71 research outputs found
Inactivated and live bivalent fowl adenovirus (FAdV8b + FAdV11) breeder vaccines provide broad-spectrum protection in chicks against inclusion body hepatitis (IBH)
No full textFowl adenovirus (FAdV) is comprised of five species (A to E) and 12 serotypes (1–7, 8a, 8b, 9–11). Inclusion body hepatitis (IBH) is caused by FAdV-7, 8a, 8b (species E) and FAdV-2 and 11 (species D). Commercial vaccines against IBH are not available in Canada. Autogenous FAdV broiler breeder vaccines are now used in some areas where outbreaks of IBH are occurring. The objective of this study was to evaluate the efficacy of a bivalent (species D and E) live and an inactivated FAdV broiler breeder vaccine in protecting broiler chicks against IBH through maternal antibody (MtAb) transfer. FAdV seronegative broiler breeders (n = 300/group) received either a live or inactivated bivalent (FAdV-8b-SK + FAdV-11-1047) vaccine. The live vaccine (1 × 104 TCID50 of each virus/bird) was given orally once at 16 weeks of age and the inactivated vaccine (1 × 106TCID50 of each virus + 20% Emulsigen D) was given intramuscularly at 16 and 19 weeks of age. Controls (n = 150) were given saline orally. The inactivated vaccine group was boosted 3 weeks later with the same vaccine. Neutralizing antibodies (NAb) in sera (n = 10) were detected at 19, 22, 30 and 48 weeks of age. NAb were able to neutralize various FAdV serotypes within species D and E. Mean NAb were similar in the both live and killed vaccine groups at 19, 30 and 48 weeks and ranged from 2.4 to 3.7 log10. Approximately 26 ± 7% of MtAbs were passively transferred through eggs to day-old chicks. Progeny challenged with a lethal dose (1 × 107 TCID50/bird intramuscularly) of FAdV-8b-SK, FAdV-11-1047, or FAdV-2-685 (n = 90/group) at 14 days post-hatch (dph) showed 98–100% protection in broiler chicks to homologous or heterologous FAdV challenges. Our data suggests that a bivalent live and an inactivated FAdV vaccine are equally effective and have the potential for the control of IBH.Chicken Farmers of Saskatchewan (Saskatchewan Chicken Industry Development Fund)Saskatchewan Agriculture Development FundNatural Sciences and Engineering Research Council of Canada and AgricultureAgri-Food Canada (AAFC) Growing Forward
Broad spectrum protection of broiler chickens against inclusion body hepatitis by immunizing their broiler breeder parents with a bivalent live fowl adenovirus vaccine
No full textHistorically, fowl adenovirus (FAdV) associated inclusion body hepatitis (IBH) was considered a secondary disease in broiler chickens associated with immunosuppression. However, we previously reported the occurrence of IBH as a primary disease in the broiler chicken industry in Canada as a result of infections with various FAdV serotypes. Therefore, the objectives of this study were to develop an immunization strategy in broiler breeders using live FAdV 11-1047 and FAdV8a-TR59 to confer homologous and heterologous protection in broiler progeny against IBH and to study the efficacy of natural exposure of naïve broiler breeders to a vaccine virus from live FAdV vaccinated birds as an immunization technique. Broiler breeders vaccinated orally with FAdV8a-TR59 (1 × 104 TCID50/bird) and FAdV11–1047 (1 × 104 TCID50/bird), FAdV8a-TR59 (1 × 106 TCID50/bird) and FAdV11-1047 (1 × 106 TCID50/bird) or FAdV8b (1 × 106 TCID50/bird) transferred substantial levels of neutralizing antibodies to their progeny. The efficacy of maternal antibodies was studied by challenging 14-day old broiler chickens with 1 × 107 TCID50 of FAdV2–685, FAdV7-x11a like, FAdV8a-TR59, FAdV8b-SK or FAdV11-1047 which are the dominant serotypes causing IBH outbreaks in Canada. Broiler chickens from the low and high dose vaccinated breeders were significantly protected against all serotypes of FAdV (P < 0.05). Comingling of unvaccinated broiler breeders with FAdV-vaccinated broiler breeders was an effective immunization technique for in-contact naïve birds. This study confirms that IBH can be effectively controlled in Canada by vaccination of broiler breeder parents with a bivalent vaccine containing live FAdV8a-TR59 and FAdV11-1047.Saskatchewan Chicken Industry Development FundSaskatchewan Agriculture Development FundNatural Sciences and Engineering Research Council of Canada and AgricultureAgri-Food Canada (AAFC) Growing Forward
