Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| the contribution of the immune response to enhanced colibacillosis upon preceding viral respiratory infection in broiler chicken in a dual infection model. | colibacillosis in chickens caused by avian pathogenic escherichia coli (apec) is known to be aggravated by preceding infections with infectious bronchitis virus (ibv), newcastle disease virus (ndv) and avian metapneumovirus (ampv). the mechanism behind these virus-induced predispositions for secondary bacterial infections is poorly understood. here we set out to investigate the immunopathogenesis of enhanced respiratory colibacillosis after preceding infections with these three viruses. broilers ... | 2021 | 34126552 |
| impact of nematode infections on non-specific and vaccine-induced humoral immunity in dual-purpose or layer-type chicken genotypes. | nematode infections may induce immune-modulatory effects and influence host-immune responses to other pathogens. the aim of the study was to investigate whether a mixed nematode-infection influences non-specific and vaccine-induced humoral immunity against newcastle disease virus (ndv), infectious bronchitis virus (ibv), and avian metapneumovirus (ampv) in already vaccinated hens of a dual-purpose (lohmann dual, ld) or a layer genotype (lohmann brown plus; lb). until 17 weeks-of-age, ld (n = 70) ... | 2021 | 34046445 |
| seroprevalences of specific antibodies against avian pathogens in free-ranging ring-necked pheasants (phasianus colchicus) in northwestern germany. | infectious diseases in captive pheasants (phasianus colchicus) are well known, but there is a lack of knowledge about occurrence and distribution of pathogens in free-ranging pheasants in germany. we investigated 604 sera from hunted pheasants and 152 sera from wild caught pheasants between 2011 to 2015, with the aim to determine the prevalence of specific antibodies against different viruses: avian influenza virus (aiv) of subtypes h5, h7, h9, paramyxovirus type 1 (pmv-1), avian encephalomyelit ... | 2021 | 34347834 |
| research note: detection of avian metapneumovirus subgroup c specific antibodies in a mallard flock in italy. | avian metapneumovirus (ampv) is a viral pathogen that causes respiratory signs and drops in egg production most notably in turkeys but also affects chickens, ducks and other species. four subgroups (ampv-a, -b, -c and -d) have been characterized to date, which differ genetically, antigenically and in terms of geographic distribution and host range. despite the rising awareness towards ampv, many aspects of its epidemiology are still poorly understood. in this pilot study, a serological survey wa ... | 2021 | 34089934 |
| efficacy of a novel avian metapneumovirus live vaccine candidate based on vaccination route and age. | this article describes a series of animal studies for the development of an avian metapneumovirus (ampv) live vaccine. although ampv causes continual economic loss in the poultry industry, there are no live ampv vaccines available in korea. furthermore, information is limited with respect to standard field practices for vaccinations at an early age. here, the development of an ampv live vaccine was attempted, and its efficacy was investigated with respect to the vaccination route and age to deve ... | 2020 | 33518307 |
| novel inactivated subtype b avian metapneumovirus vaccine induced humoral and cellular immune responses. | avian metapneumovirus (ampv), a highly contagious agent, is widespread and causes acute upper respiratory tract disease in chickens and turkeys. however, currently, there is no vaccine licensed in china. herein, we describe the development of an inactivated ampv/b vaccine using the ampv/b strain ln16. combined with a novel adjuvant containing immune-stimulating complexes (iscoms), the novel vaccine could induce high virus-specific and vn antibodies. in addition, it activated b and t lymphocytes ... | 2020 | 33327513 |
| development of a recombinant nucleocapsid based indirect elisa for the detection of antibodies to avian metapneumovirus subtypes, a, b, and c. | nucleocapsid (n) protein is the most highly expressed of all avian metapneumovirus (ampv) viral proteins and stimulates a substantial immune response in infected animals. codon optimized recombinant n (rec-n) protein from ampv subtypes a, b, and c were expressed using the baculoviral expression system in trichoplusia ni (tni) insect cells. a mixture of purified rec-n antigens from each subtype was used as a coating antigen and was evaluated in indirect elisa (ielisa) to assess antibody response ... | 2020 | 33227621 |
| molecular epidemiology and genotyping of infectious bronchitis virus and avian metapneumovirus in backyard and commercial chickens in jimma zone, southwestern ethiopia. | poultry production plays a relevant role in the ethiopian economy and represents a source of poverty alleviation for several social classes. infectious diseases can therefore significantly impact the economy and welfare. despite infectious bronchitis virus (ibv) and avian metapneumovirus (ampv) being present, the knowledge of their epidemiology and impact is extremely limited. in the present work, a cross-sectional study based on 500 tracheal swabs collected from 50 intensive and backyard unvacc ... | 2020 | 33255570 |
