Effect of temperature shifts on shrimp lightly infected with white spot syndrome virus (WSSV)

溫度改變對白點症病毒潛伏感染蝦類之影響

許惠貞(Hui-Chen Hsu) ； 羅竹芳(Chu-Fang Lo) ； 邱雅琳(Ya-Lin Chiu) ； 張正芳(Cheng-Fang Chang) ； 郭光雄(Guang-Hsiung Kou)

《Acta Zoologica Taiwanica》 11卷2期 (2000/07) Pp. 63-81

https://doi.org/10.6576/AZT.2000.11.(2).1

摘要

蝦類白點症病毒是目前嚴重危害台灣及其他地區養殖蝦類的重要病原體。本研究乃利用罹病死亡之斑節蝦表皮及蝦殼配製病毒液，以不同稀釋度浸泡健康之草蝦及斑節蝦，以造成蝦類潛伏性感染，再施以不同溫度的 緊迫，觀察蝦體的死亡狀況。在高溫緊迫的環境下，潛伏感染草蝦及斑節蝦於一天內即迅速死亡，對照組則無。溫度由15℃提高至24℃時，於72 小時內潛伏感染草蝦的死亡率即達100％，而潛伏感染斑節蝦的死亡率僅約40％；當溫度由15℃提高至29℃時，不論潛伏感染草蝦或斑節蝦其死亡率均高達100％，顯示感染病毒的草蝦對於高溫緊迫因子的適應性比感染病毒的斑節蝦低。利用聚合?鏈反應證明其均因白點症桿狀病毒感染而死亡。本研究結果顯示溫度變化造成的緊迫的確會引爆白點症的發生。

關鍵字

白點症 ； 白點症病毒 ； 草蝦 ； 斑節蝦 ； 聚合 ； 鏈反應

並列摘要

Healthy juvenile kuruma shrimp, Marsupenaeus japonicus, and giant black tiger shrimp, Penaeus monodon, were immersed in a filtrate prepared from the epidermis of either white spot syndrome virus (WSSV)-infected M. japonicus or healthy P. monodon (control). Ten days after immersion, infection of the experimental shrimp were confirmed by two-step polymerase chain reaction (PCR) diagnosis. The sublethally infected and the healthy control shrimp were both subjected to different temperature conditions. For both shrimp species, the experimental groups began to die after 1 d of high temperature (29 ℃) treatment, while only a few shrimp died in the control groups. At low temperatures (15 ℃), the mortalities were lower in the first 24 h than when the shrimp were maintained at a water temperature of 24 ℃. With an initial exposure to low temperatures for 24 h, after the water temperature was increased to 24 or 29 ℃, P. monodon mortality reached 90% 100% after a further 36 h at either temperature, while at 29 ℃, M japonicus mortality reached 100% within a further 48 h, but only reached 40% at 24 ℃. When WSSV DNA specific primer sets were used for one-step and two-step diagnostic PCR, the moribund experimentally infected shrimp under temperature shifts all yielded the specific 1447-bp (WSSV DNA) PCR product in the first step. No 1447-bp PCR product was found in the control groups, whether experiencing a temperature shift or not. These results demonstrate that temperature shifts alone can induce an outbreak of WSS disease in populations in which viral infection is only two-step WSSV positive.

並列關鍵字

white spot syndrome ； WSSV ； Penaeus monodon ； Marsupenaeus japonicus ； polymerase chain reaction