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The fifth epidemic wave of avian influenza A(H7N9) virus in China during 2016-2017 demonstrated a geographic range expansion and caused more human cases than any previous wave. The factors that may explain the recent range expansion and surge in incidence remain unknown. We investigated the effect of anthropogenic, poultry, and wetland variables on all epidemic waves. Poultry predictor variables became much more important in the last 2 epidemic waves than they were previously, supporting the assumption of much wider H7N9 transmission in the chicken reservoir. We show that the future range expansion of H7N9 to northern China may increase the risk of H7N9 epidemic peaks coinciding in time and space with those of seasonal influenza, leading to a higher risk of reassortments than before, although the risk is still low so far. [ABSTRACT FROM AUTHOR]

In Vietnam, live bird markets are found in most populated centres, providing the means by which fresh poultry can be purchased by consumers for immediate consumption. Live bird markets are aggregation points for large numbers of poultry, and therefore, it is common for a range of avian influenza viruses to be mixed within live bird markets as a result of different poultry types and species being brought together from different geographical locations. We conducted a cross-sectional study in seven live bird markets in four districts of Thua Thien Hue Province in August and December, 2014. The aims of this study were to (i) document the prevalence of avian influenza in live bird markets (as measured by virus isolation); and (ii) quantify individual bird-, seller- and market-level characteristics that rendered poultry more likely to be positive for avian influenza virus at the time of sale. A questionnaire soliciting details of knowledge, attitude and avian influenza practices was administered to poultry sellers in study markets. At the same time, swabs and faecal samples were collected from individual poultry and submitted for isolation of avian influenza virus. The final data set comprised samples from 1,629 birds from 83 sellers in the seven live bird markets. A total of 113 birds were positive for virus isolation; a prevalence of 6.9 (95% CI 5.8-8.3) avian influenza virus-positive birds per 100 birds submitted for sale. After adjusting for clustering at the market and individual seller levels, none of the explanatory variables solicited in the questionnaire were significantly associated with avian influenza virus isolation positivity. The proportions of variance at the individual market, seller and individual bird levels were 6%, 48% and 46%, respectively. We conclude that the emphasis of avian influenza control efforts in Vietnam should be at the individual seller level as opposed to the market level. [ABSTRACT FROM AUTHOR]

Infectious laryngotracheitis virus (ILTV) has a high proclivity to replicate in the larynx and trachea of chickens causing severe lesions. There is a lack of knowledge on the ability of ILTV to replicate in other respiratory associated tissues apart from in the trachea. The objective of this study was to investigate how tissues that first encounter the virus dictate further sites of viral replication during the lytic stage of infection. Replication patterns of the pathogenic strain 63140 and the chicken embryo origin (CEO) vaccine in the conjunctiva, the Harderian gland, nasal cavity and trachea were evaluated after ocular, oral, intranasal or intratracheal inoculation of specific pathogen-free chickens. Viral replication was assessed by detection of microscopic cytolytic lesions, detection of viral antigen and viral genome load. The route of viral entry greatly influenced virus replication of both strain 63140 and CEO vaccine in the conjunctiva and trachea, while replication in the nasal cavity was not affected. In the Harderian gland, independently of the route of viral entry, microscopic lesions characteristic of lytic replication were absent, whereas viral antigen and viral genomes for either virus were detected, suggesting that the Harderian gland may be a key site of antigen uptake. Findings from this study suggest that interactions of the virus with the epithelial-lymphoid tissues of the nasal cavity, conjunctiva and the Harderian gland dictate patterns of ILTV lytic replication. [ABSTRACT FROM AUTHOR]

Avian leukosis virus subgroup J (ALV-J) is an avian oncogenic retrovirus that has led to severe economic losses in the poultry industry in China in recent decades. Here, using high throughput transcriptome sequencing of HD11 and CEF cells infected with ALV-J, a set of 4804 novel long non-coding transcripts and numerous differentially expressed long non-coding RNAs (lncRNAs) were identified. We also found that they share relatively shorter transcripts and fewer exon numbers compared to mRNA. Correlation analysis suggested that many lncRNAs may activate gene expression in an enhancer-like manner other than through transcriptional regulation. Expression level analyses in vivo showed that three lncRNAs (NONGGAT001975.2, NONGGAT005832.2 and NONGGAT009792.2) may be associated with immune response regulation and could function as novel biomarkers for ALV-J infection. Our findings provides new insight into the pathological process of ALV-J infection and should serve as a high-quality resource for further research on epigenetic influences on disease-resistance breeding as well as immune system and genomic studies. [ABSTRACT FROM AUTHOR]

Aim: This study was designed to optimize and apply the use of loop-mediated isothermal amplification (LAMP) as an alternative to conventional polymerase chain reaction (PCR) for the detection of herpesvirus of turkeys (HVT) (FC 126 strain) in vaccinated and non-vaccinated poultry in Nigeria. Materials and Methods: HVT positive control (vaccine) was used for optimization of LAMP using six primers that target the HVT070 gene sequence of the virus. These primers can differentiate HVT, a Marek's disease virus (MDV) serotype 3 from MDV serotypes 1 and 2. Samples were collected from clinical cases of Marek's disease (MD) in chickens, processed and subjected to LAMP and PCR. Results: LAMP assay for HVT was optimized. HVT was detected in 60% (3/5) and 100% (5/5) of the samples analyzed by PCR and LAMP, respectively. HVT was detected in the feathers, liver, skin, and spleen with average DNA purity of 3.05-4.52 µg DNA/mg (A260/A280) using LAMP. Conventional PCR detected HVT in two vaccinated and one unvaccinated chicken samples, while LAMP detected HVT in two vaccinated and three unvaccinated corresponding chicken samples. However, LAMP was a faster and simpler technique to carry out than PCR. Conclusion: LAMP assay for the detection of HVT was optimized. LAMP and PCR detected HVT in clinical samples collected. LAMP assay can be a very good alternative to PCR for detection of HVT and other viruses. This is the first report of the use of LAMP for the detection of viruses of veterinary importance in Nigeria. LAMP should be optimized as a diagnostic and research tool for investigation of poultry diseases such as MD in Nigeria. [ABSTRACT FROM AUTHOR]

Low pathogenic avian influenza (LPAI) viruses are a source of sporadic human infections and could also contribute to future pandemic outbreaks but little is known about inter-species differences in the host responses to these viruses. Here, we studied host gene expression signatures of cell lines from three species (human, chicken, and canine) in response to six different viruses (H1N1/WSN, H5N2/F59, H5N2/F118, H5N2/F189, H5N3 and H9N2). Comprehensive microarray probe set re-annotation and ortholog mapping of the host genes was necessary to allow comparison over extended functionally annotated gene sets and orthologous pathways. The annotations are made available to the community for commonly used microarray chips. We observe a strong tendency of the response being cell type- rather than virus-specific. In chicken cells, we found up-regulation of host factors inducing virus infectivity (e.g., oxysterol binding protein like 1A (OSBPL1A) and Rho GTPase activating protein 21 (ARHGAP21)) while reducing apoptosis (e.g., mitochondrial ribosomal protein S27 (MRPS27)) and increasing cell proliferation (e.g., COP9 signalosome subunit 2 (COPS2)). On the other hand, increased antiviral, pro-apoptotic and inflammatory signatures have been identified in human cells while cell cycle and metabolic pathways were down-regulated. This signature describes how low pathogenic avian influenza (LPAI) viruses are being tolerated and shed from chicken but potentially causing cellular disruption in mammalian cells. [ABSTRACT FROM AUTHOR]

