Fig. 1

Clinical signs of DIV1-infected shrimp a. Penaeus vannamei infected with DIV1 showed symptoms of empty stomach and gut, and pale hepatopancreas; b. Some dead Penaeus vannamei and P. monodon showed clinical signs of black spots on the abdominal carapace (black arrows)[23]; c. Exopalaemon carinicauda infected with DIV1 showed clinical signs of empty stomach and gut, pale hepatopancreas and slightly turbid white hematopoietic tissue(ST. Stomach; HP. Hepatopancreas; MG. Midgut; HM. Hematopoietic tissue)[6]; d. Symptoms of diseased Macrobrachium rosenbergii (blue arrows indicate "white head" and white arrows indicate a pale hepatopancreas)[5]; e. P. monodon infected with DIV1 by intramuscular injection show obvious clinical signs of black body[23]"

Fig. 2

Histopathological characterization of DIV1 infected shrimp, HE staining[5] a. Lymphoid organs; b. Hematopoietic tissues; c. Epithelium; d. Hemocytes in the hepatopancreatic sinus. Black arrows. Karyopyknosis; White arrows. Eosinophilic inclusions"

Fig. 3

TEM of hematopoietic tissue of naturally infected M. rosenbergii samples[5] a. Large numbers of virions in hematopoietic tissue; b. DIV1 budded and acquired an envelope from the plasma membrane; c. DIV1 replication and assembly in hematopoietic cells; d. The stages of nucleocapsid assembly, which are indicated with numbers 1-3, and a complete nucleocapsid is indicated with number 4. The capsids at stage 2 and 3 should have a small opening at one vertex but may not be visible in the picture due to the ultrathin section. N. Nucleus; *. A large electron-lucent virogenic stroma; White arrows. Paracrystalline array of viral particles; Black arrows. Budding virions; White triangles. Budded virions that acquired an envelope"

Table 1

Comparison of various DIV1 detection methods"