Grossly normal M. rosenbergii at various life stages were obtained from six
individual culture or hatchery farms I–VI. in southern Taiwan. The juveniles and adults
collected from farms I to V weighed 2 to 40 g. Postlarvae and larvae with opaque
musculature syndrome were taken from farm VI. For the challenge experiments, the
larvae and postlarvae were collected from another hatchery. The challenge experiments
were performed at the Tung Kang Marine Laboratory of the Taiwan Fisheries Research
Institute in Ping Tung Prefecture southern Taiwan.. Before the challenge experiments,
samples of the larvae and postlarvae were tested by two-step WSBV diagnostic PCR Lo
et al., 1996b. to confirm that they were negative for WSBV. The postlarvae were
cultured in fresh water and the larvae were cultured in 25‰ brackish water.
Diseased P. monodon and M. rosenbergii were collected from culture farms in
southern Taiwan. The carapaces were removed and observed with a differential interfer-
ence microscope Axiovert 135, DIC Zeiss, Germany..