primary isolation from clinical material. Typically, the CPE effect of avian reoviruses is the production of syncytia. CPE, or cytopathic effects are the visible changes in a host cell that takes place because of viral infection. Syncytia is a single cell or cytoplasmic mass containing several nuclei, formed by fusion of cells or by division of nuclei. Genome structure The complete genome sequence of avian reovirus is 23,494 bp long and is broken up into 10 segments. The full lengths of each segment are L1 (3,959 nt), L2 (3,830 nt), L3 (3,907 nt), M1 (2,283 nt), M2 (2,158 nt), M3 (1,996 nt), S1 (1,643 nt), S2 (1,324 nt), S3 (1,202 nt), and S4 (1,192 nt). There are 10 proteins that are also involved in the composition of this virus. The lengths of these structural and non-structural proteins are λa (1,293 amino acids), λB (1,259 aa), λC (1,285 aa), μA (732 aa), μB (676 aa), μNS (635 aa), σC (326 aa), σA (416 aa), σB (367 aa), and σNS (367 aa). Virus-host interactions Alpha and beta interferons belong to a family of multifunctional cytokines, which are expressed and activated/distributed by fibroblasts and leukocytes in response to infections. In an experiment where primary cultures of chicken embryo fibroblasts were treated with alpha/beta interferon, results indicated that this interaction induced an antiviral state that strongly inhibited vaccinia and vesicular stomatitis virus (VSV) replication, but didn't have an effect on avian reovirus, specifically the replication of the S1133 strain. Instead, extracts of cells that were infected with avian-reovirus were able to block the activation of dsRNA-dependent enzymes, enabling the virus to relieve the translation-inhibitory activity of dsRNA. Also, protein σA, which is a core protein of the S1133 strain, binds to dsRNA irreversibly. Removing this protein from this particular viral strain disables the posttranslational capacity of infected cells. Research has shown that this core protein may possibly disrupt the IFN-induced cellular response against avian reovirus through the blockage of enzyme pathways that are dependent on dsRNA. In addition to the possible disruption of IFN-induced cellular responses, chicken embryo fibroblasts that are infected with strain S1133 have displayed significant cytopathic effects. Strain S1133 led to the activation of the intracellular death in the early stages of infection. Although viral gene expression is not necessary, intracellular viral uncoating is the significant process that induces apoptosis. The ability of avian reovirus to induce apoptosis is not restricted