Avian Adenovirus Research Articles

Fiber knob domain lacking the shaft sequence but fused to a coiled coil is a candidate subunit vaccine against egg-drop syndrome

Egg-drop syndrome (EDS) virus is an avian adenovirus that causes a sudden drop in egg production and in the quality of the eggs when it infects chickens, leading to substantial economic losses in the poultry industry. Inactivated EDS vaccines produced in embryonated duck eggs or cell culture systems are available for the prophylaxis of EDS. However, recombinant subunit vaccines that are efficacious and inexpensive are a desirable alternative. In this study, we engineered chimeric fusion proteins in which the trimeric fiber knob domain lacking the triple β-spiral motif in the fiber shaft region was genetically fused to trimeric coiled coils, such as those of the engineered form of the GCN4 leucine zipper peptide or chicken cartilage matrix protein (CMP). The fusion proteins were expressed predominantly as soluble trimeric proteins in Escherichia coli at levels of 15–80mg/L of bacterial culture. The single immunization of chickens with the purified fusion proteins, at a dose equivalent to 10μg of the knob moiety, elicited serum antibodies with high hemagglutination inhibition (HI) activities, similar to those induced by an inactivated EDS vaccine. A dose–response analysis indicated that a single immunization with as little as 1μg of the knob moiety of the CMP–knob fusion protein was as effective as the inactivated vaccine in inducing antibodies with HI activity. The immunization of laying hens had no apparent adverse effects on egg production and effectively prevented clinical symptoms of EDS when the chickens were challenged with pathogenic EDS virus. This study demonstrates that the knob domain lacking the shaft sequence but fused to a trimeric coiled coil is a promising candidate subunit vaccine for the prophylaxis of EDS in chickens.

The spread of non-OIE-listed avian diseases through international trade of chicken meat: an assessment of the risks to New Zealand.

Twelve avian diseases are listed by the World Organisation for Animal Health (OIE), although more than 100 infectious diseases have been described in commercial poultry. This article summarises a recent assessment of the biosecurity risks posed by non-listed avian diseases associated with imports of chilled or frozen chicken meat and meat products into New Zealand. Following the guidelines described in Chapter 2.1 of the OIE Terrestrial Animal Health Code, avian adenovirus splenomegaly virus, avian paramyxovirus-2 (APMV-2), Bordetella avium, Mycoplasma spp., Ureaplasma spp., Ornithobacterium rhinotracheale, Riemerella anatipestifer, and Salmonella arizonae have been identified as hazards. However, of all the non-listed avian diseases discussed here, only APMV-2 and S. arizonae are assessed as being risks associated with the commercial import of chicken meat into New Zealand. Specific control measures may have to be implemented to mitigate such risks. This conclusion is likely to reflect both the high-health status of New Zealand poultry and the threat posed by these infectious agents to New Zealand's unique population of native psittacine species.

Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California.

Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats.

Bioaccumulation of animal adenoviruses in the pink shrimp.

Adenoviruses are among the most promising viral markers of fecal contamination. They are frequently found in the water, sediment and soil of regions impacted by human activity. Studies of the bioaccumulation of enteric viruses in shrimp are scarce. The cities located in the northern coast of the lake systems in Southern Brazil have high urbanization and intensive farming rates, and poor sewage collection and treatment. One hundred (n = 100) Farfantepenaeus paulensis pink-shrimp specimens and 48 water samples were collected from coastal lagoons between June 2012 and May 2013. Water samples were concentrated and the shrimp, mashed. After DNA extraction, samples were analyzed by real time polymerase chain reaction (qPCR) in order to detect and quantify viral genomes. Thirty-five percent of shrimp samples were positive for contamination, predominantly by avian adenoviruses. A total of 91.7% of water samples contained adenoviruses DNA, with the human form being the most frequent. Our results provided evidence of significant bioaccumulation of adenoviruses in shrimp, showing the extent of the impact of fecal pollution on aquatic ecosystems.

English

English

Expression and in vitro functional analyses of recombinant Gam1 protein

Gam1, an early gene product of an avian adenovirus, is essential for viral replication. Gam1 is the first viral protein found to globally inhibit cellular SUMOylation, a critical posttranslational modification that alters the function and cellular localization of proteins. The interaction details at the interface between Gam1 and its cellular targets remain unclear due to the lack of structural information. Although Gam1 has been previously characterized, the purity of the protein was not suitable for structural investigations. In the present study, the gene of Gam1 was cloned and expressed in various bacterial expression systems to obtain pure and soluble recombinant Gam1 protein for in vitro functional and structural studies. While Gam1 was insoluble in most expression systems tested, it became soluble when it was expressed as a fusion protein with trigger factor (TF), a ribosome associated bacterial chaperone, under the control of a cold shock promoter. Careful optimization indicates that both low temperature induction and the chaperone function of TF play critical roles in increasing Gam1 solubility. Soluble Gam1 was purified to homogeneity through sequential chromatography techniques. Monomeric Gam1 was obtained via size exclusion chromatography and analyzed by dynamic light scattering. The SUMOylation inhibitory function of the purified Gam1 was confirmed in an in vitro assay. These results have built the foundation for further structural investigations that will broaden our understanding of Gam1’s roles in viral replication.

