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Avian influenza (AI) is one of the most important viral diseases in poultry, wildlife and humans. Available data indicate that pigeons play a minimum role in the epidemiology of AI. However, a degree of variation exists in the susceptibility of pigeons to highly pathogenic AI viruses (HPAIVs), especially since the emergence of the goose/Guangdong H5 lineage. Here, the pathogenesis of H5N8 HPAIV in comparison with a H7N1 HPAIV and the role of pigeons in the epidemiology of these viruses were evaluated. Local and urban pigeons (Columba livia var. domestica) were intranasally inoculated with 105 ELD50 of A/goose/Spain/IA17CR02699/2017 (H5N8) or A/Chicken/Italy/5093/1999 (H7N1) and monitored during 14 days. Several pigeons inoculated with H5N8 or H7N1 seroconverted. However, clinical signs, mortality, microscopic lesions and viral antigen were only detected in a local pigeon inoculated with H5N8 HPAIV. This pigeon presented prostration and neurological signs that correlated with the presence of large areas of necrosis and widespread AIV antigen in the central nervous system, indicating that the fatal outcome was associated with neurological dysfunction. Viral RNA in swabs was detected in some pigeons inoculated with H7N1 and H5N8, but it was inconsistent, short-term and at low titres. The present study demonstrates that the majority of pigeons were resistant to H5N8 and H7N1 HPAIVs, despite several pigeons developing asymptomatic infections. The limited viral shedding indicates a minimum role of pigeons as amplifiers of HPAIVs, regardless of the viral lineage, and suggests that this species may represent a low risk for environmental contamination. RESEARCH HIGHLIGHTS H7N1 and H5N8 HPAIVs can produce subclinical infections in pigeons. The mortality caused by H5N8 HPAIV in one pigeon was associated with neurological dysfunction. Pigeons represent a low risk for environmental contamination by HPAIVs. [ABSTRACT FROM AUTHOR]

Summary: H7N9 virus infection is a global concern, given that it can cause severe infection and mortality in humans. However, the understanding of H7N9 epidemiology, animal reservoir species and zoonotic risk remains limited. This work evaluates the pathogenicity, transmissibility and local innate immune response of three avian species harbouring different respiratory distribution of α2,6 and α2,3 SA receptors. Muscovy ducks, European quails and SPF chickens were intranasally inoculated with 105 embryo infectious dose (EID)50 of the human H7N9 (A/Anhui/1/2013) influenza isolate. None of the avian species showed clinical signs or macroscopic lesions, and only mild microscopic lesions were observed in the upper respiratory tract of quail and chickens. Quail presented more severe histopathologic lesions and avian influenza virus (AIV) positivity by immunohistochemistry (IHC), which correlated with higher IL‐6 responses. In contrast, Muscovy ducks were resistant to disease and presented higher IFNα and TLR7 response. In all species, viral shedding was higher in the respiratory than in the digestive tract. Higher viral shedding was observed in quail, followed by chicken and ducks, which presented similar viral titres. Efficient transmission was observed in all contact quail and half of the Muscovy ducks, while no transmission was observed between chicken. All avian species showed viral shedding in drinking water throughout infection. [ABSTRACT FROM AUTHOR]

Inclusion body hepatitis caused by different fowl aviadenovirus (FAdV) serotypes has been described in several countries in recent years. In Spain, from the spring of 2011 to 2013, an increased number of outbreaks in broiler and broiler breeder flocks from different regions occurred. The objectives of the present work were to carry out the molecular characterization of FAdV strains from Spanish inclusion body hepatitis cases and to study the pathogenicity and viral dynamics of these strains in specific pathogen-free (SPF) chickens. A total of 52 inclusion body hepatitis clinical cases, including 45 from broiler farms and seven from broiler breeder farms, were analysed by conventional polymerase chain reaction and sequencing targeting the FAdV hexon gene. From these, 37 strains were classified as FAdV type 8b, while the remaining 15 were classified as FAdV types 11 (n = 10), 2 (n = 4) and 8a (n = 1). In addition, two different FAdVs belonging to the genotypes 8b and 11 were used for experimental infection. Specific pathogen-free five-day-old birds were inoculated intramuscularly with a high (106.5tissue culture infective dose (TCID)50/ml) or low (104TCID50/ml) dose of the above-mentioned FAdVs. No mortality was observed in any of the experimental groups, and only one bird showed evident clinical signs. However, macroscopic and microscopic hepatic lesions, as well as viral DNA, were detected in birds from all infection groups. Inclusion bodies and viral DNA were also detected in the pancreas and in the small and the large intestine in some birds. Long-lasting shedding and transmission to contact birds were confirmed in all infected groups. [ABSTRACT FROM PUBLISHER]

