Observations on host range and control of goose virus hepatitis

A number of experiments were done with a strain of goose hepatitis virus (isolated from sick goslings in the Netherlands in 1969. This virus was easily grown in embryonating eggs of the Muscovy duck (Cairina moschata) as well as in embryonating goose eggs. It also proved possible to adapt it to White Pekin duck eggs. The susceptibility of embryonating eggs obtained by crossing Muscovy drakes with Pekin ducks was intermediate between that of eggs from the two parental breeds. It was not possible to adapt goose hepatitis virus to growth in chicken embryos. The sensitivity of goslings to the goose hepatitis virus was found to vary considerably according to the farms from which they came. These differences were caused by variations 'in the quantity of parentally derived antibodies. One day-old Muscovy ducklings appeared to be at least as sensitive to the virus as goslings. However, disease symptoms could not be produced with goose hepatitis virus in Pekin ducklings nor in ducklings obtained by crossing Muscovy drakes and Pekin ducks. Treatment with homologous immune serum protected susceptible goslings and Muscovy ducklings against the disease. Under farm conditions, mortality was reduced from 30 to 3%. A breeding flock of adult Muscovy ducks, which had by serum therapy survived a goose hepatitis infection at an early age, produced ducklings resistant to the goose hepatitis virus. Over 100 flocks of geese, totalling more than 6,000 birds, were actively immunized with goose hepatitis Virus. The progeny produced in the following breeding season resisted, almost without exception, a challenge at one day of age with virulent goose hepatitis virus.     

Geese not susceptible to virulent subgroup J avian leukosis virus isolated from chickens

ABSTRACT

To determine whether geese are susceptible to infection by avian leukosis virus (ALV), 702 serum samples from domestic and foreign goose breeds were screened for p27 antigen as well as being inoculated into DF-1 cell cultures to isolate ALV. Although 5.7% of samples were positive for p27 antigen, reactivity appeared to be non-specific because no ALV was detected in the corresponding DF-1 cultures. To further determine whether geese are susceptible to ALV-J isolated from chickens, ALV-J strain JS09GY7 was artificially inoculated into 10-day-old goose embryos, with one-day-old hatched goslings then screened for p27 antigen and the presence of ALV. In all cases, the results of both tests were negative. Liver tissues from the 1-day-old goslings were screened using a polymerase chain reaction-based assay, which failed to amplify ALV-J gene fragments from any of the samples. Further, no histopathological damage was observed in the liver tissues. ALV-J was further inoculated intraperitoneally into one-day-old goslings, with cloacal swabs samples and plasma samples then collected every 5 days for 30 days. All samples were again negative for the presence of p27 antigen and ALV, and liver tissues from the challenged geese showed no histopathological damage and were negative for the presence of ALV-J gene fragments. Furthermore, p27 antigen detection, PCR-based screening, and indirect immunofluorescence assays were all negative following the infection of goose embryo fibroblasts with ALV-J. Together, these results confirm that virulent chicken-derived ALV-J strains cannot infect geese, and that p27 antigen detection in goose serum is susceptible to non-specific interference.     

Studies on mycoplasma infection of laying geese

Infertile eggs, dead embryos and tissues from laying geese (airsacs, peritoneum, oviduct, ovary, ova) were examined for presence of myco-plasmas. Forty-three of 110 eggs and the birds laying mycoplasma-containing eggs proved to be positive for mycoplasmas. One of the strains was used for experimental infection of laying geese. A reduction in egg production, an increased number of infertile eggs, egg transmission of mycoplasmas and loss of body weight of hatched goslings, were observed due to the mycoplasma infection.     

Pathogenicity of a variant goose parvovirus,from short beak and dwarfism syndrome of Pekin ducks,in goose embryos and goslings

The pathogenicity of a variant goose parvovirus (GPV), isolated from short beak and dwarfism syndrome of Pekin ducks (strain Cherry Valley), was investigated in embryonating goose eggs and goslings. The virus was easily grown in GPV antibody-free goose embryos and caused high mortality and severe lesions of goose embryos, indicating that the variant GPV has good adaptation and high pathogenicity to embryonated goose eggs similar to the classical GPV. Like the third egg-passage virus (strain H) of a classical GPV, the third egg-passage virus (strain JS1) of the variant GPV caused Derzsy’s disease in 2-day-old goslings with high mortality. The findings suggest that the variant GPV strain, which had specifically adapted to Pekin ducks, still retained high pathogenicity for its original host. The mortality (73.3–80%) caused by the first and third egg-passages of the variant GPV was somewhat lower than that (93.3%) caused by the third passage virus of the classical GPV, reflecting the higher pathogenicity of the classical GPV for its original host. These findings are likely to reinforce the importance of surveillance for parvoviruses in different waterfowl species and stimulate further study to elucidate the impact of mutations in the GPV genome on its pathogenicity to goslings and ducks.     

