Infection with IBV DMV/1639 at a Young Age Leads to Increased Incidence of Cystic Oviduct Formation Associated with False Layer Syndrome.

Infectious bronchitis virus (IBV) is an avian coronavirus that causes respiratory disease but can affect the reproductive tract of laying-type chickens. If infection occurs in pullets, false layer syndrome, which is characterized by the development of large, fluid-filled cystic oviducts, can occur. Recently, IBV strain DMV/1639 has been detected in parts of Canada and the U.

Quantitative real-time PCR assays for the concurrent diagnosis of infectious laryngotracheitis virus, Newcastle disease virus and avian metapneumovirus in poultry.

Newcastle disease (ND), infectious laryngotracheitis (ILT) and avian metapneumovirus (aMPV) can be similar making it critical to quickly differentiate them. Herein, we adapted pre-existing molecular-based diagnostic assays for NDV and ILTV, and developed new assays for aMPV A and B, for use under synchronized thermocycling conditions. All assays performed equivalently with linearity over a 5 log dynamic range, a reproducible (R² > 0.

Molecular Evolution of Infectious Bronchitis Virus and the Emergence of Variant Viruses Circulating in the United States.

Infectious bronchitis virus (IBV) is a highly infectious and transmissible gammacoronavirus that is nearly impossible to control through biosecurity. Coronaviruses are RNA viruses with an enormous capacity for rapid replication and high rates of mutation, leading to a tremendous amount of genetic diversity. Viral evolution occurs when selection working on genetic diversity leads to new mutations being fixed in the population over time.

Protection following simultaneous vaccination with three or four different attenuated live vaccine types against infectious bronchitis virus.

Two or more different live attenuated infectious bronchitis virus (IBV) vaccine types are often given to broilers to induce homologous protection as well as to broaden protection against other IBV types in the field. However, the ability of broilers to respond to three or four different antigenic types of IBV vaccine has not been examined experimentally. In this study, we vaccinated one-day-old broiler chicks by eyedrop with three or four different IBV vaccine types simultaneously.

Validation of specific quantitative real-time RT-PCR assay panel for Infectious Bronchitis using synthetic DNA standards and clinical specimens.

Infectious bronchitis (IB) is a highly contagious upper respiratory tract disease of chickens caused by infectious bronchitis virus (IBV), which has various serotypes that do not cross-protect. Vaccine control strategies for this virus are only effective when designed around the currently circulating serotypes. It is essential to not only rapidly detect IBV but also to identify the type of virus causing disease.

Effect of Pullet Vaccination on Development and Longevity of Immunity.

Avian respiratory disease causes significant economic losses in commercial poultry. Because of the need to protect long-lived poultry against respiratory tract pathogens from an early age, vaccination programs for pullets typically involve serial administration of a variety of vaccines, including infectious bronchitis virus (IBV), Newcastle disease virus (NDV), and infectious laryngotracheitis virus (ILTV). Often the interval between vaccinations is only a matter of weeks, yet it is unknown whether the development of immunity and protection against challenge when vaccines are given in short succession occurs in these birds, something known as viral interference.

GENETIC RELATEDNESS OF EPIZOOTIC HEMORRHAGIC DISEASE VIRUS SEROTYPE 2 FROM 2012 OUTBREAK IN THE USA.

During summer and early fall of 2012, the US experienced the largest outbreak of hemorrhagic disease (HD) on record; deer (both Odocoileus virginianus and Odocoileus hemionus) in 35 states were affected, including many northern states where HD typically does not occur. Epizootic hemorrhagic disease virus (EHDV) was the predominant virus isolated, with serotype 2 (EHDV-2) representing 66% (135/205) of all isolated viruses. Viruses within the EHDV serogroup are genetically similar, but we hypothesized that subtle genetic distinctions between viruses would exist across the geographic range of the outbreak if multiple EHDV-2 strains were responsible.

Biological and molecular characterization of ArkGA: A novel Arkansas serotype vaccine that is highly attenuated, efficacious, and protective against homologous challenge.

Almost all commercial poultry are vaccinated against avian coronavirus infectious bronchitis virus (IBV) using live attenuated vaccines mass administered by spray at day of hatch. Although many different types of IBV vaccines are used successfully, the ArkDPI serotype vaccine, when applied by spray, does not infect and replicate sufficiently to provide protection against homologous challenge. In this study, we examined a different Ark vaccine strain (Ark99), which is no longer used commercially due to its reactivity in one day old chicks, to determine if it could be further attenuated by passage in embryonated eggs but still provide adequate protection.

Different evolutionary trajectories of vaccine-controlled and non-controlled avian infectious bronchitis viruses in commercial poultry.

