Investigation Of Canine Distemper In Pet Dogs From Some Areas Of Liaoning Province And Analysis Of The H And F Genes Of Pathogens

Canine distemper(CD)is an acute,highly contagious infectious disease caused by canine distemper virus(CDV).It can cause canine,ferret and raccoon infection suffering from disease.Clinically manifested that: biphasic fever,rhinitis,pneumonia,conjunctivitis,gastroenteritis,bronchitis and neurological symptoms.The disease is popular in many areas of China fur animals and wild animals,especially the dog,it is not only huge harm but also caused a huge economic losses.In recent years,the disease is more prevalent in the Liaoning province,clinical symptoms:pathological changes and difficult to prevent and control and the higher mortality rate,It has brought a serious threat to pet industry of the Liaoning region.In order to gain a better understanding of the popular characteristics of CDV and the variation of CDV in Liaoning,this study has carried out the following work:The first chapter:Investigation of Canine Distemper in Pet Dogs in Areas of the Liaoning Province.From the epidemiology,clinical symptoms,case histology,histopathology and other aspects of the 2014 ~ 2016 part of Liaoning Province,nine pet hospitals admitted to the clinical suspected canine distemper disease 281 swabs and tissue samples.Using colloidal gold antigen detection card and RT-PCR detection,of which 23 samples were positive canine distemper virus,the positive rate was8.19%.Liaoning Province,the dog clinical symptoms,to hybrid type followed by respiratory type gastrointestinal type nerve type and skin type,various types of sick dogs have biphasic heat through.Detection of eye,nose,oral secretions and feces in dogs by CDV pathogens,of which there are 281 positive samples.Transplantation of diseased dogs can be seen systemic lymphadenopathy,bleeding,especially the mesenteric lymph nodes among all the obvious symptoms,Meningeal congestion,bleeding,lung bleeding,necrosis,splenomegaly,dark red,Gastrointestinal manifestations of catastitis,congestion,Pancreatic atrophy and other typical symptoms.Histopathological examination can be seen that extensive pulmonary congestion,alveolar wall structure disappeared,alveolar cavity filled with macrophages,Spleen congestion,bleeding,white pulp almost disappeared,significantly reduced lymphocytes,Hepatocyte massive vacuole,granulardegeneration,fat-like degeneration,Lymph nodes have obvious congestion,bleeding,atrophy and edema,lymph node is not obvious.The second chapter:Analysis of H and F Gene of Dog Canine Distemper Virus in Some Areas of Liaoning Province.In order to comprehensively understand the genetic variation and evolution of CDV,we collected 281 samples of swabs and tissue samples from clinical canine distemper dogs from nine pet hospitals of Shenyang,Jinzhou and Liaoyang.At the same time,23 CDV positive samples were screened by using canine distemper virus antigen test strip by RT-PCR.In this study,the gene H and H gene sequence analysis of the 12 strains of CDV showed that the 12 strains of CDV wild strains between the homology of 97.5% to 99.9%,and the vaccine strains(Onderstepoort,CDV3)homology 90.3% to 91.5%;Genetic evolution analysis showed that the 12 strains of wild strains belonge to the China current popular Asia-1type,which derived from Shenyang SY-6,SY-35,and found in Beijing CDV virulent strain BJ-09 in the same evolution Branching,the rest from Shenyang,Jinzhou and Liaoyang 10 and the northeastern region is the popular of CDV in the same evolutionary branch.The amino acid sequence alignment showed that there was high variation in the amino acid of H protein 235-245,415-425,559-605,and the amino acid non-synonymous substitution probability of 355 region of H protein was higher.The results of glycosylation and epitope prediction showed that the glycosylation site and antigen epitope of H gene of 12 CDVs were similar to the Asia-1 CDV,but the variation was much than the vaccine strain.In addition,we found that JZ-6 strain lost a potential N-glycosylation site.According to the sequence of CDV F gene published in Genbank,1 pair of specific primers were designed for its sequence.The isolates were cloned and sequenced by RT-PCR.The amino acid sequences were deduced by MEGA6 of the genetic gene of the F gene.The results showed that the open reading frame(ORF)of the F gene of the two CDV was isolated have 1989 nt,encoding 662 amino acids with 17 cys residue sites and 4 potential glycosylation sites in the protein structure,the amino acid sequence of the cleavage site was 220R-R-Q-R-224 R.Genetic analysis showed that the two strains belonged to the same lineage as CDV representative strains HeB(07)1,all of them were virulent strains.Among them,SY-11 strain was close to DL-8 strain,and the relationship with other vaccine strains was relatively far.The above studies show that Liaoning Province,the dog canine distemper virusstrains to Asia-1 canine distemper virus-based,and there are genetic diversity among different virus strains.