| 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 pneumovirus infection of laying hens: experimental studies. | administration of a virulent strain of avian pneumovirus (apv) to specific pathogen free laying hens by the oculonasal route failed to induce a drop in egg production or any adverse effects on eggshell quality. however, intravenous (i.v.) inoculation of the same strain caused a substantial drop in egg production and a high incidence of soft and thin-shelled eggs. some respiratory signs were also observed and the hens appeared sick, with diarrhoea being observed in approximately one-half of the h ... | 2000 | 19184850 |
| infectious bronchitis virus vaccine interferes with the replication of avian pneumovirus vaccine in domestic fowl. | experiments were performed in chickens to ascertain whether application of infectious bronchitis (ib) h120 vaccine had an effect on the replication of an attenuated avian pneumovirus (apv) strain, using as indicators virus detection, humoral antibody responses and clinical protection against in vivo apv challenge. a preliminary experiment demonstrated that pharyngeal swabs were as efficient for recovery of apv as were buccal cavity swabs, and that either site was superior to swabbing the nasal c ... | 2001 | 19184905 |
| 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 ... | 2009 | 19937513 |
| 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 ... | 2009 | 19937531 |
| cloning, expression and immunogenicity of the avian pneumovirus (colorado isolate) f protein. | the f protein of the colorado isolate of avian pneumovirus (apv), expressed from a dna plasmid, was recognized by antiserum to both a and b subgroup apvs. after two intramuscular injections of turkeys with this plasmid, a homologous antibody response was detected by enzyme-linked immunosorbent assay. this antibody also recognized subgroup a apv. however, there was no neutralization of the colorado isolate or of subgroup a or b viruses. although no significant clinical protection was detected fol ... | 2001 | 19184935 |
| 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 ... | 2009 | 19937539 |
| effects of cyclosporin a induced t-lymphocyte depletion on the course of avian metapneumovirus (ampv) infection in turkeys. | the avian metapneumovirus (ampv) causes an economically important acute respiratory disease in turkeys (turkey rhinotracheitis, trt). while antibodies were shown to be insufficient for protection against ampv-infection, the role of t-lymphocytes in the control of ampv-infection is not clear. in this study we investigated the role of t-lymphocytes in ampv-pathogenesis in a t-cell-suppression model in turkeys. t-cell-intact turkeys and turkeys partly depleted of functional cd4(+) and cd8(+) t-lymp ... | 2010 | 20043941 |
| innovation and discovery: the application of nucleic acid-based technology to avian virus detection and characterization. | polymerase chain reaction (pcr)-based approaches to the detection, differentiation and characterization of avian pathogens continue to be developed and refined. the pcrs, or reverse transcriptase-pcrs, may be general, designed to detect all or most variants of a pathogen, or to be serotype, genotype or pathotype specific. progress is being made with respect to making nucleic acid approaches more suitable for use in diagnostic laboratories. robotic workstations are now available for extraction of ... | 2001 | 19184952 |
| isolation and characterization of avian metapneumovirus from chickens in korea. | avian metapneumovirus (ampv) causes upper respiratory tract infections in chickens and turkeys. although the swollen head syndrome (shs) associated with ampv in chickens has been reported in korea since 1992, this is the study isolating ampv from chickens in this country. we examined 780 oropharyngeal swab or nasal turbinate samples collected from 130 chicken flocks to investigate the prevalence of ampv and to isolate ampv from chickens from 2004-2008. twelve ampv subtype a and 13 subtype b stra ... | 2010 | 20195066 |
| 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 ... | 2009 | 19264630 |
| propagation of avian metapneumovirus subtypes a and b using chicken embryo related and other cell systems. | primary isolation of avian metapneumovirus (ampv) is carried out using tracheal organ culture (toc) or chicken embryonated eggs with subsequent adaptation in chicken embryo fibroblasts (cef) or vero cultures. this study was conducted to evaluate six different cell lines and two avian culture systems for the propagation of ampv subtypes a and b. the chicken embryo related (cer) cells were used successfully for primary isolation. in addition to vero and baby hamster kidney (bhk-21) cells, cer cell ... | 2010 | 20219543 |
| detection of avian metapneumovirus subtypes in turkeys using rt-pcr. | this study investigated the prevalence of avian metapneumovirus (ampv) and the detection of molecular subtypes of field strains of the virus using rt-pcr in clinically healthy turkeys and those showing signs of respiratory disease. in the rt-pcr examination of 624 tracheal tissue samples collected from a local turkey abattoir, 2.9 per cent (18/624) of samples tested positive. in the examination of tracheal swab samples collected from flocks with respiratory problems, 18 of 20 samples tested posi ... | 2010 | 20305292 |
| 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 ... | 2009 | 19286505 |
| 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 ... | 2010 | 20390564 |
| 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 ... | 2009 | 19435637 |
| 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 ... | 2009 | 19630222 |
