Isolation of avian pneumovirus from mallard ducks that is genetically similar to viruses isolated from neighboring commercial turkeys

Our earlier studies demonstrating avian pneumovirus (APV) RNA in wild geese, sparrows, swallows, starlings and mallard ducks suggested that wild birds might be involved in the circulation of APV in the United States. To determine whether turkey virus can be transmitted to the free flying birds, we placed APV-negative mallard ducks next to a turkey farm experiencing a severe APV outbreak and in an area with a large population of waterfowls. The sentinel ducks did not develop clinical APV disease but infectious APV (APV/MN-12) was recovered from choanal swabs after 2 weeks, and anti-APV antibodies detected after 4 weeks. Four APV isolates recovered from the neighboring turkeys that were experiencing an APV outbreak at the same time shared 95-99% nucleotide identity and 97-99% predicted amino acid identity with the duck isolate. In addition experimental infection of turkey poults with APV/MN-12 resulted in detection of viral RNA in nasal turbinates and APV-specific IgG in serum. These results indicate that the APV isolates from turkeys and ducks shared a common source, and the viruses from different avian species can cross-infect.     

Molecular analysis of the hemagglutinin genes of Australian H7N7 influenza viruses: Role of passerine birds in maintenance or transmission?

In 1985 a fowl plague-like disease occurred in chickens in Lockwood, Victoria, Australia and caused high mortality. An H7N7 influenza virus was isolated from the chickens (A/Chicken/Victoria/1/85); additionally, an antigenically similar virus was isolated from starlings (A/Starling/Victoria/5156/85) and serological evidence of H7N7 virus infection was found in sparrows. Antigenic analysis with monoclonal antibodies to H7, oligonucleotide mapping of total vRNA, and sequence analysis of the HA genes established that the chicken and starling influenza viruses were closely related and probably came from the same source. There was high nucleotide sequence homology (95.3%) between the HA genes of A/Chick/Vic/85 and a fowl plague-like virus isolated from chickens in Victoria 9 years earlier [A/Fowl/Vic/76 (H7N7)]. The sequence homologies indicated that the A/Chick/Vic/85 and A/Fowl/Vic/76 were derived from a common recent ancestor, while another recent H7N7 virus, Seal/Mass/1/80 originated from a different evolutionary lineage. Experimental infection of chickens and starlings with A/Chick/Vic/1/85 (H7N7) was associated with high mortality (100%), transmission to contact birds of the same species, and virus in all organs. In sparrows one-third of the birds died after infection and virus was isolated from most organs; transmission to contact sparrows did not occur. In contrast, the H7N7 virus replicated in ducks and spread to contact ducks but caused no mortality. These studies establish that the host species plays a role in determining the virulence of avian influenza viruses, and provide the first evidence for transmission of virulent influenza viruses between domestic poultry and passerine birds. They support the hypothesis that potentially virulent H7N7 influenza viruses could be maintained in ducks where they cause no apparent disease and may sometimes spread to other wild birds and domestic poultry.     

Virulence genes,antibiotic resistance and integrons in Escherichia coli strains isolated from synanthropic birds from Spain

The aim of this study was to determine the presence of virulence genes and antibiotic resistance profiles in 164 Escherichia coli strains isolated from birds (feral pigeons, hybrid ducks, house sparrows and spotless starlings) inhabiting urban and rural environments. A total of eight atypical enteropathogenic E. coli strains were identified: one in a house sparrow, four in feral pigeons and three in spotless starlings. Antibiotic resistance was present in 32.9% (54) of E. coli strains. The dominant type of resistance was to tetracycline (21.3%), ampicillin (19.5%) and sulfamethoxazole (18.9%). Five isolates had class 1 integrons containing gene cassettes encoding for dihydrofolate reductase A (dfrA) and aminoglycoside adenyltransferase A (aadA), one in a feral pigeon and four in spotless starlings. To our knowledge, the present study constitutes the first detection of virulence genes from E. coli in spotless starlings and house sparrows, and is also the first identification worldwide of integrons containing antibiotic resistance gene cassettes in E. coli strains from spotless starlings and pigeons.     

Morphology ofBlastocystis sp. from domestic birds

A study ofBlastocystis sp. from domestic birds was undertaken to determine if morphological differences occurred. Fresh faecal material from domestic chickens, ducks, and geese and from commercially farmed ostriches was obtained.Blastocystis sp. from chickens was morphologically very different from that from the other hosts having within the nucleus discrete spots of chromatin rather than a crescentic band (ducks and geese) or an elliptical band (ostrich). A thick surface coat surrounded allBlastocystis sp. cells in the faecal material, with isolates from the ostrich having the thickest surface coat relative to the cell diameter. Cysts were more commonly found in the chicken samples but were also detected in the duck and ostrich samples. This study suggests that three morphologically distinct groups are represented: one in the chicken, one in the ostrich and another in ducks and geese. These tentative conclusions require confirmation by molecular techniques.     

