Super-Sentinel Chickens and Detection of Low-Pathogenicity Influenza Virus

Chicken interferon-α administered perorally in drinking water acts on the oropharyngeal mucosal system as an adjuvant that causes chickens to rapidly seroconvert after natural infection by low-pathogenicity Influenza virus. These chickens, termed super sentinels, can serve as sensitive early detectors of clinically inapparent infections

Population dynamics of an RNA virus and its defective interfering particles in passage cultures

<p>Abstract</p> <p>Background</p> <p>Viruses can fall prey to their defective interfering (DI) particles. When viruses are cultured by serial passage on susceptible host cells, the presence of virus-like DI particles can cause virus populations to rise and fall, reflecting predator-prey interactions between DI and virus particles. The levels of virus and DI particles in each population passage can be determined experimentally by plaque and yield-reduction assays, respectively.</p> <p>Results</p> <p>To better understand DI and virus particle interactions we measured vesicular stomatitis virus and DI particle production during serial-passage culture on BHK cells. When the multiplicity of infection (MOI, or ratio of infectious virus particles to cells) was fixed, virus yields followed a pattern of progressive decline, with higher MOI driving earlier and faster drops in virus level. These patterns of virus decline were consistent with predictions from a mathematical model based on single-passage behavior of cells co-infected with virus and DI particles. By contrast, the production of virus during fixed-volume passages exhibited irregular fluctuations that could not be described by either the steady-state or regular oscillatory dynamics of the model. However, these irregularities were, to a significant degree, reproduced when measured host-cell levels were incorporated into the model, revealing a high sensitivity of virus and DI particle populations to fluctuations in available cell resources.</p> <p>Conclusions</p> <p>This study shows how the development of mathematical models, when guided by quantitative experiments, can provide new insight into the dynamic behavior of virus populations.</p

Immune-Related Gene Expression in Two B-Complex Disparate Genetically Inbred Fayoumi Chicken Lines Following Eimeria maxima Infection

To investigate the influence of genetic differences in the MHC on susceptibility to avian coccidiosis, M5.1 and M15.2 B-haplotype-disparate Fayoumi chickens were orally infected with live Eimeria maxima oocysts, and BW gain, fecal oocyst production, and expression of 14 immune-related genes were determined as parameters of protective immunity. Weight loss was reduced and fecal parasite numbers were lower in birds of the M5.1 line compared with M15.2 line birds. Intestinal intraepithelial lymphocytes from M5.1 chickens expressed greater levels of transcripts encoding interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-6, IL-8, IL-12, IL-15, IL-17A, inducible nitric oxide synthase, and lipopolysaccharide-induced tumor necrosis factor-α factor and lower levels of mRNA for IFN-α, IL-10, IL-17D, NK-lysin, and tumor necrosis factor superfamily 15 compared with the M15.2 line. In the spleen, E. maxima infection was associated with greater expression levels of IFN-γ, IL-15, and IL-8 and lower levels of IL-6, IL-17D, and IL-12 in M5.1 vs. M15.2 birds. These results suggest that genetic determinants within the chicken MHC influence resistance to E. maxima infection by controlling the local and systemic expression of immune-related cytokine and chemokine genes

Avian Influenza: Should China Be Alarmed?

Avian influenza has emerged as one of the primary public health concern of the 21st century. Influenza strain H5N1 is capable of incidentally infecting humans and other mammals. Since their reemergence in 2003, highly pathogenic avian influenza A (H5N1) viruses have been transmitted from poultry to humans (by direct or indirect contact with infected birds) in several provinces of Mainland China, which has resulted in 22 cases of human infection and has created repercussions for the Chinese economy. People have been concerned whether a new pandemic will occur in the future. The eradication of pathogenic avian influenza viruses appears to be the most effective way to prevent an influenza pandemic. This paper will examine the features of H5N1, including incidence, infection, immunity, clinical management, prevention and control, and therapy in Mainland China

Full Scale Regenerable HEPA Filter Design Using Sintered Metal Filter Elements: Final Technical Report

