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avian metapneumovirus (ampv) attachment protein involvement in probable virus evolution concurrent with mass live vaccine introduction.avian metapneumoviruses detected in northern italy between 1987 and 2007 were sequenced in their fusion (f) and attachment (g) genes together with the same genes from isolates collected throughout western european prior to 1994. fusion protein genes sequences were highly conserved while g protein sequences showed much greater heterogeneity. phylogenetic studies based on both genes clearly showed that later italian viruses were significantly different to all earlier virus detections, including ea ...201020447777
analysis of expression and glycosylation of avian metapneumovirus attachment glycoprotein from recombinant baculoviruses.recently, we reported the expression and glycosylation of avian metapneumovirus attachment glycoprotein (ampv/c g protein) in eukaryotic cell lines by a transient-expression method. in the present study, we investigated the biosynthesis and o-linked glycosylation of the ampv/c g protein in a baculovirus expression system. the results showed that the insect cell-produced g protein migrated more rapidly in sds-page as compared to llc-mk2 cell-derived g proteins owing to glycosylation differences. ...201020713098
viral respiratory diseases (ilt, ampv infections, ib): are they ever under control?1. the use of vaccines is the main approach to control of the economically important poultry viral respiratory diseases infectious laryngotracheitis (ilt), avian metapneumovirus (ampv) infections and infectious bronchitis (ib). this paper appraises the current methods of vaccine control in the light of the nature of each virus and epidemiological factors associated with each disease. 2. infectious laryngotracheitis virus (iltv) exists as a single type with a wide range of disease severity. it is ...201020390564
compromised t-cell immunity in turkeys may lead to an unpredictable avian metapneumovirus vaccine response and variable protection against challenge.avian metapneumovirus (ampv) is an important respiratory pathogen of turkeys with considerable economic impact on poultry production. although vaccination is widely used for the control of the disease, questions regarding vaccine safety and efficacy remain to be elucidated. this report describes the problems associated with reproducibility of the ampv-vaccine response, comparing t-lymphocyte-compromised and t-cell-intact turkeys. in three consecutive experiments, turkeys partially depleted of t- ...201020954011
charged amino acids in the ampv fusion protein have more influence on induced protection than deletion of the sh or g genes.modifications to f, g and sh genes of an avian metapneumovirus (ampv) field isolate were made by reverse genetics and their virulence and protective capacity were tested in young turkeys. infection of one-day-old turkeys with a subtype a ampv neither caused disease nor stimulated detectable protection against subsequent virulent challenge. while serial passage of this virus in tracheal tissue increased virulence, protection stimulated remained moderate. substitution of the fusion protein from a ...201020656031
complete nucleotide sequences of avian metapneumovirus subtype b genome.complete nucleotide sequences were determined for subtype b avian metapneumovirus (ampv), the attenuated vaccine strain vco3/50 and its parental pathogenic strain vco3/60616. the genomes of both strains comprised 13,508 nucleotides (nt), with a 42-nt leader at the 3'-end and a 46-nt trailer at the 5'-end. the genome contains eight genes in the order 3'-n-p-m-f-m2-sh-g-l-5', which is the same order shown in the other metapneumoviruses. the genes are flanked on either side by conserved transcripti ...201020676749
a single polymerase (l) mutation in avian metapneumovirus increased virulence and partially maintained virus viability at an elevated temperature.previously, a virulent avian metapneumovirus, farm isolate italy 309/04, was shown to have been derived from a live vaccine. virulence due to the five nucleotide mutations associated with the reversion to virulence was investigated by their addition to the genome of the vaccine strain using reverse genetics. virulence of these recombinant viruses was determined by infection of 1-day-old turkeys. disease levels resulting from the combined two matrix mutations was indistinguishable from that produ ...201021048037
protection against avian metapneumovirus subtype c in turkeys immunized via the respiratory tract with inactivated virus.avian metapneumovirus subtype c (ampv/c) causes a severe upper respiratory tract (urt) infection in turkeys. turkeys were inoculated oculonasally with inactivated ampv/c adjuvanted with synthetic double-stranded rna polyriboinosinic polyribocytidylic acid (poly ic). immunized turkeys had elevated numbers of mucosal iga+ cells in the urt and increased levels of virus-specific igg and iga in the lachrymal fluid and igg in the serum. after 7 or 21 days post immunization, turkeys were challenged ocu ...201021073989
pathogenic and immunogenic responses in turkeys following in ovo exposure to avian metapneumovirus subtype c.commercial turkey eggs, free of antibodies to avian metapneumovirus subtype c (ampv/c), were inoculated with ampv/c at embryonation day (ed) 24. there was no detectable effect of virus inoculation on the hatchability of eggs. at 4 days post inoculation (dpi) (the day of hatch (ed 28)) and 9 dpi (5 days after hatch), virus replication was detected by quantitative rt-pcr in the turbinate, trachea and lung but not in the thymus or spleen. mild histological lesions characterized by lymphoid cell inf ...201021146877
local and systemic immune responses following infection of broiler-type chickens with avian metapneumovirus subtypes a and b.infections with avian metapneumovirus (ampv) are often associated with swollen head syndrome in meat type chickens. previous studies in turkeys have demonstrated that local humoral and cell-mediated immunity plays a role in ampv-infection. previous experimental and field observations indicated that the susceptibility of broilers and their immune reactions to ampv may differ from turkeys. in the presented study local and systemic immune reactions of broilers were investigated after experimental i ...201021183227
generation and biological assessment of recombinant avian metapneumovirus subgroup c (ampv-c) viruses containing different length of the g gene.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 containing either the full-length g gene derived from a canadian goose isolate or a c-terminally truncated g gene of the co strain. the truncate ...201019891997
characterization of the biosynthesis and cell surface expression of avian metapneumovirus attachment glycoprotein.biosynthesis, glycosylation and cell surface expression of the ampv/c g protein were examined in eukaryotic cell lines (llc-mk2, cho-k1, cho-1d1d). immature g gene products with a molecular mass of 42, 45 and 58-90 kilodaltons (kda) were identified by sds-page and represented glycosylated intermediates. tunicamycin treatment of transfected cells confirmed the presence of n-linked carbohydrate moieties on these intermediate species and identified a 38 kda unglycosylated precursor. a fully process ...201019896993
field avian metapneumovirus evolution avoiding vaccine induced immunity.live avian metapneumovirus (ampv) vaccines have largely brought turkey rhinotracheitis (trt) under control in europe but unexplained outbreaks still occur. italian ampv longitudinal farm studies showed that subtype b ampvs were frequently detected in turkeys some considerable period after subtype b vaccination. sequencing showed these to be unrelated to the previously applied vaccine. sequencing of the entire genome of a typical later isolate showed numerous sh and g protein gene differences whe ...201019931381
