| turkey rhinotracheitis virus isolated from broiler chicken with swollen head syndrome in japan. | turkey rhinotracheitis (trt) virus was first isolated from a commercial broiler chicken with swollen head syndrome (shs) in japan. at the same time, newcastle disease virus (ndv), infectious bronchitis virus (ibv), avian reovirus (arv), escherichia coli (e.coli), morganella morganii, and proteus mirabilis were also isolated from the same broiler chicken. the presence of antibodies to trt virus was confirmed in the sera of 34-day-old chickens of the flock with shs, however the antibodies to trt v ... | 1995 | 8593307 |
| detection of three avian respiratory viruses by single-tube multiplex reverse transcription-polymerase chain reaction assay. | acute respiratory tract infections are leading causes of morbidity in poultry farms throughout the world. avian pneumovirus (apv), avian influenza virus (aiv), and newcastle disease virus (ndv) have been recognized as the most important pathogens of both chicken and turkeys. single-virus reverse transcription-polymerase chain reaction (srt-pcr) assays are used extensively to detect these viruses in clinical samples. this study reports the development and evaluation of a single-tube multiplex rt- ... | 2004 | 15152843 |
| avian metapneumovirus excretion in vaccinated and non-vaccinated specified pathogen free laying chickens. | vaccinated and non-vaccinated specified pathogen-free white leghorn laying chickens were challenged at peak of lay by the intravenous or oculonasal route with a virulent avian metapneumovirus (ampv) subtype b chicken strain. severe clinical signs and a drop in egg production were induced in the non-vaccinated intravenously challenged birds whereas the vaccinates were not affected. live virus excretion was demonstrated in the faeces and respiratory tract of non-vaccinated hens for up to 7 days po ... | 2004 | 14681066 |
| presence of avian pneumovirus subtypes a and b in japan. | four avian pneumovirus (apv) isolates from chickens clinically diagnosed with swollen head syndrome were genetically characterized as to the subtypes of the virus in japan. the results of reverse transcriptase-polymerase chain reactions based on subtype-specific primers and direct sequence analysis of g genes indicated subtypes a and b but not c or d of apv were present in japan. several routes or sources are conceivable for apv to invade into japan. | 2003 | 12887210 |
| lack of antigenic relationships between avian pneumovirus and four avian paramyxoviruses. | avian paramyxoviruses (pmvs) and avian pneumovirus (apv) belong to the family paramyxoviridae. antigenic relationships between pmvs were shown previously, hence, this study was designed to investigate possible antigenic relationships between apv and four avian pmvs (pmv-1, pmv-2, pmv-3, and pmv-7). enzyme-linked immunosorbent assay (elisa), hemagglutination inhibition (hi) test, and virus neutralization (vn) test in chicken embryos and in vero cells were used. the hi test was performed with the ... | 2003 | 12713174 |
| experimental and field evaluation of a live vaccine against avian pneumovirus. | the attenuation of an avian pneumovirus (apv) isolate (apv/mn/turkey/1-a/97) by 63 serial passages in cell culture (seven in chicken embryo fibroblasts and 56 in vero cells) and its evaluation as a live attenuated vaccine in turkey poults is described. the birds were vaccinated with two different doses of attenuated virus (10(4.5) median tissue culture infectious dose (tcid(50))/ml and 10(2.5) tcid(50) /ml) at 2 weeks of age, and were challenged 2 weeks later with virulent apv. no clinical signs ... | 2002 | 12396339 |
| avian pneumoviruses and emergence of a new type in the united states of america. | avian pneumovirus (apv) primarily causes an upper respiratory disease recognized as turkey rhinotracheitis (trt) or swollen head syndrome (shs) in chickens. the virus was first isolated in south africa during the early 1970s and has subsequently been reported in europe, asia and south america. in february 1997, a serologically distinct apv isolate was officially reported in the usa following an outbreak of trt during the previous year. this was the first report of these virus types in the usa; t ... | 2000 | 11706845 |
