If confirmed, this would be the first case of bird flu in humans in the Scandinavian country, the Danish news agency Ritzau reported.
On the basis of blood tests in the local hospital of Nykoebing, southern Denmark, the man was diagnosed with bird flu, and was on Friday urgently transferred to the Royal hospital, one of two hospitals in Denmark authorised to treat bird flu patients.
Ritzau said it is unknown where the man may have contracted the virus.
The H5N1 strain of bird flu, its most aggressive form, has killed more than 100 people worldwide, according to the World
Health Organisation (WHO).