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

What causes hemorrhages seen in the skin of animals infected with CSF and other diseases?

1. Virulence factors acting on bone marrow

2. Damage to the liver

3. Toxins exerting effects on platelets

4. Infection and secretion of cytokines damaging endothelial cells

The correct answer is: Infection and secretion of cytokines damaging endothelial cells

The answer is based on the understanding that the hemorrhages observed in the skin of animals infected with Classical Swine Fever (CSF) and similar diseases are primarily due to the infection's impact on the vascular system. When animals are infected with certain viruses, such as those causing CSF, there is an immune response that includes the secretion of cytokines. These cytokines play a significant role in regulating various immune functions, but in the context of an infection, they can also contribute to inflammation and damage to endothelial cells. Endothelial cells line the blood vessels, and when they are damaged, it can lead to increased permeability of the vascular system as well as a disruption of normal hemostasis (the process that prevents and stops bleeding). This damage can trigger coagulation cascades, leading to either localized or widespread hemorrhages in the skin and other tissues. Therefore, the cytokine-induced damage to endothelial cells is a direct cause of the hemorrhages seen in diseased animals, making this the correct explanation for the observed symptoms in CSF infections and related conditions.