| Canine Distemper, caused by Canine Distemper Virus (shorts for CDV), is one of the most serious infectious diseases against Kennel industry in the world, the breeding of fur-bearing animals and protection of wildlife. The main characteristics include Clinical hyperthermia in two-phase, acute nasal catarrh and subsequent bronchial, catarrhal pneumonia, severe gastroenteritis and neurological symptoms. It has strong infectivity with high incidence of the disease and various clinical symptoms, and easily causes bacterial or virus infections and superinfection. The mortality reaches up to 80%.It is very difficult to make a diagnosis on Canine Distemper only by clinical symptom and pathological changes as the CD is a pan-tropic virus to infect a variety of cells and tissues. And it has the strongest pro-tropic on the lymphocytes and the epithelial cells by doing destruction to body cells immunity and humoral immune function, and then leading to secondary infection. Clinical symptoms are different, relating to dog's age, immune status, infected strains with strong or weak. The course can be divided into acute, subacute, chronic and silent infection. Secondly, the clinical symptoms of CD are easy to mix with diseases symptoms, such as the upper respiratory tract infection, canine infectious hepatitis, canine coronavirus infection. For the diagnosis on CDV, preliminary diagnosis can be made according to epidemiological data and clinical symptoms, and final diagnosis can be got by laboratory.It comes to a conclusion that the genome encoding of CD contains 6 types of proteins, including the nucleocapsid protein (N), phosphoprotein (P), matrix protein (M), large protein (L), the fusion protein (F) and hemagglutinin protein (H). As the required protein to invade host in the process of CD infecting cells, H protein is the main antibody generated in neutralization antigen, and it is also the structure antigen with the largest variation. accompanied by environment changes, and the evolution of the animals and virus, the natural host of CDV infection has extended from traditional families, such as Canidae family, Mustelidae family and Procyonidae family, to many other animals, including Section 8 of Carnivoa Oder, Suidae family, Macaca Lacepede Phocidae family. And the range of natural CDV infection host has the trend of continuous expansion, even the CDV nucleic acid also has been detected from the body of hominal Paget. In recent years, in particular, many countries and regions all over the world have reported the cases of canine distemper on immunization animals. The genetic analysis revealed that the acting wild strain of CDV has multiple genotypes and it has significant difference compared with the antigenicity of the current weak strain vaccine. The result causes that people have a query on whether the vaccine CDV has ability to protect immune animals from the infection of CDV resistance prevalence in wild strain. Even if the vaccine used to control canine distemper in recent years, there are still some reports on dogs or wild animals all over the world infected with canine distemper caused by canine.In this study, positive serum prepares fluorescent antibody of Canine Distemper by extracting IgG from positive serum and marking fluorescein. The fluorescent antibody can detect the cells infected with CDV and its virus antigen. Prepared fluorescent antibody separately used to detect the vero cells infected with CDV and canine distemper virus in the material organization of CD disease. Both of results are positive, and both of blank are negative. The establishment of testing method of CDV direct immunofluorescence can be used to laboratory diagnosis for CDV.The direct immunofluorescence is a common method used to diagnose canine distemper(CD) in laboratory. It is a convenient and specific method. Therefore, it provides practical technology for diagnosis of Canine Distemper.This study takes epidemiological investigations of Canine Distemper in the northeast region, including serological surveys, clinical investigation, molecular epidemiological investigations.1 The investigation of 335 dogs'serum antibody reveals the antibody level of dogs in northeast region. The result shows the existence of the Northeast natural infection in dogs, and has some effect on the prevention of canine distemper vaccine for CD vaccination.2 The investigation of 541 clinical CD cases reveals that the following aspects will show more clinical investigation results, including infected species, diseased month age, gender, incidence season, mortality rate of treated cases, treatment and prognosis, incidence type and vesting, and disease course. Firstly ,from the infected