To determine the genetic and epidemiological relationship of infectious bronchitis virus (IBV) isolates from commercial poultry to attenuated live IBV vaccines we conducted a phylogenetic network analysis on the full-length S1 sequence for Arkansas (Ark), Massachusetts (Mass) and Delmarva/1639 (DMV/1639) type viruses isolated in 2015 from clinical cases by 3 different diagnostic laboratories. Phylogenetic network analysis of Ark isolates showed two predominant groups linked by 2 mutations, consistent with subpopulations found in commercial vaccines for this IBV type. In addition, a number of satellite groups surrounding the two predominant populations were observed for the Ark type virus, which is likely due to mutations associated with the nature of this vaccine to persist in flocks.

Minimum Infectious Dose Determination of the Arkansas Delmarva Poultry Industry Infectious Bronchitis Virus Vaccine Delivered by Hatchery Spray Cabinet.

The Arkansas Delmarva Poultry Industry (ArkDPI) infectious bronchitis virus (IBV) vaccine is effective when administered by eye drop, where the vaccine virus is able to infect and replicate well in birds and is able to induce protection against homologous challenge. However, accumulating evidence indicates that the ArkDPI vaccine is ineffective when applied by hatchery spray cabinet using the same manufacturer-recommended dose per bird. For this study, we aimed to determine the minimum infectious dose for the spray-administered ArkDPI vaccine, which we designate as the dose that achieves the same level of infection and replication as the eye drop-administered ArkDPI vaccine.

Insights from molecular structure predictions of the infectious bronchitis virus S1 spike glycoprotein.

Infectious bronchitis virus is an important respiratory pathogen in chickens. The IBV S1 spike is a viral structural protein that is responsible for attachment to host receptors and is a major target for neutralizing antibodies. To date, there is no experimentally determined structure for the IBV S1 spike.

Polymorphisms in the S1 spike glycoprotein of Arkansas-type infectious bronchitis virus (IBV) show differential binding to host tissues and altered antigenicity.

Sequencing avian infectious bronchitis virus spike genes re-isolated from vaccinated chicks revealed that many sequence changes are found on the S1 spike gene. In the ArkDPI strain, Y43H and ∆344 are the two most common changes observed. This study aims to examine the roles of Y43H and ∆344 in selection in vivo.

Vaccine Protection of Turkeys Against H5N1 Highly Pathogenic Avian Influenza Virus with a Recombinant Turkey Herpesvirus Expressing the Hemagglutinin Gene of Avian Influenza.

Outbreaks of H5 highly pathogenic avian influenza (HPAI) in commercial poultry are a constant threat to animal health and food supplies. While vaccination can enhance protection and reduce the spread of disease, there is considerable evidence that the level of immunity required for protection varies by subtype and virulence of field virus. In this study, the efficacy of a recombinant turkey herpesvirus (rHVT) vector vaccine expressing the hemagglutinin gene from a clade 2.

S1 gene-based phylogeny of infectious bronchitis virus: An attempt to harmonize virus classification.

Infectious bronchitis virus (IBV) is the causative agent of a highly contagious disease that results in severe economic losses to the global poultry industry. The virus exists in a wide variety of genetically distinct viral types, and both phylogenetic analysis and measures of pairwise similarity among nucleotide or amino acid sequences have been used to classify IBV strains. However, there is currently no consensus on the method by which IBV sequences should be compared, and heterogeneous genetic group designations that are inconsistent with phylogenetic history have been adopted, leading to the confusing coexistence of multiple genotyping schemes.

Evaluating Protection Against Infectious Bronchitis Virus by Clinical Signs, Ciliostasis, Challenge Virus Detection, and Histopathology.

In this study, we examined the association among clinical signs, ciliostasis, virus detection, and histopathology for evaluating protection of vaccinated chickens against homologous and heterologous infectious bronchitis virus (IBV) challenge. At 5 days following challenge with IBV, we found a good correlation among clinical signs, ciliostasis in the trachea, challenge virus detection, and microscopic lesions in the trachea, with all four criteria being negative in fully protected birds and positive in fully susceptible birds. In partially protected birds we observed clinical signs and detected challenge virus; however, the ciliated epithelium was intact.

Hatchery Spray Cabinet Administration Does Not Damage Avian Coronavirus Infectious Bronchitis Virus Vaccine Based on Analysis by Electron Microscopy and Virus Titration.

studies in our laboratory showed that the Arkansas-Delmarva Poultry Industry (Ark-DPI) vaccine given to 1-day-old chickens by hatchery spray cabinet replicated poorly and failed to adequately protect broilers against homologous virus challenge, whereas the same vaccine given by eye-drop did replicate and the birds were protected following homologous virus challenge. To determine if mechanical damage following spray application plays a role in failure of the Ark-DPI vaccine, we examined the morphology of three Ark-DPI vaccines from different manufacturers using an electron microscope and included a Massachusetts (Mass) vaccine as control. One of the Ark-DPI vaccines (vaccine A) and the Mass vaccine had significantly (P < 0.

