Infectious bronchitis virus in Australia: a model of coronavirus evolution - a review.

Infectious bronchitis virus (IBV) was first isolated in Australia in 1962. Ongoing surveillance and characterization of Australian IBVs have shown that they have evolved separately from strains found throughout the rest of the world, resulting in the evolution of a range of unique strains and changes in the dominant wild-type strains, affecting tissue tropism, pathogenicity, antigenicity, and gene arrangement. Between 1961 and 1976 highly nephropathogenic genotype GI-5 and GI-6 strains, causing mortalities of 40% to 100%, predominated, while strains causing mainly respiratory disease, with lower mortality rates, have predominated since then.

Genome Sequences of Newcastle Disease Virus Strains from Two Outbreaks in Indonesia.

The genomes of two newly emerged Newcastle disease virus strains, chicken/Indonesia/Mega/001WJ/2013 and chicken/Indonesia/Cimanglid/002WJ/2015, from disease outbreaks in chickens in Indonesia are reported. Phylogenetic analysis of different genotypes of Newcastle disease virus using the F gene coding sequences suggests that these two strains belong to genotype VII.2, in class II of avian paramyxoviruses.

Genome Sequences of Newly Emerged Newcastle Disease Virus Strains Isolated from Disease Outbreaks in Indonesia.

Here, we report two genomes of newly emerged strains of (NDV), Chicken/Indonesia/Tangerang/004WJ/14 and Chicken/Indonesia/VD/003WJ/11, from disease outbreaks in chickens in Indonesia. Phylogenetic study results of the fusion (F) protein's gene-coding sequences of different genotypes of NDV revealed that these two strains belong to genotype VII.1 in the class II cluster of avian paramyxoviruses.

Analysis of antibody response to an epitope in the haemagglutinin subunit 2 of avian influenza virus H5N1 for differentiation of infected and vaccinated chickens.

The H5N1 subtype of highly pathogenic avian influenza virus has been circulating in poultry in Indonesia since 2003 and vaccination has been used as a strategy to eradicate the disease. However, monitoring of vaccinated poultry flocks for H5N1 infection by serological means has been difficult, as vaccine antibodies are not readily distinguishable from those induced by field viruses. Therefore, a test that differentiates infected and vaccinated animals (DIVA) would be essential.

Developing Farm-Level Post-vaccination Sero-Monitoring Systems for H5N1 Highly Pathogenic Avian Influenza in an Endemically Infected Country.

Whilst the serological responses of poultry following vaccination against highly pathogenic avian influenza H5N1 has been extensively investigated under laboratory conditions, there have been fewer studies conducted in the field. This applies particularly to the endemically infected countries routinely practicing vaccination, where the combination of multiple circulating clades and/or the use of vaccines with different seed strains makes the design and interpretation of field studies especially problematic. To address this for the particular situation of layer hens in the small to medium commercial sector in Indonesia, we developed a sampling regime before and after the vaccination given to point-of-lay pullets, and assessed serological response with a panel of test antigens.

Characterisation of the antigenic epitopes in the subunit 2 haemagglutinin of avian influenza virus H5N1.

Monitoring avian influenza (AI) infection and detecting silent infection in vaccinated chickens has been challenging due to the lack of effective serological diagnostic assays to differentiate between vaccinated and infected animals. Very few studies have identified suitable proteins in AI virus that can be used in successfully differentiating infected from vaccinated animals (DIVA). An HA2 peptide: HA2 position 197-201 (HA position 488-516) described by Khurana et al.

Field effectiveness of highly pathogenic avian influenza H5N1 vaccination in commercial layers in Indonesia.

Although vaccination of poultry for control of highly pathogenic avian influenza virus (HPAIV) H5N1 has been practiced during the last decade in several countries, its effectiveness under field conditions remains largely unquantified. Effective HPAI vaccination is however essential in preventing incursions, silent infections and generation of new H5N1 antigenic variants. The objective of this study was to asses the level and duration of vaccine induced immunity in commercial layers in Indonesia.

