FREDERICK, Md. (AP) -- An Army scientist who contracted a potentially deadly infection while working in a germ warfare defense laboratory broke a safety rule by failing to report his symptoms while continuing to work for six weeks, a spokesman said Monday.

The unidentified, 33-year-old civilian microbiologist is expected to recover from glanders, which he contracted while working on a vaccine to shield troops from the disease, Fort Detrick spokesman Charles Dasey said.

Dasey said it wasn't clear how the man contracted glanders, a bacterial infection typically found in horses that is usually fatal in humans if left untreated.

Lab rules require employees working with infectious materials who develop fevers greater than 100.5 degrees to report for medical evaluation after attempting to notify their supervisor.

The scientist developed symptoms in mid-March, including a fever he later estimated at 102 to 103 degrees, said Dr. Anusha Belani, an infectious disease specialist at Frederick Memorial Hospital.

He was treated with antibiotics but the fever returned, she said. He was referred to her in mid-April with symptoms that worsened to include painful liver and spleen abscesses and respiratory distress, she said.

Belani admitted the scientist to the hospital on May 2. That was when people at Fort Detrick began suspecting glanders.

''Once he came forward and told his supervisor he was sick and going to the hospital, then the people in his lab started to look at what was wrong with him and they started thinking about whether this was related to his work,'' Dasey said.

Dasey said a fever that high should have been reported under lab rules, but ''I don't think anybody here is thinking about penalizing the employee right now.''