Vaccine protection of chickens against antigenically diverse H5 highly pathogenic avian influenza isolates with a live HVT vector vaccine expressing the influenza hemagglutinin gene derived from a clade 2.2 avian influenza virus.

Vaccination is an important tool in the protection of poultry against avian influenza (AI). For field use, the overwhelming majority of AI vaccines produced are inactivated whole virus formulated into an oil emulsion. However, recombinant vectored vaccines are gaining use for their ability to induce protection against heterologous isolates and ability to overcome maternal antibody interference.

Detection of infectious bronchitis virus with the use of real-time quantitative reverse transcriptase-PCR and correlation with virus detection in embryonated eggs.

Real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) assays have been used to detect the presence of challenge virus when the efficacy of infectious bronchitis virus (IBV) vaccine against field viruses is being experimentally evaluated. However, federal guidelines for licensing IBV vaccines indicate that challenge-virus detection following vaccination is to be conducted in embryonated eggs. In this study, we examined qRT-PCR data with the use of universal and type-specific primers and probe sets for IBV detection and compared those data with challenge-virus detection in embryonated eggs to determine if the two methods of evaluating vaccine efficacy are comparable.

Identification of avian coronavirus in wild aquatic birds of the central and eastern USA.

Coronaviruses (CoVs) are worldwide in distribution, highly infectious, and difficult to control because of their extensive genetic diversity, short generation time, and high mutation rates. Genetically diverse CoVs have been reported from wild aquatic birds that may represent a potential reservoir for avian CoVs as well as hosts for mutations and recombination events leading to new serotypes or genera. We tested 133 pooled samples representing 700 first-passage (in eggs) and 303 direct cloacal swab transport media samples from wild aquatic birds in the US that were avian influenza-negative.

Simultaneous detection of five major serotypes of Avian coronavirus by a multiplex microsphere-based assay.

Avian coronavirus (commonly known as Infectious bronchitis virus [IBV]) is of major economic importance to commercial chicken producers worldwide. Due to the existence of multiple serotypes and variants of the virus that do not cross-protect, it is important to diagnose circulating serotypes and choose the right vaccine type for successful protection. In an effort to improve conventional diagnostic tests, a microsphere-based assay was developed and evaluated for simultaneous detection of the most common IBV vaccine serotypes in the United States: Arkansas (Ark), Connecticut (Conn), Massachusetts (Mass), Delaware (DE072), and Georgia 98 (GA98).

Review of infectious bronchitis virus around the world.

Infectious bronchitis virus (IBV) is a gamma coronavirus that causes a highly contagious disease in chickens. The virus can affect the upper respiratory tract and the reproductive tract, and some strains can cause a nephritis. Different serotypes and genetic types of the virus have been identified worldwide and for the most part do not cross-protect.

Association of the chicken MHC B haplotypes with resistance to avian coronavirus.

Clinical respiratory illness was compared in five homozygous chicken lines, originating from homozygous B2, B8, B12 and B19, and heterozygous B2/B12 birds after infection with either of two strains of the infectious bronchitis virus (IBV). All chickens used in these studies originated from White Leghorn and Ancona linages. IBV Gray strain infection of MHC homozygous B12 and B19 haplotype chicks resulted in severe respiratory disease compared to chicks with B2/B2 and B5/B5 haplotypes.

Genetic diversity and selection regulates evolution of infectious bronchitis virus.

Conventional and molecular epidemiologic studies have confirmed the ability of infectious bronchitis virus (IBV) to rapidly evolve and successfully circumvent extensive vaccination programs implemented since the early 1950s. IBV evolution has often been explained as variation in gene frequencies as if evolution were driven by genetic drift alone. However, the mechanisms regulating the evolution of IBV include both the generation of genetic diversity and the selection process.

Molecular evolution and emergence of avian gammacoronaviruses.

Coronaviruses, which are single stranded, positive sense RNA viruses, are responsible for a wide variety of existing and emerging diseases in humans and other animals. The gammacoronaviruses primarily infect avian hosts. Within this genus of coronaviruses, the avian coronavirus infectious bronchitis virus (IBV) causes a highly infectious upper-respiratory tract disease in commercial poultry.

Use of FTA sampling cards for molecular detection of avian influenza virus in wild birds.

Current avian influenza (AI) virus surveillance programs involving wild birds rely on sample collection methods that require refrigeration or low temperature freezing to maintain sample integrity for virus isolation and/or reverse-transcriptase (RT) PCR. Maintaining the cold chain is critical for the success of these diagnostic assays but is not always possible under field conditions. The aim of this study was to test the utility of Finders Technology Associates (FTA) cards for reliable detection of AI virus from cloacal and oropharyngeal swabs of wild birds.