| avian metapneumovirus subtypes circulating in brazilian vaccinated and nonvaccinated chicken and turkey farms. | avian metapneumovirus (ampv) causes turkey rhinotracheitis and is associated with swollen head syndrome in chickens, which is usually accompanied by secondary infections that increase mortality. ampvs circulating in brazilian vaccinated and nonvaccinated commercial chicken and turkey farms were detected using a universal reverse transcriptase (rt)-pcr assay that can detect the four recognized subtypes of ampv. the ampv status of 228 farms with respiratory and reproductive disturbances was invest ... | 2011 | 21500641 |
| 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 ... | 2009 | 19720091 |
| 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 ... | 2009 | 19762861 |
| 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 ... | 2009 | 19834081 |
| 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 ... | 2010 | 19896993 |
| 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 |
| 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 ... | 2010 | 19931381 |
| vaccination of commercial broiler chicks against avian metapneumovirus infection: a comparison of drinking-water, spray and oculo-oral delivery methods. | avian metapneumovirus (ampv) has become an important cause of viral respiratory infections in turkey and chickens. live and inactivated vaccinations are available worldwide for prevention of disease and economic losses caused by this pathogen. the efficacy of these vaccines is vigorously tested under laboratory conditions prior to use in the field. in this study, a live subtype b ampv vaccine was administered by spray, drinking water or oculo-oral methods to separate groups of broiler chicks und ... | 2010 | 20392431 |
| 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 |
| generation and evaluation of a recombinant newcastle disease virus expressing the glycoprotein (g) of avian metapneumovirus subgroup c as a bivalent vaccine in turkeys. | virulent strains of newcastle disease virus (ndv) and avian metapneumovirus (ampv) can cause serious respiratory diseases in poultry. vaccination combined with strict biosecurity practices has been the recommendation for controlling both ndv and ampv diseases in the field. in the present study, an ndv based, lasota strain recombinant vaccine virus expressing the glycoprotein (g) of ampv subgroup c (ampv-c) was generated as a bivalent vaccine using a reverse genetics approach. the recombinant vir ... | 2011 | 21925228 |
| 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 ... | 2009 | 19052092 |
| contribution of the attachment g glycoprotein to pathogenicity and immunogenicity of avian metapneumovirus subgroup c. | avian metapneumovirus (ampv) causes an upper respiratory tract infection in turkeys leading to serious economic losses to the turkey industry. the g glycoprotein of ampv is known to be associated with viral attachment and pathogenesis. in this study, we determined the role of the g glycoprotein in the pathogenicity and immunogenicity of ampv strain colorado (ampv/co). recombinant ampv/co lacking the g protein (rampv/co-deltag) was generated using a reverse-genetics system. the recovered rampv/co ... | 2010 | 20408400 |
| 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 ... | 2010 | 20447777 |
| 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 ... | 2010 | 20608539 |
| 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 ... | 2010 | 20656031 |
| 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 ... | 2010 | 20676749 |
| 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. ... | 2010 | 20713098 |
| tmprss12 is an activating protease for subtype b avian metapneumovirus. | the entry of avian metapneumovirus (ampv) into host cells initially requires the fusion of viral and cell membranes, which is exclusively mediated by fusion (f) protein. proteolysis of ampv f protein by endogenous proteases of host cells allows f protein to induce membrane fusion; however, these proteases have not been identified. here, we provide the first evidence that the transmembrane serine protease tmprss12 facilitates the cleavage of subtype b ampv (ampv/b) f protein. we found that overex ... | 2016 | 27707927 |
| 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- ... | 2010 | 20954011 |
| 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 ... | 2010 | 21048037 |
| phosphorylation of human metapneumovirus m2-1 protein upregulates viral replication and pathogenesis. | human metapneumovirus (hmpv) is a major causative agent of upper- and lower-respiratory-tract infections in infants, the elderly, and immunocompromised individuals worldwide. like all pneumoviruses, hmpv encodes the zinc binding protein m2-1, which plays important regulatory roles in rna synthesis. the m2-1 protein is phosphorylated, but the specific role(s) of the phosphorylation in viral replication and pathogenesis remains unknown. in this study, we found that hmpv m2-1 is phosphorylated at a ... | 2016 | 27252537 |
| 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 ... | 2010 | 21073989 |
| 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 ... | 2010 | 21146877 |
| 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 ... | 2010 | 21183227 |
| the cellular endosomal sorting complex required for transport pathway is not involved in avian metapneumovirus budding in a virus-like-particle expression system. | avian metapneumovirus (ampv) is a paramyxovirus that principally causes respiratory disease and egg production drops in turkeys and chickens. together with its closely related human metapneumovirus (hmpv), they comprise the genus metapneumovirus in the family paramyxoviridae. little is currently known about the mechanisms involved in the budding of metapneumovirus. by using ampv as a model system, we showed that the matrix (m) protein by itself was insufficient to form virus-like-particles (vlps ... | 2011 | 21248175 |
| deletion of the m2-2 gene from avian metapneumovirus subgroup c impairs virus replication and immunogenicity in turkeys. | the second matrix (m2) gene of avian metapneumovirus subgroup c (ampv-c) contains two overlapping open reading frames (orfs), encoding two putative proteins, m2-1 and m2-2. both proteins are believed to be involved in viral rna transcription or replication. to further characterize the function of the m2-2 protein in virus replication, the non-overlapping region of the m2-2 orf was deleted from an infectious cdna clone of the ampv-c strain, and a viable virus was rescued by using reverse genetics ... | 2011 | 21287257 |
