(CNN) A couple from Japan tested positive for novel coronavirus shortly after visiting Hawaii this month, and Delta Airlines says it is notifying passengers who were on their flight home about the couple's diagnosis.

Hawaiian officials, meanwhile, say they've been looking into the couple's activities in Hawaii, and are trying to find people who may have been in close contact with the couple.

The man and woman were on Maui from January 28 to February 3, and then on Oahu from February 3 until their Delta flight home on February 6 to Nagoya, Japan, Hawaiian health officials say.

"We are proactively reaching out to customers who were onboard that flight as well as taking the necessary steps to ensure the safety of our customers and crew," Delta said Monday.

That roughly 10-hour flight, Delta Flight 611 , departed Honolulu on the afternoon of February 6 and, after crossing over the International Date Line, landed in Nagoya on the evening of February 7.

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