesday.

On Tuesday, the acting Navy secretary, Thomas Modly, resigned after creating an uproar by insulting the ship’s former commander, Capt. Brett Crozier, while visiting Guam to speak to the crew. Modly, who removed Crozier from his position last week, told the sailors that the captain either had deliberately leaked a letter raising concerns about the Navy’s care for his crew, or was “too naive or too stupid” to be in charge.

Modly apologized for insulting Crozier, who has also tested positive for the virus, but insisted that the captain had written the letter with the intention of it being leaked. Several Democratic lawmakers and the families of some crew members had called for Modly to step down.

The Nimitz, which typically sails with about 4,800 personnel, relied on temperature checks and screenings that included asking some, but not all, sailors whether they felt ill, said the father of one sailor who has been in regular contact with his son. The sailors were not tested for the virus before embarking, he said.

“I think he’s pretty worried. He feels like they’re not taking it serious,” the father said. “It’s how the chiefs are handling it, and the fact that there are cases on board and they’re still thinking of pulling out.”

Crew members have been using T-shirts to make face masks, the father said. Discussions about the coronavirus have come up aboard the ship, sometimes while sailors are crowded together, he added.

The issue on the Nimitz, first reported by Politico on Tuesday, surfaced as the ship prepares for at-sea trials this month that will last weeks. The carrier’s crew plans to deploy to the Pacific this summer from its home port in Bremerton, Wash.

The USS Ronald Reagan, under maintenance in Japan, and the USS Carl Vinson, under maintenance in Bremerton, have also reported cases of the coronavirus among their crews. The Reagan typically deploys each summer as a “forward-deployed” vessel.

The Navy has documented 513 coronavirus cases among its personnel as of Wednesday morning, according to Pentagon statistics, while the Army has recorded 470 cases. The Air Force has 351 cases, and the Marine Corps has 140.

This story was updated with new information from the Navy.

Missy Ryan contributed to this report.