Astroviruses associated with stunting and pre-hatching mortality in duck and goose embryos

The first detection of avian nephritis virus (ANV) in goose embryos and of turkey astrovirus-1 (TAstV-1) in duck embryos is described. Intestinal samples from duck and goose embryos from five duck and four goose flocks in Croatia were tested by polymerase chain reaction for the presence of ANV, TAstV-1, turkey astrovirus-2, chicken astrovirus, duck astrovirus and also for the presence of avian reovirus, Derzsy's disease virus and duck enteritis virus. The kidneys from duck and goose embryos were also tested for ANV, while liver samples were tested for duck astrovirus. Duck embryos were also tested to detect duck circovirus and goose embryos for the presence of goose circovirus and goose haemorrhagic polyomavirus. All embryos were in the final stage of incubation and were characterized by moderate to markedly retarded growth. ANV was confirmed in the intestines and kidneys of embryos from two duck and two goose flocks and TAstV-1 was found in embryos from two duck flocks. One duck flock was positive for both ANV and TAstV-1. No other viruses were found in tested flocks. Phylogenetic analysis based on the ANV polymerase gene fragment of ANV sequences detected in duck and goose embryos revealed greatest similarity (88.1 to 97.2%) with ANV isolates from chickens. Further, the existence of at least two types of ANV circulating in Croatian duck and goose flocks was confirmed. Based on the phylogenetic analysis of the portion of TAstV-1 polymerase gene, two detected TAstV-1 nucleotide sequences were 99.5% similar. Compared with six TAstV-1 sequences, Croatian sequences showed one unique nucleotide change. In addition to other possible causes of stunted growth and late embryonic death, these findings suggest that ANV and/or TAstV-1 infection may be a contributing factor in the pre-hatching mortality of ducklings and goslings.     

Studies with a duck embryo adapted goose parvovirus vaccine

A goose parvovirus isolated from goslings with Derzsy's disease was adapted to growth in embryonating duck eggs. After 22 passages the adapted parvovirus was evaluated in 1 to 3-day-old susceptible goslings for attenuation and immunogenicity. The response to vaccination was measured by virus neutralisation (VN) tests and resistance to experimental challenge. The results showed that the duck embryo adapted parvovirus vaccine was apathogenic for goslings and stimulated significant VN antibody levels for up to 20 weeks. Virus was reisolated from the faeces of vaccinated goslings for up to 3 weeks after vaccination. In contact control goslings remained serologically negative until 6 weeks after contact when low levels of antibody were detected. Goslings vaccinated subcutaneously were resistant to experimental challenge 2 days after vaccination. Vaccination of goslings by subcutaneous and foot web routes produced complete protection to challenge. Goslings given vaccine via their drinking water were not resistant to challenge. The results suggest that the duck embryo adapted goose parvovirus vaccine induces a good immune response in susceptible goslings. However, further work is necessary to investigate whether the vaccine retains its attenuation following gosling to gosling passage.     

Mycoplasma infection of geese. II. Studies on pathogenicity of mycoplasmas in goslings and goose and chicken embryos

Of various mycoplasma strains of goose original, axanthum strains (609 and 612) caused the death both of goose and chicken embryos, A. laid-lawii strain (606) killed only goose embryos, whereas M. gallinarum (598) failed to kill either. Infection of 3-day-old goslings with these mycoplasmas resulted in no mortality but lesions were produced with A. axanthum in 9 of 10 birds. Less severe lesions were seen in fewer birds infected with other strains. Dual infection of 3-day-old goslings, with maternal antibody to goose parvovirus, with M. gallinarum (598) or A. axanthum (612) and a virulent parvovirus resulted in some death and all birds showed lesions.     