| 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 ... | 2010 | 21313844 |
| avian metapneumovirus subtype b experimental infection and tissue distribution in chickens, sparrows, and pigeons. | avian metapneumovirus (ampv) is a respiratory virus that infects a range of avian hosts, including chickens and turkeys. migratory and local wild birds are implicated in ampv spread among farms, countries, and seasonal outbreaks of the disease. a subtype b ampv isolate from commercial chicken flocks suffering from respiratory disease was experimentally inoculated oculonasally into 7-week old chickens, young pigeons, and sparrows. chickens showed minimal tracheal rales, whereas pigeons and sparro ... | 2011 | 21527377 |
| multi-locus sequence typing and plasmid profile characterization of avian pathogenic escherichia coli associated with increased mortality in free-range layer flocks. | avian pathogenic escherichia coli strains originating from 10 free-range layer flocks were characterized by multi-locus sequence typing and plasmid profile analysis to investigate their phylogenetic relationship and diversity, respectively. in addition to colibacillosis, all flocks tested positive for antibodies against avian metapneumovirus (ampv) during production, and six of the flocks were concurrently affected by histomonosis. accumulated average mortality for flocks concurrently affected b ... | 2011 | 21780978 |
| detection of and phylogenetic studies with avian metapneumovirus recovered from feral pigeons and wild birds in brazil. | the aim of the present study was to determine whether avian metapneumovirus (ampv)-related viruses were present in wild and synanthropic birds in brazil. therefore, we analysed samples from wild birds, feral pigeons and domestic chickens in order to perform a phylogenetic comparison. to detect the presence of ampv, a nested reverse transcriptase-polymerase chain reaction was performed with the aim of amplifying a fragment of 270 bases for subtype a and 330 bases for subtype b, comprising the gen ... | 2011 | 21777083 |
| effect of amino acid sequence variations at position 149 on the fusogenic activity of the subtype b avian metapneumovirus fusion protein. | the entry of enveloped viruses into host cells requires the fusion of viral and cell membranes. these membrane fusion reactions are mediated by virus-encoded glycoproteins. in the case of avian metapneumovirus (ampv), the fusion (f) protein alone can mediate virus entry and induce syncytium formation in vitro. to investigate the fusogenic activity of the ampv f protein, we compared the fusogenic activities of three subtypes of ampv f proteins using a tcsd50 assay developed in this study. interes ... | 2015 | 26175070 |
| topology and cellular localization of the small hydrophobic protein of avian metapneumovirus. | the small hydrophobic protein (sh) is a type ii integral membrane protein that is packaged into virions and is only present in certain paramyxoviruses including metapneumovirus. in addition to a highly divergent primary sequence, sh proteins vary significantly in size amongst the different viruses. human respiratory syncytial virus (hrsv) encodes the smallest sh protein consisting of only 64 amino acids, while metapneumoviruses have the longest sh protein ranging from 174 to 179 amino acids in l ... | 2011 | 21683102 |
| serologic evidence of avian metapneumovirus infection among adults occupationally exposed to turkeys. | abstract genetically similar, the avian metapneumovirus (ampv) and the human mpv (hmpv) are the only viruses in the metapneumovirus genus. previous research demonstrated the ability of hmpv to cause clinical disease in turkeys. in this controlled, cross-sectional, seroepidemiological study, we examined the hypothesis that ampv might infect humans. we enrolled 95 adults occupationally exposed to turkeys and 82 nonexposed controls. sera from study participants were examined for antibodies against ... | 2011 | 21736487 |
| A turkey rhinotracheitis outbreak caused by the environmental spread of a vaccine-derived avian metapneumovirus. | Avian metapneumovirus (aMPV) subtype A was isolated from 7-week-old turkeys showing respiratory disease typical of turkey rhinotracheitis. Comparison of the virus sequence with previously determined vaccine marker sequences showed that the virulent virus had originated from a licensed live subtype A aMPV vaccine. The vaccine had neither been in use on the farm within a period of at least 6 months nor had it been used on farms within a distance of approximately 5 km. Isolation of the virus and ex ... | 2011 | 21854180 |
| longitudinal monitoring for respiratory pathogens in broiler chickens reveals co-infection of chlamydia psittaci and ornithobacterium rhinotracheale. | chlamydia psittaci is prevalent in broiler chicken production. however, the role of c. psittaci in the respiratory disease complex needs to be clarified. our aim was to identify the time point when a c. psittaci infection appeared on a broiler farm and to examine the presence of other respiratory pathogens at that time. we focused on the 'major' respiratory pathogens occurring in belgian broilers, namely infectious bronchitis virus (ibv), avian metapneumovirus (ampv), ornithobacterium rhinotrach ... | 2015 | 25724936 |
| lack of correlation between virus barosensitivity and the presence of a viral envelope during inactivation of human rotavirus, vesicular stomatitis virus, and avian metapneumovirus by high-pressure processing. | high-pressure processing (hpp) is a nonthermal technology that has been shown to effectively inactivate a wide range of microorganisms. however, the effectiveness of hpp on inactivation of viruses is relatively less well understood. we systematically investigated the effects of intrinsic (ph) and processing (pressure, time, and temperature) parameters on the pressure inactivation of a nonenveloped virus (human rotavirus [hrv]) and two enveloped viruses (vesicular stomatitis virus [vsv] and avian ... | 2011 | 22003028 |
