To combat a growing outbreak of COVID-19 on the carrier Theodore Roosevelt, the Navy has ordered the ship to pull into Guam and have the whole crew of 5,000-plus sailors tested for the novel coronavirus, the service’s acting secretary announced Thursday.

“We found several more cases,” Thomas Modly said in a news conference. "We are in the process of testing 100 percent of the crew of that ship.

“The ship is operationally capable if called upon to do so,” he added, “but we are pulling the ship into Guam. Nobody from the ship will be allowed to leave the ship other than on the pier.”

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The sidelining of a deployed U.S. aircraft carrier to combat a COVID-19 is the most dramatic development to date in the military’s fighting to contain the spread of the virus. There have been 104 active duty cases documented in the Navy, which Modly characterized as trending higher.

The Wall Street Journal reported Wednesday that eight sailors on Roosevelt have tested positive for COVID-19, up from three announced on Tuesday.

The sailors who have been flown off are in quarantine on Guam and still are only showing mild symptoms, Modly said.

“The sailors flown off the ship are doing fine, none of them have been required to be hospitalized,” he said. “Their symptoms are aches and pains, sore throats but nothing that required hospitalization. So they are in quarantine on Guam.”

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The Roosevelt was last in port in Da Nang, Vietnam, 15 days before the first infections were detected, Chief of Naval Operations Adm. Michael Gilday said during a Tuesday press conference. The decision to go forward with the port visit in early March was made when Vietnam had only 16 total cases, all isolated in the northern city of Hanoi, he said.

It is unknown yet how the sailors may have contracted the illness, noting that aircraft land on the ship regularly from outside the command, Gilday said, but that the Navy is trying to trace the sailors’ movements and isolate sailors they’ve been in contact with.

“Our medical team aboard USS Theodore Roosevelt is performing testing for the crew consistent with CDC guidelines, and we are working to increase the rate of testing as much as possible,” Gilday said in a statement released Thursday.

“Immediate priority will be symptomatic Sailors, those in close contact with Sailors who have tested positive already, and essential watch standers. We are isolating those who test positive. Testing will continue as necessary to ensure the health of the entire ship’s crew.”

Naval medical resources available in Guam will allow for more effective testing measures than would be available if the ship was at sea, Gilday added.

“We expect additional positive tests, and those Sailors who test positive will be transported to the U.S. Naval Hospital Guam for further evaluation and treatment as necessary.”

Gilday also announced the ship’s spaces would continue with ongoing deep cleaning procedures.

“We’re taking this day by day,” Gilday said.

“Our top two priorities are taking care of our people and maintaining mission readiness. Both of those go hand in glove.”