Molecular characterization of avian adenoviruses in Iranian broiler flocks

Summary This study was conducted to molecularly detect avian adenoviruses in broiler flocks showing liver lesions and respiratory syndrome in northeast Iran. In total, 60 tissue samples were collected from broiler farms with liver lesions, respiratory syndrome and also from clinically healthy flocks. Six samples were positive; however, three samples were selected for molecular studies. PCR products were sequenced to confirm the identity of avian adenoviruse. Based on the sequence analysis of the L1 region of the hexon gene, the NRB/FAV/4 should be classified as FAdV 8b strain and two other isolates - NRB/FAV/1 and NRB/FAV/5 - classified in cluster of the FAdV 2 & 11. As far as we know, this preliminary investigation is the only documented study to confirm the presence of avian adenoviruses in broiler flocks in Iran.

SEROSURVEY FOR SELECTED INFECTIOUS AGENTS IN TWO SYMPATRIC SPECIES OF CORMORANTS (PHALACROCORAX ATRICEPS AND PHALACROCORAX MAGELLANICUS) FROM COASTAL PATAGONIA, ARGENTINA

We conducted a serologic survey for selected infectious agents on two sympatric cormorants, the Imperial Cormorant (Phalacrocorax atriceps) and the Rock Shag (Phalacrocorax magellanicus). Blood was collected from 267 Imperial Cormorants and 106 Rock Shags at 17 colonies along the Patagonia Atlantic shore during nine breeding seasons (1994, 1999-2001-2005-2008-2010). Antibodies to four pathogens were common to both species and frequently observed: avian paramyxovirus type 1 (56% of Imperial Cormorants and 56% of Rock Shags); avian adenovirus (67% of Imperial Cormorants and 40% of Rock Shags); infectious bronchitis virus serotypes IBV-41, IBV-46, IBV-99, and IBV-JMK (53% of Imperial Cormorants and 64% of Rock Shags); and Salmonella pullorum (18% of Imperial Cormorants and 7% of Rock Shags). Antibody prevalence for these pathogens varied significantly between species, except for avian paramyxovirus type 1. Exposure to avian paramyxovirus type 1 and all serotypes of infectious bronchitis virus varied significantly among seasons in both species. In contrast, the sporadic occurrence of positive titers suggest that cormorants had occasional exposure to Aspergillus spp. (3% of Rock Shags, only in 2000), avian paramyxovirus type 3 (5% of Rock Shags, only in 2008), Chlamydophila spp. (1% of Imperial Cormorants, only in 2010), and avian reovirus (1% of Rock Shags, only in 1999; 29% of Imperial Cormorants, in 2008 and 2010). Both species were antibody negative for avian encephalomyelitis virus, avian influenza virus, avian laryngotracheitis virus, avian paramyxovirus type 2, and infectious bursal disease virus. We provide the first information on pathogen exposure, indicated by detection of antibody in blood samples, for two sympatric species of South Atlantic cormorants. To determine major causes of morbidity and mortality in these birds future efforts should focus on necropsy surveys in cormorant colonies.

Development and Application of Quantitative Real-Time PCR for the Rapid Detection of Hemorrhagic Enteritis Virus in Tissue Samples

Hemorrhagic enteritis virus (HEV) is a type II avian adenovirus that causes intestinal hemorrhages accompanied with immunosuppression in 4-to-12-wk-old turkeys. In the present study, a hexon gene-based, quantitative real-time PCR with TaqMan probe was developed and applied to tissue samples from poultry farms to detect and quantify HEV genome copy numbers. The method was confirmed to be rapid, specific, and sensitive for the detection of HEV. This method is an excellent research and diagnostic tool that can be used to study pathogenesis and to gain insights into different phases of infection on poultry farms and for high-throughput epidemiologic investigations.

