中华绒螯蟹肝胰腺坏死症病理学诊断及两种病原的检测

Pathological diagnoses and two etiology detection of hepatopancreas necrosis disease from pond reared Eriocheir sinensis

为探究中华绒螯蟹(Eriocheir sinensis)肝胰腺坏死症病理特征和发病规律,确定该病临床诊断标准,实验从80只自然发病的中华绒螯蟹肝胰腺坏死综合征病蟹中,选取12只具有典型临床症状且病变程度不同的病蟹,解剖检查并采集肝胰腺、鳃、肌肉三种病灶组织样品,进行了组织病理学研究,对肝胰腺和肌肉组织进行了病原检测实验。剖检结果显示,病蟹体表发黑,肝胰腺有肿大、部分白化、完全白化、坏死萎缩症状,副肢肌肉萎缩,部分个体腮部变黑。病理学研究结果显示,肝小管发生不同程度有规律的病变,患病早期的肝小管上皮细胞增生,中期部分肝小管空泡化,中后期全部肝小管上皮细胞空泡化,最终肝小管上皮细胞坏死溶解,认为肝胰腺为该病的主要受损器官,同时可依据肝小管组织病理变化,将该病完整病程划分为四个阶段并命名;鳃组织出现局部充血、水肿、鳃小叶上皮融合等症状,个体差异性较大,未发现规律性病变;副肢肌肉纤维随着肝胰腺病变的恶化而逐步萎缩。病原检测结果,白斑综合征病毒(WSSV)在病蟹肝胰腺和肌肉组织中的检出率为91.7%和83.3%,微孢子虫在病蟹肝胰腺和肌肉组织中的检出率为33.3%和0%,结果表明:WSSV和微孢子虫分别属于携带和继发性感染的可能性较大。实验结果倾向于支持非生物因素作为该病致病因子的观点。

A total of 12 sick crabs(Eriocheir sinensis)with typical clinical symptoms and different degrees of lesions were selected from 80 the sick crabs collected in Xinghua city of Jiangsu Province,Chinam in order to explore the pathological features and occurrence rule,determine the standard of clinical diagnosis of hepatopancreas necrosis disease(HPND)in pond reared Chinese mitten crab.They were dissected for anatomical examination,the hepatopancreas,gills and muscles ware collected.The histopathological study and pathogen detection experiment of hepatopancreas and muscle tissues ware carried out.The results of anatomical examination showed that the hepatopancreas cash out swelling,partial albinism,complete albinism,necrotic atrophy,the surfaces ware darker,the accessory limbs softened,the gills of some sick crabs ware blackened.The results of pathological showed that hepatic tubule lesions were varying degrees and regularity.The hepatic tubular epithelial cells of the sick crabs proliferated in the early stage,through part of the hepatic tubule epithelial cells were vacuolated.All the epithelial cells are vacuolated,at last the epithelial cells are necrotic.It could be diagnosed that the pathological changes of hepatopancreas were closely related to the disease.According to the pathological changes of hepatic tubule,the complete course of the disease could be divided into four stages and named them.Gills have some symptoms such as local hyperemia,edema,and branchial lobular epithelial fusion.The individual difference was large and no regular pathological changes were found.With the progression of the pathological changes of hepatopancreas,the degree of muscular atrophy in the epipodite gradually increased.The hepatopancreas necrosis disease crabs detected by PCR showed that the rates of white spot syndrome virus(WSSV)in hepatopancrea and muscle were 91.7%and 83.3%respectively,and that of microsporidia in hepatopancrea and muscle were 33.3%and 0%,respectively.It was concluded that WSSV and microsporidium were more likely to be carrier and secondary infections respectively.The experimental results tend to support the view that abiotic factors are the causative factors for the disease.