Histopathology and cytopathology of white spot syndrome virus (WSSV) in cultured Penaeus monodon from peninsular Malaysia with emphasis on pathogenesis and the mechanism of white spot formation
Yg. Wang et al., Histopathology and cytopathology of white spot syndrome virus (WSSV) in cultured Penaeus monodon from peninsular Malaysia with emphasis on pathogenesis and the mechanism of white spot formation, DIS AQU ORG, 39(1), 1999, pp. 1-11
Since 1994, white spot syndrome virus (WSSV) has been detected in cultured
shrimp Penaeus monodon in Peninsular Malaysia. The gross signs, target orga
ns and histo-cytopathology for the viral infection were studied and it was
found to infect most organs and tissues including oocytes, but not hepatopa
ncreatocytes and epithelial cells of the midgut, which were regarded as ref
ractory tissues. Based on a time-sequence of ultrastructural cytopathology,
4 cytopathic profiles and 6 phases of viral morphogenesis were described.
The virions were elliptical to short rods with trilamilar envelopes that me
asured 305 +/- 30 x 127 +/- 11 nm. Viral nucleosomes were often present sin
gly in infected nuclei and were associated with the early stages of viral r
eplication. The structure of WSSV pathognomonic white, cuticular lesions wa
s examined at the microscopic and ultrastructural levels and the mechanism
of their formation appeared to be related to the disruption of exudate tran
sfer from epithelial cells to the cuticle via cuticular pore canals.