Molecular Detection of Gumboro Disease Virus in Broiler Flocks with Acute Clinical Signs in Guilan Province

Infectious bursal disease virus (IBDV/GD) is an acute, highly contagious viral disease and important immunosuppressive pathogen of chickens and pullets worldwide. The aim of this research was the molecular detection of Gumboro strains in clinical cases of broiler chickens in Guilan province. On the basis of clinical signs and postmortem findings, 4 flocks (10%) out of 40 flocks were suspected to Gumboro disease. RNA was extracted from fabricious bursal samples of 4 flocks and RT-PCR was performed. IBDV was detected in every 4 flock samples as evidenced by amplification of 643 bp fragment of the very variable region of VP2 gene. The authenticity of the amplicons was further confirmed by Nested-PCR generating 552-bp amplicons using specific primers. To distinguish the viral virulence, PCR products of positive samples were digested with two restriction enzymes (SacI and BspMI ) and results were recorded. Results showed that vvIBD was detected in all 4 flock bursal samples. In conclusion, in spite of redction in incidence rate of Gumboro clinical signs in recent years, passage of vvIBD virus in chicken flocks are observed. Future study on subclinical Gumboro diseases detection in early age of broiler flocks are recommended.