| health status of free-ranging ring-necked pheasant chicks (phasianus colchicus) in north-western germany. | being a typical ground-breeding bird of the agricultural landscape in germany, the pheasant has experienced a strong and persistent population decline with a hitherto unexplained cause. contributing factors to the ongoing negative trend, such as the effects of pesticides, diseases, predation, increase in traffic and reduced fallow periods, are currently being controversially discussed. in the present study, 62 free-ranging pheasant chicks were caught within a two-year period in three federal sta ... | 2020 | 32544211 |
| avian metapneumovirus subtype b around europe: a phylodynamic reconstruction. | avian metapneumovirus (ampv) has been recognized as a respiratory pathogen of turkey and chickens for a long time. recently, a crescent awareness of ampv, especially subtype b, clinical and economic impact has risen among european researchers and veterinarians. nevertheless, the knowledge of its epidemiology and evolution is still limited. in the present study, the broadest available collection of partial g gene sequences obtained from european ampv-b strains was analyzed using different phylody ... | 2020 | 32641149 |
| characterization of novel, pathogenic field strains of infectious bronchitis virus (ibv) in poultry in trinidad and tobago. | avian coronaviruses, including infectious bronchitis virus (ibv) and turkey coronavirus (tcov), are economically important viruses affecting poultry worldwide. ibv is responsible for causing severe losses to the commercial poultry sector globally. the objectives of this study were to identify the viruses that were causing outbreaks of severe respiratory disease in chickens in trinidad and tobago (t&t) and to characterize the strains. swab samples were collected from birds showing severe respirat ... | 2020 | 32438523 |
| complete genome sequence of an avian metapneumovirus subtype b strain from hungary. | avian metapneumoviruses (ampvs), which have been reported in many countries, cause acute upper respiratory tract disease in chickens and turkeys. using next-generation sequencing, we report here the complete genome sequence of an ampv subtype b strain that was isolated from a turkey in hungary in 1989. | 2020 | 32381608 |
| molecular epidemiology of respiratory viruses in commercial chicken flocks in pakistan from 2014 through to 2016. | viral diseases are a matter of great concern for poultry farmers in pakistan. multiple common viral respiratory diseases (cvrds) cause huge economic losses in the poultry industry. the prevalence of cvrds in many countries, including pakistan, is not clearly understood. | 2019 | 31638995 |
| comparative protective immunity provided by live vaccines of newcastle disease virus or avian metapneumovirus when co-administered alongside classical and variant strains of infectious bronchitis virus in day-old broiler chicks. | this study reports on the simultaneous administration of live ndv or ampv subtype b vaccines alongside two live ibv (massachusetts-h120 and 793b-cr88) vaccines in day-old maternal-antibody positive commercial broiler chicks. in the first experiment, chicks were divided into four groups; one unvaccinated and three groups vaccinated with live ndv vg/ga-avinew, live h120 + cr88, or vg/ga-avinew + h120 + cr88. in the second experiment, live ampv subtype b vaccine was used in place of ndv. clinical s ... | 2019 | 31607602 |
| host specificity of avian metapneumoviruses. | to date, four subgroups of avian metapneumoviruses have been defined (ampv-a, b, c and d) based on genetic and antigenic differences. the extent of infection in the three principal species (turkeys, chickens and ducks) by these subgroups is, however, not well defined. here, a series of controlled and ethically approved experimental infections were performed in specific pathogen-free turkeys, chickens and ducks with each of the four ampv subgroups. for subgroup c, one strain isolated from turkeys ... | 2019 | 30777452 |
| genomic sequence and pathogenicity of the first avian metapneumovirus subtype b isolated from chicken in china. | avian metapneumovirus (ampv), which has been reported in many countries, causes an acute upper respiratory tract disease in chickens and turkeys. although ampv was first detected in china in 1999, there has been no further effort to isolate and characterize the ampv subtype b (ampv/b) from field outbreaks. in the present study, we used vero cells to culture a viral strain, ln16, isolated from chickens with swollen head syndrome. the results of rt-pcr, indirect immunofluorescent antibody, and g g ... | 2019 | 30593377 |
