Aug 28, 2007, 17:34 GMT
Erlangen, Germany - The outbreak of bird flu found on a duck farm near the southern German city of Erlangen last week was probably more widespread and of longer duration than first thought, veterinary officials said Tuesday.
Examination of birds destroyed to contain the outbreak revealed that ducks from two other enclosures other than the one where the outbreak was first found had been infected, Ottmar Fick, head of the local veterinary authority said.
Fick noted, however, that it was unclear whether these birds had also been infected with the H5N1 virus, which is potentially deadly to humans.
He added that it was possible that the H5N1 virus had been present for some time on the farm but that the symptoms had shown only in one of the 15 enclosures.
Experts are still trying to find out where the virus originated. Earlier reports said it might have been transferred in straw.
Not all waterfowl suffered acute symptoms from the virus, and the incubation period could drag on over weeks, Fick said.
He added that it was not clear whether infected birds had been offered for sale commercially. 'We cannot exclude delivery,' Fick said.
Following the discovery on Friday, all 166,000 ducks and ducklings on the farm were destroyed.
The H5N1 strain of avian influenza is fatal to humans but cannot be transferred between humans. It has hit wild water-birds and some domestic poultry in other parts of Germany this year.
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