Interpretation of the epizootic outbreak among wild and domestic birds in the south of the European part of Russia in December 2007

The paper presents the results of interpreting the epizootic outbreak etiologically associated with high-virulent influenza virus A/H5N1 among domestic and wild birds in the Zernogradsky and Tselinsky districts of the Rostov Region. Epizooty was characterized by a high infection rate in the synanthropic birds of a ground-based complex. RT-PCT revealed influenza virus A/H5 in 60% of pigeons and crows and in around 20% of starlings, and in 10% of tree sparrows. Fifteen viral strains from chickens (Gallus gallus domesticus), Indian ducks (Cairina moschata), rooks (Corvus frugilegus), rock pigeons (Columba livia), tree sparrows (Passer montanus), common starlings (Sturnus vulgaris), and great white herons (Egretta alba) were isolated and deposited in the State Collection of Viruses of the Russian Federation. Full-sized genomes of 5 strains were sequenced and deposited in the international database GenBank. The isolated strains belong to the Quinhai-Siberian (2.2) genotype, an Iranian-Northern Caucasian subgroup, they are phylogenetically closest to the strain A/chicken/Moscow/2/2007 (inducing epizooty among poultry in the near-Moscow Region in February 2007) and have 13 unique amino acid replacements as the consensus of the Quinhai-Siberian genotypes in the proteins PB2, PA, HA, NP, NA, and M2, by preserving thereby 4 unique replacements first describes for the strain A/chicken/Moscow/2/2007. The findings are indicative of a different mechanism that is responsible for bringing the virus into the northeastern part of the Azov Sea area in September 2007 (during the fall migration of wild birds) and in December 2007 in the south-western Rostov Region where a human factor cannot be excluded. Mass infection of synanthropic birds endangers the further spread of epizooty, including that in the central regions of the Russian Federation in spring after near migrants return after wintering.     

Isolation of mycoplasma cloacale from a number of different avian hosts in great Britain and France

Following the original isolation of Mycoplasma cloacale from a turkey in Great Britain, only one further turkey isolate has been obtained whereas the mycoplasma has been recovered from 2 species of wild ducks in Britain, and from 2 breeds of domestic ducks and from domestic geese in France. A few isolations have also been made from wild and exotic birds but M. cloacale has not been found in chickens.     

Antibodies against EDS-76 avian adenovirus in bird species before 1975

A retrospective serological survey was performed to demonstrate HI antibodies against EDS-76 virus in sera collected between 1964 to 1975 from domesticated and wild birds. No antibody to EDS virus was detected in the chicken, pheasant and turkey sera. However, HI antibodies to EDS-76 virus could be demonstrated in sera from domestic ducks (60%), wild ducks (59%), geese (70%) and herring gulls (20%). The presence of antibodies indicates that the EDS-76 virus existed in waterfowls prior to 1975. This supports the concept of McFerran that the EDS-76 virus is a duck adenovirus.     

Investigation of outbreaks of highly pathogenic H5N1 avian influenza in waterfowl and wild birds in Hong Kong in late 2002.

Outbreaks of highly pathogenic H5N1 avian influenza have occurred in Hong Kong in chickens and other gallinaceous poultry in 1997, 2001, twice in 2002 and 2003. High mortality rates were seen in gallinaceous birds but not in domestic or wild waterfowl or other wild birds until late 2002 when highly pathogenic H5N1 avian influenza occurred in waterfowl (geese, ducks and swans), captive Greater Flamingo (Phoenicopterus ruber) and other wild birds (Little Egret Egretta garzetta) at two waterfowl parks and from two dead wild Grey Heron (Ardea cinerea) and a Black-headed Gull (Larus ridibundus) in Hong Kong. H5N1 avian influenza virus was also isolated from a dead feral pigeon (Columba livia) and a dead tree sparrow (Passer montanus) during the second outbreak. The first waterfowl outbreak was controlled by immediate strict quarantine and depopulation 1 week before the second outbreak commenced. Control measures implemented for the second outbreak included strict isolation, culling, increased sanitation and vaccination. Outbreaks in gallinaceous birds occurred in some live poultry markets concurrently with the second waterfowl outbreak, and infection on a chicken farm was detected 1 week after the second waterfowl park outbreak was detected, on the same day the second grey heron case was detected. Subsequent virus surveillance showed the outbreaks had been contained.     

