Abstract: 84 10-day old healthy Muscovy ducks were infected with Muscovy Duck Reovirus (MDRV). The distribution of virus was detected by immunohistochemistry at 6, 12, 24, 48, 60, 72, 84, 108, 144, 204, 312 and 384 hours after infection. The purpose of this study is to explore infected cells and the pathogenesis. The results of detection showed that 6 and 12 hours post infection, all organs were negative; 24 hours post infection, liver, intestine and cerebrum showed positive cells first; 144 hours post infection, all organs were strongly positive; 204 hours post infection, spleen, lung and thymus kept the strongly positive reaction while the positive reaction of other organs began to decrease. The most strongly tissue tropism of MDRV was liver, spleen and cecum, and these tissues were the target organs of MDRV. The infected cells were as follows: capillary endothelial cells in all detected organs; liver cells and Kupffer’s cells in liver; lymphocyte, macrophage in spleen; epithelial cells of renal tubules, podocyte in kidney; cardiac muscle cells in heart; epithelial cells of alveolus, dust cells in lung; lymphocyte and macrophage in thymus; lymphocyte in Fabricius’bursa; epithelial cell, goblet cells, lymphocyte in intestine; oligodendrocyte in cerebrum and cerebellum. The infiltrated inflammatory lymphocytes were also positive in liver, kidney, heart, lung and other tissues.

Key words: reovirus; immunohistochemistry; distribution; Muscovy duck