stability of the glycoprotein gene of avian metapneumovirus (canada goose isolate 15a/01) after serial passages in cell cultures.the glycoprotein (g) gene sequences of avian metapneumovirus (ampv) subtypes a, b, c, and d are variable in size and number of nucleotides. the g gene of early u.s. turkey isolates of ampv-c have been reported to be 1798 nucleotides (nt) (585 aa) in length, whereas the g genes of more recent turkey isolates have been reported to be 783 nucleotides. in some studies, the g gene of ampv-c turkey isolates was found to be truncated to a smaller g gene of 783 nt (261 aa) upon serial passages in vero c ...201020608539
diagnostic utility of egg yolk for the detection of avian metapneumovirus antibodies in laying hens.surveillance and diagnosis of avian metapneumovirus (ampv) infection typically involve measurement of serum antibodies. in the current study, eggs instead of serum samples were used for the detection of ampv antibodies in egg-laying chicken hens by enzyme-linked immunosorbent assay (elisa). ampv-free commercial layer hens were experimentally challenged with ampv strain sc1509 through intravenous or oculonasal administration. antibody levels were determined by elisa. ampv antibodies were detected ...201021313844
efficacy of four enrofloxacin treatment regimens against experimental infection in turkey poults with avian pneumovirus and ornithobacterium rhinotracheale.drinking-water treatment with enrofloxacin is widely used to cure respiratory infections in turkeys. the current treatment regimen advises a 5-day treatment at 10 mg/kg body weight. since enrofloxacin exerts a concentration-dependent activity it might be useful to provide the total treatment dose of 50 mg/kg total dose in a single-day treatment regimen. we therefore assessed whether single-day treatment regimens with 50 mg/kg body weight were clinically equivalent to the advised multiple-day tre ...200919937513
pathogenesis of riemerella anatipestifer in turkeys after experimental mono-infection via respiratory routes or dual infection together with the avian metapneumovirus.riemerella anatipestifer (ra) is the causative agent of septicaemic and exudative diseases in a variety of bird species. despite numerous outbreaks, little is known about the pathogenicity of ra for turkeys. we investigated the development of ra-induced disease in commercial turkey poults following ra inoculation via different respiratory routes. inoculation by aerosol or injection into the abdominal air sac led to systemic infection and mild gross lesions, including pericarditis, epicarditis an ...200919937539
chlamydophila psittaci infections in turkeys: overview of economic and zoonotic importance and vaccine development.we provide evidence on the multifactorial infectious etiology of respiratory disease in turkeys. although chlamydophila psittaci is difficult to diagnose, this entity should not be neglected in veterinary diagnostic laboratories. the present results suggest a pathogenic interplay between chlamydophila, avian metapneumovirus and ornithobacterium rhinotracheale. additionally, we demonstrate zoonotic transmission from turkeys to humans. psittacosis due to contact with poultry probably occurs more o ...200920011707
investigations on the protective role of passively transferred antibodies against avian metapneumovirus infection in turkeys.the avian metapneumovirus (ampv) is the causative agent of an acute respiratory disease in turkeys, which causes considerable economic losses to the poultry industry. currently attenuated live and inactivated vaccines are widely used to control the disease, but vaccine breaks are frequently observed. for improvement of current vaccination strategies it is necessary to gain enhanced knowledge of the immune mechanisms against ampv infection. field observations suggest that vaccine-induced ampv-spe ...200919937531
simultaneous zoonotic transmission of chlamydophila psittaci genotypes d, f and e/b to a veterinary scientist.two groups of five 1-day-old conventional turkeys were housed in negative pressure stables to become experimentally infected with avian metapneumovirus (ampv) and ornithobacterium rhinotracheale (ort) at the age of 3 weeks. however, during the first 2 weeks, turkeys started to show respiratory disease characterized by rhinitis and dyspnoea. routine bacterial and viral diagnoses remained negative. therefore, pharyngeal swabs from the turkeys and from the veterinary scientist handling the animals ...200918963600
population dynamics and rates of molecular evolution of a recently emerged paramyxovirus, avian metapneumovirus subtype c.we report the existence of two distinct sublineages of avian metapneumovirus (mpv) subtype c, a virus which has caused serious economic loss in commercial turkey farms in the united states. this subtype is closely related to human mpv, infects multiple avian species, and is globally distributed. the evolutionary rates of this virus are estimated to be 1.3 x 10(-3) to 7 x 10(-3) substitutions per site per year, and coalescent estimates place its emergence between 1991 and 1996. the four genes exa ...200919052092
fusion protein is the main determinant of metapneumovirus host tropism.human metapneumovirus (hmpv) and avian metapneumovirus subgroup c (ampv-c) infect humans and birds, respectively. this study confirmed the difference in host range in turkey poults, and analysed the contribution of the individual metapneumovirus genes to host range in an in vitro cell-culture model. mammalian vero-118 cells supported replication of both hmpv and ampv-c in contrast to avian quail fibroblast (qt6) cells in which only ampv-c replicated to high titres. inoculation of vero-118 and qt ...200919264630
in vitro antiviral activity of chestnut and quebracho woods extracts against avian reovirus and metapneumovirus.field evidences have suggested that a natural extract, containing tannins, could be effective against poultry enteric viral infections. moreover previous studies have shown that vegetable tannins can have antiviral activity against human viruses. based on this knowledge three different chestnut (castanea spp.) wood extracts and one quebracho (schinopsis spp.) wood extract, all containing tannins and currently used in the animal feed industry, were tested for in vitro antiviral activity against a ...200919435637
longitudinal survey of avian metapneumoviruses in poultry in israel: infiltration of field strains into vaccinated flocks.avian metapneumovirus (ampv) is a respiratory pathogen and includes four subtypes, which are differentially distributed worldwide. in israel, two ampv subtypes, a and b, are cocirculating in an area with a relatively high density of poultry houses. we performed a longitudinal survey in commercial flocks of turkeys and chickens (six and two flocks, respectively) with differing vaccination programs. this study revealed that all monitored flocks were infected by ampv during the sampling period, as ...200919630222
identification of two regions within the subtype a avian metapneumovirus fusion protein (amino acids 211-310 and 336-479) recognized by neutralizing antibodies.the fusion (f) protein of a subtype a ampv was expressed in sections in escherichia coli. six genome sections were selected which encoded the majority of the protein. these were cloned then expressed from a his tag expression plasmid and, following purification on nickel columns, identities were confirmed by western blot analysis. the interactions of each fragment with ampv neutralizing antisera were determined. purified fragments were mixed with ampv sera raised against a-c subtypes by a natura ...200919720091