Immunogenicity and protective efficacy of virus-like particles and recombinant fiber proteins in broiler-breeder vaccination against fowl adenovirus (FAdV)-8b
No full textInclusion body hepatitis (IBH) is an economically important diseases in broiler chicken industry. Several serotypes of fowl adenovirus (FAdV) can cause IBH, among them, serotype FAdV-8b is associated with the majority of the IBH cases in Canada. Here, we evaluated FAdV-8b virus-like particles (VLPs) and recombinant FAdV-8b fiber proteins (expressed in E. coli) as potential broiler-breeder vaccines against IBH. For assessing the immunogenicity of vaccines, we investigated both humoral and cellular immunity. The humoral immune response was evaluated by determining total IgY and virus-neutralizing antibody in serum at 14, 28, 35 and 60 days post-immunization (dpi). We examined cellular immunity using flow cytometry by determining CD4:CD8 ratio change in peripheral blood after the booster vaccination. The protective effect of vaccines was tested by challenging 14 day-old progeny (n = 30/group) carrying maternal antibodies (MtAb) by challenging with virulent FAdV-8b virus (1 × 107 TCID50, FAdV-8b-SK). Although total IgY levels were comparable in all groups, the neutralizing antibody response in broiler-breeders at 35 and 60 dpi was significantly (p < 0.05) higher those vaccinated with FAdV-8b VLPs followed by FAdV-8b fiber compared to fiber-knob. Moreover, vaccines comprised of FAdV-8b VLPs and FAdV-8b fiber rather than FAdV-8b fiber-knob efficiently elicited the cell-mediated immune response as evidenced by a statistically significant (p < 0.05) CD8+ T-cell proliferative response in broiler-breeders four days after the booster vaccination. Unlike FAdV-8b fiber-knob, FAdV-8b VLPs, and FAdV-8b fiber vaccinated broiler-breeders were able to transfer a substantial amount (28.4 ± 9%) of MtAb to their progeny. Challenge revealed that MtAb provided 100% and 82.7% protection in progeny hatched from FAdV-8b VLPs, and FAdV-8b fiber vaccinated broiler-breeders, respectively. Collectively, our data suggest that FAdV-8b subunit vaccine-induced MtAb efficiently protected progeny against clinical IBH and broiler-breeder vaccination with subunit vaccines is a potential approach to protect against IBH.Saskatchewan Chicken Industry Development FundSaskatchewan Agriculture Development FundNatural Sciences and Engineering Research Council of Canada and AgricultureAgri-Food Canada (AAFC) Growing Forward
Tapping Economies of Scale and Scope in Consumer Cooperation - A Case Analysis of Possible Cooperation among selected Cooperatives
No full textBecause of its narrow and negative perspective of safeguarding the interests of only poor consumers against unethical practices of the private traders, consumer cooperation in India seems to have failed, except probably in some isolated pockets. A number of social welfare functions like poverty alleviation and public distribution of essential items of consumption have been imposed on them at the cost of their basic economics. With the basic micro and macro-economic rationale for consumer cooperatives as a positive form of economic organization being lost sight of, they seem to be facing enormous problems both historically as well as currently in a era of economic liberalization. Their worries seem to have been compounded with the threat of impending competition from large private enterpriss - both domestic and foreign, which highlights the need for evolving strategies to rectivy their systemic weaknesses and tackling the competition head on. This case has attempted to document just such an initiative through a round table conference with several doyens of the consumer cooperative movement in India such as Warana Bazar and Amalsad Mandali as well as some fledging consumer cooperatives from West Bengal which are already in existence for some time or contemplating entry into this field. The roundtable conference organized in the spirit of Cooperation among Cooperatives attempted to evolve strategies to capture economies of scale and scope in order to take on the competition, as well as to facilitate dissemination of ideas and information across the country.
