Skane University hospital told the BBC that Ebola was "not a likely diagnosis". The patient had come into the hospital with symptoms of fever.
Maria Josephsson, head of Skane's infectious diseases department, said tests were being carried out because of where the patient had been staying.
An ongoing Ebola outbreak in DR Congo has claimed more than 2,100 lives.
Another case was confirmed in Uganda earlier this year.
On Tuesday Ms Josephsson told the BBC: "The patient is kept in isolation. We don´t know the exact time for the test results."
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Standard procedures were being followed and Ebola could not be ruled out until there was a negative result, she said.