As said, the only way to know if there is a virus is to test for a virus and, I have heard it recommended by those who do testing as a career, to always do at least two tests to prevent false results.
I do not see signs of virus and, because I do not know the history, I cannot say exactly what the cause is (injury, Calcium deficiency, temperatures, fungus/bacterial....).
Here is a good guide, with pictures, to help with orchid issues:
https://staugorchidsociety.org/PDF/O...ySueBottom.pdf