Adenoviral Gizzard Erosion in Broiler Chickens in Germany

Avian adenovirus infections cause important disease complexes in chickens, but many of the viruses also infect chickens without resulting in overt disease. Previously several outbreaks of gizzard erosions caused by a fowl adenovirus A serotype-1 (FAdV-1) were reported from Japan. Here we report an outbreak of gizzard erosions in 12 broiler flocks in Germany in 2011. Chickens had a reduced daily weight gain and a higher total mortality rate of up to 8%. The birds showed a severe detachment of the koilin layer and ulcerative to necrotizing lesions of the underlying mucosa. Histopathologically, necrotizing ventriculitis with basophilic, intranuclear inclusion bodies in epithelial cells was diagnosed. Immunohistochemistry, egg culture, and electron microscopic examination revealed adenovirus-like particles in the samples. No concurrent infectious agent could be identified. The virus was genotyped as FAdV-1 by PCR and subsequent sequencing. Phylogenetic analysis of the hexon loop L1 gene yielded 100% sequence identity to the chicken embryo lethal orphan strain. These findings suggest that outbreaks of adenoviral gizzard erosion can lead to significant economic losses in Germany and may be caused by an unusual virulent FAdV-1 strain.

Pathogenicity of recent field isolate of Avian Adenovirus Serotype-IV of hydropericardium syndrome (Angara disease)

The pathogenicity of recent field isolate of Avian Adenovirus Serotype IV (AAS-IV) was determined during the present study. During the present investigations, Hydropericardium Hepatitis Syndrome (HHS) showed reduced pathogenicity as compared to the isolates studied on the inception of the syndrome in 1987-1988. Pathogenicity of the virus was determined through LD50 and challenge protection test. The LD50 titre of the 10% viral suspension prepared from liver filtrate was found to be 10-2.5 per ml in 26 days old broiler chicks. None of the chick showed mortality however, Hydropericardium syndrome of Angara disease was observed on postmortem of the challenged chicks and observations grossly observed in the form of lesions on liver, hydronephrosis and water around heart (yellow straw coloured). These findings proved that the injected virus suspension was biologically active. Formalinized vaccines for HHS including Aqua Base Liver Organ (ABLO) vaccine and Oil Base Tissue Culture (OBTC) vaccine are effective for the control of the syndrome. The vaccination against HHS has positive effect on the immune response of the chicks against HHS. Due to extensive vaccination in the field there is a reduction in the virulence of the virus. Key words: Pathogenicity, adenovirus, Angara disease, LD50.

A retrospective PCR investigation of avian Orthoreovirus, chicken infectious anemia and fowl Aviadenovirus genomes contamination in commercial poultry vaccines in Brazil

Vacinas avicolas vivas comerciais produzidas entre 1991 e 2005 foram examinadas para a presenca de genomas dos virus da anemia infecciosa das galinhas (Gyrovirus CAV), da hepatite por corpusculo de inclusao (Aviadenovirus FAdV) e da artrite viral/sindrome da ma absorcao (Orthoreovirus aviario ARV). Vinte e seis partidas de vacinas vivas liofilizadas de oito fabricantes com lacre original foram examinadas. As extracoes de DNA e PCR de CAV e FAdV, e de RNA e RT-PCR para ARV, foram descritas previamente. Contaminacoes triplas de ARV, CAV e FAdV foram detectadas em vacinas de mesmo fabricante, produzidas em 1991 e 1992 contra a doenca de Newcastle (DN), e para a encefalomielite aviaria, produzida em 1994. ARV e CAV em co-infeccao foram encontrados em vacinas contra a doenca de Marek liofilizadas produzidas em 1996 por dois fabricantes diferentes. Genoma de ARV foi detectado em vacinas contra a bronquite infecciosa de setembro e dezembro de 1998, doenca infecciosa bursal, de dezembro de 1998 e DN de janeiro de 1998. Tres dos oito fabricantes apresentaram vacinas com contaminacao e cinco nunca apresentaram vacinas contaminadas. Nenhuma vacina produzida a partir de 2001 apresentou contaminacao. Cogita-se um papel epidemiologico para vacinas vivas, como fonte de infeccao para ARV, CAV e FAdV e, potencialmente determinante da atual alta disseminacao destes.

Molecular charecterization of Avian Adeno virus causing Inclusion Body Hepatitis-Hydropericardium syndrome in broiler chickens of Anand, Gujarat, India

Molecular charecterization of Avian Adeno virus causing Inclusion Body Hepatitis-Hydropericardium syndrome in broiler chickens of Anand, Gujarat, India

Rapid Detection of Group I Avian Adenoviruses by a Loop-Mediated Isothermal Amplification

A loop-mediated isothermal amplification (LAMP) assay was optimized for the rapid detection of Group I avian adenoviruses. A set of six primers was designed from the DNA sequences of hexon genes from Group I avian adenovirus. The assay was performed in a water bath for 60 min at 63 C, and the amplification result was visualized by adding a fluorescence dye reagent or by inspecting the white sediment. The results showed that the LAMP assay could detect all 12 serotypes of Group I avian adenovirus and nine Guangxi Group I avian adenovirus isolates. This avian adenovirus Group I-specific LAMP assay could detect 238 copies of avian adenovirus. No cross-reactions were detected using the LAMP assay with avian adenoviruses type II and III or with other avian viruses. The ability of LAMP to detect Group I avian adenovirus isolates was further evaluated with 184 cloacal swab samples from poultry. In total, 72 out of 184 cloacal swab samples from poultry were identified as positive by LAMP, whereas 45 out of 184 were identified as positive by conventional PCR test. The Group I avian adenovirus specific LAMP results were further confirmed by real-time PCR. This specific LAMP method holds promise as a rapid and specific diagnostic assay for detection of samples from birds suspected of adenovirus infection.

