Pathogenesis is a term used to describe how the virus causes disease in the animal.
Virus enters body via mucous membranes of the eye and nose. Bone marrow stem cells are infected and there i s extensive viral multiplication in neutrophil and platelet precursors. Virus spreads to and replicates in salivary glands, respiratory epithelium, pharyngeal mucosa, cell marrow elements, the pancreas and intestinal epithelial cells. This is the most likely scenario. Mild illness such as fever, poor appetite, lethargy and swollen lymph nodes may occur 3-10 days post infection.