Epidemiological Investigation Of Canine Distemper And Analysis Of Epidemic Strain H Gene Mutation Of The Shihezi

Canine distemper is a kind of actual and highly contagious disease which is caused by Canine distemper Virus (CDV). It is worldly distributed with a wide range of susceptible hosts and infection of it is not limited by seasons, ages or spice of dogs. It can lead to an acute, highly contagious disease, Include Canidae, Mustelidae, and raccoon. The disease is prevalent in many parts of China, Causing huge economic losses for Dog breeding and Fur animal breeding.In recent years the disease serious epidemic in Shihezi, And its upward trend, clinical symptoms, pathological changes varied and difficult to prevention and control, The mortality rate of more than80%, Poses a serious threat to pets in the Shihezi. In order to study the situation of CD’s prevalence, this study makes epidemiological survey of CDV and analyzes H gene’s variances.1Epidemiological Survey of CDV in ShiheziFrom the five aspects includ epidemiology, clinical symptoms, serological tests and pathological examinations of2416dogs, which come from three major animal epidemic prevention centers indicate between2011～2012. The Results:There are211Dogs initial diagnosis of Canine Distemper, accounting for8.73%of the total2416dogs.Tracking diagnosed as canine distemper dogs.①Epidemiology:Throughout the year of the disease have occurred, but the onset of winter and spring more; different ages, genders and breeds of dogs can be infected, underage puppies are the most susceptible, purebred dogs are more susceptibility than the soil, and severe illness, and higher mortality; unvaccinated dogs are more incidence than immune.②Clinical symptoms:The observed clinical symptoms consist of respiratory, gastrointestinal, neurological, cutaneous ones and all of those are companied with two-phase heat.③Serology:Serological tests were carried out by using colloidal gold strip to test samples like tears, snivel, saliva and blood.detected positive diseased211.④Necropsy of cases:The dogs body tissues and organs have different degrees of lesions, lymphadenopathy, bleeding, particularly in the mesenteric lymph nodes is the most obvious, catarrhal inflammation of the gastrointestinal tract, pancreatic atrophy, meningoencephalitis and typical symptoms, the majority of dogs, lungs,spleen lesions are obvious.⑤Histopathology:Granular degeneration, fatty degeneration, was a large number of vacuoles of the liver cells; Extensive congestion, pulmonary alveolar wall structure almost disappeared, there are a large number of degeneration necrosis of alveolar epithelial cells and macrophages in the alveolar space;Splenic congestion, hemorrhage, white pulp almost disappeared, lymphocytes was significantly reduced;Lymph congestion, hemorrhage and edema, lymphoid nodules is not obvious, obvious atrophy, lymphopenia. 2The canine distemper virus H Cloning and Genetic Variation Analysis of epidemic strain in Shihezi.Primers were designed according to full length of H gene from Onderstepoort (EU143737.1). RT-PCR was applied to isolate7positive samples from29susceptible clinical samples. Named:CDVshzl、CDVshz2、CDVshz3、CDVshz4、CDVshz5、CDVshz6、CDVshz7. Sequence alignment results showed that7H gene sequence homology of the vaccine strain Onderstepoort were:89.0%、89.4%、90.0%、89.7%、88.8%、87.8%、89.2%, Seven epidemic strains in more than160sites in55,60,87,95varying degrees of mutation, which55,186,452,1020,1107,1116,1350Loci higher concentration.The homology of the amino acid sequence deduced from the nucleotide vaccine strains were95.1%、95.3%、96.3%、94.4%、94.2%、94.2%、95.0%. According to the forecast Predict protien software, the number of the epidemic strains glycosylation sites, location changed, There are eight glycosylation sites of CDVshz7, and the remaining six strains plant has seven glycosylation sites, the reference strain Onderstepoort only four glycosylation sites. According to Immunomedicine Grioup epitope prediction:There are25Epitope of Onderstepoort, CDVshzl have26, and there are five same as the vaccine strain.CDVshz2have26and there are seven same as the vaccine strain, CDVshz3have25and there are eleven same as the vaccine strain, CDVshz4have23and there are ten same as the vaccine strain, CDVshz5have25and there are one same as the vaccine strain, CDVshz6have24and there is no one same as the vaccine strain, CDVshz7have27and there are five same as the vaccine strain. Phylogenetic tree was constructed with Epidemic strains and vaccine strains, Epidemic strains is located in a separate branch, CDVshz7far away with the other six. The results suggest that:The variance in H gene maybe the reason of CDV’s popularity.