| discovery and characterization of novel rna viruses in aquatic north american wild birds. | wild birds are recognized viral reservoirs but our understanding about avian viral diversity is limited. we describe here three novel rna viruses that we identified in oropharyngeal/cloacal swabs collected from wild birds. the complete genome of a novel gull metapneumovirus (gumpv b29) was determined. phylogenetic analyses indicated that this virus could represent a novel avian metapneumovirus (ampv) sub-group, intermediate between ampv-c and the subgroup of the other ampvs. this virus was detec ... | 2019 | 31438486 |
| genome sequence of a divergent avian metapneumovirus from a monk parakeet (myiopsitta monachus). | here, we report the coding-complete genome sequence of an avian metapneumovirus from a monk parakeet (myiopsitta monachus), identified by metagenomic next-generation sequencing during an investigation into a disease outbreak in a captive parrot breeding facility. based on divergence from known strains, this sequence represents a new subgroup of avian metapneumovirus. | 2019 | 31000555 |
| avian metapneumovirus circulation in italian broiler farms. | with increasing frequency, avian metapneumovirus (ampv) is reported to induce respiratory signs in chickens. an adequate knowledge of current ampv prevalence among italian broilers is lacking, with little information available on its economical and health impact on the poultry industry. in order to collect preliminary data on the epidemiological context of ampv in broiler flocks, a survey was performed in areas of northern italy with high poultry density from 2014 to 2016. upper respiratory trac ... | 2018 | 29253264 |
| 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 |
| serosurvey of avian metapneumovirus, orithobacterium rhinotracheale, and chlamydia psittaci and their potential association with avian airsacculitis. | seasonal outbreaks of airsacculitis in china's poultry cause great economic losses annually. this study tried to unveil the potential role of avian metapneumovirus (ampv), ornithobacterium rhinotracheale (ort) and chlamydia psittaci (cps) in avian airsacculitis. a serological investigation of 673 breeder chickens and a case-controlled study of 430 birds were undertaken. results showed that infection with ampv, ort, and cps was highly associated with the disease. the correlation between ampv and ... | 2018 | 29866224 |
| prevalence of avian metapneumovirus subtype b in live bird market in gilan province, iran. | avian metapneumovirus (ampv), also known as avian pneumovirus or turkey rhinotracheitis virus, is the causative agent of turkey rhinotracheitis and swollen head syndrome in chickens. four ampv subgroups (a-d) have been reported previously based on their genetic and antigenic differences. evidence suggests that the live bird markets (lbms) play an important role in the epidemiology of the avian viral diseases. a total number of 450 oropharyngeal samples from eight different species of birds (migr ... | 2018 | 29719670 |
| avian metapneumovirus subtype c in wild waterfowl in ontario, canada. | avian metapneumovirus (ampv) is an emerging poultry pathogen that has a significant economic impact on poultry production worldwide. the geographic range of the virus continues to expand, and wild birds have been implicated as reservoirs of ampv that have the potential to spread the virus over long distances. our objective was to determine the apparent prevalence of ampv subtype c in wild waterfowl in ontario, canada. wild waterfowl were captured in august and september, 2016 as part of routine ... | 2018 | 29457370 |
| first identification and molecular characterization of avian metapneumovirus subtype b from chickens in greece. | avian metapneumovirus (ampv) is considered a major pathogen for turkeys but its impact on chicken production is still partially neglected, even though it is fully acknowledged as a primary pathogen in chickens as well. the lack of structured diagnostic surveys does not allow a pervasive understanding of ampv epidemiology. being that ampv is almost an everyday challenge for farmers and veterinarians, a more accurate report of its presence should be detailed, posing the basis for a deep and global ... | 2017 | 28957007 |
| 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 |
| detection and subtyping avian metapneumovirus from turkeys in iran. | avian metapneumovirus (ampv) causes diseases like rhinotracheitis in turkeys, swollen head syndrome in chickens and avian rhinotracheitis in other birds. causing respiratory problems, ampv adversely affects production and inflicts immense economic losses and mortalities, especially in turkey flocks. in recent years, several serological and molecular studies have been conducted on this virus, especially in poultry in asia and iran. the purpose of the present study was detecting and subtyping ampv ... | 2017 | 28785384 |
