Isolation,Identification And Se Uence Analysis Of VP2 Gene Of Canine Parvovirus YBHC Strain

Canine parvovirus（CPV）is a highly contagious infectious disease that can infect canines and some carnivores.It is currently detected in countries all over the world.The main phenotypes of the disease can be divided into two types:hemorrhagic enteritis and myocarditis.The morbidity and lethality are extremely high,which poses a great threat to the health of dogs,and seriously endangers the breeding of canines and fur animal breeding in China.normal development.In this study,a fecal swab from a dog suspected of being infected with CPV was collected from Hunchun,Yanbian Korean Autonomous Prefecture.The fecal swab was pretreated and inoculated into MDCK cells for virus isolation test,and the isolated strains were identified by morphological and molecular biology.The CPV-VP2 gene was amplified,and the full length of the virus VP2 gene was about 1 755 bp after sequencing,encoding 584 amino acids（Uploaded to Gen Bank:OM057673）.Virus isolation and identification of YBHC strain CPV.The pretreated fecal swab sample solution was inoculated on MDCK cells,and the virus was collected after 48hours.After repeated freezing and thawing 3 times,it was inoculated on the MDCK cells in good growth condition.MDCK cells showed obvious cytopathic changes（CPE）,such as pulling nets,cells rounding,and shedding;after the virus solution was negatively stained with phosphotungstic acid,typical canine parvovirus particles were seen under the electron microscope,which were round or six-shaped without encapsulation.Edge,about 20-24 nm;specific fluorescence can be seen after identification by indirect immunofluorescence（IFA）;TCID₅₀of the virus was determined to be 10-5.14/0.1m L;it can be proved that a strain of canine microvirus was successfully isolated in Hunchun,Yanbian,named YBHC strain of canine parvovirus.Genetic evolution analysis of YBHC strain CPV 39 domestic and foreign CPV-VP2 strains of different subtypes included in the Gen Bank database were selected for comparison with the YBHC strain CPV.The results showed that the nucleotide sequence homology of this strain and other 39 CPV-VP2 strains was98.8-99.9%,and the amino acid sequence homology was 98.5-100%.The reference strain of 2c subtype is in the same branch;and it is consistent with the amino acid variation sites（Phe267Tyr,Gln370Arg,Asp426Glu）of the standard strain CPV-2c.In this study,a YBHC strain of canine parvovirus was successfully isolated and identified as CPV-2c subtype canine parvovirus by VP2 genetic evolution analysis.Provide local seeding and theoretical basis.