— Five more North Carolina residents have tested positive for the new coronavirus, public health officials said Monday, bringing the state total of presumptive positive cases to seven.

All five attended a conference biotech firm Biogen held in Boston last month, officials said. The N.C. Department of Health and Human Services is tracking the number of North Carolina patients online.

Biogen held a corporate meeting in Boston on Feb. 24-27, and a number of attendees later reported flu-like symptoms, according to NBC Boston. Thirty-two of Massachusetts' 41 confirmed cases of coronavirus have been linked to that meeting.

Biogen has asked all office workers and contractors in Research Triangle Park, Massachusetts and Switzerland to work from home for the foreseeable future.

"We recognize that this is a difficult situation for our colleagues and their loved ones. We are actively working with all relevant departments of public health and hospitals to prioritize the well-being of the people who may have been exposed to COVID-19," the company said in a statement.

All five North Carolina residents are in isolation in their Wake County homes, officials said.

Earlier Monday, officials said they had been notified by Indiana public health officials that an Indiana resident who tested positive for coronavirus was in Wake and Durham counties last week while showing symptoms of the COVID-19 illness.

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The person, who was in the Triangle March 2-6, tested positive on Sunday and is now in isolation at home in Indiana.

The person flew into Raleigh-Durham International Airport on March 1 and began showing symptoms of an upper respiratory infection the following day while working at Biogen's RTP offices. The person then drove home to Indiana on Friday.

Public health officials in Wake and Durham counties are now trying to identify close contacts all of the infected individuals had last week. They can then assess the risks of exposure and determine whether anyone needs to be tested or quarantined.

Meanwhile, Mecklenburg County health officials also confirmed Monday that a South Carolina man with a presumptive positive coronavirus test returned from Italy on a flight that landed at Charlotte Douglas International Airport.

The man, who is one of six presumptive positive cases in South Carolina, was not displaying symptoms when he flew into Charlotte, according to the South Carolina Department of Health and Environmental Control. He is not hospitalized and is isolated at home in Spartanburg.

Before Monday, North Carolina had only two presumed cases of COVID-19. Both are isolated at home – one in Wake County and one in Chatham County – and are "doing well," according to state officials.

Those who have come into contact with the men have been notified to watch for symptoms including fever, cough and difficulty breathing.

As of Monday, there were 113,579 cases of the virus worldwide, with more than 80,000 in China and about 600 in the United States.

Almost 4,000 people have died of the coronavirus strain, more than 3,000 of them in China, where the outbreak began in December.