FIGURE 1.

Gross pathology and histopathological observation in crayfish muscle. (A) Muscle gross lesions of crayfish after infection. Color is cloudy and dull (white arrow), and adhesion is strong (black arrow). (B) Pathological changes in crayfish muscle. (A’) Healthy hepatopancreatic histological characteristics; (B’) Myofibers degenerated and became indistinct, and tissues were sparse (black arrow); (C’) Muscle fibers were wavy (dotted box); (D’) Muscle bundles were dissolved and necrotic, and formed part of the cavity (red pentagram). (C) Muscle health status (organ index) of crayfish infected by C. freundii in different groups. *P < 0.05 represents a significant difference between the infected group (green bar) and the control group (red bars).