FIG. 2.

CNGV induces gill inflammation as early as 2 dpi. Carp were infected with CNGV and harvested on the indicated dpi. Gills were collected and submitted for histological analyses. (A to C) Gill filaments. Normally, gill filaments are slender structures containing numerous lamellae (A). As early as 2 dpi, many lamellae are infiltrated by inflammatory cells (B). At 6 dpi (C) and onwards, all lamellae are heavily infiltrated. (D to F) Gill rakers. As early as 2 dpi (E), an increased inflammatory infiltrate is present in the subepithelial zone. In addition, at the bottom of the photomicrograph a congested vessel in the gill arch is seen. At 6 dpi (F), the inflammatory process is more pronounced, with sloughing of the overlying epithelium (upper right). This is accompanied by increased congestion and edema. All the sections were stained with hematoxylin and eosin. Bars, 200 μm.