Carlos N. Estevez

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Virulent Newcastle disease virus isolates from the 1971 and 2002 U.S. outbreaks are of the same serotype but a different genotype than current vaccine strains. Prior experiments with inactivated vaccines in chickens show significantly less virus shed in birds vaccinated with a homologous vaccine (same genotype as challenge) compared to chickens vaccinated(More)
In order to understand the molecular mechanisms by which different strains of avian influenza viruses overcome host response in birds, we used a complete chicken genome microarray to compare early gene expression levels in chicken embryo fibroblasts (CEF) infected with two avian influenza viruses (AIV), A/CK/Hong Kong/220/97 and A/Egret/Hong Kong/757.2/02,(More)
A major factor in the pathogenicity of Newcastle disease virus (NDV) is the amino acid sequence of the fusion protein cleavage site, but the role of other viral genes that contribute to virulence and different clinical forms of the disease remain undefined. To assess the role of other NDV genes in virus pathogenicity, a reverse genetics system was developed(More)
Virulent strains of Newcastle disease virus (NDV) and avian metapneumovirus (aMPV) can cause serious respiratory diseases in poultry. Vaccination combined with strict biosecurity practices has been the recommendation for controlling both NDV and aMPV diseases in the field. In the present study, an NDV based, LaSota strain recombinant vaccine virus(More)
Avian metapneumovirus (aMPV) and Newcastle disease virus (NDV) are threatening avian pathogens that can cause serious respiratory diseases in poultry worldwide. Vaccination, combined with strict biosecurity practices, has been the recommendation for controlling these diseases in the field. In the present study, we generated NDV LaSota vaccine strain-based(More)
The fusion (F) and haemagglutinin-neuraminidase (HN) proteins of Newcastle disease virus (NDV) are multifunctional proteins that play critical roles during infection. Here, we assessed the ability of NDV to replicate in macrophages and investigated the contribution of the F and HN proteins to NDV infection/replication in these cells. Results of our study(More)
Attachment of Newcastle disease virus (NDV) to the host cell is mediated by the haemagglutinin-neuraminidase (HN), a multifunctional protein that has receptor recognition, neuraminidase (NA) and fusion promotion activities. The process that connects receptor binding and fusion triggering is poorly understood and amino acid residues important for the(More)
A major route of infection of avian influenza virus (AIV) and Newcastle disease virus (NDV) in chickens is through cells of the respiratory epithelium. Here we describe the development of a method for culture of tracheal epithelial cells from chicken embryos as well as their use in studies of infection with avian respiratory viruses such as(More)
Genetic variation in length of the G gene among different avian metapneumovirus subgroup C (aMPV-C) isolates has been reported. However, its biological significance in virus replication, pathogenicity and immunity is unknown. In this study, we developed a reverse genetics system for aMPV-C and generated two Colorado (CO) strain-based recombinant viruses(More)
The aim of this study was to evaluate the disease-inducing ability of four chimeric Newcastle disease viruses (NDV) by clinicopathological assessment. The infectious clones were previously generated by insertion of hemagglutinin–neuraminidase (HN) and/or fusion (F) genes from virulent strains (Turkey North Dakota and California 02) into a mesogenic strain(More)