| use of ovotransferrin as an antimicrobial in turkeys naturally infected with chlamydia psittaci, avian metapneumovirus and ornithobacterium rhinotracheale. | respiratory pathogens are difficult to control in large-scale turkey production. this report describes a clinical trial of antimicrobial ovotf aerosol on a large belgian turkey farm. ovotf was administered to reduce chlamydia psittaci (c. psittaci) infections and to study the impact of this action on the occurrence of ornithobacterium rhinotracheale (o. rhinotracheale) and avian metapneumovirus (ampv) infections. two subsequent broods were included; (i) a control brood receiving no ovotf and (ii ... | 2011 | 21885218 |
| immune responses and interactions following simultaneous application of live newcastle disease, infectious bronchitis and avian metapneumovirus vaccines in specific-pathogen-free chicks. | interactions between live newcastle disease virus (ndv), avian metapneumovirus (ampv) and infectious bronchitis virus (ibv) vaccines following simultaneous vaccination of day old specific pathogen free (spf) chicks were evaluated. the chicks were divided into eight groups: seven vaccinated against ndv, ampv and ibv (single, dual or triple) and one unvaccinated as control. haemagglutination inhibition (hi) ndv antibody titres were similar across all groups but were above protective titres. ampv v ... | 2015 | 25482324 |
| clinical aspects of immunosuppression in poultry. | chickens, turkeys, and other poultry in a production environment can be exposed to stressors and infectious diseases that impair innate and acquired immunity, erode general health and welfare, and diminish genetic and nutritional potential for efficient production. innate immunity can be affected by stressful physiologic events related to hatching and to environmental factors during the first week of life. exposure to environmental ammonia, foodborne mycotoxins, and suboptimal nutrition can dimi ... | 2010 | 20408392 |
| development of vaccine-induced immunity against trt in turkeys depends remarkably on the level of maternal antibodies and the age of birds on the day of vaccination. | avian metapneumovirus (ampv) infections are a huge economical issue for the poultry industry worldwide. although maternal antibodies do not protect turkey poults against turkey rhinotracheitis (trt), almost no studies have been conducted so far regarding the impact of these antibodies on vaccine induced immunity development against ampv infection. we conducted four experiments on commercial turkeys aimed at comparing local humoral and cell mediated immune response of maternally delivered anti-am ... | 2015 | 25889279 |
| methyltransferase-defective avian metapneumovirus vaccines provide complete protection against challenge with the homologous colorado strain and the heterologous minnesota strain. | avian metapneumovirus (ampv), also known as avian pneumovirus or turkey rhinotracheitis virus, is the causative agent of turkey rhinotracheitis and is associated with swollen head syndrome in chickens. since its discovery in the 1970s, ampv has been recognized as an economically important pathogen in the poultry industry worldwide. the conserved region vi (cr vi) of the large (l) polymerase proteins of paramyxoviruses catalyzes methyltransferase (mtase) activities that typically methylate viral ... | 2014 | 25122790 |
| an avian coronavirus in quail with respiratory and reproductive signs. | an avian coronavirus was detected in pools of lungs, tracheas, female reproductive tracts, kidneys, and enteric contents from quail (coturnix coturnix japonica) and laying hen flocks, with and without infectious bronchitis (ib)-like signs, cohoused in farms located in two states of southeastern brazil during 2009-2010. although avian metapneumovirus subtype b was found in two layers samples, newcastle disease virus was not found in quail or in hens. based on dna sequences for the 3'-untranslated ... | 2013 | 24689189 |
| detection of infectious bronchitis virus 793b, avian metapneumovirus, mycoplasma gallisepticum and mycoplasma synoviae in poultry in ethiopia. | a survey was conducted into respiratory infectious diseases of poultry on a chicken breeder farm run by the ethiopian institute of agricultural research (eiar), located in debre zeit, ethiopia. oropharyngeal swabs were collected from 117 randomly selected birds, and blood was taken from a subset of 73 of these birds. a combination of serological and molecular methods was used for detection of pathogens. for the first time in ethiopia, we report the detection of variant infectious bronchitis viru ... | 2017 | 27924415 |
| human metapneumovirus infection in immunocompromised patients. | human metapneumovirus (hmpv) is a pathogen associated with respiratory tract infection and is related to avian pneumovirus. typically, children, the elderly, and those who are immunocompromised are the most susceptible to hmpv infection; however, the virus can infect persons of all ages. in otherwise healthy individuals, hmpv infection is generally self-limiting, but immunocompromised individuals can develop fatal complications. we present a case series of 3 severely immunocompromised patients w ... | 2016 | 27842334 |
| molecular detection and isolation of avian metapneumovirus in mexico. | we conducted a longitudinal study to detect and isolate avian metapneumovirus (ampv) in two highly productive poultry areas in mexico. a total of 968 breeder hens and pullets from 2 to 73 weeks of age were analysed. serology was performed to detect ampv antibodies and 105 samples of tracheal tissue were collected, pooled by age, and used for attempted virus isolation and ampv nested reverse transcriptase-polymerase chain reaction (nrt-pcr). the serological analysis indicated that 100% of the sam ... | 2014 | 24617750 |
