Study On Histopathology And Localization Of Viral Antigen Based On Experimental Cases In Pigs Infected With ASFV

In this thesis,the histological examination of pigs infected with the virulent strain of African swine fever virus at different time,combined with the localization and distribution of viral antigens in tissues and organs,was carried out to clarify the characteristic histopathological changes caused by ASFV infection,and to provide the basis for the pathological diagnosis and pathogenesis of ASFV.In this experiment,14 pigs were selected for ASFV antibody test negative,of which 12 pigs were used as test challenge pigs and 2 pigs were used as control pigs.After tapping the poison,1 ～ 6 days,autopsy two pigs everyday,obtained the lymph nodes,spleen,tonsils,lungs,liver,kidney,bone marrow,brain,muscle,gland tissue and digestive tract,after fixation with 10% formalin solution and routine paraffin section,HE staining was performed for histopathological examination and immunohistochemical staining was performed for viral antigen localization.The results showed that,lymph node,spleen,brain,myocardium,tonsil,lung,thymus,kidney,liver,bone marrow and other tissues showed no obvious lesions at 1-5 d after challenge,but showed obvious lesions at 6 d after challenge.The lesions of cerebellum,thyroid,parotid,submandibular gland,pancreas,duodenum,bladder and skeletal muscle were not obvious at day 1 to 6.ASFV mainly affected immune organs(lymph nodes and spleen),and the main pathological changes were hemorrhagic necrotizing lymphadenitis,acute inflammatory splenomegaly,interstitial pneumonia,interstitial hepatitis,non-suppurative encephalitis and interstitial myocarditis.The antigen of experimental infected ASFV mainly exists in the cytoplasm of macrophages in lymph nodes,spleen,tonsil,lung,thymus and bone marrow,the second is in the cytoplasm of lymphocytes,in the later stage,there is a brownish yellow positive signal in the cytoplasm of liver cells and renal epithelial cells.Studies have shown that the disease of ASF is characterized by hemorrhagic necrotizing inflammation of lymphatic tissue,hemorrhage of multiple tissues and organs,and hemorrhagic septicemia characterized by interstitial inflammation.Virus antigens mainly exist in macrophages and lymphocytes of lymphatic tissue.