A Department of Energy funded contract involved the development of porous metal as a HEPA filter, and the subsequent design of a full-scale regenerable HEPA filtration system (RHFS). This RHFS could replace the glass fiber HEPA filters currently being used on the high level waste (HLW) tank ventilation system with a system that would be moisture tolerant, durable, and cleanable in place. The origins of the contract are a 1996 investigation at the Savannah River Technology Center (SRTC) regarding the use of porous metal as a HEPA filter material. This contract was divided into Phases I, IIA and IIB. Phase I of the contract evaluated simple filter cylinders in a simulated High Level Waste (HLW) environment and the ability to clean and regenerate the filter media after fouling. Upon the successful completion of Phase I, Phase IIA was conducted, which included lab scale prototype testing and design of a full-scale system. The work completed under Phase IIA included development of a full-scale system design, development of a filter media meeting the HEPA filtration efficiency that would also be regenerable using prescribed cleaning procedures, and the testing of a single element system prototype at Savannah River. All contract objectives were met. The filter media selected was a nickel material already under development at Mott, which met the HEPA filtration efficiency standard. The Mott nickel media met and exceeded the HEPA requirement, providing 99.99% removal against a requirement of 99.97%. Double open-ended elements of this media were provided to the Savannah River Test Center for HLW simulation testing in the single element prototype filter. These elements performed well and further demonstrated the practicality of a metallic media regenerable HEPA filter system. An evaluation of the manufacturing method on many elements demonstrated the reproducibility to meet the HEPA filtration requirement. The full-scale design of the Mott RHFS incorporated several important features in its design and operation. The element bundle would be an all welded assembly, which could be removed and replaced as a unit if the elements ever needed replacement. Each element had a spray nozzle mounted above it for cleaning; it could also be cleaned by a soak and backwash technique. The inlet nozzle incorporated a cyclonic separator to initially remove large suspended material and droplets. Tests indicated a significant reduction of dirt load getting to the filter elements, which would extend the operating time between cleanings. A high capacity blower was selected to overcome the higher pressure drop of the metallic elements. The blower, having a 25 horsepower motor, would be capable of operating the system to higher pressure drops than available on the glass fiber HEPA filters. This additional capacity further increases the operating duration of the filter. Upon successful testing and acceptance of the full-scale design, Phase IIB would involve the construction and test of a full-scale prototype system on an actual HLW tank. Phase IIA was completed but for funding and priority reasons the contract was halted; thus Phase IIB would not be pursued at this time. The Mott RHFS has been proven at each stage of the development process to meet the requirements of a suitable replacement system for the glass fiber HEPA filters enabling great cost savings. It remains to test a full-scale operating system on an actual high level waste tank to fully demonstrate the performance and anticipated cost savings of the Mott RHFS. Mott is confident that the performance will be more than acceptable

Interferon Induction by Viruses. XXV. Adenoviruses as inducers of interferon in deelopmentally aged primary chicken embryo cells

Chicken embryonic cells (CEC) are nonpermissive hosts for the replication of human adenoviruses, yet they respond to infection by producing interferon (IFN). The nature of the IFN inducer moiety in these viruses has been elusive since its initial study by Ilona Béládi and colleagues some 40 years ago. We tested the hypothesis that viral dsRNA was the IFN inducer molecule - for two reasons: dsRNA has been identified as a potent inducer of IFN, and developmentally mature CEC cells as cultured in vitro can develop a hyper-responsive state to dsRNA such that a single molecule of dsRNA per cell constitutes the threshold of detection. Furthermore, the number of particles in a virus population capable of inducing-IFN, irrespective of their replication capacity, can be quantified through the analysis of dose (multiplicity)-response (IFN yield) curves, thus allowing a determination of the number particles in virus populations that possess the capacity to induce IFN. This study demonstrates that type 5 wild type adenovirus (Ad5) and mutants dl312, dl334, and ts19 induce from 8,000 to 80,000 IFN U per 107 CEC. UV irradiation showed that transcription of about 20-50% of the Ad5 genome was required to produce the IFN inducer moiety. The ratio of IFN-inducing particles to plaque-forming particles (IFP: PFP) was as low as 1:6, indicating that only a small fraction of the total particles in a virus population ever function as IFP. We conclude that adenovirus dsRNA produced during symmetric transcription of some regions of the viral genome, coupled with fine-tuning of the IFN-induction pathway, account for the IFN-inducing capacity of adenoviruses in the non-permissive chicken cell