Outbreak of acute colisepticemia in commercial layer hen
2009
Koizumi, S.(Chiba-ken. Government Office (Japan)) | Ogawa, A. | Kinoshita, T. | Hirahata, J. | Ashizawa, T. | Haketa, M.
The sudden deaths of 75 weeks-old birds were reported in a layer chicken farm in Chiba Prefecture, Japan, from January to February 2007. They had no clinical signs. Daily mortality rates rose to 0.28% in comparison with 0.03% before the outbreak. At necropsy, a few birds had very mild perihepatitis; other birds had no lesions. Histopathologically, necrosis of lymphoid follicles and ellipsoids with fibrin exudation were observed in the spleen, and fibrinous thrombi were seen in the blood vessels of the lung, liver, brain, heart, kidney and small intestines. The birds presented the disseminated intravascular coagulation (DIC) condition. These cases were first suspected to be highly pathogenic avian influenza based on the outbreak situation. However, tests for highly pathogenic avian influenza were negative, and Escherichia coli O78 was isolated in pure cultures from systemic parenchymatous organs. The cases were diagnosed as colisepticemia by Escherichia coli O78. We regarded that poor ventilation and chicken-house dust produced by scattering the diatomaceous earth were inducing factors. This study suggests acute colisepticemia in adult chickens is a disease to be differentiated from highly pathogenic avian influenza.
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