Development Of Porcine Epidemic Diarrhea Virus Vaccine Strain And Characteristic

Porcine epidemic diarrhea（PED） is common causes of severe viral diseases, it can lead to seriouslyvomiting, diarrhea, losing of water and high mortality in suckling piglets. The disease spreads verywidely in Europe and Asia,a number of countries and regions cause serious economic losses andbrought great harm to the pig industry every year.So for the prevention and control of porcine epidemicdiarrhea is necessary.For most viral diarrhea disease,prevention measures are generally chosenvaccine.Although the research scholar uses the existing vaccine against porcine epidemic diarrheavirus,but the virus appeared in the immune swine.The damage caused by porcine epidemic diarrheavirus still continued to increase.In recent years,some progress has been made in research on porcineepidemic diarrhea virus vaccine,including inactivated vaccine and attenuated vaccine and the transgenicplant vaccines and lactobacillus vaccines and subunit vaccines and combination vaccines and soon.However,The current problems are the complicate breeding condition and the low virus titer of thevirus in the seed virus preparation process so these are seriously hampered porcine epidemic diarrheadisease prevention.In this study, in order to improve the porcine epidemic diarrhea virus propagation titer,optimize theculture condition of PEDV and continuous subculture in vitro,include trypsin concentration andadsorption time and culture method.It was found that the optimum trypsin concentration was1-5μg/mL,and the optimum culture method was discard the adsorption solution after the adsorptionsolution adsorbed1.5h, add maintenance media cultured72h and to collect the virus.Through theculture method above increased the TCID₅₀at last,the TCID₅₀was10^6.17/0.1mLTCID₅₀,reduced thepathogenicity of the virus.The experiment also through the research of PEDV HLJBY strain’s physicochemical propertiesfound that the PEDV HLJBY strain was sensitive to the temperature above50℃,higher than thistemperature could achieve the effect of hest inactivation; this strain also sensitive to chloroform;The pHvalue of PEDV HLJBY strain was stable relatively.The pH value of the strain adjusted to pH3and thenadjusted to the original pH value,the titer of the virus did not change significantly.In this study, we research the characteristics of the virus press the "Veterinary Pharmacopoeia OfThe People’s Republic Of China" requirements.Cells and Viruses purely check were in accordance withthe requirements of "Veterinary Pharmacopoeia Of The People’s Republic Of China".The results showthere was no presence of bacterium and mould and mycoplasma and exogenous viruses in the PEDVculture with Vero cells and PEDV viruses. This test is the PEDV HLJBY strain as an attenuated vaccinecandidate strain study provides further references and provides a theoretical basis of prevent the PED.