field estimation of the flock-level diagnostic specificity of an enzyme-linked immunosorbent assay for avian metapneumovirus antibodies in turkeys.routine serologic testing for avian metapneumovirus (ampv) infection of turkey flocks at slaughter is currently being used to monitor changes in the occurrence of ampv infection in endemic areas and can also be used to detect the emergence of infection in currently unaffected areas. because of the costs associated with false-positive results, particularly in areas that are free of ampv infection, there is a need to obtain improved estimates of flock-level specificity (sp). the objective of this ...200919286505
analysis of antigenic cross-reactivity between subgroup c avian pneumovirus and human metapneumovirus by using recombinant fusion proteins.avian pneumovirus subgroup c (apv/c) has recently been reported to be more closely related to human metapneumovirus (hmpv) as determined by sequence analysis. to examine the antigenic relationship between apv/c and hmpv, the apv/c fusion (f) gene was cloned and expressed as an uncleaved glycoprotein in a baculovirus system. the reactivity of the apv/c f protein with antibodies against apv subgroups a, b, c, and hmpv was examined by western blot analysis. the results showed that the expressed apv ...200919548897
genetic diversity and evolution of human metapneumovirus fusion protein over twenty years.human metapneumovirus (hmpv) is an important cause of acute respiratory illness in children. we examined the diversity and molecular evolution of hmpv using 85 full-length f (fusion) gene sequences collected over a 20-year period.200919740442
effect of multiple- and single-day enrofloxacin medications against dual experimental infection with avian pneumovirus and escherichia coli in turkeys.escherichia coli infections are a common cause of respiratory disease in turkeys. to control these respiratory infections in turkeys, drinking water treatment with enrofloxacin is widely used. the current treatment schedule advises a 5-d treatment at 10 mg/kg of bw. because enrofloxacin exerts a concentration-dependent activity, it might be useful to provide this 50 mg/kg total dose in a single-day treatment regimen. therefore, we assessed whether a single-day treatment schedule with 50 mg/kg of ...200919762861
the effect of reduced treatment time and dosage of enrofloxacin on the course of respiratory disease caused by avian metapneumovirus and ornithobacterium rhinotracheale.a dose titration and reduced duration medication study were performed to evaluate the current enrofloxacin treatment schedule in growing turkeys experimentally infected with avian metapneumovirus and ornithobacterium rhinotracheale. experimental groups of 17 four-week-old turkeys were first infected with avian metapneumovirus and 3 d later with o. rhinotracheale. enrofloxacin treatment in the drinking water was started 24 h after o. rhinotracheale inoculation. in the dose titration study, enrofl ...200919834081
[human metapneumovirus].the human metapneumovirus (hmpv) is a new pneumovirinae related to the avian metapneumovirus type c. hmpv genome differs from human respiratory syncytial virus (rsv) genome by the gene order and the lack of nonstructural genes. two genetic sub-groups and four sub-types of hmpv are identified. hmpv infections evolve as regular winter outbreaks which have roughly the same size and overlaping rsv epidemics. among hospitalized children in caen, hmpv is detected in 9.7% of the cases after rsv (37%), ...200918515017
evidence of avian metapneumovirus subtype c infection of wild birds in georgia, south carolina, arkansas and ohio, usa.metapneumoviruses (mpvs) were first reported in avian species (ampvs) in the late 1970s and in humans in 2001. although ampvs have been reported in europe and asia for over 20 years, the virus first appeared in the united states in 1996, leaving many to question the origin of the virus and why it proved to be a different subtype from those found elsewhere. to examine the potential role of migratory waterfowl and other wild birds in ampv spread, our study focused on determining whether population ...200818568663
reproducibility of swollen sinuses in broilers by experimental infection with avian metapneumovirus subtypes a and b of turkey origin and their comparative pathogenesis.swollen head syndrome (shs) associated with avian metapneumovirus (ampv) subtype a or subtype b in broilers and broiler breeders has been reported worldwide. data about pathogenesis of ampv subtypes a and b in broilers are scarce. it has been difficult to reproduce swollen sinuses in chickens with ampv under experimental conditions. in the field, shs in broilers is suspected to be induced by combined infections with different respiratory pathogens. the objectives of the present study were to com ...200818202952
efficacy of disinfectants and hand sanitizers against avian respiratory viruses.disinfectants play a major role in the control of animal diseases by decontaminating the farm environment. we evaluated the virucidal efficacy of nine commonly used disinfectants on a nonporous surface contaminated experimentally with avian metapneumovirus (ampv), avian influenza virus, or newcastle disease virus (ndv). phenolic compounds and glutaraldehyde were found to be the most effective against all three viruses. quaternary ammonium compounds were effective against ampv but not against the ...200818646446
glycoprotein gene truncation in avian metapneumovirus subtype c isolates from the united states.the length of the published glycoprotein (g) gene sequences of avian metapneumovirus subtype-c (ampv-c) isolated from domestic turkeys and wild birds in the united states (1996-2003) remains controversial. to explore the g gene size variation in ampv-c by the year of isolation and cell culture passage levels, we examined 21 turkey isolates of ampv-c at different cell culture passages. the early domestic turkey isolates of ampv-c (ampv/co/1996, ampv/mn/1a-b, and 2a-b/97) had a g gene of 1,798 nuc ...200818663568
specificity and functional interaction of the polymerase complex proteins of human and avian metapneumoviruses.human metapneumovirus (hmpv) and avian metapneumovirus (ampv) have a similar genome organization and protein composition, but a different host range. ampv subgroup c (ampv-c) is more closely related to hmpv than other ampvs. to investigate the specificity and functional interaction of the polymerase complex proteins of human and avian metapneumoviruses, a minireplicon system was generated for ampv-c and used in combination with minireplicon systems for hmpv lineages a1 and b1. viral rna-like mol ...200818343839
mucosal vaccination with formalin-inactivated avian metapneumovirus subtype c does not protect turkeys following intranasal challenge.studies were performed to determine if mucosal vaccination with inactivated avian metapneumovirus (ampv) subtype c protected turkey poults from clinical disease and virus replication following mucosal challenge. decreases in clinical disease were not observed in vaccinated groups, and the vaccine failed to inhibit virus replication in the tracheas of 96% of vaccinated birds. histopathologically, enhancement of pulmonary lesions following virus challenge was associated with birds receiving the in ...200818459292
species-specific deletion of the viral attachment glycoprotein of avian metapneumovirus.the avian metapneumovirus (ampv) genome encodes the fusion (f), small hydrophobic (sh), and attachment glycoprotein (g) as envelope glycoproteins. the f and g proteins mainly function to allow viral entry into host cells during the early steps of the virus life cycle. the highly variable ampv g protein is a major determinant for distinguishing virus subtypes. sequence analysis was used to determine if any differences between avian or mammalian cell propagated subtype c ampv could be detected for ...200818160118
