Pathogenicity of field strain of fowl aviadenovirus serotype 11 isolated from chickens with inclusion body hepatitis in Morocco

Outbreaks of inclusion body hepatitis have emerged in Morocco since 2013 and has resulted in significant economic losses to poultry farms. Three isolates of the causative virus, Fowl adenonovirus (FAdV)were characterized from chickens with IBH, but their pathogenicity has never been investigated. In this work, the pathogenicity of an isolate FAdV 11 (MOR300315 strain) was evaluated by inoculating a group of 40 SPF chickens at 3 days of age by oral route. A group of 40 chicks injected with phosphate-buffered saline solution was used as a control group. The infected chickens showed decreased weight gain from 3dpi. Necropsy displayed pallor and enlargement in liver, swelling and slight hemorrhage in kidney and spleen at 6 dpi. Histopathological changes were mainly characterized by severe and extensive hepatic necrosis associated with the presence of basophilic intra-nuclear inclusion bodies within hepatocytes. The FAdV was reisolated in chicken embryo fibroblast cell culture from liver tissue homogenate of infected chicken from 3 to 6 dpi. Viral DNA was detected by PCR in liver, kidney, spleen and cloacal swabs from 3 to 13 dpi. Antibody response against inoculated FAdV was appeared from 9 dpi. These results confirmed that the FAdV 11 strain is pathogenic in chicken. This study is the first experimental infection of FAdV 11 in chicken in Morocco, which increase our understanding of its pathogenicity in chickens and indicate that preventive measures against FAdV infection in poultry farms should be implemented in Morocco.

Complete Genome Sequence of a Fowl Adenovirus D Strain Isolated from Chickens with Inclusion Body Hepatitis in Japan

We report the complete genome sequence of fowl adenovirus D (FAdV-D) strain JP/Tokushima/2010IBH, which was isolated from chickens with inclusion body hepatitis in Japan. This FAdV-D isolate was genetically highly similar to recent isolates from China, suggesting a common origin.

Isolation and Molecular Characterization of Fowl Adenoviruses Associated with Inclusion Body Hepatitis-hydropericardium Syndrome in Broiler Chickens in Egypt

Avian adenoviruses are an extremely diversified group of pathogens that recently triggering a variety of problems for poultry production. In particular, Inclusion Body Hepatitis-Hydropericardium Syndrome (IBH-HPS), which has been observed in broiler birds from 3 to 6 weeks of age and is associated with anemia, hemorrhagic disorders, hydropericardium, and high mortality. The disease has been reported worldwide, and recently it was reported in many Egyptian farms, causing severe economic losses. Therefore, the current study aimed to isolate, and genetically type the most common Adenovirus serotypes associated with this syndrome in Egyptian farms. A total of 50 broiler chicken farms (3-6 weeks old) located in different Egyptian governorates were examined. Macroscopically, the diseased flock revealed hydropericardium, enlarged friable livers with ecchymotic hemorrhages, and varying mortality rates (1 to 7.5%). Histopathologically, severe diffuse necrotizing enteritis, hepatitis, pericarditis, and diffuse lymphoid depletion of the spleen were the most prominent lesions. Liver tissues and cloacal swabs were collected from all examined flocks for FAdVs detection by conventional polymerase chain reaction (PCR) targeting the L1 loop in the hexon gene. The PCR products were sequenced for typing of the detected viruses. It was found that 10 out of 50 flocks examined were PCR positive for FAdVs (20%). Phylogenetic analysis of the sequenced genes revealed that the obtained viruses clustered with reference strains belonging to FAdV type D and E serotype 2, 11, and 8a respectively. The isolation of both FAdV type D and FAdV type E were carried out on a primary cell culture chicken embryo liver cell (CEL) and the presence of these viruses was confirmed by PCR after the appearance of cytopathic effect (CPE). From this study, it could be concluded that both FAdVs types D and E are the most common adenoviruses circulating in poultry farms suffering from hydropericardium and inclusion body hepatitis.

Fowl adenovirus strains 1/A and 11/D isolated from birds with reovirus infection

Inclusion body hepatitis (IBH) is, in some cases, a fatal disease affecting fowl by adenovirus strains which are subdivided into 5 species (A-E). In the current study, we investigated sequences from the Loop L1 region of the hexon gene of sequences of adenovirus field stains 1/A and 11/D isolated from a poultry flock co-infected with IBH and avian reoviruses ARVs. In early 2021, an epidemiologic survey highlighted the coinfection adenoviruses with other viruses (orthoreovirus infection) as being particularly deleterious within the poultry industry. Here, we investigated the Loop L1 HVR1-4 region of the hexon gene with relative synonymous codon usage (RSCU) designation and RSCU inclusive of all the mutations. These are the first results that have been presented on fowl adenovirus species A and D with simultaneous reovirus infection in 38-days old broiler chickens in Poland.