Characterization of fowl adenoviruses from outbreaks of inclusion body hepatitis/hydropericardium syndrome in Chile
No full textThree fowl adenovirus (FAV) isolates (341, 344, and 215) obtained during 1996-97 from field outbreaks of inclusion body hepatitis/hydropericardium syndrome (IBH/HPS) affecting broilers and broiler breeders in Chile were characterized by virus neutralization tests (VNTs) and restriction enzyme analysis of a DNA fragment. Furthermore, the pathologic characteristics of one of these FAV isolates (FAV 341) was studied in experimentally infected chickens. The VNTs conducted with isolates 341 and 344 against reference strains and antisera belonging to each of 12 FAV serotypes demonstrated a close antigenic relationship with strain KR5 of the FAV serotype 4. Polymerase chain reaction using the primers H3/H4 and subsequent HpaII digestion was used for serotype identification of isolates 341 and 215. The length of the PCR products and the restriction profiles of isolates 341, 215, and the reference strain KR5 (FAV4) were identical. The present results confirmed the classification of all three isolates as FAV4. The pathogenicity test with 1000 mean tissue infectious dose of isolate 341 inoculated intramuscularly in 20-day-old specific-pathogen-free chickens resulted in the death of 9% (two birds) six days postinoculation (PI). Both birds showed characteristic IBH/HPS gross and microscopic lesions; the remaining birds, sacrificed at day 10 PI, showed less severe lesions. On the basis of epidemiologic and experimental data of the virulence of Chilean FAV isolates, and the pathogenicity results with isolate 341, we speculate that Chilean FAV strains may require an association with other agents (immunosuppressive agents) to induce IBH/HPS outbreaks in the field
Pathogenicity and immunogenicity of live attenuated and inactivated fowl adenovirus in commercial broiler chickens
No full textFowl Adenovirus (FAdV) is a non-enveloped DNA virus which is the primary pathogen of Inclusion Body Hepatitis (IBH) in chickens. IBH outbreaks were reported worldwide and was first reported in Malaysia in 2005 due to FAdV strain of serotype 8b infection. It was objective of the study to determine pathogenicity and immunogenicity of live attenuated and/or inactivated FAdV strain of serotype 8b (UPM1137) of Malaysian isolate in commercial broiler chickens. The 54, 1-day-old Cobb 500 broiler chicks were divided into four groups, namely groups A-D. Feed and water were provided ad-libitum. The chicks in groups A-C were inoculated with inactivated FAdV (0.2 mL) with virus titer of 106.5 TCID50 /0.2 mL, live attenuated FAdV (0.1 mL) with virus titer of 105.2 TCID50 /0.1 mL and the combination of the inactivated (0.2 mL) and live attenuated (0.1 mL) FAdV, respectively at day old and day 14 post-inoculation (pi). Body weight and blood samples were collected prior to necropsy at days 14 and 28 pi, except sampling was also conducted at day 0 pi in the group D (control). On necropsy, the gross lesions and liver weight were recorded and samples of liver were collected for histological examination. The study showed that neither clinical signs nor gross and histological lesions were recorded in all group of chickens throughout the trial. The body weight of chickens at days 14 and 28 pi were not significantly different (p>0.05) among all the groups. The liver to body weight ratio of group C was significantly higher (p<0.05) than groups A and D at day 28 pi. The FAdV antibody titer in group D (control) was 938±1596 on day old and was not detected at days 14 and 28 pi. However, the FAdV antibody was induced at high titer in all the inoculated groups at days 14 and 28 pi. The FAdV antibody titer of group C was significantly (p<0.05) higher than groups A and B at day 28 pi. It was concluded that the live attenuated and inactivated FAdV are safe and able to induce FAdV antibody titer in broiler chickens with moderate level of maternally derived antibody at day old of age. The combination of live attenuated and inactivated FAdV was able to induce higher antibody titer when compared to sole use of live attenuated or inactivated FAdV. It has high potential to be used as vaccination strategy against IBH outbreaks
Shedding, Kinetics, Molecular Epidemiology and Improved Surveillance of Inclusion Body Hepatitis (IBH) Caused by Fowl Adenovirus Type-8b in Broiler Chicken
