Infectious laryngotrachitis at a layer farm in Miyazaki [Japan] Prefecture
2010
Saito, S., Miyazaki-ken. Livestock Hygiene Service Center (Japan) | Katayama, T. | Inai, K. | Kamata, H.
In February 2008, infectious laryngotrachitis (ILT) was detected in Miyazaki Prefecture for the first time in 24 years. At the infected layer farm, the mortality of chickens with slight respiratory symptoms increased in a 322-day-old flock. Macroscopically, the trachea of some chickens exhibited congestion and white necrotic foci. The trachea homogenates were inoculated into embryonated eggs and produced pocks on the chorioallantoic membrane. Histopathologically, intranuclear inclusion bodies and syncytial cells were found at the epithelium of trachea, larynx, and lungs. The inclusions were found to be positive against the ILT virus by immunohistochemistry. These chickens hardly had antibodies against ILT virus in spite of vaccination at the late chick stage. Emergency vaccination was immediately performed for the surrounding flocks, and the mortality of chickens decreased in approximately 10 days. The mortality in the chicken house where ILT broke out was 1.2%.
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