| a newly discovered human pneumovirus isolated from young children with respiratory tract disease. | from 28 young children in the netherlands, we isolated a paramyxovirus that was identified as a tentative new member of the metapneumovirus genus based on virological data, sequence homology and gene constellation. previously, avian pneumovirus was the sole member of this recently assigned genus, hence the provisional name for the newly discovered virus: human metapneumovirus. the clinical symptoms of the children from whom the virus was isolated were similar to those caused by human respiratory ... | 2001 | 11385510 |
| susceptibility of broiler chicks to infection by avian pneumovirus of turkey origin. | in this paper we present the results of studies on the infectivity of an isolate of avian pneumovirus (apv) from turkeys to broiler chickens. two-week-old broiler chicks free of antibodies to apv were exposed either by oculonasal or oral route with a cell cultured apv of turkey origin. chickens from both apv-inoculated groups exhibited clinical signs that included coughing, sneezing, nasal discharge, and watery eyes during 2-8 days postinoculation. tissue samples from birds in the apv-inoculated ... | 2000 | 11195633 |
| avian pneumovirus infections of turkeys and chickens. | avian pneumoviruses (apvs) cause major disease and welfare problems in many areas of the world. in turkeys the respiratory disease and the effect on egg laying performance are clearly defined. however, in chickens, the role of apv as a primary pathogen is less clear, although it is widely believed to be one of the factors involved in swollen head syndrome. the mechanisms of virus transmission over large distances are not understood, but wild birds have been implicated. apv has recently been repo ... | 2000 | 10985803 |
| avian rhinotracheitis. | turkey rhinotracheitis, now commonly termed avian pneumovirus (apv) infection, is associated with serious welfare and economic problems in susceptible populations of turkeys and probably also of chickens. the infection principally affects the upper respiratory tract, although egg-laying performance may also be affected in breeding turkeys. secondary infections exacerbate the effects of the primary virus infection. the virus persists for only a short time both in the host and in the environment a ... | 2000 | 10935282 |
| a modified enzyme-linked immunosorbent assay for the detection of avian pneumovirus antibodies. | avian pneumovirus (apv) infection of turkeys in minnesota was first confirmed in march 1997. serum samples (n = 5,194) from 539 submissions to minnesota veterinary diagnostic laboratory were tested by a modified enzyme-linked immunosorbent assay (elisa). of these, 2,528 (48.7%) samples from 269 submissions were positive and 2,666 (51.3%) samples from 270 submissions were negative for apv antibodies. most positive samples were from kandiyohi, stearns, morrison, and meeker counties in minnesota. i ... | 2000 | 10907873 |
| avian pneumovirus infection in minnesota turkeys: experimental reproduction of the disease. | avian pneumovirus (apv) is an emerging viral respiratory disease agent of turkeys in minnesota. clinical signs of apv infection include open mouth breathing, ocular and nasal discharge, and swelling of infraorbital sinuses. the virus spreads rapidly among flocks of susceptible turkeys and is associated with increased mortality rates. a flock of 11-wk-old turkeys experienced a respiratory problem characterized by coughing, sneezing, swollen sinuses, and nasal discharge. the reverse transcriptase- ... | 2000 | 10737667 |
| experimental and serologic observations on avian pneumovirus (apv/turkey/colorado/97) infection in turkeys. | an avian pneumovirus (apv) was isolated from commercial turkeys in colorado (apv/colorado) showing clinical signs of a respiratory disease. the results of virus neutralization and indirect fluorescent antibody tests showed that the apv/colorado was partially related to apv subgroup a but was unrelated to apv subgroup b. turkeys experimentally inoculated with the apv/colorado were observed for signs, lesions, seroconversion, and virus shedding. thirty-six 7-wk-old turkeys were distributed into th ... | 2000 | 10737640 |
| protective efficacy of high-passage avian pneumovirus (apv/mn/turkey/1-a/97) in turkeys. | a u.s. isolate of avian pneumovirus (apv), apv/mn/turkey/1-a/97, was attenuated by serial cell culture passages in chicken embryo fibroblasts (seven passages) and vero cells (34 passages). this virus was designated as apv passage 41 (p41) and was evaluated for use as a live vaccine in commercial turkey flocks. the vaccine was inoculated by nasal and ocular routes in 2-to-4-wk-old turkeys in 10 turkey flocks, each with 20,000-50,000 birds. only 2 birds per 1000 birds were inoculated in each flock ... | 2001 | 11569731 |
