Clinicopathological characterization and genomic sequence differences observed in a highly virulent fowlAviadenovirusserotype 4

Abstract

Highly virulent fowl aviadenoviruses (genus: Aviadenovirus) represent a significant risk in poultry farming that may contribute to increased mortality rates and may adversely affect the growth performance of poultry flocks. In this study, we performed the clinicopathological characterization of a FAdV strain SHP95 isolated from a commercial farm and its whole genome sequencing. The study revealed that the isolated strain is a highly virulent serotype 4 FAdV that can cause 100% mortality in day-old specific pathogen free (SPF) chickens with a dose of 2.5 × 10(5) TCID50. At a lower viral dose (1.5 × 10(4) TCID50), the infection in day-old SPF chickens caused 40% mortality and lesions characteristic for Hepatitis-hydropericardium syndrome (HHS). The viral strain was detectable by real time PCR in chicken organs, including the lymphoid organs until day 28 after infection. The whole genome assembly of strain SHP95 revealed a size of 45,641 bp, which encodes for 42 viral open reading frame (ORF). The comparative analysis in the genome shows 98.1% similarity between strain SHP95 and other FAdV-4 genomes reported. The major differences in the genome sequence between pathogenic and non-pathogenic fowl Adenovirus were identified in the right arm of the genome.

Genetic characterization of novel fowl aviadenovirus 4 isolates from outbreaks of hepatitis-hydropericardium syndrome in broiler chickens in China

“…The G+C content (54.87% for HNJZ, SXCZ, JSXZ and AHBZ and 54.86% for SDDZ) was similar to those of other reported FAdV-4 strains, including ON1, KR5, JSJ13 and MX-SHP95 (54.63% to 54.88%). The gene order and shared open reading frames (ORFs) were similar to those of other reported FAdV-4 strains, 31, 32, 33, 34, 35 except that there were deletions in the 22 kDa protein, ORF19, ORF27 and ORF19A (Figure 2). …”

“…32 When compared with the FAdV-4 strains reported earlier, that is, the highly pathogenic MX-SHP95 strain, the non-pathogenic KR5 strain and the ON1 strain, 31, 33, 35 nucleotide identities of 98.8%, 98.3% and 98.5% were observed for the complete genomes, 95.8%, 96.7% and 95.7% identities were observed for fiber 1, 97.2%, 95.9% and 95.8% identities for fiber 2, 98.6%, 98.9% and 98.7% identities for hexon, and 99.2%, 99.0% and 98.9% identities for the penton base.…”

“…31, 33, 35 Alignment of the Chinese FAdV-4 isolate genome sequences with the available complete genomes of FAdV-4 strains in GenBank showed various nucleotide sequence deletions. The effects of these deletions and sequence differences in various regions of the Chinese isolates' genomes on viral replication and pathogenicity remain to be investigated.…”

Different Dynamic Distribution in Chickens and Ducks of the Hypervirulent, Novel Genotype Fowl Adenovirus Serotype 4 Recently Emerged in China

“…HHS appears with high frequency in chickens, particularly in broilers, with a mortality that ranges from 10 to 100% (Vera-Hernández et al, 2016; Pan et al, in press). However, the disease has rarely emerged in other hosts with severe clinical signs and high mortality.…”

“…However, the disease has rarely emerged in other hosts with severe clinical signs and high mortality. Fowl adenovirus serotype 4 (FAdV-4) plays a primary role in the etiology of HHS based on epidemiological studies, and many hypervirulent strains have been isolated from cases of HHS (Vera-Hernández et al, 2016; Ye et al, 2016; Pan et al, in press). For diagnosis of FAdVs infection, several routine PCR methods have been reported based on serotype-specific hexon gene (Steer et al, 2009; Kaján et al, 2013) and a SYBR Green based real-time PCR within 52K gene was developed for detection and quantitation of all FAdV species (Günes et al, 2012).…”