When working up a downer cow suspected of having BSE, blood samples are taken to...

When working up a downer cow suspected of having BSE, blood samples are taken to...

• A. Evaluate antibody titers to BSE
• B. Rule out/rule in other diseases
• C. Determine alkaline phosphatase levels to support a diagnosis of BSE
• D. Evaluate antibody titers to rabies

Answer: (B)

When a downer cow is suspected of BSE, blood testing is used to sort out other diseases that could cause the same signs rather than to confirm BSE itself. BSE is a prion disease, and there isn’t a reliable ante-mortem blood test to diagnose it. In fact, cattle don’t mount a measurable antibody response to BSE that would make serology useful. Definitive diagnosis relies on examination of brain tissue after necropsy (using immunohistochemistry, Western blot, or related methods). So the purpose of the blood work is to rule in or rule out other conditions that could explain the cow’s illness, not to confirm BSE. Tests for BSE antibodies aren’t helpful, and markers like alkaline phosphatase would not support a BSE diagnosis. Rabies antibody testing is not relevant to evaluating BSE.

When a downer cow is suspected of BSE, blood testing is used to sort out other diseases that could cause the same signs rather than to confirm BSE itself. BSE is a prion disease, and there isn’t a reliable ante-mortem blood test to diagnose it. In fact, cattle don’t mount a measurable antibody response to BSE that would make serology useful. Definitive diagnosis relies on examination of brain tissue after necropsy (using immunohistochemistry, Western blot, or related methods).

So the purpose of the blood work is to rule in or rule out other conditions that could explain the cow’s illness, not to confirm BSE. Tests for BSE antibodies aren’t helpful, and markers like alkaline phosphatase would not support a BSE diagnosis. Rabies antibody testing is not relevant to evaluating BSE.