From 2013 to 2015, 32 H1-subtype avian influenza viruses (AIVs), H1N2 (n = 12), H1N3 (n = 14), H1N4 (n = 4) and H1N9 (n = 2), were isolated from poultry in Zhejiang Province in eastern China. These strains were characterized by whole-genome sequencing with subsequent phylogenetic analysis and genetic comparison. Phylogenetic analysis of all eight viral genes showed that these strains clustered in the AIV Eurasian lineage. These strains were found to be minimally pathogenic in mice and were able to replicate in mice without prior adaptation. Continued surveillance is needed, considering the important role of poultry in AIV reassortment. [ABSTRACT FROM AUTHOR]

Avian influenza A virus (AIV) subtype H9N2 is the most prevalent subtype found in terrestrial poultry throughout Eurasia and has been isolated from poultry outbreaks worldwide. Tracheal tissue specimens from 100 commercial broiler flocks in Afghanistan were collected between 2016 and 2017. After real-time RT-PCR, AI-positive samples were further characterized. A part of the HA gene was amplified using RT-PCR and sequenced. The results of real-time RT-PCR showed that 40 percent of the flocks were AI positive. Phylogenetic studies showed that these H9N2 AIVs grouped within the Eurasian-lineage G1 AIVs and had a correlation with H9N2 AIV circulating in the poultry population of the neighboring countries over the past decade. Analysis of the amino acid sequence of HA revealed that the detected H9N2 viruses possessed molecular profiles suggestive of low pathogenicity and specificity for the avian-like SAα2,3 receptor, demonstrating their specificity for and adaptation to domestic poultry. The results of the current study provide great insights into H9N2 viruses circulating in Afghanistan's poultry industry and demonstrate the necessity of planning an applied policy aimed at controlling and managing H9N2 infection in Afghan poultry. [ABSTRACT FROM AUTHOR]

In this study, six pairs of specific primers that can amplify DNA fragments of different sizes were designed and synthesized according to viral protein gene sequences published in GenBank. Then, a multiplex PCR method was established for rapid detection of duck hepatitis virus 1, duck plague virus, duck Tembusu virus, muscovy duck parvovirus, muscovy duck reovirus, and duck H9N2 avian influenza virus, and achieve simple and rapid detection of viral diseases in ducks. Single PCR was used to confirm primer specificity, and PCR conditions were optimized to construct a multiplex PCR system. Specificity and sensitivity assays were also developed. The multiplex PCR was used to detect duck embryos infected with mixed viruses and those with clinically suspected diseases to verify the feasibility of the multiplex PCR. Results show that the primers can specifically amplify target fragments, without any cross-amplification with other viruses. The multiplex PCR system can amplify six DNA fragments from the pooled viral genomes and specifically detect nucleic acids of the six duck susceptible viruses when the template amount is 10 2 copies/μl. In addition, the system can be used to detect viral nucleic acids in duck embryos infected with the six common viruses. The detection results for clinical samples are consistent with those detected by single PCR. Therefore, the established multiplex PCR method can perform specific, sensitive, and high-throughput detection of six duck-infecting viruses and can be applied to clinical identification and diagnosis of viral infection in ducks. [ABSTRACT FROM AUTHOR]

Mycoplasma synoviae (MS) is an important pathogen of domestic poultry and is prevalent in commercial layers. Avian influenza (AI; H9N2) infections are emerging respiratory problems causing huge economic losses to the poultry industry, especially in the presence of other co-infecting pathogens. The possible role of MS vaccination and response to AI (H9N2) virus in commercial layers was evaluated during this study. Experimental commercial layers were divided into different groups which were identified as follows: non-vaccinated non-challenged (NVNC), non-vaccinated challenged (NVC), vaccinated nonchallenged (VNC), and vaccinated challenged (VC). The titer of AI antibodies was measured pre- and post-challenge to confirm experimental infection. Infected layers showed clinical signs of differing severity, with the most prominent disease signs and mortality (25%) appearing in layers of the VC group. Moreover, the layers in VC group showed a significant decrease in weight and enhanced gross lesions. All infected layers showed positive results for virus shedding; however, the pattern of virus shedding was different, with layers of VC group showing more pronounced virus excretion than the layers in the NVC group. In addition, layers of VC group showed significantly reduced antibody responses and interferon gene expression when compared with the layers of NVC group. The present study revealed that MS vaccine could facilitate replication of avian influenza viruses and thus avian influenza virus infections can be worse after MS vaccination, especially in AIV-endemic areas. [ABSTRACT FROM AUTHOR]

The infectious bronchitis virus is a coronavirus that causes a highly contagious disease of the upper respiratory tract affecting chickens and hens of all ages. The disease is characterized by respiratory symptoms although it can also infect the reproductive tract causing a decrease in egg production, poor quality of the shell and abnormalities in the internal quality of the egg. The virus represents a concern from the economic point of view since it is one of the main causes of losses in the commercial production of poultry and predisposes them to secondary infections that can result in further economic losses and even death. The ability of the virus to experience short-term mutations and recombination events leads to the emergence of new genotypes/serotypes and makes diagnosis and control a challenge. This review aims to provide updated information on different aspects related to the virus, such as its general characteristics, taxonomy and classification, organization of the viral genome, viral proteins, recombinant RNA, antigenic diversity, global distribution, pathogenesis, as well as consecuences caused by the disease, its history, clinical manifestations and lesions, epidemiology, diagnosis, and prevention/control. [ABSTRACT FROM AUTHOR]

Fowl adenovirus serotype 4 (FAdV-4) is a new emerging viral disease of chickens worldwide. It causes inclusion body hepatitis and hepatitis-hydropericardium syndrome. Little is known about its prevalence in the Middle East. Here we report the prevalence of FAdV-4 in five chicken farms in eastern Saudi Arabia. High mortality rates were reported from birds from those five farms at 15 weeks of age. Gross examination revealed typical hydropericardium syndrome and accumulation of jelly-like materials in the pericardial cavities. We isolated FAdV-4 by using embryonated chicken egg inoculation. The inoculated embryos showed dwarfing, deformities, hemorrhage, and death after 3-5 days of inoculations. Detection of FAdV-4 in the heart and liver tissues was achieved by polymerase chain reaction (PCR) and real-time PCR using the primers targeted to the partial hexon gene. Further confirmation was done by restriction fragment length polymorphism and the digestion patterns of the isolated FAdV-4 DNAs were close to those of other known FAdV-4 strains. The average genome size of the virus was ~43 kb. Phylogenetic analysis of the partial hexon gene sequences confirmed that these strains were closely related to other Asian strains from Kuwait, India, and Pakistan reported to GenBank. To our knowledge, this is the first study that reports the isolation and molecular characterization of FAdV-4 in chickens in Saudi Arabia. [ABSTRACT FROM AUTHOR]

