Infectious bronchitis virus variants in chickens: evolution, surveillance, control and prevention

Infectious bronchitis is a disease of the upper respiratory tract of chickens caused by a Gammacoronavirus (infectious bronchitis virus, IBV). Severe economic losses are caused by IBV due to a reduction in egg production and/or egg quality in layers in addition to poor feed conversion and increased condemnations in broiler chickens. The extreme variability of this virus is in part due to its RNA genome, which predisposes it to mutations and generates genetic variation. In addition, recombination events add to the variability of this virus. IBV variability was first described in 1956 by Jungherr. Since then, dozens of serotypes and hundreds of genotypes have been reported. Variant IBV strains are those that, can escape from the immunity generated by conventional strains, despite not being fully different from conventional strains affecting a geographic region. At the genomic level, these differences can be equal or greater than 5% of the hypervariable region of the S1 gene. These variant strains are usually restricted to geographic regions and most of the time are transient, reason why diagnostics and epidemiological surveillance are crucial to determine their existence and persistence. The main goal of surveillance is to assist the development of efficient preventative measures in the field. This review aims to critically analyse the literature related to IBV variability and judiciously comment and discuss on how to better prevent this poultry endemic disease

The effect of diatomaceous earth in live, attenuated infectious bronchitis vaccine, immune responses, and protection against challenge.

Live virus vaccines are commonly used in poultry production, particularly in broilers. Massive application and generation of a protective local mucosal and humoral immunity with no adverse effects is the main goal for this strategy. Live virus vaccines can be improved by adding adjuvants to boost mucosal innate and adaptive responses. In a previous study we showed that diatomaceous earth (DE) can be used as adjuvant in inactivated vaccines. The aim of this study was to test DE as adjuvant in an Ark-DPI live infectious bronchitis virus (IBV) vaccine after ocular or spray application. Titrating the virus alone or after addition of DE showed that DE had no detrimental effect on the vaccine virus. However, adding DE to the vaccine did not induce higher IgG titers in the serum and IgA titers in tears. It also did not affect the frequency of CD4+ T cells, CD8+ T cells and monocytes/macrophages in the blood and the spleen determined by flow cytometry. In addition, protection generated against IBV homologous challenges, measured by viral load in tears, respiratory signs and histopathology in tracheas, did not vary when DE was present in the vaccine formulation. Finally, we confirmed through our observations that Ark vaccines administered by hatchery spray cabinet elicit weaker immune responses and protection against an IBV homologous challenge compared to the same vaccine delivered via ocular route

Transcriptome Analysis in Spleen Reveals Differential Regulation of Response to Newcastle Disease Virus in Two Chicken Lines.

Enhancing genetic resistance of chickens to Newcastle Disease Virus (NDV) provides a promising way to improve poultry health, and to alleviate poverty and food insecurity in developing countries. In this study, two inbred chicken lines with different responses to NDV, Fayoumi and Leghorn, were challenged with LaSota NDV strain at 21 days of age. Through transcriptome analysis, gene expression in spleen at 2 and 6 days post-inoculation was compared between NDV-infected and control groups, as well as between chicken lines. At a false discovery rate <0.05, Fayoumi chickens, which are relatively more resistant to NDV, showed fewer differentially expressed genes (DEGs) than Leghorn chickens. Several interferon-stimulated genes were identified as important DEGs regulating immune response to NDV in chicken. Pathways predicted by IPA analysis, such as "EIF-signaling", "actin cytoskeleton organization nitric oxide production" and "coagulation system" may contribute to resistance to NDV in Fayoumi chickens. The identified DEGs and predicted pathways may contribute to differential responses to NDV between the two chicken lines and provide potential targets for breeding chickens that are more resistant to NDV

Millimagnitude Photometry for Transiting Extrasolar Planetary Candidates IV: The Puzzle of the Extremely Red OGLE-TR-82 Primary Solved