species point of view the mortality rate of canine distemper is 70.63%(89/126). Secondly, there are total of 24 species, which covers most breeds of dogs, including some foreign varieties, such as Satsuma, German shepherd, lady dogs, and also some Chinese varieties, like Tibetan mastiff, Pekingese, as well as impure mongrel. The range of infected species illustrates that any kind of dog has the incidence to infect Canine Distemper; Third, from diseased month age point of view, the percentage of the highest incidence month accounting for the total number of months is 13.86%(75/541) for 2-month-old, followed by 12.75%(71/541)for the 3-month-old. And the lowest incidence rate is 3.14%(11/541) for 11-months-old; Fourth, from a gender, both of male and female dogs can come on CD, the incidence of male dog is 54.71%(296/541),the incidence of female dog is 45.29%(235/541),the incidence of male dog is slightly higher than that of female dog (P <0.05); Fifth, from the Incidence season, CD can occur throughout the year, during Feb. to Jun., the incidence gradually increases and in May the highest incidence rate is 13.86(75/541); Sixth, and from Jul. to Sep., there is a downward trend; and in October, the incidence rate increases,; but during Nov. and Dec., it downwards to the lowest point as 5.55%(30/541);from the mortality rate from the treatment of cases, the highest rate is in May as 16.85%(15/89), followed in October as 12.36%(11/89). It appears that Canine Distemper is a kind of epidemic throughout the whole year, and the most serious seasons are May and October; Seventh,from the treatment and prognosis, 106 cases of total 541 cases haven't received any treatment, accounting for 19.59%(106/541) of the total number of cases; and 79 cases of total 541 cases took only once treatment in the animal hospital, accounting for 14.60% (79/541)of the total number of cases; and other 56 cases took twice treatments, accounting for 10.91%(56/541)of the total number of cases; and 126 cases of total 541 cases accepted for the continuous treatment, which of 89 cases died, the cure rate accounts of cases with the continuous treatment is 29.37%(37/126); Eighth,from the incidence type and vesting terms, breathing type of CD mortality rate was lower as 54.29%(18/28), digestion type of CD mortality rate was higher as 85.29%(29/34). Neural type and mixed type have no significant difference (P> 0.05), breathing type and neural type and mixed type have a significant difference (P <0.05), compared with significant difference in digestion type (P <0.01); Finally, from the disease course point of view, with the exception of acute cases, most of infected dogs significantly reduce the clinical symptoms within 3~7 days by timely treatment and cured within two weeks. If does not enhance the treatment, the symptoms will become more serious, and even cause neurological symptoms, which of diseased course should be up to 1 month or more and it is more difficult to cure. For the infected dogs with obvious abatement symptoms and the recovery, it is necessary to consolidate the care and strengthen the treatment, otherwise it easily lead to disease recurrence and increase the treatment difficulty.3 The investigation of the molecular epidemiology to Canine Distemper, The investigation also analyzes and research H protein of molecular evolution and variation in Northeast China, which can reflect the prevalence of CDV and evolutionary trends. From 36 of suspected CD materials, 11 materials have been successfully cloned H gene of CDV and took sequencing. while among these rest strains, the homology is higher as 97.3% to 99.7% and it is also high compared with other inland regions. The investigation used MAGA4.0 to analyze the strain of H-based evolutionary genetic status between the Northeast area and other regions, and discover CDV genotype with characteristics of regional distribution and no obvious correlation with time. Asian countries mainly have I-type strain and V-type strain, but China has no V-type strain. The strain in the Northeast and other regions of China is most in I-type. The investigation also used N-glycoside web utility to analyze 7 genotypes with potential asparamide glycosylation sites, and discover that the gap is greater among the different genotypes, i.e., vaccine strains of potential asparagine glycosylation sites are for 4 or 7 and wild strains for 7 ~ 9. The purpose of this study is to prove variation trend of H protein gene of Canine Distemper in the Northeast, to lay the foundation of selection or development of vaccines, and to provide reference for the prevention and treatment of Canine Distemper.
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