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In this study, postlarvae of the fleshy shrimp Fenneropenaeus chinensis "Huanghai No. 2" (a new shrimp variety bred in China) were fed with white spot syndrome virus (WSSV)-toxic bait with amount of 25% of the total shrimp body weight and were evaluated WSSV loads at different postinfection periods (i.e. early, peak and late periods). A total of 83 of 4,424 shrimp (1.88%) survived at the end of the experiment, which lasted 358 h, 662 h, and 232 h in 3 ponds, respectively. The WSSV loads were 8.8 × 104-1.5×105,4.4×105-1.2×106, and 8.5×105-4.6×106 copies/ng DNA, respectively, averaging 9.5×105 copies per anograms DNA of all sampled shrimp (n = 229). The viral loads in the shrimp that died during the late postinfection period were significantly higher than in those shrimp that died during the early and peak periods (P < 0.01). The viral load in surviving shrimp was 2.2×105 (n = 44) copies/ng DNA. Among the surviving shrimp, 18.2% (n = 8) had a viral load greater than 1.0×104 copies/ng DNA and 52.3% (n = 23) had less than 100 copies/ng DNA. Based on these result, the range of 7.0×104-107 copies/ng DNA is suggested to be the lethal amount for shrimp death caused by WSSV. These results could be an important reference in an advance warning of a WSSV outbreak in the culture process of these shrimp, and could provide valuable information in further selective breeding of WSSV-tolerant or -resistant varieties of F. chinensis. [ABSTRACT FROM AUTHOR]