We do not see symptoms of a virus. Epimedium can contract Tobacco Rattle Virus, but the symptoms are quite different; you can search for images of examples online using the virus name along with the plant name. The purple coloration here could be a sign of stress (too much sun, nutrient deficiency, drought, or too much water) and is likely temporary. As to the dried leaves, they could be dieback from root loss if the patch is getting too dry between rain storms and if tree roots are in the area competing for moisture. You can check the base of the stems on the sections with dried leaves and see if any apparent fungal growth is evident on the soil surface. If so, please send us a photo for assessment. If not, check the planting bed for moisture by feeling the soil about a finger's depth or trowel's depth down and soak the area as needed. Although Epimedium is generally quite tolerant of drought and root competition, our recent excessively-hot and mostly-dry weather has been stressing plants.

Miri