Due to the ongoing need to protect poultry from virulent Newcastle disease virus, all commercial poultry flocks in Israel are vaccinated according to a defined programme using a combination of live and inactivated vaccines. The vaccination protocol for broilers during the years of the study comprised a live vaccine administered by spray on the day of hatching, inactivated vaccine by subcutaneous injection at 10–12 days of age, and another live vaccine given by aerosol at 17–21 days of age. A cross-sectional study was designed in order to examine the influence of herd immunity on the risk of Newcastle disease outbreak in broiler flocks. The study was based on the extensive field data kept in the Poultry Health Laboratories database. The results of serology tests employing haemagglutination inhibition for Newcastle disease virus were analysed and crossed with the list of flocks that had been diagnosed with ND in the years 2007–2014. At the peak of induced immunization (fifth week of growth), 87.5% of the tested flocks had achieved herd immunity (≥85% of birds in the flock with an HI titre ≥4). Based on a logistic regression model, the odds ratio for ND in flocks without herd immunity was 3.7 (95% CI 1.8–7.3,P-value < 0.001). The higher the percentage of birds with low HI titres the higher the risk of ND outbreak. Under field conditions, herd immunity is an important indicator for the risk of ND outbreak. [ABSTRACT FROM AUTHOR]

Background: Recently, avian influenza virus has caused repeated worldwide outbreaks in humans. Live Poultry Markets (LPMs) play an important role in the circulation and reassortment of novel Avian Influenza Virus (AIVs). Aerosol transmission is one of the most important pathways for influenza virus to spread among poultry, from poultry to mammals, and among mammals. Methods: In this study, air samples were collected from LPMs in Nanchang city between April 2014 and March 2015 to investigate possible aerosol transmission of AIVs. Air samples were detected for Flu A by Real-Time Reverse Transcription-Polymerase Chain Reaction (RRT-PCR). If samples were positive for Flu A, they were inoculated into 9-to 10-day-old specific-pathogen-free embryonated eggs. If the result was positive, the whole genome of the virus was sequenced by MiSeq. Phylogenetic trees of all 8 segments were constructed using MEGA 6.05 software. Results: To investigate the possible aerosol transmission of AIVs, 807 air samples were collected from LPMs in Nanchang city between April 2014 and March 2015. Based on RRT-PCR results, 275 samples (34.1%) were Flu A positive, and one virus was successfully isolated with embryonated eggs. The virus shared high nucleotide homology with H9N2 AIVs from South China. Conclusions: Our study provides further evidence that the air in LPMs can be contaminated by influenza viruses and their nucleic acids, and this should be considered when choosing and evaluating disinfection strategies in LPMs, such as regular air disinfection. Aerosolized viruses such as the H9N2 virus detected in this study can increase the risk of human infection when people are exposed in LPMs. [ABSTRACT FROM AUTHOR]

In Egypt, currently two geographically restricted genotypes of the infectious bronchitis coronavirus (IBV) are circulating with detrimental effects for poultry industry. A sensitive real-time RT-PCR assay targeting the IBV nucleocapsid gene (N) was developed to screen clinical samples for presence of IBV. Conventional RT-PCRs amplifying hypervariable regions (HVRs 1–2 and 3) of the IBV S1 gene were developed and amplificates used for nucleotide sequence-based typing of IBV field strains in Egyptian chickens directly from clinical samples. [ABSTRACT FROM AUTHOR]

An investigation was undertaken of the extent of genetic variation occurring within infectious bronchitis virus (IBV) vaccine strains following vaccination of day-old broiler chicks. Chicks were divided into seven groups, with two groups receiving single Massachusetts (Mass) vaccinations while the other four were inoculated with combinations of different IBV serotypes; Mass, 793B, D274 and Arkansas (Ark). The remaining group was maintained as an unvaccinated control. Following vaccination, swabs and tissues collected at intervals were pooled and RNA was extracted for detection of IBV by reverse transcription polymerase chain reaction. Positive amplicons were sequenced for the part-S1 gene and compared to the original vaccine strain sequences. Single nucleotide polymorphisms, amino acid variations and hydrophobicity changes were identified and recorded for each sampling point. A total of 106 single nucleotide polymorphisms were detected within 28 isolates. The average single nucleotide polymorphism counts of swab isolates were greater than those found in tissue samples. This translated into 64 amino acid changes; however only six resulted in a change to the hydrophobicity properties. All hydrophobic alterations occurred within swab isolates and the majority were recovered at 3 days post vaccination suggesting such changes to be detrimental to early virus survival. Nucleotide deletions were seen only in the group given the combination of Mass and Ark. Of the 16 sequenced samples in this group, 13 contained the same AAT deletion at position 1033 1035 in the Ark strains. Findings presented in this study demonstrate alteration in the S1 nucleotide sequence following co-administration of live IBV vaccines. [ABSTRACT FROM AUTHOR]

Riemerella anatipestifer causes anatipestifer disease in many avian species. A total of 185 R. anatipestifer strains isolated in Hungary between 2000 and 2014 from geese and ducks were tested against 13 antibiotics (ampicillin, doxycycline, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, penicillin, spectinomycin, streptomycin, sulphamethoxazole—trimethoprim, sulphonamide compounds, and tetracycline) by the Kirby-Bauer disk diffusion method. The majority of the strains were susceptible to florfenicol (97.9%), ampicillin (95.1%), penicillin (93%), sulphamethoxazole—trimethoprim (92.4%), and spectinomycin (86.5%). The highest resistance rates were observed for flumequine, tetracycline, erythromycin and streptomycin (94%, 91.4%, 75.1% and 71.4% resistance, respectively). The resistance patterns showed some variation depending on the geographical origin of the strains. The average rate of extensive drug resistance was 30.3%, and its proportion tended to increase in the period examined. [ABSTRACT FROM AUTHOR]

Newcastle disease virus (NDV) is pathogenic to both avian and non-avian species but extensively finds poultry as its primary host and causes heavy economic losses in the poultry industry. In this study, a total of 186 polymerase complex comprising of nucleoprotein (N), phosphoprotein (P), and large polymerase (L) genes of NDV was analyzed for synonymous codon usage. The relative synonymous codon usage and effective number of codons (ENC) values were used to estimate codon usage variation in each gene. Correspondence analysis (COA) was used to study the major trend in codon usage variation. Analyzing the ENC plot values against GC3s (at synonymous third codon position) we concluded that mutational pressure was the main factor determining codon usage bias than translational selection in NDV N, P, and L genes. Moreover, correlation analysis indicated, that aromaticity of N, P, and L genes also influenced the codon usage variation. The varied distribution of pathotypes for N, P, and L gene clearly suggests that change in codon usage for NDV is pathotype specific. The codon usage preference similarity in N, P, and L gene might be detrimental for polymerase complex functioning. The study represents a comprehensive analysis to date of N, P, and L genes codon usage pattern of NDV and provides a basic understanding of the mechanisms for codon usage bias. [ABSTRACT FROM AUTHOR]

Newcastle disease (ND) is one of the highly contagious disease responsible for devastating outbreaks and considerable economic losses to poultry industry in China. However, no information is available about NDV in Tibet region; the aim of this study was to determine the genetic characterization and evolutionary analysis of NDV in Tibetan chickens. Four NDVs were isolated from an outbreak in Tibetan chickens. The pathogenicity of the isolates was determined by mean death time (MDT), intracerebral pathogenicity index (ICPI) and amino acid sequencing (112 to 117) of F protein. While the genetic characterization of F gene was determined by sequencing the isolated NDVs and phylogenetic relationship was established with the help of reference strains. Pathogenicity experiments revealed that XZ-F10 and XZ-F20 strains were lentogenic pathotype, while the remaining XZ-F2-1 and XZ-F4-6 strains were velogenic pathotype. The deduced amino acid sequences of the cleavage site of the F protein confirmed our results. Phylogenic analysis of these strains indicated that both XZ-F2-1 and XZ-F4-6 belong to genotype VII. However, XZ-F10 and XZ-F20 strains were assigned to genotypes II. The present study highlights the need for continuous surveillance of NDV in Tibetan chickens; moreover, this study will provide a reference for the local government to make the strategies and control emerging NDV in Tibet. [ABSTRACT FROM AUTHOR]

