Transboundary Emerging and Exotic Animal Disease/ Exotic Animal Disease Practice Exam

Which of the following is a pathognomonic clinical sign for classical swine fever?

1. Vesicles and ulcers

2. Fever

3. Reddened Skin

4. None of the above

The correct answer is: None of the above

In the context of classical swine fever (CSF), it's essential to identify what constitutes a pathognomonic sign. A pathognomonic sign is a specific clinical sign that is characteristic of a particular disease and can be used to confirm its diagnosis. Although fever and reddened skin are commonly observed in cases of classical swine fever, they are not unique to this disease and can occur with various other conditions that affect swine. Fever, for instance, is a general sign of infection or inflammation, and reddened skin can also be present in other diseases such as porcine dermatitis or other infectious processes. On the other hand, vesicles and ulcers are more specifically associated with other swine diseases, such as foot-and-mouth disease (FMD). These lesions would not be considered pathognomonic for CSF as they do not typically occur in this disease. Therefore, none of the options provided accurately represent a pathognomonic clinical sign for classical swine fever, which confirms that selecting "None of the above" is reasonable given that no distinct clinical sign uniquely identifies CSF in swine.