| molecular characterization of brazilian avian pneumovirus isolates: comparison between immunochemiluminescent southern blot and nested pcr. | avian pneumovirus (apv) causes acute respiratory tract infection both in turkeys (turkey rhinotracheitis) and chickens (swollen head syndrome (shs)) with sudden onset and rapid spread through the flocks. in this study, an immunochemiluminescent southern blot rt-pcr assay was employed to detect a f gene transcript of the apv in two european turkey isolates and two brazilian chicken isolates. limiting dilution pcr was carried out to compare the sensitivity of immunochemiluminescent southern blot a ... | 1999 | 10381093 |
| serologic evidence of pneumovirus in chile. | chicken and turkey serum samples were obtained and tested in an enzyme-linked immunosorbent assay to establish the presence or absence of antibodies to avian pneumovirus in the commercial poultry population of chile. a total of 600 serum samples representing 15 different poultry farms of the central region of chile were considered. these samples were obtained from 52 different flocks and included 220 turkey and 380 chicken sera. the results showed three flocks of market turkeys belonging to the ... | 1998 | 9876855 |
| significance of interactions between escherichia coli and respiratory pathogens in layer hen flocks suffering from colibacillosis-associated mortality. | this study aimed to examine the significance of interactions between escherichia coli and various respiratory pathogens during outbreaks of colibacillosis-associated mortality in layer hen flocks under field conditions. for this purpose, a case-control study involving 20 control flocks with baseline mortality and 20 flocks with increased mortality due to e. coli septicaemia and polyserositis, was conducted. in each colibacillosis flock, blood samples were taken from 20 hens at the onset of clini ... | 2004 | 15223556 |
| towards the routine application of nucleic acid technology for avian disease diagnosis. | the use of nucleic acid technology (polymerase chain reaction, probing, restriction fragment analysis and nucleotide sequencing) in the study of avian diseases has largely been confined to fundamental analysis and retrospective studies. more recently these approaches have been applied to diagnosis and what one might call real-time epidemiological studies on chickens and turkeys. at the heart of these approaches is the identification and characterisation of pathogens based on their genetic materi ... | 1997 | 9276989 |
| absence of antibodies to avian pneumovirus in canadian poultry. | | 1993 | 8456552 |
| isolation of an avian pneumovirus-like agent from broiler breeder chickens in south africa. | | 1994 | 8085314 |
| isolation of an avian pneumovirus from broiler chickens. | | 1994 | 8017018 |
| development and evaluation of an enzyme-linked immunosorbent assay for the detection of antibodies to avian pneumovirus. | the development and evaluation of an enzyme-linked immunosorbent assay (elisa) for the detection of antibodies to avian pneumovirus (apv) in chicken or turkey sera is described. the assay was capable of detecting serological responses as early as 11 days after chickens had been experimentally exposed to apv. the assay was evaluated by testing 4989 chicken or turkey sera from canada (a known apv-negative country) and by testing 1190 chicken or turkey sera assumed positive from evidence of other l ... | 1994 | 7702500 |
| persistence of mycoplasma gallisepticum in chickens after treatment with enrofloxacin without development of resistance. | the ability of the avian pathogen mycoplasma gallisepticum to persist despite fluoroquinolone treatment was investigated in chickens. groups of specific pathogen free chickens were experimentally infected with m. gallisepticum and treated with enrofloxacin at increasing concentrations up to the therapeutic dose. when m. gallisepticum could no longer be re-isolated from chickens, birds were stressed by inoculation of infectious bronchitis virus or avian pneumovirus. although m. gallisepticum coul ... | 2005 | 15737482 |