Attenuation of the goose parvovirus strain B. Laboratory and field trials of the attenuated mutant for vaccination against Derzsy's disease

Serial transfer of the goose parvovirus strain B, causal agent of Derzsy's gosling disease, in cultured goose-embryo fibroblast (GEF) resulted in a mutant (designated as Bav) apathogenic for both goose embryos and susceptible goslings. Goose embryos inoculated with the 38th or higher passages of strain B survived the infection, although the virus replicated in their organs. Susceptible goslings survived challenge with the Bav strain without showing symptoms, and developed normally. Only 4.2% of gosling progeny of parents vaccinated twice with strain Bav died after challenge with the virulent strain B goose parvovirus compared with 95% of gosling progeny of unvaccinated parents. Progeny of vaccinated and unvaccinated geese were placed on a farm on which Derzsy's disease was present. During the first month of life mortality was 7.7% in the progeny of vaccinated geese compared with 59.8% in the progeny of the unvaccinated geese. At 8 weeks of age the mean weight of the vaccinated goslings was 20% greater than for the unvaccinated goslings. These results indicate that the attenuated apathogenic Bav mutant is suitable for the immunisation of layers to protect their progeny by passive immunisation against Derzsy's disease.     

Astrovirus-induced “white chicks” condition – field observation,virus detection and preliminary characterization

Chicken astrovirus (CAstV) was recently indicated as the factor of the “white chicks” condition associated not only with increased embryo/chick mortality but also with weakness and white plumage of hatched chicks. In February 2014, organ samples (livers and kidneys) from dead-in-shell embryos, as well as 1-day-old whitish and normal chicks, were delivered from one hatchery in Poland for disease diagnosis. The samples originated from the same 30-week-old breeder flock in which the only observed abnormal signs were 4–5% decrease in the number of hatched chickens and the presence (about 1%) of weaker chicks with characteristic whitish plumage among normal ones. CAstV was detected in submitted samples and was then isolated in 10-day-old embryonated specific pathogen free (SPF) chicken eggs. We also reproduced an infection model for the “white chicks” condition in SPF layer chickens using the isolated PL/G059/2014 strain as the infectious agent. Results of experimental reproduction of the “white chicks” condition were somewhat more serious than field observation. The administration of the CAstV material into the yolk sac of 8-day-old SPF chicken eggs caused delay and prolongation of hatching, as well as death of embryos/chicks, and also a change of plumage pigmentation. Only two chicks of a total of 10 inoculated SPF eggs survived and were observed for 2 months. A gradual elimination of the CAstV genome was noted in this period. Moreover, a few contact-naive SPF chicks, which had been placed in the same cage, were infected with CAstV. Molecular characterization of detected CAstV was performed by nucleotide sequencing of the full ORF2 region encoding the capsid precursor protein gene. Phylogenetic studies showed that the PL/G059/2014 isolate clustered in the subgroup Aiii of CAstV. In the light of the new classification rules, the Polish PL/G059/2014 CAstV isolate could be assigned to a new species of the Avastrovirus genus.     

Immunoglobulin classes in the hen's egg: their segregation in yolk and white

Hen's egg yolk contains at least two antigen-binding subclasses of IgG, derived from the hen serum and transmitted to the chick. IgM and IgA, absent in yolk and in newly hatched chick serum, were detected in the white of unembryonated eggs, in the amniotic fluid of embryonating eggs and in the digestive tract of 19-day embryos, which also contained IgG. The dual mode of transfer found for maternal Ig of different classes in the fowl is compared with the transfer of maternal immunity in mammals.     

Occurrence of avian bornavirus infection in captive psittacines in various European countries and its association with proventricular dilatation disease

A total of 1442 live birds and 73 dead birds out of 215 bird collections in Spain, Germany, Italy, the UK and Denmark were tested for avian bornavirus (ABV) infection by four different methods. The majority of the birds were psittacines belonging to 54 different genera of the order Psittaciformes. In total, 22.8% of the birds reacted positive for ABV in at least one of the tests. Combined testing of swabs from the crop and cloaca, and serum for the diagnosis of ABV infection in live birds revealed that virus shedding and antibody production coincided in only one-fifth of the positive birds so that the examination of these three samples is recommended for reliable ABV diagnosis. By statistical analysis of this large number of samples, the ABV infection proved to be highly significant (P <0.001) associated with histopathologically confirmed proventricular dilatation disease (PDD) in dead birds as well as with clinically assumed PDD in live birds. However, ABV infection was also detected in psittacines without pathological lesions or clinical signs of PDD. Twelve non-psittacine birds belonging to the genera Aburria, Ciconia, Geopelia, Leucopsar and Pavo were tested negative for ABV infection. Within the order of Psittaciformes, birds belonging to 33 different genera reacted positive for ABV. In 16 of these psittacine genera, the ABV infection was demonstrated for the first time. The present study emphasizes the widespread occurrence of clinically variable ABV infections in Europe by analysing a large number of specimens from a broad range of bird species in several assays.     

