Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| development and evaluation of a blocking enzyme-linked immunosorbent assay for detection of avian metapneumovirus type c-specific antibodies in multiple domestic avian species. | the first cases of infection caused by avian metapneumoviruses (ampvs) were described in turkeys with respiratory disease in south africa during 1978. the causative agent was isolated and identified as a pneumovirus in 1986. ampvs have been detected in domestic nonpoultry species in europe, but tests for the detection of these viruses are not available in the united states. to begin to understand the potential role of domestic ducks and geese and wild waterfowl in the epidemiology of ampv, we ha ... | 2003 | 12904358 |
| use of a japanese quail fibrosarcoma cell line (qt-35) in serologic assays to determine the antigenic relationship of avian metapneumoviruses. | the ability of a japanese quail fibrosarcoma cell line (qt-35) to support the replication of avian metapneumoviruses belonging to the 3 subgroups a (14/1 virus), b (colorado virus), and c (hungary virus) enabled the development of assays for the detection and evaluation of virus-specific antibodies. on the basis of the results of enzyme-linked immunosorbent assay (elisa), plaque reduction neutralization assay (prna), immunofluorescent assay (ifa), and western blot analysis, some degree of antige ... | 2003 | 14535544 |
| seroprevalence of avian pneumovirus in minnesota turkeys. | avian pneumovirus (apv) causes respiratory tract infection in turkeys and was first seen in the united states in colorado in late 1996. in early 1997, the disease was recognized in minnesota and caused estimated losses of up to 15 million dollars per year. this virus has not been reported in the other turkey producing states. we here report the seroprevalence of apv in minnesota from august 1998 to july 2002. the average rate of seroprevalence has been 36.3% (range = 14.2%-64.8%). a seasonal bia ... | 2003 | 14562899 |
| avian pneumovirus and its survival in poultry litter. | the survival of avian pneumovirus (apv) in turkey litter was studied at different temperature (room temperature, [approximately 22-25 c], 8 c, and -12 c) conditions. built-up turkey litter from a turkey breeder farm known to be free of apv was obtained and was divided into two portions. one portion was sterilized by autoclaving and the other portion was kept nonautoclaved. both samples were inoculated with a vero cell-propagated minnesota isolate of apv subtype c (apv/mn2a) with a titer of 10(5) ... | 2003 | 14562910 |
| metapneumoviruses in birds and humans. | avian pneumovirus (apv, turkey rhinotracheitis virus) and human metapneumovirus (hmpv) are pathogens of birds and humans, respectively, that are associated with upper 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, apv and hmpv have been classified into a new genus referred to as metapneumovirus. first isolated in 1970s, apv strains have since been isolated in ... | 2003 | 12573494 |
| immunity to avian pneumovirus infection in turkeys following in ovo vaccination with an attenuated vaccine. | fertile turkey eggs after 24 days of incubation were vaccinated in ovo with a commercial live attenuated subtype a avian pneumovirus (apv) vaccine. hatchability was not adversely affected. when a high dose (10 times maximum commercial dose) of vaccine was tested in maternal antibody negative (ma-) eggs, mild clinical signs developed in a small proportion of the poults for 1-4 days only. post-vaccination antibody titres at 3 weeks of age were significantly higher than those seen when the same dos ... | 2003 | 12615430 |
| cold adapted avian pneumovirus for use as live, attenuated vaccine in turkeys. | we report the development of a cold adapted strain of avian pneumovirus (apv) and its evaluation as a live vaccine candidate in 2-week-old turkey poults. a us isolate of apv (apv/mn/turkey/1-a/97) was serially passaged in vero cells for 41 passages and then adapted to grow at sub-optimal temperatures by growing successively at 35, 33 and 31 degrees c for eight passages at each temperature. the virus thus adapted to grow at 31 degrees c was used as a candidate vaccine. the birds were vaccinated w ... | 2003 | 12615432 |
| regulation of host cell transcriptional physiology by the avian pneumovirus provides key insights into host-pathogen interactions. | infection with a viral pathogen triggers several pathways in the host cell that are crucial to eliminating infection, as well as those that are used by the virus to enhance its replication and virulence. we have here used suppression subtractive hybridization and cdna microarray analyses to characterize the host transcriptional response in an avian pneumovirus model of infection. the results of our investigations reveal a dynamic host response that includes the regulation of genes with roles in ... | 2003 | 12663796 |
