Retrospective Study of Turkey Viral Hepatitis in California Turkey Flocks, 2000–2012

Turkey viral hepatitis (TVH) is a disease characterized by an inflammation of the liver, and occasionally of the pancreas, of turkeys. Little is known about the occurrence of TVH in turkey flocks; thus, the aim of the present article is to summarize retrospectively 76 cases of TVH diagnosed at the California Animal Health and Food Safety System (CAHFS), University of California, Davis, in the years 2000 through 2012. Flocks diagnosed with TVH were between 7 and 61 days old, with an average age of 29.4 days and a median age of 28 days. In the majority of cases, increased mortality was reported. In 55 cases, gross lesions were present in the liver; the most common lesions were a few to numerous pale white foci in 35 cases. In livers of 74 cases, histologic lesions were observed. Multifocal necrosis with inflammation was observed in livers of 42 cases, inflammation but no necrosis in 22 cases, and necrosis without inflammation in 8 cases. In 17 cases, pale white foci were found in the pancreas; in 4 cases, larger areas of the organ were pale. In 33 cases, histologic changes were observed in the pancreas. Necrosis with inflammation was observed in the pancreas of 17 cases, necrosis without inflammation in 7 cases, and inflammation without necrosis in 9 cases. No Salmonella was isolated from any of the livers cultured. Transmission electron microscopy of liver and pancreas demonstrated viral particles between 23 and 25 nm in two cases. Concurrent diseases were mostly poult enteritis (65 cases), but also respiratory diseases and colibacillosis. TVH occurred more often in turkeys during winter months. In conclusion, TVH was observed on a regular basis in California turkey flocks during the last 12 yr. Estudio retrospectivo de la hepatitis viral de los pavos en parvadas de pavos en California entre los años 2000 al 2012. La hepatitis viral de los pavos (con las siglas en inglés TVH) es una enfermedad caracterizada por una inflamación del hígado, y ocasionalmente del páncreas, de los pavos. Poco se sabe acerca de la presentación de esta enfermedad en parvadas de pavos, por lo que el objetivo del presente artículo fue resumir de forma retrospectiva 76 casos de la hepatitis viral de los pavos diagnosticados en el Sistema de Salud Animal y Seguridad Alimentaria del estado de California (CAHFS), Universidad de California, Davis, entre los años 2000 al 2012. Las parvadas que fueron diagnosticadas con esta enfermedad tenían entre 7 y 61 días de edad, con una edad promedi