deletion of the sh gene from avian metapneumovirus has a greater impact on virus production and immunogenicity in turkeys than deletion of the g gene or m2-2 open reading frame.subgroup a avian metapneumoviruses lacking either the sh or g gene or the m2-2 open reading frame were generated by using a reverse-genetics approach. the growth properties of these viruses were studied in vitro and in vivo in their natural host. deletion of the sh gene alone resulted in the generation of a syncytial-plaque phenotype and this was reversed by the introduction of the sh gene from a subgroup b, but not a subgroup c, virus. infected turkeys were assessed for antibody production and ...200818198384
molecular characterization and complete genome sequence of avian paramyxovirus type 4 prototype strain duck/hong kong/d3/75.avian paramyxoviruses (apmvs) are frequently isolated from domestic and wild birds throughout the world. all apmvs, except avian metapneumovirus, are classified in the genus avulavirus of the family paramyxoviridae. at present, the apmvs of genus avulavirus are divided into nine serological types (apmv 1-9). newcastle disease virus represents apmv-1 and is the most characterized among all apmv types. very little is known about the molecular characteristics and pathogenicity of apmv 2-9.200818937854
a method for the rapid isolation of virus from cultured cells.a simple and efficient collection method using hypotonic burst to isolate virions from infected cultured cells is described. distilled water treatment of avian metapneumovirus (ampv)-infected cells with thorough mixing and repeated pipeting was considerably faster for virion collection in avian cells compared to the widely used freeze-thaw (f-t) method (30 min vs. 3-4 h). this method was also more effective for virion collection. the total number of virions recovered from ampv-infected immortal ...200818254386
comparative pathogenicity of early and recent isolates of avian metapneumovirus subtype c in turkeys.the objective of the present study was to compare the pathogenicity of early and recent isolates of avian metapneumovirus subtype-c (ampv-c) in turkeys. two-week-old turkeys were inoculated with early and recent isolates of ampv-c. clinical signs were monitored. tissues were examined for viral ribonucleic acid (rna), lesions, and viral antigen by reverse transcription-polymerase chain reaction (rt-pcr), histopathology and immunohistochemistry, respectively. birds infected with the recent isolate ...200818783028
human metapneumovirus nucleoprotein and phosphoprotein interact and provide the minimal requirements for inclusion body formation.human metapneumovirus (hmpv) is a recently discovered paramyxovirus of the subfamily pneumovirinae, which also includes avian pneumovirus and human respiratory syncytial virus (hrsv). hmpv is an important cause of respiratory disease worldwide. to understand early events in hmpv replication, cdnas encoding the hmpv nucleoprotein (n), phosphoprotein (p), matrix protein (m), m2-1 protein and m2-2 protein were cloned from cells infected with the genotype a1 hmpv wild-type strain tn/96-12. hmpv n an ...200818931065
avian metapneumovirus subtype a in china and subtypes a and b in nigeria.in order to detect and characterize avian metapneumovirus, organs or swabs were collected from 697 chicken and 110 turkeys from commercial farms in southwestern nigeria and from 107 chickens from live bird markets in southeastern china. in nigeria, 15% and 6% of the chicken and turkey samples, respectively, and 39% of the chicken samples from china, were positive for ampv genome by pcr. the sequence of a 400 nt fragment of the attachment protein gene (g gene) revealed the presence of ampv subtyp ...200818939643
molecular survey of avian respiratory pathogens in commercial broiler chicken flocks with respiratory diseases in jordan.acute respiratory tract infections are of paramount importance in the poultry industry. avian influenza virus (aiv), infectious bronchitis virus (ibv), newcastle disease virus (ndv), avian pneumovirus (apv), and mycoplasma gallisepticum (mg) have been recognized as the most important pathogens in poultry. in this study, trachea swabs from 115 commercial broiler chicken flocks that suffered from respiratory disease were tested for aiv subtype h9n2, ibv, ndv, and apv by using reverse transcription ...200818281569
effects of temperature and stabilizer on the viability of a live attenuated avian metapneumovirus vaccine.a commercial live attenuated, freeze-dried avian metapneumovirus vaccine, pneumomune, was assessed for its viability at three different temperatures (5.6 c, 21 c, and 37 c). no significant reduction in virus titer was observed when the vaccine was stored at 5.6 c for a period of 24 hr. however, reductions in virus titer of 1 log10 and 2 log10 were observed after 24 hr at 21 c and 37 c, respectively. batch-to-batch variation in virus reduction was also observed. the addition of a dye or a vaccine ...200718251412
induction of local and systemic immune reactions following infection of turkeys with avian metapneumovirus (ampv) subtypes a and b.most of the studies regarding the immunopathogenesis of avian metapneumovirus (ampv) have been done with subtype c of ampv. not much is known about the immunopathogenesis of ampv subtypes a and b in turkeys. specifically, local immune reactions have not been investigated yet. we conducted two experiments in commercial turkeys. we investigated local and systemic humoral and cell mediated immune reactions following infection with an attenuated vaccine strain of ampv subtype b (experiment i) and vi ...200717207537
coupled translation of the second open reading frame of m2 mrna is sequence dependent and differs significantly within the subfamily pneumovirinae.coupled translation, first described in the m2 gene of pneumovirus respiratory syncytial virus (rsv), is an alternative mechanism of translational initiation in which the ribosomes which translate the first (m2-1) open reading frame (orf) move a short distance upstream after termination and reinitiate translation from a second (m2-2) overlapping orf. here, we show that the same mechanism occurs in two closely related viruses, avian pneumovirus (apv) and pneumonia virus of mice (pvm), although wi ...200717522208
avian metapneumovirus sh gene end and g protein mutations influence the level of protection of live-vaccine candidates.a prototype avian metapneumovirus (ampv) vaccine (p20) was previously shown to give variable outcomes in experimental trials. following plaque purification, three of 12 viruses obtained from p20 failed to induce protection against virulent challenge, whilst the remainder retained their protective capacity. the genome sequences of two protective viruses were identical to the p20 consensus, whereas two non-protective viruses differed only in the sh gene transcription termination signal. northern b ...200717485538
first detection of human metapneumovirus in children with respiratory infections in romania.the human metapneumovirus (hmpv) was first isolated in 2001 in the netherlands (van der hoogen and collaborators) from a nasopharyngeal aspirate sampled from an infant. based on the morphological, biochemical and genetic characteristics, the hmpv was initially classified in the genus metapneumovirus with the avian metapneumovirus (apv), the agent causing the respiratory infections of the upper tract in turkeys and other birds. subsequently, together with the respiratory syncytial virus (rsv), it ...200718928061