| plaque assay for avian metapneumovirus using a japanese quail fibrosarcoma cell line (qt-35). | a plaque assay for detecting, isolating and titrating avian pneumoviruses using a japanese quail fibrosarcoma cell line (qt-35) is described. plaques are produced after application of either an agarose or carboxymethyl-cellulose (cmc) overlay onto cell monolayers infected with representative avian metapneumoviruses which belong to subgroup a, b or c. virus plaques can be easily visualized by light microscopy or after staining. the parameters affecting plaque appearance include: cell seeding conc ... | 2003 | 12445932 |
| immunization of turkeys with a dna vaccine expressing either the f or n gene of avian metapneumovirus. | in this study we compared protection by dna vaccination with the f (pcmv-f) or n (pcmv-n) gene from avian metapneumovirus (ampv) in turkeys. one-week-old turkey poults received two intramuscular injections 2 wk apart. birds were challenged with a turkey-embryo-adapted ampv at 5 wk of age. birds vaccinated with pcmv-f had decreased clinical signs of disease as well as significantly reduced virus load in tracheal swabs compared with birds vaccinated with pcmv-n or unvaccinated control birds. serum ... | 2003 | 14708985 |
| sequence polymorphism of the predicted human metapneumovirus g glycoprotein. | the putative g glycoprotein genes of 25 human metapneumovirus (hmpv) field isolates obtained during five consecutive epidemic seasons (1997 to 2002) were sequenced. sequence alignments identified two major genetic groups, designated groups 1 and 2, and two minor genetic clusters within each major group, designated subgroups a and b. extensive nucleotide and deduced amino acid sequence variability was observed, consisting of high rates of nucleotide substitutions, use of alternative transcription ... | 2004 | 14993653 |
| development of a nucleoprotein-based enzyme-linked immunosorbent assay using a synthetic peptide antigen for detection of avian metapneumovirus antibodies in turkey sera. | avian metapneumoviruses (ampv) cause an upper respiratory tract disease with low mortality but high morbidity, primarily in commercial turkeys, that can be exacerbated by secondary infections. there are three types of ampv, of which type c is found only in the united states. the ampv nucleoprotein (n) amino acid sequences of serotypes a, b, and c were aligned for comparative analysis. on the basis of the predicted antigenicity of consensus sequences, five ampv-specific n peptides were synthesize ... | 2004 | 15013970 |
| effects of bacterial coinfection on the pathogenesis of avian pneumovirus infection in turkeys. | four- and nine-week-old poults were inoculated with cell culture propagated avian pneumovirus (apv) into each conjunctival space and nostril, followed by inoculation 3 days later with escherichia coli, bordetella avium (ba), or ornithobacterium rhinotracheale or a mixture of all three (ebo). clinical signs were evaluated on days 3, 5, 7, 9, 11, and 14 postinoculation (pi) of apv. the poults were euthanatized on days 2, 4, 6, 10, and 14 pi, and blood and tissues were collected. the poults that re ... | 2004 | 15077796 |
| cold-adapted strain of avian pneumovirus as a vaccine in one-day-old turkeys and the effect of inoculation routes. | to determine the optimum route of vaccination, we inoculated 1-day-old turkeys with a cold-adapted strain of avian pneumovirus (apv) by oculonasal, oral, or aerosol route. another two groups served as nonvaccinated-challenged and nonvaccinated-nonchallenged groups. birds in all vaccinated and nonvaccinated-challenged groups were challenged with virulent apv 3 wk postvaccination. after challenge, no vaccinated bird developed clinical signs or virus shedding, whereas nonvaccinated-challenged birds ... | 2004 | 15077809 |
| animal pneumoviruses: molecular genetics and pathogenesis. | pneumoviruses are single-stranded, negative-sense, nonsegmented rna viruses of the family paramyxoviridae, subfamily pneumovirinae, and include pathogens that infect humans (respiratory syncytial virus and human metapneumovirus), domestic mammals (bovine, ovine, and caprine respiratory syncytial viruses), rodents (pneumonia virus of mice), and birds (avian metapneumovirus). among the topics considered in this review are recent studies focused on the roles of the individual virus-encoded componen ... | 2004 | 15084507 |