| three-step anti-ampv iga expression profile evaluation in turkeys of different immunological status after trt vaccination. | maternally derived antibodies (mda) don not protect turkeys against rhinotracheitis (trt) but high mda influences upper respiratory tract (urt) immunity stimulation after avian metapneumovirus (ampv) vaccination. humoral immunity can not be considered as an indicator of protection against trt, but specific antibodies inhibit ampv replication and alleviate the course of trt. scarce reports indicate the role of iga in protection against trt. the aim of our study was to investigate the impact of md ... | 2016 | 27760036 |
| survey for zoonotic pathogens in norway rat populations from europe. | the norway rat rattus norvegicus is an important reservoir of various zoonotic pathogens, such as cowpox virus and leptospira, but also for agents of no or unknown zoonotic potential. we describe a survey of 426 norway rats originating from five european countries and different habitats for leptospira spp., rickettsiae, orthopoxvirus (opv), avian metapneumovirus subtypes a and b (ampv) and rat polyomavirus (rat pyv). | 2017 | 27299665 |
| rapid detection of subtype b avian metapneumoviruses using rt-pcr restriction endonuclease digestion indicates field circulation of vaccine-derived viruses in older turkeys. | live vaccines predominantly control avian metapneumovirus (ampv) infection in poultry flocks, but vaccine virus can be found for extended periods after application. the most frequently used ampv vaccine in italy, vco3 subtype b, was shown to contain a unique tru9i restriction endonuclease site within the amplicons produced by a commonly used ampv diagnostic reverse transcriptase (rt)-nested polymerase chain reaction (pcr). analysis of european and database logged subtype b ampv sequences confirm ... | 2014 | 24397865 |
| integrin αvβ1 modulation affects subtype b avian metapneumovirus fusion protein-mediated cell-cell fusion and virus infection. | avian metapneumovirus (ampv) fusion (f) protein mediates virus-cell membrane fusion to initiate viral infection, which requires f protein binding to its receptor(s) on the host cell surface. however, the receptor(s) for ampv f protein is still not identified. all known subtype b ampv (ampv/b) f proteins contain a conserved arg-asp-asp (rdd) motif, suggesting that the ampv/b f protein may mediate membrane fusion via the binding of rdd to integrin. when blocked with integrin-specific peptides, amp ... | 2016 | 27226547 |
| antiviral activity of favipiravir (t-705) against a broad range of paramyxoviruses in vitro and against human metapneumovirus in hamsters. | the clinical impact of infections with respiratory viruses belonging to the family paramyxoviridae argues for the development of antiviral therapies with broad-spectrum activity. favipiravir (t-705) has demonstrated potent antiviral activity against multiple rna virus families and is presently in clinical evaluation for the treatment of influenza. here we demonstrate in vitro activity of t-705 against the paramyxoviruses human metapneumovirus (hmpv), respiratory syncytial virus, human parainflue ... | 2016 | 27185803 |
| efficacy of gamithromycin against ornithobacterium rhinotracheale in turkey poults pre-infected with avian metapneumovirus. | ornithobacterium rhinotracheale is an avian respiratory pathogen that affects turkeys. the objective of this study was to evaluate the clinical efficacy of gamithromycin (gam) against o. rhinotracheale in turkeys. the birds were inoculated oculonasally with 10(8) colony-forming units (cfu) of o. rhinotracheale, preceded by infection with avian metapneumovirus. in addition to a negative (contr-) and a positive control group (contr+) there were two treated groups administered gam (6 mg/kg) either ... | 2016 | 27171615 |
| immunization with avian metapneumovirus harboring chicken fc induces higher immune responses. | in this study, we evaluated the immune responses of avian metapneumovirus harboring chicken fc molecule. stable vero cells expressing chicken fc chimera on its surface (vero-cfc) were established, and we confirmed that ampv grown in vero-cfc incorporated host derived chimera fc into the ampv virions. immunization of chicken with ampv-cfc induced higher level of antibodies and inflammatory cytokines; (interferon (ifn)-γ and interleukin (il)-1β) compared to those of ampv. the increased levels of a ... | 2016 | 27130629 |
| a reverse genetics approach for the design of methyltransferase-defective live attenuated avian metapneumovirus vaccines. | avian metapneumovirus (ampv), also known as avian pneumovirus or turkey rhinotracheitis virus, is the causative agent of turkey rhinotracheitis and is associated with swollen head syndrome in chickens. ampv belongs to the family paramyxoviridae which includes many important human pathogens such as human respiratory syncytial virus (rsv), human metapneumovirus (hmpv), and human parainfluenza virus type 3 (piv3). the family also includes highly lethal emerging pathogens such as nipah virus and hen ... | 2016 | 27076293 |
| a comparison of ampv subtypes a and b full genomes, gene transcripts and proteins led to reverse-genetics systems rescuing both subtypes. | avian metapneumovirus (ampv) infection of poultry causes serious disease in most countries and subtype a reverse-genetic (rg) systems have allowed a generation of viruses of known sequence, and proved useful in developments towards better control by live vaccines. while subtype b viruses are more prevalent, bacterial cloning issues made subtype b rg systems difficult to establish. a molecular comparison of subtype a and b viruses was undertaken to assess whether subtype a rg components could be ... | 2016 | 26958846 |
