[show abstract][hide abstract] ABSTRACT: In the present study day-old specific-pathogen-free (SPF) and commercial broilers with maternally derived fowl adenovirus serotype 1 (FAdV-1) antibodies were orally infected with a European "pathogenic" FAdV-1, isolated from broilers showing signs of gizzard erosion. During the experiment, broilers were observed and weighed daily up to 17 days post infection (dpi). Clinically, both infected groups showed significant decrease of weight compared to respective negative control groups. Birds were examined by necropsy at 3, 7, 10, 14 and 17 dpi. Pathological changes in the gizzards were noticed in both experimentally infected groups from 7 dpi onwards. Macroscopically, erosion of the koilin layer and inflammation or ulceration of the gizzard mucosa were observed. Histologically, presence of FAdV-1 in intranuclear inclusion bodies of degenerated glandular epithelial cells was demonstrated by in-situ hybridization and inflammatory cell infiltration of the lamina propria, submucosa and muscle layer was detected. Tissue samples were investigated by a recently developed real-time PCR and the viral DNA load was calculated from gizzard, liver, spleen and cloacal swabs with the highest amounts of FAdV-1 DNA found in the gizzard. For the first time, successful reproduction of clinical signs in broilers as well as pathological lesions in the gizzard were achieved with a European FAdV-1 isolate displaying some genetic differences to so far reported virulent FAdV-1 from Japan. Furthermore, highest viral load in gizzards could be linked with macroscopical and histological lesions. Therefore, the conducted analyses provide important insights into the pathogenesis of adenoviral gizzard erosion.
Veterinary Research 05/2013; 44(1):38. · 3.43 Impact Factor
[show abstract][hide abstract] ABSTRACT: The present study describes the development of a SYBR Green based real-time polymerase chain reaction (real-time PCR) for detection and quantitation of all fowl adenovirus (FAdV) species. Primers were designed based on conserved nucleotide sequences within the 52K gene. Ten-fold serial dilutions of a vector DNA were used as standard for quantitation. The real-time PCR had an efficiency of 98%, a regression squared value of 0.999 and showed a range of 6.73-6.73×10(8) copies of FAdV DNA per reaction. The assay was highly specific for FAdVs and an exact quantitation of all 5 FAdV species (FAdV-A to FAdV-E) could be demonstrated. It was shown, that twelve FAdV serotypes (FAdV-1 to 8a, and 8b to 11) were detectable and quantifiable. Other viral genomes as well as uninfected chicken embryo liver (CEL) cells did not produce positive signal. Cloacal swabs were taken during the animal experiment, which was performed with all FAdV species. Shedding of FAdVs was investigated in cell culture, by conventional PCR and by the developed real-time PCR. The real-time PCR was found more sensitive than cell culture and conventional PCR. Detection and quantitation of FAdVs in different type of samples was possible by the new real-time PCR.
Journal of virological methods 04/2012; 183(2):147-53. · 2.13 Impact Factor
[show abstract][hide abstract] ABSTRACT: A total of 44 fowl adenovirus (FAdV) samples from 6 European countries, Pakistan, India, Kuwait, Mexico, Peru and Ecuador were used in this study and the phylogenetic analyses based on the loop 1 (L1) region of hexon gene were performed. For comparison, available hexon sequences of representatives of different FAdV species were also used. At least 12 genotypes within the five FAdV species (A-E) were revealed and the existence of these genotypes was supported by high bootstrap values. Furthermore, three primer pairs binding to the conserved pedestal regions (HexL1s/HexL1as and HexA/HexB) and pedestal (P1) region and loop 2 (L2) region (HexF1/HexR1) of the FAdV hexon gene were used for high-resolution melting (HRM)-curve analysis and results were compared with those of phylogenetic analyses. HRM-curve analysis based on the HexL1s/HexL1as region grouped all tested field isolates and reference strains into 22 subgroups, consistently with phylogenetic analysis. This method is a rapid and cost-effective alternative to existing serotype identification methods and offers a possibility to classify FAdV isolates more precisely. However, it has limitations such as need for extensive interpretation of results and potential for indeterminate results. Gaining of hexon sequences of further field isolates offers the potential for novel and additional information in analysis of the molecular epidemiology of FAdV.
Journal of virological methods 12/2010; 170(1-2):147-54. · 2.13 Impact Factor