Use of M2e ELISAs for longitudinal surveillance of commercial poultry in Indonesia vaccinated against highly pathogenic avian influenza.

In countries where highly pathogenic avian influenza virus (HPAIV) H5N1 is endemic and controlled by vaccination, post-vaccination serological monitoring is essential to differentiate vaccinated poultry from those that are infected. The objectives of this study were to validate two experimental ELISAs that detect antibodies raised against the M2e protein of avian influenza virus that can be used for DIVA purposes. Results from the sM2e and tM2e ELISAs were compared with other conventional tests for the detection of H5N1influenza virus (virus isolation and RT-PCR) using samples collected from 16 commercial flocks in Indonesia.

Epitope Mapping of Avian Influenza M2e Protein: Different Species Recognise Various Epitopes.

A common approach for developing diagnostic tests for influenza virus detection is the use of mouse or rabbit monoclonal and/or polyclonal antibodies against a target antigen of the virus. However, comparative mapping of the target antigen using antibodies from different animal sources has not been evaluated before. This is important because identification of antigenic determinants of the target antigen in different species plays a central role to ensure the efficiency of a diagnostic test, such as competitive ELISA or immunohistochemistry-based tests.

Defining "Sector 3" Poultry Layer Farms in Relation to H5N1-HPAI-An Example from Java, Indonesia.

To help guide surveillance and control of highly pathogenic avian influenza subtype H5N1 (H5N1-HPAI), the Food and Agriculture Organization of the United Nations in 2004 devised a poultry farm classification system based on a combination of production and biosecurity practices. Four "Sectors" were defined, and this scheme has been widely adopted within Indonesia to guide national surveillance and control strategies. Nevertheless, little detailed research into the robustness of this classification system has been conducted, particularly as it relates to independent, small to medium-sized commercial poultry farms (Sector 3).

Evaluation of a conserved HA274-288 epitope to detect antibodies to highly pathogenic avian influenza virus H5N1 in Indonesian commercial poultry.

A peptide enzyme linked immunosorbent assay (ELISA) based on an epitope in the haemagglutinin (HA) of avian influenza virus H5N1, amino acid positions 274-288 (HA274-288) was evaluated for detection of H5N1-specific antibodies. An optimized ELISA based on the tetrameric form of the HA274-288 epitope designated MP15 gave low background with non-immune chicken sera and detected vaccinated and infected birds. The HA274-288 epitope was highly conserved in Indonesian H5N1 strains and antibody responses were detected in the majority of the vaccinated chickens regardless of the H5N1 strain used for vaccination.

Avian Influenza Virus and DIVA Strategies.

Vaccination is becoming a more acceptable option in the effort to eradicate avian influenza viruses (AIV) from commercial poultry, especially in countries where AIV is endemic. The main concern surrounding this option has been the inability of the conventional serological tests to differentiate antibodies produced due to vaccination from antibodies produced in response to virus infection. In attempts to address this issue, at least six strategies have been formulated, aiming to differentiate infected from vaccinated animals (DIVA), namely (i) sentinel birds, (ii) subunit vaccine, (iii) heterologous neuraminidase (NA), (iv) nonstructural 1 (NS1) protein, (v) matrix 2 ectodomain (M2e) protein, and (vi) haemagglutinin subunit 2 (HA2) glycoprotein.

Unique ability of pandemic influenza to downregulate the genes involved in neuronal disorders.

Pandemic influenza remains as a substantial threat to humans with a widespread panic worldwide. In contrast, seasonal (non-pandemic) has a mild non-lethal infection each year. The underlying mechanisms governing the detrimental effects of pandemic influenza are yet to be known.

Characterization of the M2e antibody response following highly pathogenic H5N1 avian influenza virus infection and reliability of M2e ELISA for identifying infected among vaccinated chickens.