We present precise new V, I, and K-band photometry for the planetary transit candidate star OGLE-TR-82. Good seeing V-band images acquired with VIMOS instrument at ESO VLT allowed us to measure V=20.6+-0.03 mag star in spite of the presence of a brighter neighbour about 1" away. This faint magnitude answers the question why it has not been possible to measure radial velocities for this object. One transit of this star has been observed with GMOS-S instrument of GEMINI-South telescope in i and g-bands. The measurement of the transit allows us to verify that this is not a false positive, to confirm the transit amplitude measured by OGLE, and to improve the ephemeris. The transit is well defined in i-band light curve, with a depth of A_i=0.034 mag. It is however, less well defined, but deeper (A_g=0.1 mag) in the g-band, in which the star is significantly fainter. The near-infrared photometry obtained with SofI array at the ESO-NTT yields K=12.2+-0.1 and V-K=8.4+-0.1, so red that it is unlike any other transit candidate studied before. Due to the extreme nature of this object, we have not yet been able to measure velocities for this star, but based on the new data we consider two different possible configurations:(1) a nearby M7V star, or (2) a blend with a very reddened distant red giant. The nearby M7V dwarf hypothesis would give a radius for the companion of R_p=0.3+-0.1 R_J, i.e. the size of Neptune. Quantitative analysis of near-IR spectroscopy finally shows that OGLE-TR-82 is a distant, reddened metal poor early K giant. This result is confirmed by direct comparison with stellar templates that gives the best match for a K3III star. Therefore, we discard the planetary nature of the companion. Based on all the new data, we conclude that this system is a main-sequence binary blended with a background red giant.Comment: 26 pages, 9 figures, ApJ accepte

Does Gener Impact the Immune Response of Chicks?

Sequencing technology allows us tosee how the gene expression of each genechanges under different treatment conditions. In this study, chicks of two inbred lines were challenged with Newcastle Disease Virus (NDV), a pathogen with devastating impacts on poultry throughout the world. At each of the three time points post-infection, one-third of the chicks were sacraficed and their lungs were harvested. When comparing males and females infected with NDV, differences in gene expression that were predicted to impact growth and apoptosis were identified. Differences between the response of males and females to viral challenges could be useful information for production operations. The interaction between production traits and immune related traits require further study

Meisenheimer complexes as hidden intermediates in the aza-S_NAr mechanism

In this work we report a computational study about the aza-S_NAr mechanism in fluorine- and chlorine-containing azines with the aim to unravel the physical factors that determine the reactivity patterns in these heterocycles towards propylamine. The nature of the reaction intermediate was analyzed in terms of its electronic structure based on a topological analysis framework in some non-stationary points along the reaction coordinate. The mechanistic dichotomy of a concerted or a stepwise pathway is interpreted in terms of the qualitative Diabatic Model of Intermediate Stabilization (DMIS) approach, providing a general mechanistic picture for the S_NAr process involving both activated benzenes and nitrogen-containing heterocycles. With the information collected, a unified vision of the Meisenheimer complexes as transition state, hidden intermediate or real intermediate was proposed

Meisenheimer complexes as hidden intermediates in the aza-S_NAr mechanism

In this work we report a computational study about the aza-S_NAr mechanism in fluorine- and chlorine-containing azines with the aim to unravel the physical factors that determine the reactivity patterns in these heterocycles towards propylamine. The nature of the reaction intermediate was analyzed in terms of its electronic structure based on a topological analysis framework in some non-stationary points along the reaction coordinate. The mechanistic dichotomy of a concerted or a stepwise pathway is interpreted in terms of the qualitative Diabatic Model of Intermediate Stabilization (DMIS) approach, providing a general mechanistic picture for the S_NAr process involving both activated benzenes and nitrogen-containing heterocycles. With the information collected, a unified vision of the Meisenheimer complexes as transition state, hidden intermediate or real intermediate was proposed