Safety and efficacy of an inactivated Carbopol-adjuvanted goose haemorrhagic polyomavirus vaccine for domestic geese

Haemorrhagic nephritis enteritis of the goose (HNEG) is an epizootic viral disease in domestic geese. The causal agent is a polyomavirus, namely goose haemorrhagic polyomavirus. To help control the disease, an inactivated vaccine was developed, based on viral particles produced in goose kidney cells. Viral material was quantified using real-time quantitative polymerase chain reaction, inactivated with β-propiolactone and adjuvanted with Carbopol, an acrylic acid polymer. Carbopol proved to be more immunogenic than aluminium hydroxide and was totally safe when administered to young goslings and breeders alike. Carbopol-adjuvanted vaccine induced a high serological response. Moreover, goslings hatched from vaccinated breeders were protected against viral challenge, indicating that maternally-derived neutralizing antibodies (MDA) were efficiently transferred. MDA were still detectable 15 days post-hatch. Clinical trials will be necessary to accurately evaluate a vaccine-based HNEG control strategy under field conditions.     

Application of the agar gel precipitin and virus neutralisation tests to the serological study of goose parvovirus

An agar gel precipitin (AGP) test and virus neutralisation (VN) test were developed using antigens prepared in duck eggs, to detect and measure antibodies against goose parvovirus. The tests were evaluated using sera collected from the following sources; forty three-month-old geese that had survived Derzsy's disease as goslings, adult geese from a farm where an outbreak of Derzsy's disease had occurred in goslings 14 months earlier, geese that had received a duck embryo adapted goose parvovirus vaccine and parvovirus antisera donated by other laboratories. Of the Derzsy's disease survivors, eight of nine had high AGP and VN antibody titres throughout the observation period. Eight of 19 geese from a farm in which Derzsy's disease had occurred showed a positive VN antibody response, of which five also showed a positive AGP response. Virus neutralising antibodies were detected in all sera from the vaccinated groups compared with the AGP test which detected nine out of 20. Both tests detected high antibody levels in the parvovirus antisera from other laboratories. The findings suggest that the VN test was more sensitive in detecting low levels of antibody than the AGP test. However, the simple and inexpensive AGP test is a useful method of assessing the immune status of geese to Derzsy's disease.     

Pathological and immunological studies on goose embryos and one-day-old goslings experimentally infected with a Mycoplasma strain of goose origin

Goose embryos and one-day-old goslings were inoculated either on the 10th or 20th day of incubation into the yolk sac or into the air sac or intranasally, with Mycoplasma strain 1220 isolated from a goose. Subsequently morphological, immunological and microbiological * changes were determined. Infection during incubation resulted in an acute serous inflammation of the chorioallantoic membrane, a diffuse, heterophil granulocytic interstitial hepatitis and a bronchopneumonia. One-day-old goslings developed lympho-histiocytic infiltrations of the productive type in the interstitium of the lungs, the walls of the major bronchi, the mucous membrane of the nasal conchae and in the visceral pleura. Blood lymphocytes of 28-day-old embryos infected at 10 days of incubation recognised and specifically reacted with the antigen in immunorosette formation and lymphocyte transformation tests. However, after hatching the antigen-recognising capacity of lymphocytes decreased, and had become considerably reduced by day 30 after hatching. No antibodies were demonstrable in the indirect haemagglutination test.     

A study on the vertical transmission of arthropathic and amyloidogenic Enterococcus faecalis

Ten brown layer parent hens were injected intravenously with arthropathic and amyloidogenic Enterococcus faecalis at 27 weeks of age to assess its vertical transmission during the subsequent 6-week production period. All inoculated hens developed chronic bacteraemia and arthritis, four died due to septicaemia and two of the remaining six showed amyloid arthropathy. The egg production was maintained at a lower level than the controls. Of eggs collected during the first 2 weeks after inoculation, E. faecalis was re-isolated from the yolk sac of 76% (13/17) of infertile eggs and dead embryos detected at the 18-day candling, and 100% (6/6) of non-hatching eggs, and from arthritic joints of 3% (2/66) offspring chicks of the same batch, although the latter did not develop joint amyloidosis by 8 weeks of age. E. faecalis was also re-isolated from ovary and oviduct of parent birds that died due to septicaemia. The E. faecalis organisms re-isolated from blood, ovaries and joints of diseased parent stock, yolk sac of infertile eggs and dead embryos detected at the 18-day candling, and non-hatching eggs, as well as organs and joints of offspring, had the same pulsed-field gel electrophoresis patterns as the E. faecalis isolate used to infect the parent birds. These findings indicate that vertical transmission of arthropathic and amyloidogenic E. faecalis may occur on a small scale.     