detection by reverse transcriptase-polymerase chain reaction and molecular characterization of subtype b avian metapneumovirus isolated in brazil.subtype b avian metapneumovirus (ampv) was isolated and detected by reverse transcriptase-polymerase chain reaction (rt-pcr) in brazilian commercial laying chicken flocks with no history of vaccination against ampv and presenting respiratory signs and decreased egg production. rt-pcr results from samples from three affected flocks revealed that the three isolates were subtype b. partial sequence analysis of the g glycoprotein gene confirmed that the samples belonged to subtype b and were not of ...200717899462
laboratory evaluation of a quantitative real-time reverse transcription pcr assay for the detection and identification of the four subgroups of avian metapneumovirus.avian metapneumovirus (ampv) is an important pathogen causing respiratory diseases and egg drops in several avian species. four ampv subgroups have been identified. the laboratory diagnosis of ampv infections relies on serological methods, on labour-intensive virus isolation procedures, and on recently developed subgroup specific reverse transcription pcr (rt-pcr) protocols. in the present study, both the specificity and sensitivity of a commercial real-time reverse transcription pcr (rrt-pcr) f ...200717126416
inhibition of avian metapneumovirus (ampv) replication by rna interference targeting nucleoprotein gene (n) in cultured cells.avian metapneumovirus (ampv) is the primary causative agent of severe rhinotracheitis in turkeys. it is associated with swollen head syndrome in chickens and is the source of significant economic losses to animal food production. in this study, we designed specific short interfering rna (sirna) targeting the ampv nucleoprotein (n) and fusion (f) genes. three days post-virus infection, virus titration, real time rt-pcr, and rt-pcr assays were performed to verify the effect of sirna in ampv replic ...200717275932
efficacy of enrofloxacin, florfenicol and amoxicillin against ornithobacterium rhinotracheale and escherichia coli o2:k1 dual infection in turkeys following apv priming.experimental groups of 15 susceptible 3-week-old turkeys were inoculated oculonasally with avian metapneumovirus (apv) subtype a and susceptible escherichia coli o2:k1 and ornithobacterium rhinotracheale (ort) bacteria, with a 3 days interval between viral and bacterial inoculation and approximately 8h between the two bacterial inoculations. the aims of the present study were to assess the efficacy of drinking-water administration of enrofloxacin for 3 and 5 days, amoxicillin for 5 days and flor ...200717187945
onset of immunity following in ovo delivery of avian metapneumovirus vaccines.avian metapneumovirus (ampv) is an important cause of disease in chickens and turkeys. as infection can occur early in life and spread of the virus throughout a flock is rapid, an early onset of immunity post-vaccination would be advantageous. we have studied the serological immune response and the onset of protective immunity of an ampv vaccine delivered to chickens via the in ovo route compared to oculonasal delivery at day old. a 1000-fold lower dose delivered in ovo to chicken specific patho ...200717462834
development of a vaccine-challenge model for avian metapneumovirus subtype c in turkeys.the objective of this study was to evaluate different preparations of avian metapneumovirus (ampv) subtype c as vaccine challenge in turkeys. two ampv isolates and their respective nasal turbinate homogenates after propagation in turkeys were used in the study. significantly higher clinical sign scores were recorded in birds inoculated with 20 or 2% turbinate homogenate of recent isolate. birds in the above groups showed more pronounced histopathological lesions, and a higher percentage of birds ...200717229500
avian and human metapneumovirus.pneumovirus infection remains a significant problem for both human and veterinary medicine. both avian pneumovirus (ampv, turkey rhinotracheitis virus) and human metapneumovirus (hmpv) are pathogens of birds and humans, which are associated with respiratory tract infections. based on their different genomic organization and low level of nucleotide (nt) and amino acid (aa) identity with paramyxoviruses in the genus pneumovirus, ampv and hmpv have been classified into a new genus referred to as me ...200717470912
establishment of an immortal turkey turbinate cell line suitable for avian metapneumovirus propagation.until recently, there has not been a homologous avian cellular substrate which could continuously produce high titer avian metapneumovirus (ampv); development of such a cell line should provide an excellent model system for studying ampv infection. we have established a non-tumorigenic immortal turkey turbinate cell line (tt-1) to propagate sufficiently high ampv titers. currently, immortal tt-1 cells are growing continuously at 1.2-1.4 population doublings per day and are at passage 160. kineti ...200717482704
genetic characterization of avian metapneumovirus subtype c isolated from pheasants in a live bird market.complete nucleotide sequences of two avian metapneumoviruses (ampv), designated pl-1 and pl-2, were isolated from pheasants, revealing novel sequences of the first ampv to be fully sequenced in korea. the complete genome of both pl-1 and pl-2 was composed of 13,170 nucleotides. phylogenetic analysis revealed that pl-1 belonged to ampv subtype c, sharing higher homology in deduced amino acid sequence identities with hmpv, rather than with ampv subtypes a and b. replication of pl-1 in experimental ...200717485129
protection in specific pathogen free chickens with live avian metapneumovirus and newcastle disease virus vaccines applied singly or in combination.this paper describes two experiments. in each experiment, 1-day-old specific pathogen free chicks were divided into three groups. in experiment 1 - [avian metapneumo virus (ampv) challenge] - one group served as unvaccinated controls; the second group was vaccinated with live ampv (subtype b) vaccine only, and the third group received the ampv vaccine in combination with live newcastle disease virus (ndv) vaccine (vg/ga strain). oropharyngeal swabs, tissues and blood samples were collected befor ...200717620178
the efficacy of an avian metapneumovirus vaccine applied simultaneously with infectious bronchitis and newcastle disease virus vaccines to specific-pathogen-free chickens.avian metapneumovirus (ampv), newcastle disease virus (ndv), and infectious bronchitis virus (ibv) are important respiratory pathogens of chickens. to achieve early posthatch protection against all three diseases it would be helpful to deliver live ampv, ibv, and ndv vaccines simultaneously at 1 day of age. however, previous work has indicated that the efficacy of ampv vaccines may be affected when codelivered with ibv or ndv vaccines. the efficacy of an ampv vaccine when codelivered to chickens ...200717626490
serological and molecular detection of avian pneumovirus in chickens with respiratory disease in jordan.avian pneumovirus (apv) causes upper respiratory tract infection in chickens and turkeys. there is a serious respiratory disease in chickens, resulting in catastrophic economic losses to chicken farmers in jordan. the objective of this study was to investigate the role of apv as a factor in the respiratory disease of chickens in jordan by serological and molecular methods. thirty-eight chicken flocks were examined by competitive elisa (23 broilers, 8 layers, and 7 broiler breeders), and 150 chic ...200717626813