| a multiplex rt-pcr for the detection of astrovirus, rotavirus, and reovirus in turkeys. | this study was undertaken to develop and validate a multiplex reverse transcription-polymerase chain reaction (mrt-pcr) for simultaneous detection of avian rotavirus, turkey astrovirus-2 (tastv-2), and avian reovirus. primers targeting the conserved regions of nsp4 gene of avian rotavirus, polymerase gene of tastv-2, and s4 gene of avian reovirus were used. the position of bands at 630, 802, and 1120 base pairs on agarose gel confirmed the presence of rotavirus, tastv-2, and reovirus, respective ... | 2012 | 23050480 |
| localization of a region in the fusion protein of avian metapneumovirus that modulates cell-cell fusion. | the genus metapneumovirus within the subfamily pneumovirinae of the family paramyxoviridae includes two members, human metapneumovirus (hmpv) and avian metapneumovirus (ampv), causing respiratory tract infections in humans and birds, respectively. paramyxoviruses enter host cells by fusing the viral envelope with a host cell membrane. membrane fusion of hmpv appears to be unique, in that fusion of some hmpv strains requires low ph. here, we show that the fusion (f) proteins of ampv promote fusio ... | 2012 | 22915815 |
| in vitro antiviral activity of brazilian plants (maytenus ilicifolia and aniba rosaeodora) against bovine herpesvirus type 5 and avian metapneumovirus. | medicinal plants are well known for their use in traditional folk medicine as treatments for many diseases including infectious diseases. | 2012 | 22873798 |
| avian metapneumovirus rt-nested-pcr: a novel false positive reducing inactivated control virus with potential applications to other rna viruses and real time methods. | using reverse genetics, an avian metapneumovirus (ampv) was modified for use as a positive control for validating all stages of a popular established rt-nested pcr, used in the detection of the two major ampv subtypes (a and b). resultant amplicons were of increased size and clearly distinguishable from those arising from unmodified virus, thus allowing false positive bands, due to control virus contamination of test samples, to be identified readily. absorption of the control virus onto filter ... | 2012 | 22824554 |
| trypsin- and low ph-mediated fusogenicity of avian metapneumovirus fusion proteins is determined by residues at positions 100, 101 and 294. | avian metapneumovirus (ampv) and human metapneumovirus (hmpv) are members of the genus metapneumovirus in the subfamily pneumovirinae. metapneumovirus fusion (f) protein mediates the fusion of host cells with the virus membrane for infection. trypsin- and/or low ph-induced membrane fusion is a strain-dependent phenomenon for hmpv. here, we demonstrated that three subtypes of ampv (ampv/a, ampv/b, and ampv/c) f proteins promoted cell-cell fusion in the absence of trypsin. indeed, in the presence ... | 2015 | 26498473 |
| co-infection with multiple respiratory pathogens contributes to increased mortality rates in algerian poultry flocks. | respiratory infections are a common cause for increased mortality rates in poultry worldwide. to improve intervention strategies, circulating pathogens have to be identified and further characterized. because of the lack of diagnostic tools, it was not known what pathogens contribute to the high mortality rates in association with respiratory disease in algeria. our objective was to determine if primary pathogens including mycoplasma gallisepticum (mg), mycoplasma synoviae (ms), avian influenza ... | 2015 | 26478165 |
| biochemical characterization of the small hydrophobic protein of avian metapneumovirus. | avian metapneumovirus (ampv) is a paramyxovirus that has three membrane proteins (g, f, and sh). among them, the sh protein is a small type ii integral membrane protein that is incorporated into virions and is only present in certain paramyxoviruses. in the present study, we show that the ampv sh protein is modified by n-linked glycans and can be released into the extracellular environment. furthermore, we demonstrate that glycosylated ampv sh proteins form homodimers through cysteine-mediated d ... | 2012 | 22659296 |
| avian metapneumovirus infection of chicken and turkey tracheal organ cultures: comparison of virus-host interactions. | avian metapneumovirus (ampv) is a pathogen with worldwide distribution, which can cause high economic losses in infected poultry. ampv mainly causes infection of the upper respiratory tract in both chickens and turkeys, although turkeys seem to be more susceptible. little is known about virus-host interactions at epithelial surfaces after ampv infection. tracheal organ cultures (toc) are a suitable model to investigate virus-host interaction in the respiratory epithelium. therefore, we investiga ... | 2015 | 26365279 |
| role of trypsin in the replication of avian metapneumovirus subtype c (strain mn-2a) and its entry into the vero cells. | to understand the molecular mechanisms of avian metapneumovirus (ampv) and the requirements involved in the infection and fusion, trypsin treatment was done in the different stages of virus; before infection, during entry and after virus infection followed by ampv infection. the growth kinetics of ampv was compared in time dependent manner. the effect of trypsin was found in the later stage of ampv infection increasing the numbers of infected cells with the significant higher titer of infectious ... | 2015 | 26028611 |
| subpopulations in ampv vaccines are unlikely to be the only cause of reversion to virulence. | avian metapneumovirus (ampv) infects respiratory and reproductive tracts of domestic poultry, often involving secondary infections, and leads to serious economic losses in most parts of the world. while in general disease is effectively controlled by live vaccines, reversion to virulence of those vaccines has been demonstrated on several occasions. consensus sequence mutations involved in the process have been identified in more than one instance. in one previous subtype a ampv candidate vaccine ... | 2015 | 25865471 |