| hatchability, serology and virus excretion following in ovo vaccination of chickens with an avian metapneumovirus vaccine. | the present investigation describes for the first time the effect of an avian metapneumovirus vaccine administered in ovo to 18-day-old chicken embryos. the application of the vaccine had no adverse effect on the hatchability or the health of the chicks post hatch. the antibody titres achieved were higher than those determined for birds vaccinated at 1 day old. not only were the mean titres in the in ovo vaccinated groups higher, but many more birds developed a measurable antibody response than ... | 2004 | 15763725 |
| transcriptional analysis of avian embryonic tissues following infection with avian infectious bronchitis virus. | avian infectious bronchitis virus (ibv) infection is one of the major viral respiratory diseases of chickens. better understanding of the molecular basis of viral pathogenesis should contribute significantly towards the development of improved prophylactic, therapeutic and diagnostic reagents to control infections. in the present investigation, transcriptional profiles were analyzed by using rna recovered from the lung tissue of ibv infected 18-day-old chicken embryos at 6, 24, 48 and 72 h post ... | 2005 | 15845254 |
| interaction between live avian pneumovirus and newcastle disease virus vaccines in specific pathogen free chickens. | one-day-old specific pathogen free white leghorn chicks were vaccinated with live avian pneumovirus (apv) vaccine, live newcastle disease virus (ndv) vaccine or both. at intervals up to 28 days after vaccination, distribution of the virus in the tissues was studied, together with humoral and mucosal antibody responses in lachrymal fluid and tracheal washes. apv vaccine was detected for almost twice as long in the dual vaccinates as in the single vaccinates. higher numbers of isolations of nd vir ... | 2005 | 16147565 |
| growth of vaccine strains of avian pneumovirus in different cell lines. | the isolation of avian pneumovirus (apv) (avian metapneumovirus) is usually performed in embryonated chicken eggs or chicken embryo fibroblast cell cultures followed by adaptation in continuous cell lines such as vero cells. this study was conducted to find a suitable cell line that could be used to propagate vaccine strains of apv to high titre. for this purpose, we compared the growth of two vero cell-adapted vaccine strains of apv (p63 and ca-apv) in seven different cell types with their grow ... | 2005 | 16191692 |
| subtyping of new brazilian avian metapneumovirus isolates from chickens and turkeys by reverse transcriptase-nested-polymerase chain reaction. | the aim of this study was to improve a reverse transcriptase (rt)-nested-polymerase chain reaction (pcr) able to differentiate avian pneumovirus (apv) subtypes a and b, and to characterize new brazilian isolates. representative apv strains and clinical field samples from chickens and turkey flocks were amplified in the chicken embryo-related cell line. viral rna was extracted from harvested cells, and submitted to cdna synthesis. the primers utilized for rt-pcr were compatible with the g gene of ... | 2005 | 16191694 |
| characterization of israeli avian metapneumovirus strains in turkeys and chickens. | although the disease associated with the avian metapneumovirus (ampv) has been described in israel for more than 20 years and one israeli isolate was characterized as subtype a, this is the first study investigating the strains circulating in israel (period 2002 to 2004). viral rna was detected by reverse transcription-polymerase chain reaction in 44% of the examined flocks, and one-half of the virus isolation attempts were successful. characterization showed that 34 non-vaccinated turkey flocks ... | 2005 | 16191705 |
| comparison of avian cell substrates for propagating subtype c avian metapneumovirus. | avian metapneumovirus (ampv) is a respiratory viral pathogen that causes turkey rhinotracheitis (trt) or swollen head syndrome (shs) in chickens. ampv was first isolated in south africa during the early 1970s and has subsequently spread worldwide during the 1980s to include europe, asia, and south america. in 1996, a genetically distinct ampv subgroup c was isolated in the us following an outbreak of trt. vero cells are currently the best available substrate for ampv propagation but are of non-a ... | 2006 | 16194579 |
