Pathological Chracteristics And Histo-Pathologial Observation Of Andrias Davidianus Blanchard Affected By Bacterial Septicermia

In recent years, Andrias davidianus Blanchard in fishponds was affected by diseases, leadingto economical loss for fishing farmers. In order to investigated the reason and find efficientprotection strategy, the epidemiology ofAndrias davidianus Blanchard was conducted in HunanRunfu Bio-Products Co.,Ltd and Andrias davidianus Blanchard Protection Center in Zhangjiajiefor three years. The affected Andrias davidianus Blanchard was anatomized and viruses in thesampleswere determined in Wuhan Institute of Virology, Chinese Academy of Sciences. Theresult showed that the disease neither was affected by viruses nor parasites. However, pathologicalsymptoms such as hyperemia, hemorrhage; swelling abdomen, refractory ascites and hemolysiswere observed in the body, muscle, liver, pancreas, kidney, intestine, stomach and lung ofAndrias davidianus Blanchard with infection The disease was identified as bacterial septicermiabased on above symptoms.Ten affected Andrias davidianus Blanchards in fishponds were taken fromHunan Runfu Bio-Products Co.,Ltd from 2004 to 2006. Six organs from ten ofAndrias davidianus Blanchards were chosen for pathological investigation and 600bacteria were isolated. Nine out of 600 bacteria in the affected Andrias davidianusBlanchards was used for determining medical resistance by gram staining, biologicalidentification and medical sensitivity. All of nine bacteria were sensitive tociprofloxacin, ceftriaxone sodium, ceftazidime, cefamandole Nafate, cefoperazoneSodium, gentamycin sulfate, and cefoxitin sodium, while they were resistant toclindamycin, cefazolin, metronidazole and sulfamethoxazole. One bacteria strain inAndrias davidianus Blanchards was selected for 16S rDNA PCR amplification andsequencing in a regression experiment. The result revealed that the disease wasresulted from aeromonas hydrophila.The blood of the affected Andrias davidianus Blanchards was used fordetermining 40 pathological parameters. It was fond that 9 parameters were includedin the reference range of health and others lowered the healthy references. The tissuesof liver, pancreas, intestine, stomach, lung and kidney in Andrias davidianus Btanchardwith infection was fixed in formlin solution, formed paraffin slices, stained in H.E.andthen observed trader optical microscope. The lobular structure of liver was not clear.The capillary vessel and the bile duct within lobules were destroyed. The increasedmacrophages, cell swelling, denaturalization and necrosis of liver were found in thepresent study. But central vein and cytopigment were not observed in liver. The capillaceous and lobular bile duct in liver were broken. The substances from bile ductinfiltrated into liver tissues. The grand cell of pancreas was denatured and some ofthem were necrotic. Moreover, plenty of fatty cells filled up within glandular alveolus.The intrinsic layer in inner cell wall of stomach was destroyed and stomachicepidermis cells were disaggregated. Microvillis of nonciliated columnar cells of theintestines disappeared. Mesentery and ovarian capsules were inflated and accumulatedwith water. In lung tissues, there was no integrated bronchus, while plenty oflymphoid cells. The symptom of acute tubular necrosis and denaturation were found.Some gores were founded in renal tubules. Hematid was soaked in renal tubules too.Renal corpuscle was necrotic and disintegrated.