Rapid Detection of Group I Avian Adenoviruses by a Loop-Mediated Isothermal Amplification

Rapid Detection of Group I Avian Adenoviruses by a Loop-Mediated Isothermal Amplification

Two fiber genes of nearly equal lengths are a common and distinctive feature of Fowl adenovirus C members

The complete genome or the genome region containing the two fiber genes of two reference strains and one field isolate representing both serotypes of Fowl adenovirus C were sequenced. Two fiber genes were revealed in the genomes of all three isolates. Fiber-1 and fiber-2 genes of several Fowl adenovirus C isolates were sequenced as well. Both serotypes 4 and 10 have two fiber genes. The genome region containing the fiber gene was also sequenced for the reference strain of Fowl adenovirus B. Just one fiber gene was revealed in this strain. Predicted amino acid sequences were compared to already published fiber sequences of different adenovirus isolates and one amino acid substitution within fiber-2 was detected in all of the Fowl adenovirus C isolates that were isolated from chickens with hepatitis-hydropericardium syndrome in comparison to apathogenic isolates. Phylogenetic analyses provided insights about the evolution of fiber genes in avian adenoviruses and their genetic relationships.

Duplex PCR assay for the detection of avian adeno virus and chicken anemia virus prevalent in Pakistan

Avian Adeno viruses and Chicken Anemia Viruses cause serious economic losses to the poultry industry of Pakistan each year. Timely and efficient diagnosis of the viruses is needed in order to practice prevention and control strategies. In the first part of this study, we investigated broilers, breeder and Layer stocks for morbidity and mortality rates due to AAV and CAV infections and any co-infections by examining signs and symptoms typical of their infestation or post mortem examination. In the second part of the study, we developed a duplex PCR assay for the detection of AAV and CAV which is capable to simultaneously detect both the viral types prevalent in Pakistan with high sensitivity and 100% specificity.

Avian adenoviruses infections with special attention to inclusion body hepatitis/hydropericardium syndrome and egg drop syndrome.

Avian adenoviruses infections with special attention to inclusion body hepatitis/hydropericardium syndrome and egg drop syndrome.

Construction of CELO recombinant adenoviruses expressing avian type an influenza virus hemagglutinin gene and its use as vaccine against avian influenza virus type a H5N1 and H7N1

The recombinant CELO avian adenovirus is a promising vector for gene transport into eukaryotic cells. This provides an opportunity to use this vector as vaccine against bird pathology. The humoral and immune response requires high transgene expression in transgene virus vector. A CELO recombinant avian adenovirus was constructed that yields a high rate of expression in permissive bird cells. In order to achieve this, 5′-nontranslated regulatory elements of late region of transcription of genome of CELO virus, such as the two-part leader and leader of hexon gene, were used. It was determined that the obtained CELO recombinant adenovirus characterizes by higher (by two to three times) level of expression of report gene in vitro and in ovo compared to the control. CELO recombinant adenoviruses that carry the gene of hemagglutinin of viruses of influenza A H5 and H7 as part of the enhanced expressing cassette were constructed further. The immunization of chickens by CELO-H5 and CELO-H7 recombinant adenoviruses completely protects birds from high pathogenic strains of influenza viruses A H5N1 and H7Na.

銘柄肉用鶏におけるグループⅡトリアデノウイルスによる巨脾症の発生と鶏への接種試験

2006年8～9月，食鳥処理場にて銘柄肉用鶏が，白斑を伴う脾腫によりマレック病を疑われ月別で0.53 ～1.88 ％が全廃棄となった．2007年7月にも同病態がみられ，脾臓50個を採材し検査した．病理組織検査で，リンパ濾胞と莢組織の増生，単核食細胞系（MPS）細胞にfull型核内封入体を認め，電子顕微鏡検査で，アデノウイルス様粒子を検出した．グループⅡトリアデノウイルス（GⅡAAV）検出PCRは陽性であり，シークエンス解析では，非病原性キジ出血性腸炎ウイルスVirginia系統と最も高い相同性を示した（97.3％）．8週齢の同銘柄鶏への接種試験では，4日後に脾腫がみられ，GⅡAAV検出PCRは，脾臓，胸腺などで陽性であった．