A surveillance method able to differentiate between vaccinated and infected poultry is required for those countries that practice vaccination against highly pathogenic avian influenza H5N1. The external domain of the M2 protein (M2e) of influenza virus is a potentially useful differentiating-infected from vaccinated animals (DIVA) antigen but little is known about the M2e antibody response and factors influencing its detection. In this study, the M2e antibody response was characterized in layer birds vaccinated and challenged with an Indonesian H5N1 virus isolate, using a single M2e peptide or four-branched multiple antigenic peptide form of M2e (MAP-M2e) as antigens in two separate ELISAs.

Interaction between Bovine leukemia virus (BLV) infection and age on telomerase misregulation.

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). BLV can interact with telomerase and inhibits telomere shortening, contributing in leukemogenesis and tumour induction. The role of telomerase in BLV-induced lymphosarcoma and aging has been extensively studied.

Multimeric recombinant M2e protein-based ELISA: a significant improvement in differentiating avian influenza infected chickens from vaccinated ones.

Killed avian influenza virus (AIV) vaccines have been used to control H5N1 infections in countries where the virus is endemic. Distinguishing vaccinated from naturally infected birds (DIVA) in such situations however, has become a major challenge. Recently, we introduced the recombinant ectodomain of the M2 protein (M2e) of H5N1 subtype as a novel tool for an ELISA based DIVA test.

Evaluation of a novel strain of infectious bronchitis virus emerged as a result of spike gene recombination between two highly diverged parent strains.

The emergence of new variant strains of the poultry pathogen infectious bronchitis virus (IBV) is continually reported worldwide, owing to the labile nature of the large single-stranded RNA IBV genome. High resolution melt curve analysis previously detected a variant strain, N1/08, and the present study confirmed that this strain had emerged as a result of recombination between Australian subgroup 2 and 3 strains in the spike gene region, in a similar manner reported for turkey coronaviruses. The S1 gene for N1/08 had highest nucleotide similarity with subgroup 2 strains, which is interesting considering subgroup 2 strains have not been detected since the early 1990s.

The presence of viral subpopulations in an infectious bronchitis virus vaccine with differing pathogenicity--a preliminary study.

There are currently four commercially available vaccines in Australia to protect chickens against infectious bronchitis virus (IBV). Predominantly, IBV causes clinical signs associated with respiratory or kidney disease, which subsequently cause an increase in mortality rate. Three of the current vaccines belong to the same subgroup (subgroup 1), however, the VicS vaccine has been reported to cause an increased vaccinal reaction compared to the other subgroup 1 vaccines.

Differentiation of infectious bursal disease virus strains using real-time RT-PCR and high resolution melt curve analysis.

Differentiation of infectious bursal disease virus (IBDV) strains is crucial for effective vaccination programs and epidemiological investigations. In this study, a combination of real-time RT-PCR and high resolution melt (HRM) curve analysis was developed for simultaneous detection and differentiation of IBDV strains/isolates. The hypervariable region of VP2 gene was amplified from several IBDV strains and subjected to HRM curve analysis.

Infectious bronchitis viruses with naturally occurring genomic rearrangement and gene deletion.

Infectious bronchitis viruses (IBVs) are group III coronaviruses that infect poultry worldwide. Genetic variations, including whole-gene deletions, are key to IBV evolution. Australian subgroup 2 IBVs contain sequence insertions and multiple gene deletions that have resulted in a substantial genomic divergence from international IBVs.

Naturally occurring recombination between distant strains of infectious bronchitis virus.

New variants of infectious bronchitis virus (IBV) have emerged in Australia despite its geographical isolation and intensive vaccination programs. In the present study, the 3' terminal 7.2 kb of the genome of a recently isolated variant of IBV (N1/03) was sequenced and compared with the sequences of classical and novel strains of IBV, the two main groups of these viruses in Australia.