Pathological Study And Viral Genome Sequence Analysis Of Enzootic Nasal Tumor Of Goat

Ovine endemic intranasal tumor(ENT)is a chronic,progressive infectious disease caused by ovine endemic intranasal tumor virus(ENTV).Sheep endemic intranasal tumor viruses include sheep endemic intranasal tumor virus(ENTV-1)and goat endemic intranasal tumor virus(ENTV-2).Endemic intranasal neoplasms of goats occur all over the world,which has a great impact on the global sheep industry and seriously affects the germplasm resources of goats.Three cases of endemic intranasal neoplasms of dairy goats in Inner Mongolia were studied in this study.The results showed that the infected sheep showed a thick and colorless nasal fluid,dyspnea and gradual emaciation,and the nasal bone perforation near the middle bridge of the nose on one or both sides at the late stage.The course of the disease was several months.Necropsy showed emaciation and systemic atrophy,and nodular,papilloid or caudal masses of varying sizes were found in the ethmoid and sphenoid of the nasal cavity on one or both sides,resulting in nasal stenosis or even complete occlusion.Histopathology showed that the tumor tissue was round,oval or irregular in shape,located in the submucosa of the nose,in the shape of lobed.The tumor cells were arranged into glandular tubes of different sizes and shapes.The round or oval tumor nuclei were located at the base of the glandular tubes,and the cytoplasm was abundant,homogeneous red or silky reticular mucous.The morphological characteristics were similar to those of serous glands and mucous adenoids in the submucosa.The presence of ENTV-2 was detected in nasal tumor samples from two of the infected sheep.The whole genome of the virus was amplified and sequenced for genetic evolution analysis.Results The whole genomes of two ENTV-2 strains from Inner Mongolia were amplified and named as NM-ENTV-976 and NM-ENTV-977.The total length of the gene was 7469 bp.The whole genome of two ENTV-2 strains was analyzed by sequence alignment and genetic evolution.The Sequence alignment analysis showed that compared with most other ENTV-2strains,the two ENTV-2 strains obtained in this study had more nucleotide mutation sites in the LTR non-coding region,among which NM-ENTV-976 and NM-ENTV-977 both had 18 insertion mutations,and the rest were point mutations.There were two mutation sites in the nucleotide sequence of gag gene of NM-ENTV-976,but NM-ENTV-977 had no mutation.The env gene of NM-ENTV-976 has no mutation in its nucleotide sequence,while the env gene of NM-ENTV-977 has a point mutation at 1 site,without insertion and deletion mutations.The homology and genetic evolution analysis showed that the similarity between NM-ENTV-976 and NM-ENTV-977 was 99.1%.The homology of NM-ENTV-976 and NM-ENTV-977 to Fujian ENTV-2FJ(entry number: MK559457.1)was 99.0% and99.6%,and the homology of NM-Ent V-976 and NM-Ent V-977 to Fujian ENTV-2FJ(entry number: MK559457.1)was the highest.This study elucidated the pathological features of intranasal neoplasms endemic to goats in Inner Mongolia and the whole genome structure and genetic evolution of the two virus strains,which laid the foundation for further study of diseases and pathogens.