| microwave or autoclave treatments destroy the infectivity of infectious bronchitis virus and avian pneumovirus but allow detection by reverse transcriptase-polymerase chain reaction. | a method is described for enabling safe transit of denatured virus samples for polymerase chain reaction (pcr) identification without the risk of unwanted viable viruses. cotton swabs dipped in avian infectious bronchitis virus (ibv) or avian pneumovirus (apv) were allowed to dry. newcastle disease virus and avian influenza viruses were used as controls. autoclaving and microwave treatment for as little as 20 sec destroyed the infectivity of all four viruses. however, both ibv and apv could be d ... | 2004 | 15223557 |
| seroprevalence of avian influenza virus, infectious bronchitis virus, reovirus, avian pneumovirus, infectious laryngotracheitis virus, and avian leukosis virus in nigerian poultry. | eight poultry farms in nigeria, including chickens from nine breeder, 14 broiler, 28 pullet, 11 layer, and three cockerel flocks, were tested for antibody seroprevalence to the following poultry viruses of potential economic importance: infectious bronchitis virus (ibv), avian reovirus, avian pneumovirus (apv), infectious laryngotracheitis virus (iltv), avian influenza virus (aiv), and avian leukosis virus (alv). serum samples were collected between 1999 and 2004 and were tested for antibodies u ... | 2006 | 16863071 |
| isolation of avian pneumovirus from an outbreak of respiratory illness in minnesota turkeys. | antibodies to avian pneumovirus (apv) were first detected in minnesota turkeys in 1997. virus isolation was attempted on 32 samples (28 tracheal swabs, 4 pools of trachea and turbinates) that were positive for apv by reverse transcriptase polymerase chain reaction (rt-pcr). the cell cultures used were chicken embryo fibroblast (cef), vero cells, and qt-35 cells. five virus isolates were obtained from these samples, and the identity of the isolates was confirmed by rt-pcr. four isolates were obta ... | 2000 | 10730950 |
| viral diseases of the respiratory system. | infectious bronchitis, newcastle disease, infectious laryngotracheitis, avian influenza, and pneumovirus are the viruses that more frequently affect the respiratory tract of chickens. because of the tendency to change its antigenic properties, infectious bronchitis is currently the viral disease present in most poultry producing areas of the world. new serotypes and variant strains are reported in several countries. current commercially available vaccines do not always provide protection against ... | 1998 | 9706079 |
| interaction between a live avian pneumovirus vaccine and two different newcastle disease virus vaccines in broiler chickens with maternal antibodies to newcastle disease virus. | broiler chicks with maternal antibodies to newcastle disease virus (ndv) but none to avian metapneumovirus (apv) were divided into six groups. one group was kept as an unvaccinated control group. three of the other groups were vaccinated at 1 day old with live apv vaccine or one of two live ndv vaccines (vg/ga or hb1). the remaining two groups received the apv vaccine in combination with either of the two ndv vaccines at 1 day old. at intervals after vaccination for up to 42 days, distribution o ... | 2006 | 17121730 |
| drop of egg production in chickens by experimental infection with an avian metapneumovirus strain ple8t1 derived from swollen head syndrome and the application to evaluate vaccine. | decreases in egg production and increased incidence of abnormal eggs due to malformation of egg shells were observed in specific pathogen free (spf) 173-day-old laying hens inoculated intravenously with an avian metapneumovirus (ampv) strain ple8t1. this strain was derived from an isolate from broiler birds exhibiting swollen head syndrome (shs). some spf birds inoculated with the virus showed, slight diarrhea without any respiratory symptoms. thus, the ple8t1 strain was used as a challenge viru ... | 2006 | 16953076 |
| inhibition of avian metapneumovirus (ampv) replication by rna interference targeting nucleoprotein gene (n) in cultured cells. | avian metapneumovirus (ampv) is the primary causative agent of severe rhinotracheitis in turkeys. it is associated with swollen head syndrome in chickens and is the source of significant economic losses to animal food production. in this study, we designed specific short interfering rna (sirna) targeting the ampv nucleoprotein (n) and fusion (f) genes. three days post-virus infection, virus titration, real time rt-pcr, and rt-pcr assays were performed to verify the effect of sirna in ampv replic ... | 2007 | 17275932 |