First survey of the occurrence of duck enteritis virus (DEV) in free-ranging Polish water birds

Duck plague (DP) caused by anatid herpesvirus 1, also called duck enteritis virus (DEV), presents one of the most important concerns in mass waterfowl production. Apart from geese and ducks, free-ranging water birds are the most notorious infection carriers. The epidemiology of DEV in Western Europe remains unknown. Therefore, it was reasonable to conduct a study on its occurrence using modern but simple real-time loop-mediated isothermal amplification (LAMP). Analysis of 132 field isolates showed the presence of DEV in 96 birds (72.7 %), and it was found predominantly in wild ducks (Anas platyrhynchos) and mute swans (Cygnus olor). This virus was also found in graylag geese (Anser anser), tundra bean geese (Anser fabalis), and grey herons (Ardea cinerea). The results were recorded as green colour of positive samples, fluorescence under ultraviolet light, and florescent curves in a real-time PCR system. This study indicates the high prevalence of DEV among free-ranging water birds in Poland and the possible transmission to other birds settling in the water environment. This is the first report of DEV detection among free-ranging water birds in Poland.     

Wood ducks (Aix sponsa) as potential reservoirs for avian influenza and avian paramyxoviruses

Influenza A viruses (IAVs) and avian paramyxoviruses (APMVs) are important pathogens of poultry worldwide, and both commonly occur in wild waterfowl, especially ducks in the family Anatidae. Although wood ducks (Aix sponsa) are members of the Anatidae, their behaviour differs from most other species in this family, which could affect the transmission of IAVs and APMVs. We collected cloacal and oropharyngeal swab and blood samples from more than 700 wood ducks across nine states in the eastern United States of America. No IAVs were isolated, and based on blocking enzyme-linked immunoassay ELISA results, antibodies to IAVs were only detected in 0.2% of samples. In contrast, 23 (3%) APMVs were isolated (22 Newcastle disease virus and 1 APMV-6), and antibodies to multiple serotypes of APMVs were detected in more than 60% of the samples. After-hatch-year birds were more likely to be antibody positive for APMV-4 and APMV-6 compared to hatch-year birds. Female birds were more likely to be antibody positive for APMV-4 than were male birds. Our results indicate that wood ducks are probably not an important host for IAV but are frequently infected with APMVs.     

Surveillance of pelagic birds for influenza A viruses

Within a 4-year surveillance period for influenza A virus in pelagic birds, 351 influenza A strains were isolated from the trachea or cloaca of 3344 apparently healthy ducks, gulls, swans, terns and geese. The isolated influenza A viruses represent 14 subtypes. Their haemagglutinins (HA) were mainly related to avian HA, but also to the human HA H2 and to the swine HA Hswl. The neuraminidases (NA) were identified as avian, equine and human NA. The isolated influenza A strains include fowl plague-like viruses Havl Neql, strains with the surface antigen Hswl Nav4 and the subtype Hav7 Navl isolated from unconcentrated water samples. A subtype unknown to date, with the antigen formula H2 Nav4, was isolated from ducks. 8.2% of pekin ducks showed dual infections.     

Detection of anti-West Nile virus immunoglobulin M in chicken serum by an enzyme-linked immunosorbent assay

The emergence of West Nile (WN) virus in New York and the surrounding area in 1999 prompted an increase in surveillance measures throughout the United States, including the screening of sentinel chicken flocks for antibodies. An enzyme-linked immunosorbent assay (ELISA) for the detection of chicken immunoglobulin M (IgM) to WN virus was developed, standardized, and characterized as a rapid and sensitive means to detect WN viral antibodies in sentinel flocks. Serum specimens from experimentally infected chickens were analyzed by using this assay, and IgM was detected as early as 3 to 7 days postinfection. Persistence of IgM varied from at least 19 to more than 61 days postinfection, which indicates the need to bleed sentinel flocks at least every 2 weeks for optimal results if this method is to be used as a screening tool. The ELISA was compared to hemagglutination-inhibition and plaque reduction neutralization tests and was found to be the method of choice when early detection of WN antibody is required. House sparrows and rock doves are potential free-ranging sentinel species for WN virus, and the chicken WN IgM-capture ELISA was capable of detecting anti-WN IgM in house sparrow serum samples from laboratory-infected birds but not from rock dove serum samples. The chicken WN IgM-capture ELISA detected anti-WN antibodies in serum samples from naturally infected chickens. It also detected IgM in serum samples from two species of geese and from experimentally infected ring-necked pheasants, American crows, common grackles, and redwinged blackbirds. However, the test was determined to be less appropriate than an IgG (IgY)-based assay for use with free-ranging birds. The positive-to-negative ratios in the ELISA were similar regardless of the strain of WN viral antigen used, and only minimal cross-reactivity was observed between the WN and St. Louis encephalitis (SLE) IgM-capture ELISAs. A blind-coded serum panel was tested, and the chicken WN IgM-capture ELISA produced consistent results, with the exception of one borderline result. A preliminary test was done to assess the feasibility of a combined SLE and WN IgM-capture ELISA, and results were promising.     

