When I started testing for virus about 9 years ago, the infection rate I found at the big box stores, and at several large greenhouses here in the US, was slightly more than 60%. The last time I checked a bunch of phals, the infection rate was down to about 30%, at least for ORSV and CymMV. I spent several thousand dollars cleaning up my collection and I maintain a strict barrier strategy. Everything coming in gets tested and all new plants are repotted and remain in isolation for several months. The good news for paphs is that I have found only one infected plant in all these years and it came from a grower who has primarily phals. I also put in my own displays at shows and avoid mixing my plants with plants from other growers. I must assume that all other plants are potentially contaminated. I know it sounds extreme, but I remember very well the feeling of throwing away dozens of favorite plants. I don't want to do it again.
I'm not interested in discussing the specificity of the various testing techniques, modes of transmission, or whether or not viruses are even harmful. Everyone has an opinion, but I have paid dearly for mine. Mike