Purpose suppressor of cytokine signaling 1 (SOCS-1) is inducible feedback inhibitors of cytokine signaling and involved in viral infection through regulation of both innate and adaptive immunity. In this study, we firstly cloned SOCS-1 (goSOCS-1) from duck Tembusu virus (DTMUV) infected goose. The full-length sequence of goSOCS-1 ORF is 624 bp and encoded 108 amino acids. Structurally, the mainly functional regions (KIR, SH2, SOCS-box) were conserved between avian and mammalian. The tissues distribution data showed SOCS-1 highly expressed in immune related tissues (SP, LU, HG) of both gosling and adult goose. Moreover, the goSOCS-1 transcripts were induced by goIFNs in GEFs and by TLR ligands in PBMCs. Notably, upon DTMUV infection, highly expression level of goSOCS-1 was detected in vitro and in vivo with high viral load. Our results indicated that goSOCS-1 might involve in both innate and adaptive antiviral immunity of waterfowl. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate possible causes of the pervasiveness of chicken infectious anemia virus (CIAV) infection in chickens in recent years in China. A total of 14 batches of live-virus vaccines were examined using PCR to detect CIAV contamination, of which only 2 samples (a Newcastle disease vaccine and a fowl pox vaccine) tested positive for CIAV. These Newcastle and fowl pox vaccines were then inoculated into 1-day-old specificpathogen- free chickens. Serum samples were collected from chickens infected with the PCR-positive vaccines, and these tested positive for CIAV-specific antibodies as tested using ELISA. In addition, DNA samples isolated from the serum samples also tested positive by PCR. The results indicated that the samples were contaminated with CIAV and identified 2 exogenous CIAV strains, designated CIAV-N22 and CIAV-F10, in the respective samples. The full genome sequences of these novel CIAV strains were sequenced and analyzed. Phylogenetic tree analysis indicated that the CIAV-F10 strain might represent a recombinant viral strain arising from the parental CIAV strains JQ690762 and KJ728816. Overall, the results suggested that vaccination with CIAV-contaminated vaccines contributed to the prevalence and spread of CIAV infection in chickens. Furthermore, the CIAV contaminant was likely subsequently transmitted to commercial chickens through congenital transmission. Our findings therefore highlight the need for more extensive screening of live-virus vaccines for poultry in China to reduce the threat of contamination with exogenous viruses. [ABSTRACT FROM AUTHOR]

During the surveillance for avian influenza viruses (AIVs) in live poultry markets in Eastern China, in 2016, a novel reassortant H7N6 AIV was isolated from a chicken. Phylogenetic analysis showed that this strain received its genes from H9N2, H7N9 and H5N6 AIVs infecting poultry in China. This strain showed moderate pathogenicity in mice and was able to replicate in mice without prior adaptation. Considering that this novel reassorted H7N6 virus was isolated from poultry in this study, it is possible that chickens play an important role in the generation of novel reassorted H7N6 AIVs. [ABSTRACT FROM AUTHOR]

Avian Tembusu virus (ATMUV) is a highly pathogenic flavivirus that causes significant economic losses to the Chinese poultry industry. Our previous experiments demonstrated that ATMUV infection effectively triggered host innate immune response through MDA5 and TLR3-dependent signaling pathways. However, little information is available on the role of interferon-stimulated genes (ISGs) in defending against ATMUV infection. In this study, we found that ATMUV infection induced robust expression of type I and type III interferon (IFNs) in duck tissues. Furthermore, we observed that expression of interferon-inducible transmembrane proteins (IFITMs) was significantly upregulated in DEF and DF-1 cells after infection with ATMUV. Similar results were obtained from in vivo studies using ATMUV-infected ducklings. Importantly, we showed that knockdown of endogenous IFITM1 or IFITM3 by specific shRNA markedly enhanced ATMUV replication in DF-1 cells. However, disruption of IFITM2 expression had no obvious effect on the ATMUV replication. In addition, overexpression of chicken or duck IFITM1 and IFITM3 in DF-1 cells impaired the replication of ATMUV. Taken together, these results reveal that induced expression of avian IFITM1 and IFITM3 in response to ATMUV infection can effectively restrict the virus replication, and suggest that increasing IFITM proteins in host may be a useful strategy for control of ATMUV infection. [ABSTRACT FROM AUTHOR]

H9N2 avian influenza viruses are endemic in poultry in Asia and the Middle East. These viruses sporadically cause dead-end infections in pigs and humans raising concerns about their potential to adapt to mammals or reassort with human or swine influenza viruses. We performed ten serial passages with an avian H9N2 virus (A/quail/Hong Kong/G1/1997) in influenza naïve pigs to assess the potential of this virus to adapt to swine. Virus replication in the entire respiratory tract and nasal virus excretion were examined after each passage and we deep sequenced viral genomic RNA of the parental and passage four H9N2 virus isolated from the nasal mucosa and lung. The parental H9N2 virus caused a productive infection in pigs with a predominant tropism for the nasal mucosa, whereas only 50% lung samples were virus-positive. In contrast, inoculation of pigs with passage four virus resulted in viral replication in the entire respiratory tract. Subsequent passages were associated with reduced virus replication in the lungs and infectious virus was no longer detectable in the upper and lower respiratory tract of inoculated pigs at passage ten. The broader tissue tropism after four passages was associated with an amino acid residue substitution at position 225, within the receptor-binding site of the hemagglutinin. We also compared the parental H9N2, passage four H9N2 and the 2009 pandemic H1N1 (pH1N1) virus in a direct contact transmission experiment. Whereas only one out of six contact pigs showed nasal virus excretion of the wild-type H9N2 for more than four days, all six contact animals shed the passage four H9N2 virus. Nevertheless, the amount of excreted virus was significantly lower when compared to that of the pH1N1, which readily transmitted and replicated in all six contact animals. Our data demonstrate that serial passaging of H9N2 virus in pigs enhances its replication and transmissibility. However, full adaptation of an avian H9N2 virus to pigs likely requires an extensive set of mutations. [ABSTRACT FROM AUTHOR]

This study investigated the haematological changes in vaccinated and unvaccinated laying chickens experimentally infected with a velogenic Newcastle disease virus. Two hundred and forty laying chickens were randomly assigned into four groups of 60 each: vaccinated with Newcastle disease vaccines and infected with velogenic Newcastle disease virus (VI), vaccinated uninfected (VU), unvaccinated infected (UI), unvaccinated uninfected (UU). At peak production, 32-weeks-old, groups VI & UI were each inoculated intramuscularly with 0.2 ml of velogenic Newcastle disease virus. The changes in the blood cells were assayed in the groups on the specified days. The total red blood cell count (RBC) was significantly (P < 0.05) lower in UI group on days 6 & 15 post infection (PI). The packed cell volume (PCV) and haemoglobin concentration (HbC) were significantly (P<0.05) lower in UI group on day 15 PI. There were no significant (P > 0.05) differences between the PCV, RBC and HbC in VI & VU groups from day 0 to 21 PI. The leukogram showed significant (P < 0.05) differences in leukocytosis on days 3 & 6 PI followed by significant (P < 0.05) leukopenia on days 10, 15 & 21 PI in UI group. However, significant leukocytosis on day 10 PI followed by leukopenia on day 15 PI were recorded in VI group. These findings suggest that leukocytosis in UI & VI and decreased haemogram in UI are features of Newcastle disease in laying chickens. [ABSTRACT FROM AUTHOR]