a genetically engineered prime-boost vaccination strategy for oculonasal delivery with poly(d,l-lactic-co-glycolic acid) microparticles against infection of turkeys with avian metapneumovirus.in this study we demonstrated the use of an oculonasally delivered poly(d,l-lactic-co-glycolic acid) microparticle (plga-mp)-based and genetically engineered vaccination strategy in the avian system. an avian metapneumovirus (ampv) fusion (f) protein-encoding plasmid vaccine and the corresponding recombinant protein vaccine were produced and bound to or encapsulated by plga-mp, respectively. the plga-mp as the controlled release system was shown in vitro to not induce any cytopathic effects and ...200717920166
vaccination of chicks with live attenuated subtype b avian metapneumovirus vaccines: protection against challenge and immune responses can be unrelated to vaccine dose.live attenuated subtype b avian metapneumovirus (ampv) vaccines from two different commercial sources (vac 1 and vac 2) were used to vaccinate two groups of day-old specific-pathogen-free chicks. the chicks were challenged at 21 or 49 days of age with a virulent subtype b virus. parameters compared were persistence of vaccine viruses, their ability to induce humoral antibody responses, and the protection they offered against virulent challenge. vac 1 virus was detectable for at least 14 days aft ...200717992934
b-cell infiltration in the respiratory mucosa of turkeys exposed to subtype c avian metapneumovirus.turkeys exposed to avian metapneumovirus (ampv) subtype c showed extensive lymphoid cell infiltrations in the nasal turbinates of the upper respiratory tract. the cellular infiltration occurred after the first virus exposure but not after re-exposure. quantitation of the relative proportions of mucosal immunoglobulin (ig)a+, igg+, and igm+ cells in controls and virus-exposed turkeys revealed that at 7 days after the first virus exposure, when mucosal infiltration was well pronounced, there was a ...200717992939
orchitis in roosters with reduced fertility associated with avian infectious bronchitis virus and avian metapneumovirus infections.the pathogenesis of infection involving both infectious bronchitis virus (ibv) and avian metapneumovirus (ampv) causes reproductive damage in hens after viral replication in the epithelium of the oviduct, resulting in loss of cilia and degeneration and necrosis of the epithelial and glandular cells. although ibv has been indicated as a possible cause of the formation of calcium stones in the epididymus of roosters, a definitive association has not been confirmed. this report describes the detect ...200718251400
development of a method for bacteria and virus recovery from heating, ventilation, and air conditioning (hvac) filters.the aim of the work presented here is to study the effectiveness of building air handling units (ahus) in serving as high volume sampling devices for airborne bacteria and viruses. an hvac test facility constructed according to ashrae standard 52.2-1999 was used for the controlled loading of hvac filter media with aerosolized bacteria and virus. nonpathogenic bacillus subtilis var. niger was chosen as a surrogate for bacillus anthracis. three animal viruses; transmissible gastroenteritis virus ( ...200617240906
attempts to improve on a challenge model for subtype c avian pneumovirus.respiratory disease caused by avian pneumovirus (apv) has a strong negative impact on the economy of the turkey industry in many countries. progress in developing vaccines against this infection in the us has been slow partly because of the lack of a consistent challenge model to conduct vaccine efficacy studies. this study was designed to determine whether in vivo passages of a us isolate of apv, designated subtype c (apv-c), would increase virus virulence, leading to consistent clinical signs ...200616595303
modification of the trypsin-dependent cleavage activation site of the human metapneumovirus fusion protein to be trypsin independent does not increase replication or spread in rodents or nonhuman primates.the contribution of cleavage activation of the fusion f protein of human metapneumovirus (hmpv) to replication and pathogenicity in rodents and nonhuman primates was investigated. recombinant hmpvs were generated in which the naturally occurring trypsin-dependent cleavage sequence (r-q-s-r downward arrow) was replaced by each of three sequences whose cleavage in vitro does not depend upon added trypsin. two of these were multibasic sequences derived from avian metapneumovirus type a (r-r-r-r) or ...200616731919
comparison of the efficacy of four antimicrobial treatment schemes against experimental ornithobacterium rhinotracheale infection in turkey poults pre-infected with avian pneumovirus.the clinical efficacy of drinking-water administration of enrofloxacin for 3 and 5 days, amoxicillin for 5 days and florfenicol for 5 days for the treatment of respiratory disease induced by an experimental ornithobacterium rhinotracheale infection in turkeys pre-infected with avian pneumovirus (apv) was assessed based on clinical, bacteriological and histopathological examinations. experimental groups of 15 susceptible 3-week-old turkeys were each inoculated oculonasally with apv subtype a and ...200616753615
seroprevalence of avian influenza virus, infectious bronchitis virus, reovirus, avian pneumovirus, infectious laryngotracheitis virus, and avian leukosis virus in nigerian poultry.eight poultry farms in nigeria, including chickens from nine breeder, 14 broiler, 28 pullet, 11 layer, and three cockerel flocks, were tested for antibody seroprevalence to the following poultry viruses of potential economic importance: infectious bronchitis virus (ibv), avian reovirus, avian pneumovirus (apv), infectious laryngotracheitis virus (iltv), avian influenza virus (aiv), and avian leukosis virus (alv). serum samples were collected between 1999 and 2004 and were tested for antibodies u ...200616863071
survival of two avian respiratory viruses on porous and nonporous surfaces.the transmission of pathogens from infected to susceptible hosts may occur through contaminated fomites and inanimate objects. this type of transmission depends on the ability of the pathogens to survive in the environment. in this report, we describe the survivability of two avian respiratory viruses, e.g., avian metapneumovirus and avian influenza virus on 12 different porous and nonporous surfaces. the viruses survived on some of the surfaces for up to 6 days postcontamination but not after 9 ...200616863083
demonstration of loss of attenuation and extended field persistence of a live avian metapneumovirus vaccine.a live a type avian metapneumovirus (ampv) vaccine which had been shown to be highly protective and short lived in experimental conditions was found to persist for longer periods in the field and to be associated with disease. previously other factors such as possible secondary pathogens and management considerations had made it impossible to conclude whether the observed disease was a result of an increase in the vaccine virulence. in this study, an ampv was isolated from poults on a farm which ...200616901592
permissibility of different cell types for the growth of avian metapneumovirus.vero cells are commonly used for the growth of avian metapneumovirus subtype c (ampv-c). this study was conducted to evaluate 17 different cell types for the growth of a minnesota strain of ampv-c. the virus was inoculated into these cell types and virus growth was monitored by the development of cytopathic effects (cpe) and immunofluorescence. virus growth was obtained in 6 of 17 cell types tested with the highest virus titers observed in bgm and df-1 cells. the flow cytometric analysis of cell ...200616930732