No full textWhilst working as the livestock manager of an integrated poultry company in Fiji the author was faced with the difficult task of managing the loss of production returns due to Inclusion body hepatitis (IBH) caused by Fowl Adenovirus of serotype 8b (FAdV-8b) from the Aviadenoviridae family of the Adenoviridae genus. At the same time, a Poultry CRC project looking at methods to quantify and inactivate viruses in poultry litter to allow safe re-use of spent litter was being formulated in Australia. As a result, this doctoral project aimed to investigate the viral kinetics in the host, the effect of the virus on the immune-related organs, the shedding patterns of FAdV-8b from the host and contamination of the litter associated with such shedding and, the time-temperature associations required for the inactivation of this virus in the litter. Another objective of this thesis was to determine whether FAdV-8b viral genome could be readily detected from poultry house dust samples and whether this information would have some diagnostic and surveillance value, allowing for non-invasive sampling methods that do not require a cold chain logistics for shipment to laboratories for developing countries. The final aim was to determine the main risk factors for IBH during an outbreak in Fiji. To address these aims, six different experiments were designed, implemented and the results analysed and evaluated. These included development and optimisation of methods of sample collection and extraction of nucleic acids and optimisation of a quantitative PCR that enabled detection and measure absolute quantification of FAdV-8b genome copies (GC) in tissues, faeces, dust and litter. This was preceded by a thorough search in the literature for potential gaps in the knowledge relating to the objectives being addressed. Analysis of a significant production dataset comprising 1623 broiler flocks between April 2008 and July 2014, kindly made available by the integrated poultry company from Fiji revealed the negative effects IBH disease had on production and identified as major risk factors multi-age production systems and inadequate shed rest times. Two animal challenge experiments, involving FAdV-8b maternal antibody (MAb) negative and MAb+ chickens infected soon after hatch (0 or 3 d.o.a) and 14 days later, were carried out revealing clear shedding profiles of FAdV-8b in faeces for the first time. In MAb- chicken, shedding of FAdV-8b was detected from 3 dpi and for both challenge ages the peak was at 5 days post inoculation. However, the difference was that the shedding in the group challenged at 3 days of age continued post 28 dpi whereas in those inoculated 14 days later, the viral GC was undetectable by 21 dpi. For MAb+ chicken, shedding was detected at 7 dpi and both inoculated groups displayed a similar pattern of shedding peaking between 14 and 19 dpi and continuing post 28 dpi. The level of shedding was significantly higher in 16 d.o. inoculated group. This is the first study to report detection and quantification of FAdV-8b GC in poultry house dust. The high FAdV-8b GC observed in dust samples over time is suggestive of accumulation and persistence of FAdV-8b in the environment. In this sense it may not be reflective of the actual current shedding pattern in the birds. Strong positive associations showing increases in FAdV-8b GC in liver resulting in corresponding increases in FAdV-8b GC in faeces and dust was encouraging as it suggested the potential of using dust samples as a monitoring tool and using this information in developing a sound biosecurity program for the farm to prevent future outbreaks. The detection of typical IBH lesions by histopathology, by an independent pathology laboratory, together with the significant FAdV-8b GC load in liver samples demonstrated that FAdV-8b is transmissible via contaminated air. In MAb- chickens, the total GC numbers per organ also demonstrated that younger birds were capable of producing large amounts of virus in their organs when compared to older birds. This however was different for MAb+ chickens where birds infected at 16 d.o had significantly higher levels of viral GC in liver than those infected at 0 d.o. In MAb- chickens, age resistance was observed particularly in