Background: Newcastle disease (ND) and avian influenza subtype H9N2 (H9N2 AI) are two of the most important diseases of poultry, causing severe economic losses in the global poultry industry. Vaccination is an effective way to prevent and control the spread of ND virus (NDV) and H9N2 AI virus (AIV), but the antigenic differences between the current circulating strains and the vaccine strains might account for recent ND and H9N2 AI outbreaks in vaccinated poultry flocks. Methods: We developed an inactivated bivalent H9N2 and NDV vaccine based on the current prevalent strains of H9N2 AIV and NDV in China and evaluated its efficacy in chickens in this study. Results: The results indicated that the inactivated bivalent vaccine could induce a fast antibody response in vaccinated chickens. The hemagglutination inhibition (HI) titer in the sera increased rapidly, and the highest HI titer was observed at 4 weeks post-vaccination (wpv) with a mean titre of 8.6 log2 for NDV and 9.5 log2 for H9N2. Up until 15 wpv, HI titers were still detectable at a high level of over 6 log2. The immunized chickens showed no signs of disease after challenge at 3 wpv with the prevalent strains of NDV and H9N2 AIV isolated in 2012-2014. Moreover, viral shedding was completely inhibited in vaccinated chickens after challenge with H9N2 AIV and inhibited by at least 90% with NDV compared to the controls at 5dpc. Conclusions: Our findings suggest that the inactivated NDV and H9N2 vaccine induces a fast and strong antibody response in vaccinated chickens and is efficacious in poultry against NDVs and H9N2 AIVs. [ABSTRACT FROM AUTHOR]

Highly pathogenic avian influenza viruses cause severe disease and huge economic losses in domestic poultry and might pose a serious threat to people because of the high mortality rates in case of an accidental transmission to humans. The main goal of this work was to evaluate the immune responses and hemagglutination inhibition potential elicited by a combined DNA/recombinant protein prime/boost vaccination compared to DNA/DNA and protein/protein regimens in chickens. A plasmid encoding hemagglutinin (HA) from the A/swan/Poland/305-135V08/2006 (H5N1) virus, or the recombinant HA protein produced in Pichia pastoris system, both induced H5 HA–specific humoral immune responses in chickens. In two independent experiments, anti-HA antibodies were detected in sera collected two weeks after the first dose and the response was enhanced by the second dose of a vaccine, regardless of the type of subunit vaccine (DNA or recombinant protein) administered. The serum collected from chickens two weeks after the second dose was characterized by three types of assays: indirect ELISA, hemagglutination inhibition (HI) and a diagnostic test based on H5 antibody competition. Although the indirect ELISA failed to detect superiority of any of the three vaccine regimens, the other two tests clearly indicated that priming of chickens with the DNA vaccine significantly enhanced the protective potential of the recombinant protein vaccine produced in P. pastoris . [ABSTRACT FROM AUTHOR]

Avian influenza viruses from wild birds can cause outbreaks in poultry, and occasionally infect humans upon exposure to infected poultry. Identification and characterization of viral reservoirs and transmission routes is important to develop strategies that prevent infection of poultry, and subsequently virus transmission between poultry holdings and to humans. Based on spatial, temporal and phylogenetic analyses of data generated as part of intense and large-scale influenza surveillance programs in wild birds and poultry in the Netherlands from 2006 to 2011, we demonstrate that LPAIV subtype distribution differed between wild birds and poultry, suggestive of host-range restrictions. LPAIV isolated from Dutch poultry were genetically most closely related to LPAIV isolated from wild birds in the Netherlands or occasionally elsewhere in Western Europe. However, a relatively long time interval was observed between the isolations of related viruses from wild birds and poultry. Spatial analyses provided evidence for mallards (Anas platyrhynchos) being more abundant near primary infected poultry farms. Detailed year-round investigation of virus prevalence and wild bird species distribution and behavior near poultry farms should be used to improve risk assessment in relation to avian influenza virus introduction and retarget avian influenza surveillance programs. [ABSTRACT FROM AUTHOR]

Aim: Diagnosis of velogenic viscerotropic Ranikhet disease from six different flocks of desi chicken in and around Mumbai by gross and histopathological examination, isolation of virus and molecular methods. Materials and Methods: A total of 25 carcasses (varying between 2 and 6 carcasses from each flock) of six different flocks of adult desi chicken were subjected to necropsy examination for diagnosis of the disease during the span of a year (2014-2015). After thorough gross examination, the tissue samples were collected and processed for virus isolation and histopathological examination. The 20% tissue homogenate was inoculated into 9-day-old specific pathogen free (SPF) embryonated eggs. Mean death time (MDT) of embryos after inoculation and intracerebral pathogenicity index (ICPI) were used to judge velogenic nature of the virus. Newcastle disease virus (NDV) was isolated from six cases and confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) targeting the partial fusion protein gene of the viral genome. Results: A total of 25 carcasses (varying between 2 and 6 carcasses from each flock) of six different flocks of desi chicken were presented for postmortem examination to Department of Veterinary Pathology, Bombay Veterinary College, Parel, Mumbai during 2014-2015. The gross and histopathological examination revealed lesions suggestive of viscerotropic velogenic form of the Newcastle disease (ND). The 20% tissue homogenate was inoculated into 9-day-old embryonated eggs from SPF chicken. NDV was isolated from six cases and confirmed by RT-PCR targeting the partial fusion protein gene. MDT of all the isolates was <60 h which indicated velogenic nature of the virus. ICPI of the isolates ranged between the 1.63 and 1.78. In four out of six outbreaks concurrent moderate to heavy infection of Ascardii galli in one flock and Railetina spp. in three flocks was also noted. In this study, viscerotropic velogenic form of ND was confirmed in all six outbreaks by gross and microscopic examination, virus isolation and RT-PCR. Conclusions: In this study, viscerotropic velogenic form of ND was confirmed in all six outbreaks by gross and microscopic examination, virus isolation and RT-PCR. Nowadays, vaccine strains Lasota, B1 and F strains are used widely in India to control the infection of NDV. However, virulent NDV strains are still isolated frequently in the birds under backyard and also in commercial venture which demonstrates that NDV remains an on-going threat to commercial as well as backyard poultry flocks. [ABSTRACT FROM AUTHOR]

Members of the H5 subtype of highly pathogenic avian influenza viruses pose a great threat to both poultry and humans with severe consequences for both industry and public health sectors. Here, we isolated and characterized two H5N1 highly pathogenic influenza viruses in deceased mink from eastern China. Phylogenetic analyses showed that the G15 and XB15 viruses belonged to clade 2.3.2.1b and 2.3.2.1e, respectively. Both of these viruses were highly pathogenic in chickens. They were also shown to exhibit moderate to high pathogenicity in mice without pre-adaptation. Further, the mink influenza viruses had severe antigenic drift with corresponding Re-6 vaccine and current vaccines may fail to confer protection against these H5N1 viruses in poultry. [ABSTRACT FROM AUTHOR]