| detection of three avian respiratory viruses by single-tube multiplex reverse transcription-polymerase chain reaction assay. | acute respiratory tract infections are leading causes of morbidity in poultry farms throughout the world. avian pneumovirus (apv), avian influenza virus (aiv), and newcastle disease virus (ndv) have been recognized as the most important pathogens of both chicken and turkeys. single-virus reverse transcription-polymerase chain reaction (srt-pcr) assays are used extensively to detect these viruses in clinical samples. this study reports the development and evaluation of a single-tube multiplex rt- ... | 2004 | 15152843 |
| antigenic and genetic variability of human metapneumoviruses. | human metapneumovirus (hmpv) is a member of the subfamily pneumovirinae within the family paramyxo- viridae. other members of this subfamily, respiratory syncytial virus and avian pneumovirus, can be divided into subgroups on the basis of genetic or antigenic differences or both. for hmpv, the existence of different genetic lineages has been described on the basis of variation in a limited set of available sequences. we address the antigenic relationship between genetic lineages in virus neutral ... | 2004 | 15200856 |
| significance of interactions between escherichia coli and respiratory pathogens in layer hen flocks suffering from colibacillosis-associated mortality. | this study aimed to examine the significance of interactions between escherichia coli and various respiratory pathogens during outbreaks of colibacillosis-associated mortality in layer hen flocks under field conditions. for this purpose, a case-control study involving 20 control flocks with baseline mortality and 20 flocks with increased mortality due to e. coli septicaemia and polyserositis, was conducted. in each colibacillosis flock, blood samples were taken from 20 hens at the onset of clini ... | 2004 | 15223556 |
| microwave or autoclave treatments destroy the infectivity of infectious bronchitis virus and avian pneumovirus but allow detection by reverse transcriptase-polymerase chain reaction. | a method is described for enabling safe transit of denatured virus samples for polymerase chain reaction (pcr) identification without the risk of unwanted viable viruses. cotton swabs dipped in avian infectious bronchitis virus (ibv) or avian pneumovirus (apv) were allowed to dry. newcastle disease virus and avian influenza viruses were used as controls. autoclaving and microwave treatment for as little as 20 sec destroyed the infectivity of all four viruses. however, both ibv and apv could be d ... | 2004 | 15223557 |
| development of a virosome vaccine against avian metapneumovirus subtype c for protection in turkeys. | an avian metapneumovirus (ampv) virosome vaccine was prepared and tested for protection of turkeys by ampv challenge. the vaccine was produced using a detergent-based (triton x-100) extraction of ampv subtype c followed by detergent removal with sm2 bio-beads. western blot and virus-neutralization analysis confirmed that the ampv virosomes contained both the fusion and attachment glycoproteins. specific-pathogen-free turkeys were immunized either intranasally (i.n.) or intramuscularly (i.m.) wit ... | 2004 | 15283420 |
| genetic variability of the g glycoprotein gene of human metapneumovirus. | human metapneumovirus (hmpv) has been associated with respiratory illnesses like those caused by human respiratory syncytial virus (hrsv) infection. similar to other pneumoviruses, genetic diversity has been reported for hmpv. little information is currently available on the genetic variability of the g glycoprotein (g), which is the most variable gene in rsv and avian pneumovirus. the complete nucleotide sequences of the g open reading frame (orf) of 24 canadian hmpv isolates were determined. p ... | 2004 | 15297494 |
| sequence analysis of the large polymerase (l) protein of the us strain of avian metapneumovirus indicates a close resemblance to that of the human metapneumovirus. | the complete nucleotide sequence of the large polymerase (l) protein of the avian metapneumovirus subgroup c strain colorado was determined. the l protein gene of avian pneumovirus colorado isolate (apv-c) was 6173 nucleotides in length from the gene-start to the gene-end and encoded a polypeptide of 2005 amino acids in length. the length of the l protein of apv-c was exactly the same as that of human metapneumovirus (hmpv) and one amino acid longer than the l protein of apv subgroup a. the l pr ... | 2004 | 15325081 |
| serological cross-reactivity of members of the metapneumovirus genus. | respiratory tract infections are a leading cause of morbidity and mortality worldwide. human metapneumovirus (hmpv) is a recently discovered respiratory pathogen of the paramyxovirus family in the metapneumovirus genus. hmpv was first isolated from young children in the netherlands with respiratory illness similar to human respiratory syncytial virus (rsv) infection. epidemiological data indicates that hmpv co-circulates with rsv in the community. few immunological tools are available to study t ... | 2004 | 15325082 |