| genetic characterization of avian metapneumovirus subtype c isolated from pheasants in a live bird market. | complete nucleotide sequences of two avian metapneumoviruses (ampv), designated pl-1 and pl-2, were isolated from pheasants, revealing novel sequences of the first ampv to be fully sequenced in korea. the complete genome of both pl-1 and pl-2 was composed of 13,170 nucleotides. phylogenetic analysis revealed that pl-1 belonged to ampv subtype c, sharing higher homology in deduced amino acid sequence identities with hmpv, rather than with ampv subtypes a and b. replication of pl-1 in experimental ... | 2007 | 17485129 |
| recovery of avian metapneumovirus subgroup c from cdna: cross-recognition of avian and human metapneumovirus support proteins. | avian metapneumovirus (ampv) causes an acute respiratory disease in turkeys and is associated with "swollen head syndrome" in chickens, contributing to significant economic losses for the u.s. poultry industry. with a long-term goal of developing a better vaccine for controlling ampv in the united states, we established a reverse genetics system to produce infectious ampv of subgroup c entirely from cdna. a cdna clone encoding the entire 14,150-nucleotide genome of ampv subgroup c strain colorad ... | 2006 | 16731918 |
| the efficacy of an avian metapneumovirus vaccine applied simultaneously with infectious bronchitis and newcastle disease virus vaccines to specific-pathogen-free chickens. | avian metapneumovirus (ampv), newcastle disease virus (ndv), and infectious bronchitis virus (ibv) are important respiratory pathogens of chickens. to achieve early posthatch protection against all three diseases it would be helpful to deliver live ampv, ibv, and ndv vaccines simultaneously at 1 day of age. however, previous work has indicated that the efficacy of ampv vaccines may be affected when codelivered with ibv or ndv vaccines. the efficacy of an ampv vaccine when codelivered to chickens ... | 2007 | 17626490 |
| serological and molecular detection of avian pneumovirus in chickens with respiratory disease in jordan. | avian pneumovirus (apv) causes upper respiratory tract infection in chickens and turkeys. there is a serious respiratory disease in chickens, resulting in catastrophic economic losses to chicken farmers in jordan. the objective of this study was to investigate the role of apv as a factor in the respiratory disease of chickens in jordan by serological and molecular methods. thirty-eight chicken flocks were examined by competitive elisa (23 broilers, 8 layers, and 7 broiler breeders), and 150 chic ... | 2007 | 17626813 |
| detection by reverse transcriptase-polymerase chain reaction and molecular characterization of subtype b avian metapneumovirus isolated in brazil. | subtype b avian metapneumovirus (ampv) was isolated and detected by reverse transcriptase-polymerase chain reaction (rt-pcr) in brazilian commercial laying chicken flocks with no history of vaccination against ampv and presenting respiratory signs and decreased egg production. rt-pcr results from samples from three affected flocks revealed that the three isolates were subtype b. partial sequence analysis of the g glycoprotein gene confirmed that the samples belonged to subtype b and were not of ... | 2007 | 17899462 |
| permissibility of different cell types for the growth of avian metapneumovirus. | vero cells are commonly used for the growth of avian metapneumovirus subtype c (ampv-c). this study was conducted to evaluate 17 different cell types for the growth of a minnesota strain of ampv-c. the virus was inoculated into these cell types and virus growth was monitored by the development of cytopathic effects (cpe) and immunofluorescence. virus growth was obtained in 6 of 17 cell types tested with the highest virus titers observed in bgm and df-1 cells. the flow cytometric analysis of cell ... | 2006 | 16930732 |
| onset of immunity following in ovo delivery of avian metapneumovirus vaccines. | avian metapneumovirus (ampv) is an important cause of disease in chickens and turkeys. as infection can occur early in life and spread of the virus throughout a flock is rapid, an early onset of immunity post-vaccination would be advantageous. we have studied the serological immune response and the onset of protective immunity of an ampv vaccine delivered to chickens via the in ovo route compared to oculonasal delivery at day old. a 1000-fold lower dose delivered in ovo to chicken specific patho ... | 2007 | 17462834 |
