Isolation And Identification Of Group Ⅲ Adenovirus From Geese, And Comparison Of Their E3 Region Sequence And Their Pathogenicity

Cloacae secretion of healthy geese, livers, spleens and guts of clinical young or adult geese were collected for viruses isolation. These samples were sterilized by centrifuge and antibiotics and then inoculated into duck embryos. Two virus strains named H5J24 and N8J8 respectively were isolated from 50 samples and identified by hemagglutination (HA) and hemagglutination inhibition (HI) tests. The isolation rate is 4%. Both viruses could agglutinate 0.8% red blood cells (RBC) of chicken, duck or goose. The agglutination activity could be inhibited by the serum against virus Y81G4 isolated from goose, but not by the monoclonal antibodies to Newcastle disease virus, Avian influenza virus subtype H5 or H9. The virus particles are non-enveloped, 78nm diameter , and have icosahedrad symmetry visible in the transmission electron microscope(TEM) by negative stain. Based on the morphology, physical and chemical properties of the viruses and PCR analysis, the viruses were located at group III Adenoviruses.Adenoviruse E3 region locates between the conservative genes pVIII and Fiber. We designed a pair of primers to amplify the fragement from two isolates by PCR. The results showed that E3 regions of the 2 virus strains was about240bp in size. There was no distinct opening reading frame (ORF) in sequence analysis with DNAstar software. The 2 isolate strains from geese were further classified as Group III Avianadenovirus compared with the E3 region sequences of EDS-76 and other adenovirus.The 2 isolate virus strains were experimentally inoculated into 10-day-old goslings in order to understand their pathogenicity. During different infection phases, the experimental geese did not exhibit any clinical syndrome. This result suggested that their pathogenicity were very weak for geese. Following detection made it clear that the 2 virus strains could long exist in geese and be expelled into environment for long time. Meanwhile the serum antibodies were maintained at a high level. The tilers of HI of the serum were about 211~212. Based on the tissue pathology, the 2 virus strains still could induce pathological changes in some organs, such as kidney, spleen, small intestine and lung.