Preliminary Establishment Of Gosling Models And Immunohistochemical Methods By YBLJ Strain Goose Parvovirus

Goose parvovirus GPV(Goose parvovirus GPV)is a member of the parvoviridae subfamily.It mainly infects muscovy ducks and goslings from 2 to 18 days.Moreover,when the GPV infects goslings from 1 to 4 days,which has the highest fatality rate.The disease has been reported in China,Southeast Asia,Europe and other places.It is transmitted in a variety of ways in goslings and muscovy ducks.Goslings at 20 days of age are highly susceptible and have a mortality rate of more than 90%.In order to research the pathogenicity of YBLJ strain GPV to goose,42 numbers of 3-day-old goslings infected with YBLJ strain GPV was preliminarily established in this experiment.Firstly,the YBLJ strain GPV stored separately was diluted into 1.5×10 1 PFU/mL,1.5×102 PFU/mL,1.5×103 PFU/mL,1.5×104 PFU/mL,1.5×105 PFU/mL,1.5×106 PFU/mL.On the second day after challenging,GPV symptoms began to appear in goslings,and on the third day,the most acute type of infected gosling died after convulsion.Pathological examination was conducted to observe lesions in various organs,and the initial diagnosis was death due to GPV infection.On the 5th day after challenging,blood was collected from the experimental geese,and DNA was extracted for GPV-VP3 PCR amplification,so as to determine the optimal challenge dose.Then,tissue PCR detection and pathological diagnosis were performed on liver,pancreas,cecum,heart and spleen of the optimal dose group,and the GPV positive antigen distribution in different organs was compared,so as to preliminarily establish the immunohistochemical method of YBLJ strain GPV.The results showed that the typical GPV symptoms of angle-arch atresia and extreme emaciation occurred in the 3-day-old goslings at different concentrations.Squab examination of goslings showed different degrees of lesions in the eyes,thymus and internal organs.The results of blood PCR showed that the concentration of GPV-VP3 gene in the blood of goslings with different challenge doses was different,and the best challenge dose was 1.5 ×106 PFU/mL.The GPV-VP3 gene was detected by PCR in the heart,liver,cecum and spleen,but no detection in the pancreas.The results of pathological HE staining showed that inflammatory cells were infiltrated in the caecum and heart tissue of experimental geese at the challenge dose of pericarditis and exudative enteritis.Immunohistochemical best conditions for paraffin section thickness for 4 microns,microwave repair 14 min,antibody dilution into 1:100,the reaction time of 37?,60 min,DAB chromogenic 4 min.GPV immunohistochemical results show that the GPV in the epithelial cells of the cecum are widely distributed,and can be seen in the spleen,liver,heart,blood vessels distribution of GPV,positive number of GPV antigen for "++",color is close to brownish yellow,but not in the pancreas,check out the GPV antigen,judged to be "-",indicates that the test YBLJ GPV strains of cheeper cecum,liver,heart,spleen are more serious.The preliminary establishment of the goose parvovirus infected gosling model of YBLJ strain and the immunohistochemical method laid a foundation for the further test of YBLJ strain GPV at a later stage,which will eventually provide a reference for the diagnosis and prevention of GPV.