Abstract: Objective To study the pathogenicity of avian influenza H5N1 virus to Gerbil. Method Anesthetized gerbil were inoculated intranasally with avian influenza virus isolates at a biosafety level 3 laboratory. Throughout the 14-day experiment, clinical signs were observed； body weight and body temperature were recorded； the blood was collected to analyze AIV antibodies；tissue samples from the lungs, livers, kidneys and so on were processed for virus isolation and histopathology. Result The H5N1 AIV caused severe diseases in gerbils mainly between day 2 p.i and day 6 p.i，characterized by ruffled fur, inappetence, hunched-back posture, labored breathing, hypothermia, weight loss and 44% mortality. Antibodies were detected from 8 days p.i. The histopathologic examinations showed that variable degrees of lesions including congestion and hemorrhage were observed in the lungs, livers, kidneys and so on.. The lesions of the lungs showed interstitial pneumonia, dropsy, configuration breakage. Conclusion Avian influenza （H5N1） virus is pathogenic to Gerbil.

Key words: Gerbil, Avian influenza （H5N1） virus, Pathogenicity