Mycoplasma species isolated from six avian species

Mycoplasmas were isolated from chickens, chicken embryos, turkeys, ducks, geese, pigeons and Japanese quail and their embryos. Altogether 792 birds and embryos were examined and 411 of them (52%) were infected with mycoplasmas. Isolates were identified by indirect im-munofluorescence using monospecific rabbit antisera against 16 reco-nised species of avian Mycoplasma (AM) and two species of Achole-plasma. In all 633 strains of Mycoplasma were detected and most of these belonged to recognised AM species. M. anatis was found only in ducks and geese; M. columbinasale, M. columbinum and M. colum-borale only in pigeons, while M. meleagridis and M. gallopavonis isolates were exclusive to the turkey. M. synoviae was the most frequently isolated species (172 isolates). The host range of M. gallisepticum was the same as M. synoviae but with slightly fewer isolations. M. gallinarum, M. gallinaceum, M. pullorum, M. glycophilum and M. lipofaciens were not uncommon but were mainly confined to the chicken. The exceptions were isolates of M. lipofaciens from a turkey and a duck and an isolate of M. gallinarum from a turkey. M. cloacale was isolated from a chicken, a turkey and a duck. Acholeplasmas and untyped strains were isolated from all the host species except Japanese quail. Isolations of M. synoviae from a pigeon and Japanese quail and M. cloacale from a chicken, are thought to be new findings.     

Molecular and pathological characterization of two H5N1 avian influenza viruses isolated from wild ducks

In this study, two H5N1 influenza viruses (HN021 and HN211) were isolated in wild ducks and the characteristics of these viruses were studied systemically. By studying the pathogenesis of both H5N1 isolates, the results showed that HN211 was highly pathogenic in chickens, geese, ducks, and mice, while HN021 was highly pathogenic in chickens and geese but low pathogenic in ducks and mice. Both isolates could replicate in lungs and brains of mice and be transmitted from ducks to ducks. Histopathologic analysis showed that HN211 could cause more severe pathological changes in lungs and brains of infected mice than HN021. Molecular characterization showed that both H5N1 isolates had 20 aa missing in stalk of NA protein and 5 aa missing in NS protein in comparison with most other H5N1 isolates. Phylogenetic analysis indicated that both H5N1 isolates were reassortants from Goose/Guangdong/1/96-like viruses. The results of present study with both H5N1 viruses also suggested that wild ducks may play an important role in maintaining circulation of H5N1 viruses.     

The control of adaptive hypertrophy in the salt glands of geese and ducks.

1. Factors controlling adaptive hypertrophy, which occurs when marine, or potentially marine, birds drink salt water, have been investigated in geese and ducks using changes in salt-weight weight, RNA and DNA contents as indices of this process. 2. Unilateral post-ganglionic denervation in geese prevented the changes in [RNA] and [RNA]:[DNA] that occurred in the intact gland of birds given salt water for 24 hr; denervation had no significant effect in birds on fresh water throughout. 3. Atropine treatment also prevented the adaptive changes in geese given salt water. 4. In ducks give 0.3 M-NaCl for 48 hr salt-gland weight, [RNA] and [RNA]:[DNA] increase markedly. Treatment of ducks drinking fresh water with large doses of corticosterone and mammalian ACTH for 48 hr had no significant effects on salt-gland weight, RNA or DNA; mammalian prolactin treatment for 48 hr significantly raised [RNA]. 5. No changes in the total amount of DNA in the glands were observed in these experiments, thus indicating that hyperplasia does not occur within 48 hr of a bird first drinking salt water. 6. It is concluded that adaptive hypertrophy is controlled by secretory nerves, and that hormones, if they play any part in this process, have a permissive or secondary role. It is suggested that hypertrophy and the maintenance of the secretory cells in the fully-adapted state may be obligatorily related to secretory activity induced by cholinergic secretory nerves.     

