2022年宁波市南美白对虾主要病原流行病学调查

Epidemiological investigation on the main pathogens of Litopenaeus vannamei in Ningbo in 2022

摘要:

为了解虾肝肠胞虫(EHP)、十足目虹彩病毒1(DIV1)、白斑综合征病毒(WSSV)和致急性肝胰腺坏死病副溶血弧菌(VpAHPND)在宁波地区养殖南美白对虾中的致病途径和流行规律,采用PCR方法检测了该地区不同养殖模式下南美白对虾及其周边环境和生物中这4种病原的感染情况。结果显示:南美白对虾样本中,WSSV在整个养殖过程中未检出,VpAHPND阳性率最高,为14.6%,其次是EHP和DIV1,阳性率分别为10.2%和2.9%；土塘养殖模式下对虾病原检出率最高,为61.3%,其次为小棚模式和帆布池模式,病原检出率分别为26.3%和22.2%,大棚养殖的南美白对虾中未检出病原；水样中检出WSSV、EHP、VpAHPND、DIV1阳性批次数分别为1、14、8、6；底泥样品中未检出病原；周边环境生物中,仅1个批次的脊尾白虾检出EHP阳性。结果表明:4种病原在夏季有较强的流行趋势,需要针对性地加强防控；大棚养殖模式的抗风险能力要高于其他养殖模式,在该模式下水质相对稳定,受外界因素影响较小；病原在底泥和周边环境生物中检出率较低,而在养殖水体中检出率较高,养殖水体可能在南美白对虾感染病原的过程中起着重要的传播媒介作用。因此,在养殖过程中加强水体调控十分重要。

Abstract:

In order to understand the pathogenic infections of Litopenaeus vannamei under different culture modes,surrounding environment and biology in Ningbo,and to explore the pathogenesis and epidemic regularity of Enterocytozoom hepatopenaei(EHP),decapod iridescent virus 1(DIV1),white spot syndrome virus(WSSV) and Acute hepatopancreatic necrosis disease caused by Vibrio parahaemolyticus(VpAHPND),the four pathogens were detected by PCR.The results showed that WSSV was not detected during the whole culture process,VpAHPND had the highest positive rate of 14.6%,followed by EHP and DIV1 with 10.2% and 2.9%,respectively.The highest pathogen detection rate was 61.3% in the soil pond mode,followed by 26.3% in the shed mode and 22.2% in the canvas pond mode,and no pathogens were detected in the greenhouse mode.The number of positive batches of WSSV,EHP,VpAHPND and DIV1 in the water samples was 1,14,8 and 6 respectively;no pathogens were detected in the substrate samples;and only one batch of Palaemon carincauda was detected positive for EHP in the surrounding environment.The results indicated that the pathogens had a tendency to be more prevalent in summer and needs to be targeted to strengthen prevention and control.In addition,the greenhouse model had a higher risk resistance ability than other farming models.In this model,the water body tended to be more stable and less affected by external factors.The detection rate of pathogens in sediment and surrounding environmental organisms was low,while it was relatively high in cultured water bodies.Aquaculture water bodies may play an important role in the process of pathogen infection of L. vannamei.Therefore,it is very important to strengthen the control of water bodies in the process of culture.