Temporo-Spatial Sero-epidemiology of Fowl Adenovirus (FAdV) Infection Causing Inclusion Body Hepatitis-Hydropericardium Syndrome (IBH-HPS) in Broiler Population of Assam

Background: Aviadenoviruses affect birds, particularly chickens, ducks, geese, turkeys and pheasants, which have total 12 serotypes. Inclusion body hepatitis (IBH) caused by aviadenovirus was has been reported in many countries worldwide. The diseases was first reported from Assam in 2017. Although there is increasing reports of the occurrence of IBH-HPS in the broiler population of North Eastern India, but its prevalence at different geoclimatic condition and at various seasons have not been carried out. Under these circumstances, the present study was envisaged to analyse the seroprevalence status of Fowl adenovirus infection in some broiler rearing districts of Assam. Methods: For the present study, blood samples were collected from 12 different districts of Assam including all agroclimatic regions during the period from June, 2016 to May, 2017. Association of various factors like age, season and health status with the prevalence of the affected birds were also studied. Indirect ELISA was performed by using commercially available FAdV ELISA kit. The results obtained were analyzed by the Statistical Package for Social Sciences (SPSS) version 26.0.Result: A total of 460 serum samples were screened, of which 213 were found positive for FAdV antibodies with a sero-positivity of 46.38 per cent. FAdV antibodies were observed in all age grouped birds. Highest (64.28%) positivity was recorded in the birds of 4th week of age, followed by above 4th week (63.47%), 3rd week (32.03%), 2nd week (27.36%) and 1st week (10.0%). Health status-wise 68.97 percent sero-positivity was recorded in the affected flock, where as 32.51 percent in apparently healthy flock. Season-wise, highest (61.53%) sero-positivity was recorded in post monsoon season followed by monsoon (49.00%), winter (32.49%) and pre-monsoon (32.39%).

Emergence of fowl aviadenovirus C-4 in a backyard chicken flock in California

Fowl aviadenovirus (FAdV) species D and E are associated with inclusion body hepatitis (IBH); species C, serotype 4 (hereafter, FAdV4) is associated with hepatitis–hydropericardium syndrome (HHS) in young chickens. Outbreaks of HHS have led to significant losses in the poultry industry in several countries, predominantly in China. In April 2020, FAdV4 was detected in a remote backyard flock in California. In a mixed flock of chickens of various breeds and ages (6 mo to 2 y old), 7 of 30 were found dead within a week without premonitory signs. One additional bird died after the flock was relocated to fresh pasture, bringing the total mortality to 8 of 30 (27%). Postmortem examination of 3 birds revealed good body condition scores and active laying. One chicken had subtle hemorrhages throughout the liver, and the other 2 had diffusely dark mahogany livers. On histopathology, 2 chickens had hepatic necrosis with hepatocytes containing large, mostly basophilic, intranuclear inclusion bodies, identified by electron microscopy as 82.2-nm diameter adenoviral particles. Virus isolation and genomic sequencing performed on a liver sample revealed strains with 99.9% homology to FAdV4 isolates reported from China. To our knowledge, FAdV4 has not been reported in the United States to date. Furthermore, the chickens affected here were all adults and exhibited a variation of serotype 4 disease in which IBH was present but not hydropericardium.

Molecular Markers and Phylogenetic Analysis of UPMT27, a Field Isolate of the Malaysian Fowl Adenovirus Associated with Inclusion Body Hepatitis

Inclusion body hepatitis (IBH) is considered one of the re-emerging diseases of avian virus that causes economic damage worldwide. IBH is caused by different serotypes of fowl adenovirus (FAdV), and most of the FAdV cases in Malaysia are related to the serotype 8b. The objective of this study was to determine the molecular markers of UPMT27 Malaysian FAdV isolate and to identify the evolutionary relationship through the phylogenetic approach. Propagation of the isolate was made in embryonated chicken eggs and chicken embryo liver (CEL cells) before it was subjected to viral DNA extraction. Both the fiber and hexon genes of the isolate were amplified and sequenced. The sequences were aligned with the published FAdV sequences. The results showed 100% identity between UPMT27 and the previous Malaysian isolates. A phylogenetic study showed that UPMT27 was closely related to the previous Malaysian isolates. Interestingly, the substitution of the amino acids was consistent between the Malaysia isolates of both fiber protein at positions 72 (Serine –serine), 101 (Alanine -alanine), 125 (Glycine-glycine), and hexon protein 85 (Serine-serine) 160 (Glutamate- glutamate) and 205 (Alanine-alanine) respectively. It appeared that the amino acid variations were the indicators for genetic diversity. Thus, these findings provide information on the evolutionary relationship between FAdV subtypes for IBH prevention.

Fowl adenovirus (FAdV) fiber-based vaccine against inclusion body hepatitis (IBH) provides type-specific protection guided by humoral immunity and regulation of B and T cell response

A recombinant fowl adenovirus (FAdV) fiber protein, derived from a FAdV-8a strain, was tested for its efficacy to protect chickens against inclusion body hepatitis (IBH). FAdV-E field isolates belonging to both a homotypic (FAdV-8a) and heterotypic (-8b) serotype were used as challenge. Mechanisms underlying fiber-induced protective immunity were investigated by fiber-based ELISA, virus neutralization assays and flow cytometry of peripheral blood mononuclear cells, monitoring the temporal developments of humoral and cellular responses after vaccination and challenge exposure. Birds were clinically protected from the homologous challenge and showed a significant reduction of viral load in investigated target organs, whereas fiber-based immunity failed to counteract the heterologous serotype infection. These findings were supported in vitro by the strictly type-specific neutralizing activity of fiber immune sera. In protected birds, fiber vaccination prevented a post-challenge drop of peripheral B cells in blood. Furthermore, fiber immunization stimulated CD4+ T lymphocyte proliferation while moderating the CD8α+ T cell response and prevented challenge-induced changes in systemic monocytes/macrophages and γδ+ T cell subpopulations. Both vaccinated and adjuvant-only injected birds experienced a priming of systemic B cells and TCRγδ+ T lymphocytes, which masked possible pre-challenge effects due to the antigen. In conclusion, within FAdV-E, recombinant fiber represents a vaccine candidate to control the adverse effects of homotypic infection by eliciting an effective humoral immunity and regulating B and T cell response, whereas the failure of heterotypic protection suggests a primordial role of humoral immunity for this vaccine.