Background Since the turn of the 21 st century, there have been several epidemic outbreaks of poultry diseases caused by Tembusu virus (TMUV). Although multiple mosquito and poultry-derived strains of TMUV have been isolated, no data exist about their comparative study, origin, evolution, and dissemination. Methodology Parallel virology was used to investigate the phenotypes of duck and mosquito-derived isolates of TMUV. Molecular biology and bioinformatics methods were employed to investigate the genetic characteristics and evolution of TMUV. Principal findings The plaque diameter of duck-derived isolates of TMUV was larger than that of mosquito-derived isolates. The cytopathic effect (CPE) in mammalian cells occurred more rapidly induced by duck-derived isolates than by mosquito-derived isolates. Furthermore, duck-derived isolates required less time to reach maximum titer, and exhibited higher viral titer. These findings suggested that poultry-derived TMUV isolates were more invasive and had greater expansion capability than the mosquito-derived isolates in mammalian cells. Variations in amino acid loci in TMUV E gene sequence revealed two mutated amino acid loci in strains isolated from Malaysia, Thailand, and Chinese mainland compared with the prototypical strain of the virus (MM1775). Furthermore, TMUV isolates from the Chinese mainland had six common variations in the E gene loci that differed from the Southeast Asian strains. Phylogenetic analysis indicated that TMUV did not exhibit a species barrier in avian species and consisted of two lineages: the Southeast Asian and the Chinese mainland lineages. Molecular traceability studies revealed that the recent common evolutionary ancestor of TMUV might have appeared before 1934 and that Malaysia, Thailand and Shandong Province of China represent the three main sources related to TMUV spread. Conclusions The current broad distribution of TMUV strains in Southeast Asia and Chinese mainland exhibited longer-range diffusion and larger-scale propagation. Therefore, in addition to China, other Asian and European countries linked to Asia have used improved measures to detect and monitor TMUV related diseases to prevent epidemics in poultry. [ABSTRACT FROM AUTHOR]

In view of the restricted knowledge on the diversity of coronaviruses in poultry other than chicken, this study aimed to investigate the genetic diversity of coronaviruses in quail, pheasant, and partridge from two regions of Northern Italy. To this end, pools of tracheal and cloacal swabs from European quail (Coturnix Coturnix) and intestinal tract from pheasants (Phasianus Colchicus) and partridge (Perdix Perdix) flocks, with or without enteric signs, were collected during 2015. Avian coronavirus (Gammacoronavirus) was detected in quail not vaccinated against Infectious Bronchitis Virus (IBV) and in pheasants vaccinated with an IBV Massachusetts serotype. Based on DNA sequences for the gene encoding the S protein, the avian coronaviruses detected in the quail and pheasant are related to the IBV 793B and Massachusetts types, respectively. However, RNA-dependent RNA polymerase (RdRp) analyses showed the susceptibility of quail also to Deltacoronaviruses, suggesting that quail and pheasant avian corona viruses share spike genes identical to chicken IBV spike genes and quail might host Delta-coronavirus. [ABSTRACT FROM AUTHOR]

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]

Avian leukosis virus subgroup J (ALV-J) is an oncogenic retrovirus that has a similar replication cycle to multiple viruses and therefore can be used as a model system for viral entry into host cells. However, there are few reports on the genes or microRNAs (miRNAs) that are responsible for the replication of ALV-J. Our previous miRNA and RNA sequencing data showed that the expression of miR-34b-5p was significantly upregulated in ALV-J-infected chicken spleens compared to non-infected chicken spleens, but melanoma differentiation-associated gene 5 (MDA5) had the opposite expression pattern. In this study, a dual-luciferase reporter assay showed that MDA5 is a direct target of miR-34b-5p. In vitro, overexpression of miR-34b-5p accelerated the proliferation of ALV-J-infected cells by inducing the progression from G2 to S phase and it promoted cell migration. Ectopic expression of MDA5 inhibited ALV-J-infected cell proliferation, the cell cycle and cell migration, and knockdown of MDA5 promoted proliferation, the cell cycle and migration. In addition, during ALV-J infections, MDA5 can detect virus invasion and it triggers the MDA5 signaling pathway. MDA5 overexpression can activate the MDA5 signaling pathway, and thus it can inhibit the mRNA and protein expression of the ALV-J env gene and it can suppress virion secretion. In contrast, in response to the knockdown of MDA5 by small interfering RNA (siRNA) or an miR-34b-5p mimic, genes in the MDA5 signaling pathway were significantly downregulated (P <0.05), but the mRNA and protein expression of ALV-J env and the sample-to-positive ratio of virion in the supernatants were increased. This indicates that miR-34b-5p is able to trigger the MDA5 signaling pathway and affect ALV-J infections. Together, these results suggest that miR-34b-5p targets MDA5 to accelerate the proliferation and migration of ALV-J-infected cells, and it promotes ALV-J replication, via the MDA5 signaling pathway. [ABSTRACT FROM AUTHOR]

In this study, we conducted the clinicopathological characterization of a non-pathogenic FAdV-D serotype 11 strain MX95, isolated from healthy chickens, and its entire genome was sequenced. Experiments in SPF chickens revealed that the strain is a non-pathogenic virus that did not cause death at challenge doses of 1×10 6 TCID50. Additionally, the infection in SPF chickens caused no apparent damage in most of the organs analyzed by necropsy and histopathology, but it did cause inclusion body hepatitis; nevertheless it did not generate severe infectious clinical symptoms. The virus was detected in several chicken organs, including the lymphoid organs, by real-time polymerase chain reaction (PCR) until 42 days. The genome of FAdV-11 MX95 has a size of 44,326 bp, and it encodes 36 open reading frames (ORFs). Comparative analysis of the genome indicated only 0.8% dissimilarity with a highly virulent serotype 11 that was previously reported. [ABSTRACT FROM AUTHOR]

Chicken anemia virus (CAV) is one of the important poultry pathogen. CAV infection can cause immunosuppression, aggravation of co-infections, vaccination failures and mortality. We are reporting the CAV outbreaks from the Nagpur province of India, between the years 2012–2015. The breeds included cockerel and Black Australorp of age varying from 29 to 50 days. The mortality rate observed among poultry was from 20% to 62.5%. Clinical symptoms like anemia, subcutaneous hemorrhages, growth retardation, abnormal feathers and hind limb paralysis suggested CAV infection. Postmortem analysis showed hemorrhages in thigh muscle and atrophy of the thymus and bone marrow. Seven out of 11 samples showed positive amplification of the CAV genome upon PCR. Phylogenetic analysis of all the seven isolates based on VP1 gene nucleotide sequence suggested circulation of genotype A strains in Maharashtra. The study will help us understand the circulating genotype of CAV in India and formulate its diagnosis and vaccination. [ABSTRACT FROM AUTHOR]

Infectious bursal disease (IBD) is characterized by the immune suppression of infected birds. The molecular mechanism by which IBD virus (IBDV) suppresses the host immune system remains to be elucidated. The tumor suppressor protein p53 can inhibit the replication of various viruses, but its effect on IBDV remains unknown. This study established an in vitro infection model based on DF-1 cells (chicken embryo fibroblast cell line) to investigate the antiviral effects of chicken p53 (chp53) on IBDV infection. The expression level and activity of chp53 remarkably increased in IBDV-infected DF-1 cells. The overexpression of chp53 inhibited IBDV replication and upregulated the expression of multiple chicken antiviral innate immunity genes (IPS-1, IRF3, PKR, OAS, and Mx), whereas the suppression of chp53 led to the opposite effect. This result indicates that chp53 activates the antiviral innate immune response of chickens to IBDV infection. Bioinformatics analysis and dual-luciferase reporter assay showed that gga-miR-2127 targeted the 3′UTR of chp53. qRT-PCR and western blot revealed that gga-miR-2127 overexpression in DF-1 cells not only downregulated the expression levels of chp53 and of the antiviral innate immunity genes in chickens but also promoted IBDV replication. Our results suggest that gga-miR-2127 downregulates chp53 mRNA translation by targeting its 3′UTR and attenuates chp53-mediated antiviral innate immune response against IBDV. [ABSTRACT FROM AUTHOR]

