Variability Assessment of California Infectious Bronchitis Virus Variants

On the basis of the data from the California Animal Health and Food Safety Laboratory System, 1444 infectious bronchitis (IB) cases were diagnosed between 1997 and 2012. Epidemiologic analyses demonstrated two major IB virus (IBV) outbreak peaks, affecting mainly 35-to-49-day-old broiler chickens. California variant 1737 (CA1737) and California variant 1999 (Cal 99) IBV types were the most prevalent genotypes during the analyzed period. To further understand the increased prevalence of these genotypes, we assessed and compared the variability of the S1 gene hypervariable region of CA1737 and Cal 99 with the variability of IBV strains belonging to the Massachusetts 41 (M41) and Arkansas (Ark) types during serial passages in embryonated chicken eggs. On the basis of the S1 nonsynonymous changes, seven different subpopulations were detected in M41. However, the predominant population of the field strain M41 before passages continued to be predominant throughout the experiment. In contrast, Ark passaging resulted in the detection of 13 different subpopulations, and the field sequence became extinct after the first passage. In IBV Cal 99, eight different subpopulations were detected; one of these became predominant after the second passage. In CA1737, 10 different subpopulations were detected. The field strain major sequence was not detected after the first passage but reappeared after the second passage and remained at low levels throughout the experiment. Compared with M41 and Ark, Cal 99 and CA1737 showed intermediate variability.

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 observedon a regular basis in California turkey flocks during the last 12 yr.

Omphalitis Associated with Aspergillus fumigatus in Poults

Omphalitis associated with aspergillosis was diagnosed in four cases of commercial turkey poults ranging in age from 3 to 9 days old. In two cases, the mycotic agent present in the yolk sac was isolated and identified as Aspergillus fumigatus. In the other two cases, the fungi were identified as Aspergillus sp. on the basis of morphologic characteristics of the fungi in tissue sections. The fungi present were further confirmed to be of the genus Aspergillus by immunohistochemistry. Omphalitis by A. fumigatus infection has not been documented before.

Phenotypic and Genotypic Characterization of Salmonella arizonae from an Integrated Turkey Operation

Fifty cases submitted between 2000 and 2002 were selected for retrospective analysis to evaluate possible relationships between Salmonella arizonae isolated from breeder flocks, hatching eggs, and meat bird flocks belonging to a single turkey integrator. In all the meat bird cases selected for this study, arizonosis was the primary diagnosis. In birds under 1 month of age, clinical signs and pathologic changes were observed in older birds. The Salmonella arizonae isolates were analyzed by antibiotic resistance pattern and serotype and genotyped by pulsed-field gel electrophoresis (PFGE). Serotyping and PFGE yielded similar results, but the antibiotic resistance patterns did not correspond to either serotyping or PFGE typing. The presence of common pulsed-field patterns in breeder flocks, eggs, and meat bird flocks suggested that S. arizonae was being transmitted vertically from the breeder flock.