| development of a reverse-genetics system for avian pneumovirus demonstrates that the small hydrophobic (sh) and attachment (g) genes are not essential for virus viability. | avian pneumovirus (apv) is a member of the genus metapneumovirus of the subfamily pneumovirinae. this study describes the development of a reverse-genetics system for apv. a minigenome system was used to optimize the expression of the nucleoprotein, phosphoprotein, m2 and large polymerase proteins when transfected into vero cells under the control of the bacteriophage t7 promoter. subsequently, cdna was transcribed from the virion rna to make a full-length antigenome, which was also cloned under ... | 2004 | 15483235 |
| duration of immunity produced by a live attenuated vaccine against avian pneumovirus type c. | a recently developed live, attenuated vaccine against avian pneumovirus (apv) was found to be safe and protective in experimental birds. duration of immunity following a single dose of this experimental vaccine in 1-week-old turkey poults is described. two groups each of 60 poults were housed in separate isolation rooms. birds in group one were inoculated oculonasally at 1 week of age with the vaccine. the second group served as a non-vaccinated group and was inoculated with mock-infected cell c ... | 2004 | 15545025 |
| complete sequence of the g glycoprotein gene of avian metapneumovirus subgroup c and identification of a divergent domain in the predicted protein. | the complete nucleotide sequences of the attachment glycoprotein (g) genes of three strains of avian metapneumovirus subgroup c (ampv-c) were determined from the viral genomic and mrnas. the g gene of ampv-c was 1798 nt (1015 nt longer than previously reported) and the derived polypeptide had 585 aa. the deduced amino acid sequence of the predicted g protein of ampv-c strain colorado (ampv-co) showed 21-25 % amino acid identity to the g proteins of human metapneumoviruses, but only 14-16 % amino ... | 2004 | 15557240 |
| the effect of pooling sera on the detection of avian pneumovirus antibodies using an enzyme-linked immunosorbent assay test. | pooling of samples is a cost-effective approach to estimate disease prevalence and to identify infected individuals. the objective of this study was to evaluate the use of serum pools for the detection of avian pneumovirus infection in turkey flocks by enzyme-linked immunosorbent assay, so that a minimum number of tests can be performed without compromising the sensitivity and specificity of the test. a total of 900 field samples were tested; 20 samples from each of 45 flocks. all samples were t ... | 2004 | 15586563 |
| design, validation, and absolute sensitivity of a novel test for the molecular detection of avian pneumovirus. | this study describes attempts to increase and measure sensitivity of molecular tests to detect avian pneumovirus (apv). polymerase chain reaction (pcr) diagnostic tests were designed for the detection of nucleic acid from an a-type apv genome. the objective was selection of pcr oligonucleotide combinations, which would provide the greatest test sensitivity and thereby enable optimal detection when used for later testing of field materials. relative and absolute test sensitivities could be determ ... | 2004 | 15586577 |
| hatchability, serology and virus excretion following in ovo vaccination of chickens with an avian metapneumovirus vaccine. | the present investigation describes for the first time the effect of an avian metapneumovirus vaccine administered in ovo to 18-day-old chicken embryos. the application of the vaccine had no adverse effect on the hatchability or the health of the chicks post hatch. the antibody titres achieved were higher than those determined for birds vaccinated at 1 day old. not only were the mean titres in the in ovo vaccinated groups higher, but many more birds developed a measurable antibody response than ... | 2004 | 15763725 |
| avian metapneumovirus excretion in vaccinated and non-vaccinated specified pathogen free laying chickens. | vaccinated and non-vaccinated specified pathogen-free white leghorn laying chickens were challenged at peak of lay by the intravenous or oculonasal route with a virulent avian metapneumovirus (ampv) subtype b chicken strain. severe clinical signs and a drop in egg production were induced in the non-vaccinated intravenously challenged birds whereas the vaccinates were not affected. live virus excretion was demonstrated in the faeces and respiratory tract of non-vaccinated hens for up to 7 days po ... | 2004 | 14681066 |