| orchitis in roosters with reduced fertility associated with avian infectious bronchitis virus and avian metapneumovirus infections. | the pathogenesis of infection involving both infectious bronchitis virus (ibv) and avian metapneumovirus (ampv) causes reproductive damage in hens after viral replication in the epithelium of the oviduct, resulting in loss of cilia and degeneration and necrosis of the epithelial and glandular cells. although ibv has been indicated as a possible cause of the formation of calcium stones in the epididymus of roosters, a definitive association has not been confirmed. this report describes the detect ... | 2007 | 18251400 |
| molecular survey of avian respiratory pathogens in commercial broiler chicken flocks with respiratory diseases in jordan. | acute respiratory tract infections are of paramount importance in the poultry industry. avian influenza virus (aiv), infectious bronchitis virus (ibv), newcastle disease virus (ndv), avian pneumovirus (apv), and mycoplasma gallisepticum (mg) have been recognized as the most important pathogens in poultry. in this study, trachea swabs from 115 commercial broiler chicken flocks that suffered from respiratory disease were tested for aiv subtype h9n2, ibv, ndv, and apv by using reverse transcription ... | 2008 | 18281569 |
| antigenic differentiation of avian pneumovirus isolates using polyclonal antisera and mouse monoclonal antibodies. | avian pneumovirus (avp) isolates f83, cc220 and 1260 from great britain and 1556, 657/4, 2119 and 872/s from france, hungary, italy and spain, respectively, were compared in elisa and virus neutralization (vn) tests for reactions with chicken polyclonal sera against each of the viruses and monoclonal antibodies (mabs) against two british isolates. elisa test results using the polyclonal antisera indicated that all seven viruses were antigenically related, but some variation between strains could ... | 1993 | 18671033 |
| protection in specific pathogen free chickens with live avian metapneumovirus and newcastle disease virus vaccines applied singly or in combination. | this paper describes two experiments. in each experiment, 1-day-old specific pathogen free chicks were divided into three groups. in experiment 1 - [avian metapneumo virus (ampv) challenge] - one group served as unvaccinated controls; the second group was vaccinated with live ampv (subtype b) vaccine only, and the third group received the ampv vaccine in combination with live newcastle disease virus (ndv) vaccine (vg/ga strain). oropharyngeal swabs, tissues and blood samples were collected befor ... | 2007 | 17620178 |
| vaccination of chicks with live attenuated subtype b avian metapneumovirus vaccines: protection against challenge and immune responses can be unrelated to vaccine dose. | live attenuated subtype b avian metapneumovirus (ampv) vaccines from two different commercial sources (vac 1 and vac 2) were used to vaccinate two groups of day-old specific-pathogen-free chicks. the chicks were challenged at 21 or 49 days of age with a virulent subtype b virus. parameters compared were persistence of vaccine viruses, their ability to induce humoral antibody responses, and the protection they offered against virulent challenge. vac 1 virus was detectable for at least 14 days aft ... | 2007 | 17992934 |
| 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 |
| avian pneumovirus infection in broiler chicks inoculated with escherichia coli at different time intervals. | the effects of dual infection of 1-day-old broiler chicks with a chicken isolate of avian pneumovirus (apv) and a pool of pathogenic escherichia coli strains were studied by supraconjunctival application of the bacteria simultaneously with the virus, or at 4, 7 or 11 days afterwards. when the agents were given together, the clinical disease was significantly more severe than that caused by the virus alone, but when the bacterium was given later the signs were less severe. none of the infections ... | 2001 | 19184908 |
| 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 |
| 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 |
| 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 |
