Have my Phal's caught a virus/disease?

[Kratos]

Have my Phal's caught a virus/disease?


This is a new experience for me so hope someone could help. These are the only ones affected although all my orchids are looked after in identical ways...

Two leaves have already gone completely, yellowed and fallen off, but what ever is going on seems to be working its way up the plant, oldest leaf first... I get leaf drop happens with age, but even to me this seems excessive and there is no sign of new growth to replace what's going.

The orchid with the white flowers and yellow lip, is branching left right and center so thought perhaps it was under stress, but the other affected plant has no buds/spikes in development at all. Very strange...

(Sorry for the poor picture quality, my main camera is out of action)