| zinc binding activity of human metapneumovirus m2-1 protein is indispensable for viral replication and pathogenesis in vivo. | human metapneumovirus (hmpv) is a member of the pneumovirinae subfamily in the paramyxoviridae family that causes respiratory tract infections in humans. unlike members of the paramyxovirinae subfamily, the polymerase complex of pneumoviruses requires an additional cofactor, the m2-1 protein, which functions as a transcriptional antitermination factor. the m2-1 protein was found to incorporate zinc ions, although the specific role(s) of the zinc binding activity in viral replication and pathogen ... | 2015 | 25855728 |
| high seroprevalence of respiratory pathogens in hobby poultry. | seroprevalence studies on respiratory pathogens have been done extensively in commercial laying hens, broilers, and, to a lesser extent, backyard poultry. in europe, seroprevalence studies in backyard and fancy breed poultry flocks are scarce and limited to a few pathogens, such as mycoplasma gallisepticum (mg); others, such as ornithobacterium rhinotracheale (ort), are missing. a commercial elisa for detection of antibodies against six selected pathogens was performed on 460 serum samples from ... | 2014 | 25619008 |
| molecular detection of infectious bronchitis and avian metapneumoviruses in oman backyard poultry. | infectious bronchitis virus (ibv) and avian metapneumovirus (ampv) are economically important viral pathogens infecting chickens globally. identification of endemic ibv and ampv strains promotes better control of both diseases and prevents production losses. orophrayngeal swab samples were taken from 2317 birds within 243 different backyard flocks in oman. swabs from each flock were examined by rt-pcr using part-s1 and g gene primers for ibv and ampv respectively. thirty-nine chicken flocks were ... | 2015 | 25613085 |
| Avian metapneumovirus M2:2 protein inhibits replication in Vero cells: modification facilitates live vaccine development. | Throughout the world, avian metapneumovirus (AMPV) infection of subtype A is principally controlled by two live vaccines both derived from UK field strain #8544. Improvements of those vaccines by use of reverse genetics technology was found to be hampered by the inability of #8544 to replicate in the commonly exploited Vero cell based reverse genetics system. A systematic reverse genetics based genome modification of a DNA copy of #8544, employing sequence data from a Vero grown, #8544 derived, ... | 2011 | 22019755 |
| italian field survey reveals a high diffusion of avian metapneumovirus subtype b in layers and weaknesses in the vaccination strategy applied. | the current information on the prevalence of avian metapneumovirus (ampv) infection in layers is fragmentary and its true impact on egg production often remains unknown or unclear. in order to draw an epidemiologic picture of ampv presence in layer flocks in italy, a survey was performed on 19 flocks of pullets and layers based on longitudinal studies or sporadic samplings. ampv was detected by reverse transcription (rt)-pcr, and blood samples were collected for serology by ampv elisa. occurrenc ... | 2012 | 23397844 |
| molecular comparisons of full length metapneumovirus (mpv) genomes, including newly determined french ampv-c and -d isolates, further supports possible subclassification within the mpv genus. | four avian metapneumovirus (ampv) subgroups (a-d) have been reported previously based on genetic and antigenic differences. however, until now full length sequences of the only known isolates of european subgroup c and subgroup d viruses (duck and turkey origin, respectively) have been unavailable. these full length sequences were determined and compared with other full length ampv and human metapneumoviruses (hmpv) sequences reported previously, using phylogenetics, comparisons of nucleic and a ... | 2014 | 25036224 |
| reversion to virulence of a subtype b avian metapneumovirus vaccine: is it time for regulators to require availability of vaccine progenitors? | empirically derived live avian metapneumovirus (ampv) vaccines developed during the late 80s and early 90s have generally performed well in controlling turkey rhinotracheitis. nonetheless, unstable attenuation was previously demonstrated in an ampv subtype a vaccine. until now this had not been investigated in subtype b vaccines due to lack of any similar availability of a vaccine progenitor or its sequence. the publication of the full genome sequence for the vco3 vaccine progenitor facilitated ... | 2014 | 24992716 |
| first evidence of avian metapneumovirus subtype a infection in turkeys in egypt. | although avian metapneumovirus (ampv) infection has been reported in most regions of the world, to date, only subtype b has been detected in egypt. at the end of november 2013, dry oropharyngeal swabs were collected during an outbreak of respiratory diseases in a free-range, multi-age turkey dealer farm in northern upper egypt. the clinical signs that appeared when turkeys were 3 weeks-old were characterized by ocular and nasal discharge and swelling of sinuses. ampv of subtype a was detected by ... | 2014 | 24756465 |
| viral replication and lung lesions in balb/c mice experimentally inoculated with avian metapneumovirus subgroup c isolated from chickens. | avian metapneumovirus (ampv) emerged as an important respiratory pathogen causing acute respiratory tract infection in avian species. here we used a chicken ampv subgroup c (ampv/c) isolate to inoculate experimentally balb/c mice and found that the ampv/c can efficiently replicate and persist in the lungs of mice for at least 21 days with a peak viral load at day 6 postinoculation. lung pathological changes were characterized by increased inflammatory cells. immunochemical assay showed the prese ... | 2014 | 24637582 |
