FIG 7.

Microphotographs of L. vannamei hepatopancreases (HPs) in the acute (a to d) and terminal (e to h) stage of AHPND. (a and b) Hepatopancreas from a shrimp challenged with strain M09-05 at 3 h p.i., showing a general disorganization of the tubules due the epithelium necrosis; the lumen is full of dead cells produced by the epithelium desquamation. (b) Magnification of panel a. Epithelium desquamation and hemocytic infiltration were observed (arrowhead). (c) Hepatopancreas from a shrimp challenged with strain M08-01 at 10 h p.i., showing hemocytic infiltration (arrowhead) and reduction of R and B vacuole cells (arrow). (d) At 16 h p.i. with the same strain, the HP had a larger hemocytic infiltration (arrowhead) and accumulations of necrotic cells inside the tubular lumen (arrow). (e and f) Hepatopancreas from a shrimp challenged with strain M06-06 at 24 h p.i., with severe hemocytic infiltration (arrowhead), epithelium necrosis, deposits of melanin inside the tubular lumen, and bacterial masses (arrow). (g) Hepatopancreas from a shrimp challenged with strain M09-05 at 28 h p.i., with the largest melanization of necrotic tissue inside the tubular lumen (arrow). (h) Hepatopancreas from a shrimp challenged with strain M06-05 at 41 h p.i., showing necrotic tubules without epithelium (arrow) and tubules with hemocytic capsules (arrowhead). Hematoxylin and eosin staining was used. Microphotographs by S. Abad.