| evidence of avian pneumovirus spread beyond minnesota among wild and domestic birds in central north america. | to detect avian pneumovirus (apv) in central north america, nasal turbinates or choanal deft tissues from domestic turkeys and wild birds were examined for the presence of apv rna by reverse transcriptase-polymerase chain reaction (rt-pcr), whereas serum samples from domestic turkeys were analyzed for apv antibodies by enzyme-linked immunosorbent assay (elisa). in 2002, the seroprevalence of disease in domestic turkeys in minnesota remained high (42.3% of the flocks). in addition, there is evide ... | 2004 | 15666873 |
| 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 ... | 2005 | 15690946 |
| 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 ... | 2005 | 15737482 |
| 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 ... | 2005 | 15795081 |
| 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 ... | 2005 | 15826312 |
| analysis of the complete genome sequence of avian metapneumovirus subgroup c indicates that it possesses the longest genome among metapneumoviruses. | 2005 | 15830150 | |
| transcriptional analysis of avian embryonic tissues following infection with avian infectious bronchitis virus. | avian infectious bronchitis virus (ibv) infection is one of the major viral respiratory diseases of chickens. better understanding of the molecular basis of viral pathogenesis should contribute significantly towards the development of improved prophylactic, therapeutic and diagnostic reagents to control infections. in the present investigation, transcriptional profiles were analyzed by using rna recovered from the lung tissue of ibv infected 18-day-old chicken embryos at 6, 24, 48 and 72 h post ... | 2005 | 15845254 |
| protection by recombinant viral proteins against a respiratory challenge with virulent avian metapneumovirus. | protection by recombinant avian metapneumovirus (ampv) n or m proteins against a respiratory challenge with virulent ampv was examined. n, m or n+m proteins were administered intramuscularly (im) with incomplete freund's adjuvant (ifa) or by the oculonasal (on) route with cholera toxin-b (ctb). each turkey received 40 or 80 microg of each recombinant protein. birds were considered protected against challenge if the challenge virus was not detectable in the choanal swabs by rt-pcr. at a dose of 4 ... | 2005 | 16112741 |
| interaction between live avian pneumovirus and newcastle disease virus vaccines in specific pathogen free chickens. | one-day-old specific pathogen free white leghorn chicks were vaccinated with live avian pneumovirus (apv) vaccine, live newcastle disease virus (ndv) vaccine or both. at intervals up to 28 days after vaccination, distribution of the virus in the tissues was studied, together with humoral and mucosal antibody responses in lachrymal fluid and tracheal washes. apv vaccine was detected for almost twice as long in the dual vaccinates as in the single vaccinates. higher numbers of isolations of nd vir ... | 2005 | 16147565 |
| 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 ... | 2005 | 16191692 |
| 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 ... | 2005 | 16191694 |
| 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 ... | 2005 | 16191703 |
| 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 ... | 2005 | 16191705 |
| 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 ... | 2005 | 15643005 |
| 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 ... | 2005 | 16282483 |
| mutational analysis of the avian pneumovirus conserved transcriptional gene start sequence identifying critical residues. | seven of the eight genes in the avian pneumovirus (apv) genome contain a conserved 9 nt transcriptional start sequence with the virus large (l) polymerase gene differing from the consensus at three positions. the sequence requirements of the apv transcriptional gene start sequence were investigated by generating a series of mutations in which each of the nine conserved bases was mutated to each of the other three possible nucleotides in a minigenome containing two reporter genes. the effect of e ... | 2005 | 16298980 |
| 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 ... | 2005 | 16306583 |
| comparison of the full-length genome sequence of avian metapneumovirus subtype c with other paramyxoviruses. | we determined the nucleotide (nt) sequence of the small hydrophobic (sh), attachment glycoprotein (g), and rna polymerase (l) genes, plus the leader and trailer regions of the colorado strain of avian metapneumovirus subtype c (ampv/c) in order to complete the genome sequencing. the complete genome comprised of 13,134 nucleotides, with a 40 nt leader at its 3' end and a 45 nt trailer at its 5' end. the ampv/c l gene was the largest with 6173 nt and consisting of a single open reading frame encod ... | 2005 | 15567037 |
