A serum test now available at Utah State University can be used to detect a common viral infection in Utah range sheep that can lead to serious respiratory problems.

Ovine Progressive Pneumonia (OPP) is a chronic, slow viral infection of sheep, said Clell V. Bagley, USU Extension veterinarian.The virus causes both progressive pneumonia, or lungers, as well as hardbag, also called large udders, no milk, or no mastitis.

He said both hardbag and OPP are common in some Utah range flocks. The only control method available has been culling those with clinical signs.

The virus is widespread throughout the state, with range flocks in northern Utah and southern Idaho showing a fairly high percentage of the virus, he said.

Animals that suffer from the virus infection have a difficult time breathing. The animal's health becomes progressively worse, accompanied by weight loss, despite eating well.

He said diagnosing the animal as suffering from progressive pneumonia is really a misnomer.

"The lungs turn to meat instead of air sacs," he said. "The sheep can't exchange enough air. Its lungs become very fibrous."

The serological test now available to sheep ranchers can be used to detect animals which have been exposed to the virus, he said.

The test is proposed as a means to eradicate the virus from infected flocks by testing and culling.

"Those using the test must be aware there is usually a high rate of positive animals on the initial test," he said. "Repeated testing is essential and procedures must be instituted to guard against re-infection."

The OPP test is available through the USU Diagnostic Laboratory in Logan. The fee is $5 per sample. One milliliter of good serum is needed, he said.

For more information, contact your county USU Extension agent.