study on period of persistence of foot-and-mouth disease virus in different organs in guinea pigs. After adaptation of foot-and-mouth disease viruses type O in 10 guinea pigs pad’s, 30 Animal divided to 5 groups containing 6 animals in each group so that 5 animals inoculated from each group and normal saline injected in a guinea pig as negative control.
Euthanized animal in 5 periods including: 2 days post virus generalization, 4 days post virus generalization, 14 days post virus generalization, 30 days post virus generalization, 60 days post virus generalization. Then collecting samples from: heart, lung, liver, spleen, pancreas, retropharyngeal lymph node, palntar epithelium, inguinal lymph node and tongue Epithelium, sent to Pathology Department to pathological studies also other of those sent to FMD Department to viral detection. Pathological samples fixed in formalin then prepared paraffin ،s blocks and slides with 5 microns with H&E staining. Viral samples kept in glycerinated buffer and detected the amount of virus by Sandwich Elisa according to reference. At least base on our study the maximum of FMDV lesions we observed affected plantar Epithelium, Lung, Tongue Epithelium and spleen consequently and showed that pathologic lesion contained: Intracellular spongiosis, vacuolization and pyknosis of cells from the spinous layer, Intercellular edema in spinous layer of Epithelium (plantar and Tongue) also Hyperemia and increased size of inter alveolar septa in Lung and decreased in white pulp compared to uninfected control guinea pig in spleen. In addition results of Elisa determined extreme amount of virus were in 14 days post virus generalization and we have not any evidence of being virus in 30 and 60 days post virus generalization. It is concluded that the results of Pathological observations can be confirmed by Elisa detection.