drop of egg production in chickens by experimental infection with an avian metapneumovirus strain ple8t1 derived from swollen head syndrome and the application to evaluate vaccine.decreases in egg production and increased incidence of abnormal eggs due to malformation of egg shells were observed in specific pathogen free (spf) 173-day-old laying hens inoculated intravenously with an avian metapneumovirus (ampv) strain ple8t1. this strain was derived from an isolate from broiler birds exhibiting swollen head syndrome (shs). some spf birds inoculated with the virus showed, slight diarrhea without any respiratory symptoms. thus, the ple8t1 strain was used as a challenge viru ...200616953076
live vaccines for human metapneumovirus designed by reverse genetics.human metapneumovirus (hmpv) was first described in 2001 and has quickly become recognized as an important cause of respiratory tract disease worldwide, especially in the pediatric population. a vaccine against hmpv is required to prevent severe disease associated with infection in infancy. the primary strategy is to develop a live-attenuated virus for intranasal immunization, which is particularly well suited against a respiratory virus. reverse genetics provides a means of developing highly ch ...200617181442
recovery of avian metapneumovirus subgroup c from cdna: cross-recognition of avian and human metapneumovirus support proteins.avian metapneumovirus (ampv) causes an acute respiratory disease in turkeys and is associated with "swollen head syndrome" in chickens, contributing to significant economic losses for the u.s. poultry industry. with a long-term goal of developing a better vaccine for controlling ampv in the united states, we established a reverse genetics system to produce infectious ampv of subgroup c entirely from cdna. a cdna clone encoding the entire 14,150-nucleotide genome of ampv subgroup c strain colorad ...200616731918
human metapneumovirus in turkey poults.this study was conducted to reexamine the hypothesis that human metapneumovirus (hmpv) will not infect turkeys. six groups of 2-week-old turkeys (20 per group) were inoculated oculonasally with 1 of the following: noninfected cell suspension; hmpv genotype a1, a2, b1, or b2; or avian metapneumovirus (ampv) subtype c. poults inoculated with hmpv showed nasal discharge days 4-9 postexposure. specific viral rna and antigen were detected by reverse-transcription pcr and immunohistochemical evaluatio ...200617235379
interaction between a live avian pneumovirus vaccine and two different newcastle disease virus vaccines in broiler chickens with maternal antibodies to newcastle disease virus.broiler chicks with maternal antibodies to newcastle disease virus (ndv) but none to avian metapneumovirus (apv) were divided into six groups. one group was kept as an unvaccinated control group. three of the other groups were vaccinated at 1 day old with live apv vaccine or one of two live ndv vaccines (vg/ga or hb1). the remaining two groups received the apv vaccine in combination with either of the two ndv vaccines at 1 day old. at intervals after vaccination for up to 42 days, distribution o ...200617121730
production and characterization of monoclonal antibodies that react to the nucleocapsid protein of avian metapneumovirus subtype c.monoclonal antibodies (mabs) were prepared against avian metapneumovirus (ampv) subtype c (ampv/ minnesota/turkey/1a/97). six mabs were selected based on enzyme-linked immunosorbent assay activities and characterized by isotyping, neutralization test, western blot analysis, and immunohistochemistry assay. the results showed that three mabs (3e, 9d, and 12c) belonged to the igg1 subclass, whereas the other three (5d, 8e, and 16e) were of the igg2a subclass. none of the six mabs neutralized ampv i ...200617039843
[human metapneumovirus].human metapneumovirus (hmpv), first isolated in the netherlands in 2001, is a member of the genus metapneumovirus of the sub-family pneumovirinae of the family paramyxoviridae. the genomic organization of hmpv is 3'-n-p-m-f-m2-sh-g-l-5'. hmpv resembles the sole member of this genus, avian pneumovirus. hmpv is the most closely related human pathogen to respiratory syncytial virus. phylogenetic analysis of the nucleotide sequences indicated that there were two genetic groups. furthermore, each gro ...200617446666
avian metapneumovirus phosphoprotein targeted rna interference silences the expression of viral proteins and inhibits virus replication.avian metapneumovirus (ampv) is one of the major causes of serious respiratory infections of poultry and leads to considerable economic losses to food animal production worldwide. here, we show that double stranded short interfering rna (sirna) molecules corresponding to ampv phosphoprotein (p) gene silence p rna and protein expression. these sirnas broadly reduced the expression of other viral proteins in addition to p, but did not have a discernable effect on cellular protein expression. the e ...200616310868
pathogenic interactions between chlamydophila psittaci and avian pneumovirus infections in turkeys.both chlamydophila psittaci and avian pneumovirus (apv) are highly prevalent in belgian turkeys and might contribute to the respiratory disease complex observed in turkeys. initial outbreaks of chlamydiosis occur mostly at the age of 4-8 weeks, often accompanied by an apv infection in apv non-vaccinated farms. regardless apv vaccination, breakthroughs of apv infection from 8 weeks on do occur, a period when also a second c. psittaci infection appears. therefore, this study examined the pathogeni ...200616326044
the cytoplasmic domain of the f protein of human respiratory syncytial virus is not required for cell fusion.the cytoplasmic domains of the fusion proteins encoded by several viruses play a role in cell fusion and contain sites for palmitoylation associated with viral protein trafficking and virus assembly. the fusion (f) protein of human respiratory syncytial virus (hrsv) has a predicted cytoplasmic domain of 26 residues containing a single palmitoylated cysteine residue that is conserved in bovine rsv f protein, but not in the f proteins of other pneumoviruses such as pneumonia virus of mice, human m ...200616432027
european and american subgroup c isolates of avian metapneumovirus belong to different genetic lineages.the gene encoding the attachment glycoprotein (g) was sequenced in three french isolates of-subgroup c avian metapneumovirus (apv-c) from ducks. with 1771 nt, this gene proved as long as recently published for north-american apv-c isolates from turkeys. the nt sequences of the duck viruses shared 99% identity but proved only 75-83% identical with their north-american counterparts, viruses of both origins encoding 585 amino acid (aa)-long g proteins. alignments revealed more homogeneity within th ...200616525740
duration of immunity engendered by a single dose of a cold-adapted strain of avian pneumovirus.the duration of immunity after a single dose of a cold-adapted strain of avian pneumovirus (apv) was studied. turkeys were vaccinated at 1 wk of age and challenged with virulent virus 3, 7, 10, and 14 wk later. nonvaccinated groups were also challenged at the same times. no clinical signs were observed in the vaccinated birds after vaccination or after any challenge. no viral rna was shed by the vaccinated birds after any challenge. the nonvaccinated birds shed viral rna after all challenges. av ...200616548335
comparison of avian cell substrates for propagating subtype c avian metapneumovirus.avian metapneumovirus (ampv) is a respiratory viral pathogen that causes turkey rhinotracheitis (trt) or swollen head syndrome (shs) in chickens. ampv was first isolated in south africa during the early 1970s and has subsequently spread worldwide during the 1980s to include europe, asia, and south america. in 1996, a genetically distinct ampv subgroup c was isolated in the us following an outbreak of trt. vero cells are currently the best available substrate for ampv propagation but are of non-a ...200616194579