A new technique for taking blood samples from ducks and geese

A new technique for taking blood samples from ducks and geese is described. The method could possibly be used in other bird species. It presents many advantages for the operator as well as for the birds and it allows repeated blood samples to be taken, if necessary, in large quantities.     

Specific detection of avian pneumovirus (APV) US isolates by RT-PCR

Summary.  This report details the development of an RT-PCR assay for the specific detection of US isolates of avian pneumovirus (APV). Of the several primer pairs tested, two sets of primers derived from the matrix gene of APV were able to specifically detect the viral RNA of APV. The nucleotide sequence comparison of the PCR products of APV isolates from Minnesota suggested that these viruses were closely related to the Colorado strain of APV, but were distinct from subtypes A and B European isolates of turkey APV (turkey rhinotracheitis: TRT). This M gene-based PCR was found to be very specific and sensitive. APV as low as 8 × 10⁻⁵ TCID⁵⁰ (0.0323 μg/ml) could be detected using this assay. In addition, the two primers were able to differentiate isolates from turkeys in Minnesota. Received June 15, 1999 Accepted January 3, 2000     

A serologic survey for avian polyomavirus and Pacheco's disease virus in Australian cockatoos.

Sera collected from wild and captive Australian cockatoos and other psittacine species (n = 411) were tested for antibodies to avian polyomavirus (APV) and Pacheco's disease virus (PDV). Of 144 wild sulphur-crested cockatoos (Cacatua galerita) sampled at three regions in New South Wales (NSW) 96 (64.4%) birds had positive (>/= 1:32) neutralizing antibody titres to avian polyomavirus (range 1:32-1:2048). Two of 17 wild long-billed corellas (Cacatua tenuirostris) were also APV-antibody positive. However, no samples from 107 wild galahs (Eolophus roseicapillus) were positive for neutralizing antibody to APV. Sera were also collected from captive psittacine bird flocks from NSW, Tasmania, Victoria, and Western Australia. In a mixed aviary of cockatoos and lorikeets, APV antibody was detected in sera from sulphur-crested cockatoos, Major Mitchell's cockatoos (Cacatua leadbeateri), a white-tailed black cockatoo (Calyptorhynchus baudinii latirostris), a red-tailed black cockatoo (Calyptorhynchus magnificus) a single galah, a rainbow lorikeet (Trichoglossus haematodus), and a scaley-breasted lorikeet (Trichoglossus chlorolepidotus). All 411 wild and captive birds were negative for the presence of neutralizing antibody to PDV. These results indicate that wild sulphur-crested cockatoos in NSW are enzootically infected with avian polyomavirus and that the sampled populations are free of Pacheco's disease.     

Parrot bornavirus-2 and -4 RNA detected in wild bird samples in Japan are phylogenetically adjacent to those found in pet birds in Japan

Bornaviruses (family Bornaviridae) are non-segmented negative-strand RNA viruses. Avian bornaviruses (ABVs), which are causative agents of proventricular dilatation disease, are a genetically diverse group with at least 15 genotypes, including parrot bornaviruses (PaBVs) and aquatic bird bornavirus 1(ABBV-1). Borna disease virus 1(BoDV-1), which infects mammals and causes neurological diseases, has also been reported to infect avian species, although the numbers of the cases have been markedly fewer than those of ABVs. In this study, we conducted genetic surveillance to detect ABVs (PaBV-1 to -5 and ABBV-1) and BoDV-1 in wild birds in Japan. A total of 2078 fecal or cloacal swab samples were collected from wild birds in 2006, 2007, 2008, and 2011, in two regions of Japan. The results demonstrated the presence of PaBV-2 and -4 RNA, while no positive results for other PaBVs, ABBV-1, and BoDV-1 were obtained. PaBV-2 and -4 RNA were detected in 18 samples (0.9 %) of the genera Anas, Grus, Larus, Calidris, Haliaeetus, and Emberiza, in which either PaBV-2 RNA or PaBV-4 RNA, or both PaBV-2 and -4 RNA were detected in 15 (0.7 %), 5 (0.2 %), and 2 (0.1 %) samples, respectively. The nucleotide sequences of PaBV-2 and -4 detected in these samples from wild birds are phylogenetically close to those found in samples from pet birds in Japan, with identities ranging from 99.8 to 100 % and from 98.2 to 99.4 %, respectively. To the best of our knowledge, this is the first report on the detection of PaBV-2 and -4 RNA detected in samples from wild birds.