I've never seen signs of virus in Angraecum, but it's entirely possible. Usually virus shows up in plants that are divided many times over the years, primarily cattleyas and cymbidiums but also things like masdevallias, odontoglossum, spathoglottis, miltonia, dendrobium, laelia, epidendrum and phalaenopsis. Viruses are most likely spreadable to all orchids, but some are more likely than others. It is most commonly caused by using non-sterilized cutting tools, but also by insects.
It manifests as color break in the flowers and necrosis of the leaves. There are several different viruses and they have different symptoms. Some are more severe than others.
Isolate any suspicious plant so the virus doesn't spread...
