Ducks in Pennsylvania found with a strain of bird flu

The U.S. Department of Agriculture has found bird flu in wild ducks in Crawford County in northwestern Pennsylvania as part of a routine sampling procedure, but the strain is apparently not the deadly H5N1 strain currently sweeping across Asia.

Officials are testing as many as 100,000 wild birds.

The mallards were not sick which is a good indication that they were not exposed to the virulent Asian H5N1 strain; such strains have been detected recently in Maryland and Michigan.

Experts say such low-grade strains of the virus are not uncommon in North American wild birds and pose no threat to humans.

Nevertheless the government is conducting additional tests to confirm whether it was the low-pathogenic H5N1 bird flu.

However they do expect the deadlier strain to reach U.S. shores some time this year.

The departments of Agriculture and Interior are working with states to collect between 75,000 and 100,000 wild bird samples in addition to more than 50,000 environmental tests throughout the United States.

The discovery of a highly pathogenic H5N1 strain in wild birds in the U.S. would invoke intensive monitoring and increased security measures to protect commercial poultry flocks from infection.

Since 2003, the deadly H5N1 Asian strain has killed 141 people and has been responsible for the death or destruction of millions of birds.

The virus remains a disease of birds and is caught by close contact with some aspect of infected birds.

Scientists remain fearful the virus will mutate into a form that is spread easily among humans, triggering a human pandemic.