Avian leucosis virus subgroup J (ALV-J) can cause lifelong infection and can escape from the host immune defenses in chickens. Since macrophages act as the important defense line against invading pathogens in host innate immunity, we investigated the function and innate immune responses of chicken primary monocyte-derived macrophages (MDM) after ALV-J infection in this study. Our results indicated that ALV-J was stably maintained in MDM cells but that the viral growth rate was significantly lower than that in DF-1 cells. We also found that ALV-J infection significantly increased nitric oxide (NO) production, but had no effect on MDM phagocytic capacity. Interestingly, infection with ALV-J rapidly promoted the expression levels of Myxovirus resistance 1 (Mx) (3 h, 6 h), ISG12 (6 h), and interleukin-1β (IL-1β) (3 h, 12 h) at an early infection stage, whereas it sharply decreased the expression of Mx (24 h, 36 h), ISG12 (36 h), and made little change on IL-1β (24 h, 36 h) production at a late infection stage in MDM cells. Moreover, the protein levels of interferon-β (IFN-β) and interleukin-6 (IL-6) had sharply increased in infected MDM cells from 3 to 36 h post infection (hpi) of ALV-J. And, the protein level of interleukin-10 (IL-10) was dramatically decreased at 36 hpi in MDM cells infected with ALV-J. These results demonstrate that ALV-J can induce host innate immune responses and we hypothesize that macrophages play an important role in host innate immune attack and ALV-J immune escape. [ABSTRACT FROM AUTHOR]

Necrotic enteritis of poultry is an emerging disease of substantial economic importance, but aspects of the pathogenesis of this multi-factorial disease are still unclear. We recently demonstrated that the ability of avian strains of the causative bacterium, Clostridium perfringens , to bind to specific collagen types correlated strongly with their virulence and we postulated that binding of the pathogen to collagen types IV and V and gelatin may involve the putative adhesin-encoding gene cnaA, which is found in the VR–10 B locus. In this study we have used site-directed mutagenesis to demonstrate that disruption of the cnaA gene leads to a reduction in the expression of the three genes immediately downstream of cnaA and reduced adherence to collagen types IV and V and gelatin. In addition, a cnaA mutant of strain EHE-NE18 was no longer capable of causing necrotic enteritis in a chicken disease induction model and had a significantly reduced ability to colonise the chicken intestinal mucosa. These results were confirmed by generating and analysing a similar mutant in an independent necrotic enteritis causing C. perfringens strain. This study expands our understanding of the mechanisms involved in necrotic enteritis pathogenesis by demonstrating the importance of C. perfringens adherence to extracellular matrix proteins. [ABSTRACT FROM AUTHOR]

Forty-three fowl adenovirus (FAdV) strains were isolated in China from 2007 to 2014 from poultry and ostriches with inclusion body hepatitis (IBH) and hydropericardium syndrome (HPS). Phylogenetic analysis showed that 28/43 strains clustered into Fowl aviadenovirus D (FAdV-D) and 9/43 strains clustered into FAdV-E. FAdV-C included three isolates of ostrich origin, one of goose origin and two of chicken origin. Based on hexon loop 1 gene sequencing analysis, these viruses were genetically related to FAdV-4, FAdV-8a, FAdV-8b and FAdV-11, of which FAdV-11 was dominant. The isolation in 2014 of three FAdV strains belonging to serotype 4 from ostrich flocks is to our knowledge the first finding of FAdV-4 infection and HPS cases in ostriches. Epidemiological analysis showed that FAdV has been circulating in northern and eastern China, where more than 50% of layers and broilers are raised. The hosts of this pathogen included broilers, layers, geese and ostriches. IBH and HPS cases had a sporadic or cluster distribution from 2007 to 2013; however, since 2014 the number of cases has increased sharply. To control FAdV, strict biosecurity protection measures are necessary and a multivalent vaccine may be needed. [ABSTRACT FROM AUTHOR]

The article discusses the assessment of change in avian influenza A (H7N9) virus infections which cause several human illness in China from September 2015-2016. It highlights the effect of live poultry exposure especially from live-poultry markets. An overview on the suggestions of health practice for the public, is also emphasized.

Infectious bursal disease virus (IBDV) causes an acute and highly contagious viral infection in poultry, which is highly immunosuppressive and increases susceptibility to various opportunistic pathogens. Various immunomodulators including herbs have gained wide attention in poultry production with their multiple health beneficial effects. The present study reports the effect of Aloe vera gel extract on the haematological parameters in IBDV vaccinated white leghorn chicks. Specific pathogen free (SPF) day old chicks (n=48) were divided into four groups viz., Group A (Control), B (Aloe vera), C (IBDV vaccinated), and D (IBDV vaccinated + Aloe vera). The 3% Aloe vera gel extract was given in water from day one to entire study period of 45 days. Blood samples were collected at weekly intervals to assess different haematological parameters like WBC, heterophils, lymphocytes, monocytes, RBC, Hb, PCV, MCV, MCH and MCHC. Group D chicks showed significantly (P<0.05) higher WBC and lymphocyte counts than other groups at all intervals tested. PCV, MCV and MCH did not differ significantly. The groups B, C and D showed higher (P<0.05) haematological values compared to control. The Aloe vera increased the leukocytes count in both vaccinated and unvaccinated chicks thereby stimulating non-specific immune response. This is the first report of the use of Aloe vera in relation to poultry vaccinated with IBDV, further studies could reflect its potential use as an additive in poultry ration to achieve better production and to boost immune status of poultry against infectious diseases. [ABSTRACT FROM AUTHOR]

Marek’s disease virus (MDV) is a herpesvirus that induces lymphomas and immunosuppression in chickens. MDV-induced immunosuppression (MDV-IS) is divided into two phases: early-MDV-IS occurring mainly in chickens lacking maternal antibodies (MAb) against MDV and associated with lymphoid organ atrophy; and late-MDV-IS occurring once MDV enters latency and during tumour development. Our objectives were to document the impact of late-MDV-IS on commercial poultry (meat-type chickens bearing MAb against MDV and that were vaccinated or unvaccinated against MD) and to optimize a model to study late-MDV-IS under laboratory conditions. The impact of late-MDV-IS was evaluated by assessing the effect of early infection (day of age) with a very virulent plus MDV (vv+MDV) on the efficacy of chicken-embryo-origin (CEO) infectious laryngotracheitis (ILT) virus vaccine against ILT challenge. The CEO ILT vaccine was administered in water at 14 days of age and ILT virus (ILTV) challenge was done intratracheally at 30 days of age. Development of ILT was monitored by daily evaluation of clinical signs, development of gross and histological lesions in trachea, and quantification of ILTV transcripts in trachea. Infection with vv+MDV strain 648A resulted in total abrogation of protection conferred by the CEO vaccine against ILTV challenge even in chickens vaccinated at 1 day of age with either HVT, HVT+SB-1, or CVI988. Chickens exposed to vv+MDV prior to vaccination with CEO ILTV vaccine had similar (P < 0.05) clinical scores, gross lesions, histopathologic lesion scores, and load of ILTV transcripts in trachea after ILTV challenge, as chickens that were not vaccinated with CEO ILTV vaccine. [ABSTRACT FROM AUTHOR]