| longitudinal field studies of avian metapneumovirus and turkey hemorrhagic enteritis virus in turkeys suffering from colibacillosis associated mortality. | the aim of this study was to evaluate if the exposure to avian metapneumovirus (ampv) and/or to turkey hemorrhagic enteritis virus (thev) was significant for the induction of episodes of colibacillosis in ampv and thev vaccinated turkeys. colibacillosis-associated mortality was recorded and longitudinal virological studies performed in three consecutive turkey flocks reared in the same farm. ampv and thev diagnostic swabs and blood samples were made once a week up to 14 weeks of age. swabs were ... | 2014 | 24585393 |
| evaluation of flinders technology associates cards for storage and molecular detection of avian metapneumoviruses. | the feasibility of using flinders technology associates (fta) cards for the molecular detection of avian metapneumovirus (ampv) by reverse transcriptase-polymerase chain reaction (rt-pcr) was investigated. findings showed that no virus isolation was possible from ampv-inoculated fta cards, confirming viral inactivation upon contact with the cards. the detection limits of ampv from the fta card and tracheal organ culture medium were 10(1.5) median ciliostatic doses/ml and 10(0.75) median ciliosta ... | 2014 | 24437352 |
| avian metapneumovirus subgroup c infection in chickens, china. | avian metapneumovirus causes acute respiratory tract infection and reductions in egg production in various avian species. we isolated and characterized an increasingly prevalent avian metapneumovirus subgroup c strain from meat-type commercial chickens with severe respiratory signs in china. culling of infected flocks could lead to economic consequences. | 2013 | 23763901 |
| an alternative method to determine the 5' extremities of non-segmented, negative sense rna viral genomes using positive replication intermediate 3' tailing: application to two members of the paramyxoviridae family. | determining the sequence of non-segmented, negative sense rna viral genomes is far from routine and often requires the application of several techniques. in this study, an existing method used currently just for determination of the genomic 3' extremity was used to determine both the 3' and 5' sequence extremities of a newcastle disease virus and an avian metapneumovirus. this was achieved with a single 3' nucleotide tailing reaction of both the genomic rna and the full length, positive sense, a ... | 2013 | 23707921 |
| establishment of an immortal chicken embryo liver-derived cell line. | a continuously growing immortal cell substrate can be used for virus propagation, diagnostic purposes, and vaccine production. the aim of this study was to develop an immortal chicken cell line for efficient propagation of avian infectious viruses. from the various chicken embryo cells that were tested for life span extension, an immortalized chicken embryo liver (cel) cell line, named cel-im, was derived spontaneously without either oncogenic viruses or carcinogenic chemical treatment. currentl ... | 2013 | 23687157 |
| development of a real-time rt-pcr assay for the simultaneous identification, quantitation and differentiation of avian metapneumovirus subtypes a and b. | in recent years, special attention has been paid to real-time polymerase chain reaction (pcr) for avian metapneumovirus (ampv) diagnosis, due to its numerous advantages over classical pcr. a new multiplex quantitative real-time reverse transcription-pcr (qrt-pcr) with molecular beacon probe assay, designed to target the sh gene, was developed. the test was evaluated in terms of specificity, sensitivity and repeatability, and compared with conventional rt nested-pcr based on the g gene. all of th ... | 2013 | 23650927 |
| avian metapneumoviruses expressing infectious bronchitis virus genes are stable and induce protection. | the study investigates the ability of subtype a avian metapneumovirus (ampv) to accept foreign genes and be used as a vector for delivery of infectious bronchitis virus (ibv) qx genes to chickens. initially the gfp gene was added to ampv at all gene junctions in conjunction with the development of cassetted full length dna ampv copies. after recombinant virus had been recovered by reverse genetics, gfp positions supporting gene expression while maintaining virus viability in vitro, were determin ... | 2013 | 23588091 |
| the pathogenicity of avian metapneumovirus subtype c wild bird isolates in domestic turkeys. | avian metapneumovirus subtype c (ampv/c) causes severe upper respiratory disease in turkeys. previous report revealed the presence of ampv/c in wild birds in the southeast regions of the u.s. | 2013 | 23363433 |
| co-circulation of genetically diverse population of vaccine related and unrelated respiratory mycoplasmas and viruses in uk poultry flocks with health or production problems. | respiratory diseases continue to have a major impact on poultry health, welfare and productivity. however, little information is available on their current status in uk poultry flocks. we investigated the presence of four economically important respiratory pathogens in healthy or problematic flocks; infectious bronchitis virus (ibv), avian metapneumovirus (ampv), mycoplasma gallisepticum (mg) and mycoplasma synoviae (ms). samples from 131 uk poultry flocks were received during the 12 month study ... | 2018 | 30322525 |
| the perspective of immunoprophylaxis and selected immunological issues in the course of the turkey rhinotracheitis. | this review article presents immunological issues in the course of the turkey rhinotracheitis (trt) emphasizing local immunity mechanisms, both humoral and cell-mediated, in the upper respiratory system. studies on the influence of the humoral immunity in the course of infection and vaccinations against trt have revealed many times the absence of correlation between the titre of specific igy anti-ampv (avian metapneumovirus) antibodies in the serum and in the upper respiratory washings and the i ... | 2012 | 22708375 |