Which of the following is a pathognomonic (especially indicative) clinical sign for classical swine fever?

• A. Vesicles and ulcers
• B. Fever
• C. Reddened Skin
• D. None of the above

Answer: (D)

There is no single clinical sign that uniquely identifies classical swine fever. A sign would have to be pathognomonic, meaning it points to CSF alone, but CSF presents in a variety of ways and overlaps with other swine diseases. Vesicles and ulcers are more typical of other vesicular diseases like foot-and-mouth disease, so they aren’t specific to CSF. Fever and reddened skin are common in many swine illnesses and don’t distinguish CSF. Because none of the listed signs is uniquely diagnostic, the correct choice is that none of the above is a pathognomonic clinical sign. definitive CSF diagnosis relies on laboratory confirmation (virus detection or genome, antigen tests, or specific antibodies) rather than clinical signs alone.