Infectious bronchitis virus (IBV) produces infectious bronchitis (IB) disease in poultry worldwide. In spite of proper vaccinations against the IBV, new IBV strains are continually emerging worldwide. In this study, a new highly virulent nephropathogenic IBV strain named CK/CH/XDC- 2/2013 was identified from a vaccinated flock with clinical signs of IB in the Jiangsu province of China. The full-length genome sequence of the isolate was 27,714 nucleotides long, and the genome was organized similarly to classical IBV strains. Minimum divergence, phylogenetic analysis, and distance matrix of the genome showed that the CK/CH/XDC- 2/2013 isolate had the highest similarity to the IBV BJ strain. The spike glycoprotein (S) gene had the greatest similarity to the nephropathogenic BJ strain and showed an 8 amino acid insertion (YSNGNSDV) at 73 to 80 sites and 3 amino acid deletion at sites 126 to 128 compared to the IBV vaccine strains. A recombination analysis of the S gene showed that the new isolate evolved from the IBV BJ strain and the KM91 vaccine strain. An animal challenge experiment showed a mortality of 60 to 80% in early-age chickens by different inoculation routes. Pathological examinations of the kidneys revealed inflammation, distention with uric acid deposits, and tubular degeneration. It indicated that the CK/CH/XDC-2/2013 isolate has robust kidney tissue tropism, and new nephropathogenic IBV strains are continuously evolving in China. [ABSTRACT FROM AUTHOR]

H7N7 avian influenza viruses have been widely detected in wild birds and domestic poultry since they were first detected in chickens in Italy in 1902. They can occasionally transmit to humans. Here, we isolated six H7N7 viruses in live poultry markets during routine surveillance from 2010 to 2013. Sequences analysis revealed that these viruses are reassortants bearing genes of H3N8, H7N3, H7N7, and H10N7 influenza viruses detected in wild birds and ducks, and can be categorized into three genotypes (A, B, and C). All six viruses bound to both human-type and avian-type receptors. The viruses in genotype B and C could replicate efficiently in the lungs and nasal turbinates of mice without prior adaptation, and the genotype C virus also replicated in the brain of two of three mice tested. It is important to continue to monitor the evolution of H7N7 viruses and to evaluate their potential to cause human infections. [ABSTRACT FROM AUTHOR]

The genomic diversity of Avian leukosis virus subgroup J (ALV-J) was investigated in an experimentally infected chicken. ALV-J variants in tissues from four different organs of the same bird were re-isolated in DF-1 cells, and their gp85 gene was amplified and cloned. Ten clones from each organ were sequenced and compared with the original inoculum strain, NX0101. The minimum homology of each organ ranged from 96.7 to 97.6%, and the lowest homology between organs was only 94.9%, which was much lower than the 99.1% homology of inoculum NX0101, indicating high diversity of ALV-J, even within the same bird. The gp85 mutations from the left kidney, which contained tumors, and the right kidney, which was tumor-free, had higher non-synonymous to synonymous mutation ratios than those in the tumor-bearing liver and lungs. Additionally, the mutational sites of gp85 gene in the kidney were similar, and they differed from those in the liver and lung, implying that organ- or tissue-specific selective pressure had a greater influence on the evolution of ALV-J diversity. These results suggest that more ALV-J clones from different organs and tissues should be sequenced and compared to better understand viral evolution and molecular epidemiology in the field. [ABSTRACT FROM AUTHOR]

Background: From December 2014 through June 2015, the US experienced the most costly highly pathogenic avian influenza (HPAI) outbreak to date. Most cases in commercial poultry were caused by an H5N2 strain which was a reassortant with 5 Eurasian lineage genes, including a clade 2.3.4.4 goose/Guangdong/1996 lineage hemagglutinin, and 3 genes from North American wild waterfowl low pathogenicity avian influenza viruses. The outbreak primarily affected turkeys and table-egg layer type chickens. Three isolates were selected for characterization in turkeys: the US index isolate from December 2014 (A/northern pintail/WA/40964/2014), and two poultry isolates from April 2015 (A/chicken/IA/13388/2015 and A/turkey/MN/12528/2015). Results: Four week old broad-breasted white turkeys were inoculated with one of three doses (102, 104 or 106 50% egg infectious doses [EID50] per bird) of each of the isolates to evaluate infectious dose and pathogenesis. The mean bird infectious dose of A/northern pintail/WA/40964/2014 and A/turkey/MN/12528/2015 was 105 EID50 per bird, but was 103 EID50 per bird for A/chicken/IA/13388/2015, suggesting the latter had greater adaptation to gallinaceous birds. All three isolates had unusually long mean death time of 5.3-5.9 days post challenge, and the primary clinical signs were severe lethargy and neurological signs which started no more than 24 h before death (the average pre-clinical period was 4 days). Infected turkeys also shed high levels of virus by both the oropharyngeal and cloacal routes. Conclusions: The unusually long mean death times, high levels of virus in feces, and increased adaptation of the later viruses may have contributed to the rapid spread of the virus during the peak of the outbreak. [ABSTRACT FROM AUTHOR]

Global disease suitability models are essential tools to inform surveillance systems and enable early detection. We present the first global suitability model of highly pathogenic avian influenza (HPAI) H5N1 and demonstrate that reliable predictions can be obtained at global scale. Best predictions are obtained using spatial predictor variables describing host distributions, rather than land use or eco-climatic spatial predictor variables, with a strong association with domestic duck and extensively raised chicken densities. Our results also support a more systematic use of spatial cross-validation in large-scale disease suitability modelling compared to standard random cross-validation that can lead to unreliable measure of extrapolation accuracy. A global suitability model of the H5 clade 2.3.4.4 viruses, a group of viruses that recently spread extensively in Asia and the US, shows in comparison a lower spatial extrapolation capacity than the HPAI H5N1 models, with a stronger association with intensively raised chicken densities and anthropogenic factors. [ABSTRACT FROM AUTHOR]

Marek’s disease virus (MDV), the aetiological agent of Mareks' disease (MD), is a highly cell-associated oncogenic α-herpesvirus that replicates in chicken lymphocytes and establishes a latent infection within CD4+T cells. We investigated the possible effect of MDV infection on the exacerbation of necrotic dermatitis in the combs of MD-susceptible (72) and MD-resistant (63) chicken lines at 21 days post infection. MDV-infected birds of line 63are relatively resistant to tumour development but exhibit an unusual necrosis of combs, wattles, and footpads that is intensified when infected with MDV. Chickens from line 72, on the other hand, are highly susceptible to MDV infection and tumour development. Real-Time PCR analysis revealed that IL-6, IL-8, IL-12, IL-18, iNOS, and IFNγ were all up regulated in the comb tissues of MDV-infected susceptible line 72with no visible necrotic damage. With the exception of IL-8 and iNOS, the expression of all the other tested genes was barely detected in the necrotic combs of the resistant line 63. Real-Time PCR analysis revealed the MDVmeqoncogene transcripts in the spleen tissues of both infected lines but in the comb tissues of only the susceptible line 72. A significant infiltration of macrophages and lymphocytes was detected in the comb tissues of both resistant and susceptible lines. Histopathological analysis also showed thinning and erosion of epidermis and inflammation, lympho-plasmocytic infiltration, heterophilic, and histocytic cellulitis within the connective tissues of the necrotic combs. Gram stain of the sectioned frozen comb samples exposed the presence of Gram-positive micrococcus. [ABSTRACT FROM AUTHOR]