Fig. 1 Digital images of fluorescent IPNV. (a) IPNV mounted on a membrane filter and labeled with mAb, total PP per filter was 3.6 [± SE 0.34] x 10⁷, (b) IPNV processed digital image corresponding to the image in (a), (c) IPNV mounted on a membrane filter and labeled with SYBR-Green I, total PP per filter was 0.98 [± SE 0.15] x 10⁷ and (d) IPNV processed digital image corresponding to the image in (c). Scale bars: 10 μm.