To develop a method to detect antibodies against BVDV,an PPA-ELISA was established by the recombinant E2 protein antigen expressed in E.coli prokaryotic expression system.The optimal coating concentration of E2 recombinant protein was 16.0 μg/mL.The dilution of serum sample was 1∶40 and optimal concentration of HRP-SPA labeled antibody IgG was 1∶2 000.Compared with the routine IDEXX ELISA test kit with the whole virus,the established method has good specificity,sensitivity and repeatability.In addition,285 serum samples were detected by the E2-PPA-ELISA and the IDEXX BVDV Antibody Test Kit.The results showed that the BVDV antibody positive rate was 33.4%.Therefore,the E2-PPA-ELISA was practical for serological diagnosis of BVDV and antibody surveillance.

Duck hepatitis virus is an infectious viral disease which jeopardizes the duck industry and mainly affects the young ducklings.The pathogen isolated clinically was mainly duck hepatitis virus type I and new type virus.In order to speed up the disease detection and diagnose the pathogens as soon as possible,according to the genomic sequence of two strains in GeneBank,apair of specific primers was designed respectively according to the differences between the two sequences,two pairs of primers were used in a PCR reaction system,and two strains were amplified specifically.Identified according to the amplification fragment size,a complex PCR detection method which can simultaneously detect duck hepatitis virus type I and new type strains was established,the detection method is rapid and has strong specificity and high sensitivity,and can be used for identifying the types of duck hepatitis virus detection.

Based on published duck Tembusu virus(DTMUV)gene sequences in GenBank,apair of specific primers were designed,966bp E gene fragment was amplified by RT-PCR and cloned into pMD18-T vector,the fragment was cloned into expression vector pET30acorrectly after identification,and then the positive plasmid transformed to BL21expression bacteria.After induction by IPTG,the recombinant proteins were expressed in inclusion body forms.Using nickel ion affinity chromatography,the recombinant proteins were purified.Western blot showed the recombinant protein had good antigenicity,which laid a foundation for E protein structure and function research,and research for detection kit of DTMUV antibody and new type vaccines.

应用奥芬达唑干混悬剂分别按5、10、15 mg/kg.b w剂量口服给药,驱除黄牛自然感染线虫,投药后14 d粪检结果: 15 mg/kg剂量试验组虫卵(幼虫)转阴率、减少率均为100%;10 mg/kg剂量对消化道线虫虫卵转阴率90%,减少率99.9%,原圆科线虫幼虫转阴率90%,减少率94.6%;5 mg/kg剂量对消化道线虫虫卵转阴率80%,减少率99.2%,对原圆科线虫幼虫转阴率70%,减少率91.1%;而对照组同期检查虫卵(幼虫)给药前后无明显变化.第21 d剖检结果: 15 mg/kg、10 mg/kg、5 mg/kg剂量总计驱虫率分别达99.2%、97.4%和95.7%.均达到了高效.