persistence of mycoplasma gallisepticum in chickens after treatment with enrofloxacin without development of resistance.the ability of the avian pathogen mycoplasma gallisepticum to persist despite fluoroquinolone treatment was investigated in chickens. groups of specific pathogen free chickens were experimentally infected with m. gallisepticum and treated with enrofloxacin at increasing concentrations up to the therapeutic dose. when m. gallisepticum could no longer be re-isolated from chickens, birds were stressed by inoculation of infectious bronchitis virus or avian pneumovirus. although m. gallisepticum coul ...200515737482
chimeric recombinant human metapneumoviruses with the nucleoprotein or phosphoprotein open reading frame replaced by that of avian metapneumovirus exhibit improved growth in vitro and attenuation in vivo.chimeric versions of recombinant human metapneumovirus (hmpv) were generated by replacing the nucleoprotein (n) or phosphoprotein (p) open reading frame with its counterpart from the closely related avian metapneumovirus (ampv) subgroup c. in vero cells, ampv replicated to an approximately 100-fold-higher titer than hmpv. surprisingly, the n and p chimeric viruses replicated to a peak titer that was 11- and 25-fold higher, respectively, than that of parental hmpv. the basis for this effect is no ...200516306583
expression of recombinant small hydrophobic protein for serospecific detection of avian pneumovirus subgroup c.the small hydrophobic (sh) gene of the avian pneumovirus (apv) colorado isolate (co), which belongs to subgroup c (apv/c), was expressed with a baculovirus vector. the recombinant sh protein was evaluated as a potential subgroup-specific diagnostic reagent in order to differentiate infections resulting from apv/c from those induced by apv/a, apv/b, and human metapneumovirus (hmpv). when the recombinant baculovirus was used to infect insect cells, a 31- to 38-kda glycosylated form of the sh prote ...200515643005
evaluation of five different antigens in enzyme-linked immunosorbent assay for the detection of avian pneumovirus antibodies.five different antigens were evaluated in enzyme-linked immunosorbent assay (elisa) tests for the detection of avian pneumovirus (apv) antibodies. two of the 5 antigens were prepared from recent apv isolates from minnesota. the 2 older isolates were passage 63 of a strain currently used as a live, attenuated vaccine and a colorado strain isolated for the first time in the united states and currently used in an elisa test. the fifth antigen is based on an apv recombinant n-protein. basic paramete ...200515690946
key role of chlamydophila psittaci on belgian turkey farms in association with other respiratory pathogens.two hundred turkey sera from eight belgian and two french farms were tested for the presence of antibodies against avian pneumovirus (apv), ornithobacterium rhinotracheale (ort), mycoplasma gallisepticum, mycoplasma meleagridis and chlamydophila psittaci. at slaughter, c. psittaci, apv and ort antibodies were detected in 94, 34 and 6.5% of the turkeys, respectively. no antibodies against m. gallisepticum or m. meleagridis were present. additionally, turkeys on three belgian farms were examined f ...200515795081
identification of a truncated nucleoprotein in avian metapneumovirus-infected cells encoded by a second aug, in-frame to the full-length gene.avian metapneumoviruses (ampv) cause an upper respiratory disease with low mortality, but high morbidity primarily in commercial turkeys. there are three types of ampv (a, b, c) of which the c type is found only in the united states. viruses related to ampv include human, bovine, ovine, and caprine respiratory syncytial viruses and pneumonia virus of mice, as well as the recently identified human metapneumovirus (hmpv). the ampv and hmpv have become the type viruses of a new genus within the met ...200515826312
analysis of the complete genome sequence of avian metapneumovirus subgroup c indicates that it possesses the longest genome among metapneumoviruses. 200515830150
growth of vaccine strains of avian pneumovirus in different cell lines.the isolation of avian pneumovirus (apv) (avian metapneumovirus) is usually performed in embryonated chicken eggs or chicken embryo fibroblast cell cultures followed by adaptation in continuous cell lines such as vero cells. this study was conducted to find a suitable cell line that could be used to propagate vaccine strains of apv to high titre. for this purpose, we compared the growth of two vero cell-adapted vaccine strains of apv (p63 and ca-apv) in seven different cell types with their grow ...200516191692
subtyping of new brazilian avian metapneumovirus isolates from chickens and turkeys by reverse transcriptase-nested-polymerase chain reaction.the aim of this study was to improve a reverse transcriptase (rt)-nested-polymerase chain reaction (pcr) able to differentiate avian pneumovirus (apv) subtypes a and b, and to characterize new brazilian isolates. representative apv strains and clinical field samples from chickens and turkey flocks were amplified in the chicken embryo-related cell line. viral rna was extracted from harvested cells, and submitted to cdna synthesis. the primers utilized for rt-pcr were compatible with the g gene of ...200516191694
characterization of israeli avian metapneumovirus strains in turkeys and chickens.although the disease associated with the avian metapneumovirus (ampv) has been described in israel for more than 20 years and one israeli isolate was characterized as subtype a, this is the first study investigating the strains circulating in israel (period 2002 to 2004). viral rna was detected by reverse transcription-polymerase chain reaction in 44% of the examined flocks, and one-half of the virus isolation attempts were successful. characterization showed that 34 non-vaccinated turkey flocks ...200516191705
transcriptional response of avian cells to infection with newcastle disease virus.newcastle disease virus (ndv) causes widespread disease in poultry and wild-birds throughout the world. cdna microarray analysis was used to examine the effect of ndv infection on host cell transcription. the results show that ndv infection causes an apparent suppression of the interferon response genes during the early stages of infection. in addition, the results reveal transcriptional silencing of cytoskeletal proteins such as the alpha, beta, and gamma types of actin, and a downregulation of ...200515567039
synergy between avian pneumovirus and ornithobacterium rhinotracheale in turkeys.the purpose of this study was to assess the possible synergism between ornithobacterium rhinotracheale (ort) and avian pneumovirus (apv), inoculated into turkeys via the natural route, for the reproduction of respiratory disease. three-week-old specific pathogen free turkeys were inoculated oculonasally with either apv subtype a, ort or both agents using two different time intervals (3 and 5 days) between apv and ort. the birds were observed clinically on a daily basis and swabbed intratracheall ...200516191703
a wild goose metapneumovirus containing a large attachment glycoprotein is avirulent but immunoprotective in domestic turkeys.the genomic structure and composition of an avian metapneumovirus (ampv) recently isolated from wild canada geese (goose 15a/01) in the united states, together with its replication, virulence, and immunogenicity in domestic turkeys, were investigated. the sizes of seven of the eight genes, sequence identity, and genome organization of goose ampv were similar to those of turkey ampv subtype c (ampv/c) strains, indicating that it belonged to the subtype. however, the goose virus contained the larg ...200516282483
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