Isolation of Moraxella anatipestifer from embryonated goose eggs

Twenty six embryonated goose eggs which had not hatched at term were investigated bacteriologically. Moraxella anatipestifer was isolated from seven of them. This suggests that vertical transmission is possible and might explain the problems of eradicating Moraxella infection by hygienic means only.     

Characterisation of adenoviruses isolated from geese

Viruses isolated from liver and gut of dead 2- to 4-week-old goslings were identified as adenoviruses. The main characteristics of the strains were: development of intranuclear inclusion bodies in virus-infected cells; a buoyant density of the infective particles in CsC1 of 1.33-1.34 g/ml; icosahedral virions measuring 78-83 nm in diameter which had no envelope; a linear duplex DNA genome with a molecular weight of 25-29 x 10(6) daltons. These adenoviruses did not cross-react in neutralisation tests with 11 fowl, two turkey and two duck adenovirus serotypes, however, they shared a common complement-fixing antigen with fowl adenoviruses. Based on the results of the cross-neutralisation tests and on the cleavage pattern of DNAs by BamHI and Hind III restriction endonucleases, the seven adenovirus strains studied represent three distinct goose adenovirus serotypes. The goose adenoviruses caused neither clinical symptoms nor pathological lesions after infection of 3-day-old goslings.     

Pathology of goose haemorrhagic polyomavirus infection in goose embryos.

Goose embryos were infected with goose haemorrhagic polyomavirus (GHPV) onto the chorioallantoic membrane (CAM) in order to examine the effect of GHPV on the embryos and to obtain data on whether embryos could develop into infected, virus-shedding goslings, as well as to present an accurate biological method for virus titration. The reported method of infection could offer a possibility to express the virus titre as the median embryo infective dose (EID(50)). As a special pathological feature of the disease, extensive cerebral haemorrhages were observed, which protruded the skullcap in many cases. Some embryos infected with 10(1.25) or 10(0.25) EID(50)/0.2 ml were able to hatch; however, they were in poor physical condition and died by post-hatching day 4 showing haemorrhagic nephritis and enteritis of geese. Virus shedding was revealed by polymerase chain reaction. The ability of some of the infected goose embryos to hatch may indicate the potency of GHPV to spread vertically, although this needs further study for confirmation.     

Transovarial transmission ofNosema locustae (Microsporida: Nosematidae) in the migratory locustLocusta migratoria migratorioides

Nosema locustae, a microsporidian parasite of locusts and grasshoppers, was transovarially transmitted to the progeny of infectedLocusta migratoria reared for up to F14 generations. The mortality of infected progeny in each generation was higher than that of uninfected controls and ranged from 67.6% to 95.5%. Infected female survivors transmitted the microsporidium to the progeny via eggs. The developing eggs harboured vegetative stages ofN. locustae, and development of the microsporidium occurred during embryonation. Spores accumulated in the yolk and, after blastokinesis, both the yolk and the spores were enclosed in the midgut of the embryo. germinated spores infected the functional midgut epithelium and invaded internal tissues. The mortality of newly hatched instars was high when embryonic tissue had been infected during development.     

Rapid Enzyme Immunoassay of Chicken EGG Yolk IgG

A simple and rapid enzyme immunoassay for specific antibodies in chicken egg yolk is described. As a model system, the levels of anti-Salmonella IgG in the yolk of eggs obtained from various produce retailers were compared. Polyester cloth coated with Salmonella typhimurium lipopolysaccharide was used to capture specific egg yolk antibodies, which were then detected using an anti-chicken IgG-peroxidase conjugate. This assay, requiring less than 30 min to complete, revealed considerable differences in the relative levels of anti-Salmonella IgG in the egg yolks. Anti-Salmonella IgG levels were generally lower in eggs obtained from large produce retailers than in eggs obtained from a small local farm. This assay may provide a rapid and economical means of monitoring the levels of Salmonella contamination in chicken rearing facilities.