Infectious bronchitis is considered to be one of the most devastating diseases in poultry. Control of its spread is typically attempted through biosecurity measures and extensive vaccination. However, the remarkable genetic and antigenic variability of the virus, which originate from both mutations and recombination events, represents an unsolved challenge for this disease. The present study reports on the emergence and spread of recombinant clusters detected in Italy and Spain between 2012 and 2014. A total of 36 Spanish and Italian infectious bronchitis virus (IBV) field strains were investigated and genetically characterized using phylogenetic, molecular, recombination and selection pressure analyses of the complete S1 gene. Based on the partial S1 sequencing, 27 IBV strains originating from Spain and nine from Italy were initially classified as being closely related to the Guandong/Xindadi (XDN) genotype. Phylogenetic analysis of the complete S1 gene revealed that the XDN strains formed a homogeneous clade with the Spanish IBV isolates within the QX genotype, whereas there was higher variability within the Italian strains. Recombination analysis determined that these strains belonged to four groups, which originated from independent recombination events between the QX and 793B IBV genotypes. Our data support the hypothesis of two different scenarios: firstly, in Spain, the large and homogeneous clade probably originated from a single offspring of the recombinant founder, which became dominant and spread throughout the country. Secondly, the nine Italian recombinants, which are characterized by three different recombination patterns, probably represent less fitted strains, because they were less viable with respect to their recombinant parents. [ABSTRACT FROM PUBLISHER]

Meat inspection has the ultimate objective of declaring the meat and offal obtained from carcasses of slaughtered animals fit or unfit for human consumption. This safeguards the health of consumers by ensuring that the food coming from these establishments poses no risk to public health. Concomitantly, it contributes to animal disease surveillance. The Catalan Public Health Protection Agency (Generalitat de Catalunya) identified the need to provide its meat inspectors with a support structure to improve diagnostic capacity: the Slaughterhouse Support Network (SESC). The main goal of the SESC was to offer continuing education to meat inspectors to improve the diagnostic capacity for lesions observed in slaughterhouses. With this aim, a web-based application was designed that allowed meat inspectors to submit their inquiries, images of the lesions, and samples for laboratory analysis. This commentary reviews the cases from the first 6 years of SESC operation (2008–2013). The program not only provides continuing education to inspectors but also contributes to the collection of useful information on animal health and welfare. Therefore, SESC complements animal disease surveillance programs, such as those for tuberculosis, bovine cysticercosis, and porcine trichinellosis, and is a powerful tool for early detection of emerging animal diseases and zoonoses. [ABSTRACT FROM AUTHOR]

The ferret has emerged as an excellent animal model to characterize several physiologic and pathologic conditions. The distribution and characterization of different types of immune system cells were studied in healthy ferret tissues. Eight primary antibodies were tested for immunohistochemistry in formalin-fixed tissues: anti-CD3, anti-CD79α, anti-CD20, anti-HLA-DR, anti-lysozyme, anti-CD163, anti-SWC3, and anti-Mac387. The anti-CD3 antibody labeled T cells mainly in interfollicular and paracortical areas of lymph nodes, cortex and thymic medulla, and periarteriolar lymphoid sheaths in the spleen. The anti-CD79α and anti-CD20 antibodies immunolabeled B cells located in lymphoid follicles at lymph nodes, spleen, and Peyer patches. The CD79α and CD20 antibodies also labeled cells with nonlymphoid morphology in atypical B-cell locations. The anti-HLA-DR antibody labeled macrophages, some populations of B and T lymphocytes, and different populations of dendritic cells in lymph nodes, Peyer patches, spleen, and thymus. The anti-lysozyme antibody immunolabeled macrophages in the liver, lymph nodes, spleen, and thymus. The Mac-387, CD163, and SWC3 antibodies did not show any positive reaction in formalin-fixed or frozen tissues. To elucidate the origin of the uncommon CD79α/CD20 positive cells, a double immunohistochemistry was carried out using the anti-HLA-DR + the anti-CD79α, the anti-HLA-DR + the anti-CD20, and the anti-lysozyme + the anti-CD79α antibodies. Double labeling was mainly observed when the anti-HLA-DR + the anti-CD79α antibodies were combined. The immunohistologic characterization and distribution of these immune system cells in healthy ferret tissues should be of value in future comparative studies of diseases in ferrets. [ABSTRACT FROM PUBLISHER]