Figure 1

Histology in AGD-affected gills at 0 dpi, (A) 4 dpi, (B,C) 7 dpi, (D) 14 dpi, (E) and 16 dpi (F) in AGD-affected gill tissue. Normal gill naïve control fish showing individual gill filaments with lamellae (A). Some small areas of mild epithelial hyperplasia is evident at 4 dpi, indicated by arrows, (B), also shown at a higher magnification (C). More extensive hyperplasia and lamellar fusion, indicative of AGD, can be seen at 7dpi (D) and is indicated by asterisks. The increasing hyperplasia, lamellar fusion (asterisks) with the formation of lamellar vesicles (arrowhead) is evident at 14 dpi (E). At 16 dpi (F) there is extensive lamellae fusion in adjoining gill filaments (asterisks). Slides were stained with H&E and the scale is indicated on each image.