| 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 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 |
| reproducibility of swollen sinuses in broilers by experimental infection with avian metapneumovirus subtypes a and b of turkey origin and their comparative pathogenesis. | swollen head syndrome (shs) associated with avian metapneumovirus (ampv) subtype a or subtype b in broilers and broiler breeders has been reported worldwide. data about pathogenesis of ampv subtypes a and b in broilers are scarce. it has been difficult to reproduce swollen sinuses in chickens with ampv under experimental conditions. in the field, shs in broilers is suspected to be induced by combined infections with different respiratory pathogens. the objectives of the present study were to com ... | 2008 | 18202952 |
| 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 |
| 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 |
| 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 |
| the use of virus isolation, histopathology and immunoperoxidase techniques to study the dissemination of a chicken isolate of avian pneumovirus in chickens. | a subgroup b isolate of turkey rhinotracheitis virus (trtv) or avian pneumovirus (apv), obtained from a flock of commercial breeding chickens experiencing poor egg production, mortality and swollen head syndrome, was shown to cause substantial respiratory signs in both young spf chickens and chicks with high levels of maternally derived trt antibodies. this isolate replicated to high titre in the respiratory tract of experimentally inoculated spf chickens for approximately 5 days after inoculati ... | 1998 | 18484053 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| molecular characterization of brazilian avian pneumovirus isolates using reverse transcription-polymerase chain reaction, restriction endonuclease analysis and sequencing of a g gene fragment. | a reverse transcriptase-polymerase chain reaction (rt-pcr) assay was employed to amplify a g gene transcript of the avian pneumovirus (apv) in two european turkey isolates and two brazilian chicken isolates. the pcr products were digested using restriction endonucleases and the restriction patterns were compared with earlier reported isolate patterns. the same pcr products were cloned into puc18 and sequenced. restriction patterns and sequence analyses of the approximately 600 bp products from b ... | 1999 | 26911601 |
| in vitro and in vivo studies on the pathogenicity of avian pneumovirus for the chicken oviduct. | the pathogenicity of avian pneumovirus (apv) for the chicken oviduct was studied in vitro using oviduct organ cultures (ooc), in vivo in young chicks with artificially enlarged oviducts and in adult female chickens. the oocs were prepared from artificially enlarged oviducts of young chicks induced by oestrogen treatment and from normal oviducts of adult hens. the pathogenicity of apv for oocs in vitro and oviducts in vivo were assessed by virus titrations and immunofluorescence. while in vitro e ... | 1999 | 26915381 |
| 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 |
| 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 |
| molecular characterization and complete genome sequence of avian paramyxovirus type 4 prototype strain duck/hong kong/d3/75. | avian paramyxoviruses (apmvs) are frequently isolated from domestic and wild birds throughout the world. all apmvs, except avian metapneumovirus, are classified in the genus avulavirus of the family paramyxoviridae. at present, the apmvs of genus avulavirus are divided into nine serological types (apmv 1-9). newcastle disease virus represents apmv-1 and is the most characterized among all apmv types. very little is known about the molecular characteristics and pathogenicity of apmv 2-9. | 2008 | 18937854 |
| avian metapneumovirus subtype a in china and subtypes a and b in nigeria. | in order to detect and characterize avian metapneumovirus, organs or swabs were collected from 697 chicken and 110 turkeys from commercial farms in southwestern nigeria and from 107 chickens from live bird markets in southeastern china. in nigeria, 15% and 6% of the chicken and turkey samples, respectively, and 39% of the chicken samples from china, were positive for ampv genome by pcr. the sequence of a 400 nt fragment of the attachment protein gene (g gene) revealed the presence of ampv subtyp ... | 2008 | 18939643 |
| 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 |