to a distinct cell type of virus strain due to the fact that several different isolates of this pathogen could induce apoptosis in different mammalian and avian cell lines. Apoptosis can also be induced in cells that are infected with UV-irradiated reovirus virions and cells infected with ribavirin-treated avian reovirus, which suggests that viral mRNA synthesis and crucial steps that occur during viral replication are not necessary for induction of apoptosis in infected cells. Disregarding infectivity, the number of inoculated virus particles is the significant factor that leads to apoptosis from avian reovirus. Induced apoptosis is stopped when intracellular viral uncoating is blocked. Diseases There are several diseases that are caused by avian reovirus, which includes, avian arthritis/tenosynovitis, runting-stunting syndrome, and blue wing disease in chickens. Blue wing disease affects young broiler chickens and has an average mortality rate of 10%. It causes intramuscular and subcutaneous hemorrhages and atrophy of the spleen, bursa of Fabricius, and thymus. When young chickens are experimentally infected with avian reovirus, it is spread rapidly throughout all tissues. This virus is spread most frequently in the skin and muscles, which is also the most obvious site for lesions. Avian arthritis causes significant lameness in joints, specifically the hock joints. In the most severe cases, viral arthritis has caused the tendon to rupture. Chickens that have contracted runting-stunting syndrome cause a number of individuals in a flock to appear noticeably small due to its delayed growth. Diseased chicks are typically pale, dirty, wet, and may have a distending abdomen. Some individuals may display “helicopter-like” feathers in their wings and other feather abnormalities. The virus has also been shown to cause osteoporosis. Mechanism The most common route of infection occurs orally, and occasionally through the respiratory tract from the nucleus of congenitally infected hatch mates. Experimental infection of adult chickens through the esophagus, nasal passages, or trachea caused the virus to spread throughout all areas of the enteric, respiratory tract, reproductive tract, and the hock and tendon joints. In an experiment, avian reovirus was recovered from mononuclear, plasma, and erythrocyte cell fractions of blood within 30 hours of infection in young chicks. After 3–5 days, the infection spread throughout the whole body. The main site of viral replication was observed in the enteric tract. A different study of early pathogenesis in chicks infected with virus one day after birth displayed that the bursa of Fabricius and the