| complete genome sequence of an avian metapneumovirus subtype a strain isolated from chicken (gallus gallus) in brazil. | we report here the complete genome sequence of an avian metapneumovirus (ampv) isolated from a tracheal tissue sample of a commercial layer flock. the complete genome sequence of ampv-a/chicken/brazil-sp/669/2003 was obtained using miseq (illumina, inc.) sequencing. phylogenetic analysis of the complete genome classified the isolate as avian metapneumovirus subtype a. | 2017 | 28729279 |
| first report of avian metapneumovirus subtype b field strain in a romanian broiler flock during an outbreak of respiratory disease. | avian metapneumovirus (ampv) represents one of the most prevalent diseases of turkey, especially in combination with other pathogens, and its frequency is also increasing among chickens. despite this evidence, epidemiologic data are poor and scattered, severely preventing control of the disease even in highly developed areas such as europe. in the present study, the detection and characterization of an ampv subtype b strain circulating in a vaccinated but symptomatic romanian broiler flock is re ... | 2017 | 28665722 |
| engineered newcastle disease virus expressing the f and g proteins of ampv-c confers protection against challenges in turkeys. | avian metapneumovirus (ampv) infects the respiratory and reproductive tracts of domestic poultry, resulting in substantial economic losses for producers. live attenuated vaccines appear to be the most effective in countries where the disease is prevalent. however, reversion to virulence has been demonstrated in several studies. therefore, the development of a stable and safe next generation vaccine against the ampv disease is needed. in the present study, we generated a recombinant newcastle dis ... | 2017 | 28642611 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| isolation and characterization of a subtype c avian metapneumovirus circulating in muscovy ducks in china. | subtype c avian metapneumovirus (ampv-c), is an important pathogen that can cause egg-drop and acute respiratory diseases in poultry. to date, ampv-c infection has not been documented in muscovy ducks in china. here, we isolated and characterized an ampv-c, designated s-01, which has caused severe respiratory disease and noticeable egg drop in muscovy duck flocks in south china since 2010. electron microscopy showed that the isolate was an enveloped virus exhibiting multiple morphologies with a ... | 2014 | 25060776 |
| a sensitive, reproducible, and economic real-time reverse transcription pcr detecting avian metapneumovirus subtypes a and b. | use of real-time pcr is increasing in the diagnosis of infectious disease due to its sensitivity, specificity, and speed of detection. these characteristics make it particularly suited for the diagnosis of viral infections, like avian metapneumovirus (ampv), for which effective control benefits from continuously updated knowledge of the epidemiological situation. other real-time reverse transcription (rt)-pcrs have been published based on highly specific fluorescent dye-labeled probes, but they ... | 2014 | 25055624 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| development and optimization of a direct plaque assay for human and avian metapneumoviruses. | the genus metapneumovirus within the subfamily pneumovirinae and family paramyxoviridae includes only two viruses, human metapneumovirus (hmpv) and avian metapneumovirus (ampv), which cause respiratory disease in humans and birds, respectively. these two viruses grow poorly in cell culture and other quantitation methods, such as indirect immuno-staining and immuno-fluorescent assays, are expensive, time consuming, and do not allow for plaque purification of the virus. in order to enhance researc ... | 2012 | 22684013 |
| 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 |
| the characterization of monoclonal antibodies to human metapneumovirus and the detection of multiple forms of the virus nucleoprotein and phosphoprotein. | little is known of the proteome of human metapneumovirus (hmpv). in this study a panel of monoclonal antibodies to the virus have been characterized and used to identify viral proteins present in infected cell lysates. of thirteen anti-hmpv monoclonal antibodies four reacted with recombinant fusion glycoprotein and one with recombinant g glycoprotein by immunofuorescence but not in western blots suggesting that they recognize conformation dependent epitopes. the specificity of the remaining anti ... | 2012 | 22585723 |
| a family-wide rt-pcr assay for detection of paramyxoviruses and application to a large-scale surveillance study. | family-wide molecular diagnostic assays are valuable tools for initial identification of viruses during outbreaks and to limit costs of surveillance studies. recent discoveries of paramyxoviruses have called for such assay that is able to detect all known and unknown paramyxoviruses in one round of pcr amplification. we have developed a rt-pcr assay consisting of a single degenerate primer set, able to detect all members of the paramyxoviridae family including all virus genera within the subfami ... | 2012 | 22496880 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |