Isolation And Identification On Mink Canine Distemper Virus And Sequence Analysis Of Its H Gene

The canine distemper was one kind acute and the infectious greatly strengthened ardent infectionwhich caused by the canine distemper virus. CDV belonged Paramyxoviridae Morbillivirus genus, thisvirus has only one serotype and has the common soluble antigen in different strain, which has notdistinguished in the antigenicity. This virus assumed the worldwide basis distribution, under the naturalcondition infects the carnivorous dog branch, the weasel branch, the raccoon branch, and so on many kindsof animals, is especially serious to the fur economical animal harm. The special economical animal wasvery high because of itself economic value, once has the infectious disease to lose seriously, therefore hasthe necessity to the animal which contracts the infectious disease to carry on the treatment and the urgentprevention, will lose falls slightly to. But the present canine distemper has no treatment effectiveprescription, only has been able to control through the vaccine. Therefore the canine distemper vaccineresearch always is a hot spot which the world each place scholar studies.Canine distemper virus strain was isolated from the liver of mink from Shandong using Vero cell. Itwas demonstrated to be a virulent strain of CDV by a series of systematic identification such asmorphology, cell virulence test, biological property, immunoassay and molecular virology test. The strainwas named CDVSJ. One pare of primers was designed and synthesized based on the Haemagglutinin(H)protein gene sequence the Onderstepoort strain of canine distemper virus(CDV).The length H genefragment was amplified by polymerase chain reaction Amplification product was linked topMD18-Tsimple vector and transformed in JM109 of coli bacillus competent cell. Plasmid was made toidentify by PCR and emzyme cut. The correct positive recombinant was used for sequencing. The sequencelength was 1596 bp as expected. The nucleic acid and deduced amino acid sequence of the H protein of theCDVSJ strain were compared with those of other CDV strain extracted from the Genebank database. Allthe strains were divided to two groups. One is virulent strain group; the other is vaccine strain group.CDVSJ strain was part of vaccine group. The nucleic acid and amino acid sequence homology the highestand the lowest of CDVSJ was Chinese strain CDV3 and Hamamatsu, leave each other 99.1％, 98.1％and 90.9％, 90.4％. There are 12 cysteine residue site in all strains, but strain CDV3 has a different site which isat 414(other 304), cysteine residue in all CDV is conservative. The strain CDVSJ owned 5 potentialN-glycosylation sites but 3 potential sites for Onderstepoort strain; there were 6 potential N-glycosylationsites in strain CDV3 and Convac, among which there was differentce of CDVSJ in 530aa～532aa;Hamamatsu owned 8 sites, other sites located 236Aa～238Aa,511aa～513aa and 530aa～532aa; aDanish dog owned 7sites, other sites located 236Aa～238Aa and 530aa～532aa. A potentialN-glycosylation site which located in the position of 511～513 amino acid was unique to yield isolate.This study indicated that this separation research was a low virulent strain, which may become avaccine strain. Meanwhile to the CDVSJ H gene sequence and the code amino acid comparison indicated ithas certain difference with other CDV strain, these differences were to study offer the molecular biologybasis for the distemper research immunity defeat and the theory basis for the canine distemper prevention.