P. vannamei shrimp were collected from a shrimp farm that was experiencing massive death within 35 days after stocking in Prachuap Khiri Khan province on the western coast of the gulf of Thailand.
Approximately 30 live shrimp from the affected ponds were transported to the laboratory in plastic containers with proper aeration and they were temporarily reared indoors using 48 × 70 × 41 cm plastic tanks.
Upon arrival at the laboratory, some live shrimp were immediately fixed in Davidson's fixative ( Bell and Lightner, 1988) and processed for histological examination of the hepatopancreas for the characteristic histological signs of AHPND.