Attachment of WSSV-CN03 and -CN04 to the inner surface of shrimp digestive tract. Subadult L. vannamei were orally inoculated with WSSV-CN03, WSSV-CN04, or an equal volume of normal saline (negative control). The intact digestive tract of each shrimp was collected at 4 hpi, and the viral load in each tissue was analyzed via qPCR A. The columns represent the log base 10 of the mean WSSV copy numbers of 5 shrimp in each group, and the standard deviations were calculated. The data were subjected to independent-sample t test as indicated in figure using PASW Statistics 18 software. P values of ˂0.05 were considered statistically significant, and indicated with “*”. A small fragment of the midgut of each shrimp was cross-sectioned, and probed with an anti-VP28 antibody (green). The nucleus was stained with DAPI (blue). The inner surface of the midgut is facing upwards B. Bar 100 μm. The experiment was repeated three times and representative results from one experiment are shown.