The Localization Of Foot-and-Mouth Disease Virus In Pigs

A new type, biological magnified reaction system Avidin-Biotin System (ABS) have been widely using in immunoassay. A simple, rapid, specific and sensitive method detecting FMDV in tissues, with biotin labeled antibodies IgG an avidin-biotin-peroxidase complex (ABC) immunoenzymatic histochemical technique was developed.This is the first time in our country to costruct animal model of milk mice and 12 pigs were infected with the oringinal strain O/Akesu/58 that the full-length genome has known by inoculating muscle, then various tissues samples of pigs were collected and detected, lasting70 days. Towards the samples that fixed, by H-E, indirect enzyme-labled antibody and ABC staining observe the pathology of various tissues and detect the structural protein and virus infection associated antigen(VIA) . The results showed that the skeletal muscle was the characteristics coagulative necrosis of milk mice inoculated. Cytoplasm of muscle fiber was full of a great deal of viral particle by enzyme-labeled antibody and ABC staining.It was tumefaction of skin and cells of the stratum spinosum of skin mucosa of pigs inoculated. With development of the disease, spinous cells were liquefactive necrosis and chromatolysis. The pattern of staining was extensive or weak for nucleolus. Detection of structural protein and VIA showed that the epithelium were more suitable for FMDV generation. Viral particles were present more or less in epithelial cell that detected until 7 days post-inoculation. Viral particles were prominent in lymphoid nodule of lymphoid tissue. Viral particles were lasting until 14 days post-inoculation in pharynx,pharynx dorsal lymphoid nodule,soft palate,palate tensil lung and lung lymphoid nodule .These tissues were negative at 28 days post-inoculation. Positive staining was distinct for palate tensil. Viral particleswere only detected in snout, dorsal tongue, mucosa of mouth, oesophagus, eyelid, cuneus ungulae and coronae ungulae at 7 days post-inoculation. In the lung, FMDV localized alveolar septa and alveolar macrophages. It was negative that cardiac muscle, liver, speen, kidney, pectoralis muscle and mammary gland that detected. It exist phenomenon of carriers before 14 days. FMDV was not detected after 28 days. So we can conclude that pig inoculated was not persistent carry state. In addition, it was proved that ABC is a method used detection and localization of FMDV. It is also a promising tool for studying the pathogenesis of FMD.