For LM, a mid-sagittal cut was performed on infected shrimp which were then fixed in Davidsons’ seawater fixative for 24 h, processed routinely for histology, sectioned at 5 lm and stained with haemotoxylin and eosin (H&E), Giemsa, and Chromotrope 2R modified trichrome (Weber et al., 1992). For TEM, small pieces (2 mm3) of hepatopancreatic tissue from the same shrimp specimens were fixed in 2.5%