| 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 ... | 2005 | 15567039 |
| emergence of a virulent type c avian metapneumovirus in turkeys in minnesota. | the objectives of the present study were to investigate the pathogenesis of a recent isolate of avian metapneumovirus (ampv) in turkeys and to evaluate the quantitative distribution of the virus in various tissues during the course of infection. seventy 2-week-old turkey poults were divided equally into two groups. one group was inoculated with ampv (mn 19) with a titer of 10(5.5) tcid50 oculonasally. birds in the second group were maintained as sham-inoculated controls. birds showed severe clin ... | 2005 | 16404993 |
| 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 ... | 2006 | 16432027 |
| 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 ... | 2006 | 16525740 |
| 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 ... | 2006 | 16548335 |
| 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 ... | 2006 | 16595303 |
| 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 ... | 2006 | 16731918 |
| 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 ... | 2006 | 16731919 |
| 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 ... | 2006 | 16753615 |
| 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 ... | 2006 | 16863071 |
| 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 ... | 2006 | 16863083 |
| 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 ... | 2006 | 16901592 |
| 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 ... | 2006 | 16930732 |
| 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 ... | 2006 | 16953076 |
| 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 ... | 2006 | 17039843 |
| 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 ... | 2006 | 17121730 |
| [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 ... | 2006 | 17446666 |
| 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 ... | 2006 | 16310868 |
| 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 ... | 2006 | 16326044 |
| 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 ... | 2006 | 16194579 |
| 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 ... | 2006 | 17235379 |
| 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 ( ... | 2006 | 17240906 |
| 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 ... | 2006 | 17181442 |
| 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 ... | 2007 | 17187945 |
| 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 ... | 2007 | 17207537 |
| 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 ... | 2007 | 17229500 |
| 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 ... | 2007 | 17275932 |
| 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 ... | 2007 | 18251400 |
| 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 ... | 2007 | 18251412 |
| 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 ... | 2007 | 18928061 |
| 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 ... | 2007 | 17462834 |
| 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 ... | 2007 | 17470912 |
| 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 ... | 2007 | 17482704 |
| 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 ... | 2007 | 17485129 |
| 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 ... | 2007 | 17485538 |
| 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 ... | 2007 | 17522208 |
| 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 ... | 2007 | 17620178 |
| 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 ... | 2007 | 17626490 |
| 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 ... | 2007 | 17626813 |
| 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 ... | 2007 | 17899462 |
| 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 ... | 2007 | 17920166 |
| 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 ... | 2007 | 17992934 |
| 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 ... | 2007 | 17992939 |
| 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 ... | 2007 | 17126416 |
| 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 ... | 2008 | 18160118 |
| 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 ... | 2008 | 18198384 |
| 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 ... | 2008 | 18202952 |
| 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 ... | 2008 | 18931065 |
| 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. | 2008 | 18937854 |
| 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 ... | 2008 | 18939643 |
| 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 ... | 2008 | 18783028 |
| 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 ... | 2008 | 18568663 |