terms of resistance to bursa and thymus atrophy and bodyweight. Chickens that were exposed to FAdV-8b infection earlier in life exhibited typical clinical signs to IBH and tended to have more severe effects on the immune organs and had more severely impaired performance parameters. In MAb+ chickens, the role of maternal antibodies in damping early clinical disease development prior to agerelated resistance is clearly seen. Chickens exposed to FAdV-8b infection at both ages were able to tolerate infection without showing any clinical signs. The absence of clinical syndromes is a marked difference to the results from experiment involving MAb- chickens where classical IBH signs were noticed in chickens infected with the same inoculant and at the same dosage. This is more evidence to support age-related resistance to IBH infection, as the birds are able to tolerate infection without showing any clinical signs. Two final experiments investigated time-temperature effects on inactivation of FAdV-8b in broiler litter using a chick bioassay of infectivity and qPCR detection of GC in litter as endpoints. Clear effects were demonstrated that FAdV-8b can be inactivated to safe levels when litter is exposed to temperatures of 45˚C or higher for at least 5 days. There was a clear overall correlation of detection of viral genome by qPCR with loss of viral infectivity for FAdV-8b. Enumeration of GC was also affected by temperature and time with marked reductions at higher temperatures except when litter was dry and had been stored frozen for a long period (11 months). Loss of detection of viral nucleic acids lagged behind loss of infectivity so was not an accurate direct measure of it, particularly in dry litter, but showed some promise as a marker of infective virus content in fresher litter. These findings enable more accurate prediction of viral inactivation rate in litter pasteurised by heaping, for which spatial and temporal variation in temperature has been well modelled. Effective pasteurisation of used litter making it safe for multi-batch re-use will reduce costs of production and the carbon footprint of poultry production. Additional findings included demonstration of a clear temporary immunosuppressive effect of FAdV-8b in SPF chickens, manifest as reduced relative bursal weight. The detection of high levels of FAdV-8b in darkling beetle adults and larvae from infected farms in Fiji flag the potential of darkling beetles as a vector for FAdV-8b. These findings improve our understanding of IBH infection in chickens, factors affecting this, provide some alternative sampling methods for monitoring the disease, and provide new information on the persistence of FAdV-8b in litter under different temperature conditions that can assist in better decision making for prevention and management of this disease
Systematic study of hybrid triplex topology and stability suggests a general triplex-mediated regulatory mechanism
No full textBy combining in silico, biophysical, and in vitro experiments, we decipher the topology, physical, and potential biological properties of hybrid-parallel nucleic acids triplexes, an elusive structure at the basis of life. We found that hybrid triplex topology follows a stability order: r(Py)-d(Pu)·r(Py) > r(Py)-d(Pu)·d(Py) > d(Py)-d(Pu)·d(Py) > d(Py)-d(Pu)·r(Py). The r(Py)-d(Pu)·d(Py) triplex is expected to be preferred in the cell as it avoids the need to open the duplex reducing the torsional stress required for triplex formation in the r(Py)-d(Pu)·r(Py) topology. Upon a massive collection of melting data, we have created the first predictor for hybrid triplex stability. Leveraging this predictor, we conducted a comprehensive scan to assess the likelihood of the human genome and transcriptome to engage in triplex formation. Our findings unveil a remarkable inclination-of both the human genome and transcriptome-to generate hybrid triplex formation, particularly within untranslated (UTRs) and regulatory regions, thereby corroborating the existence of a triplex-mediated regulatory mechanism. Furthermore, we found a correlation between nucleosome linkers and Triplex-forming sequence (TFS) which agree with a putative role of triplexes in arranging chromatin structure.VG thanks the European Molecular Biology Organization (EMBO) for financial support (ALTF 103-2018) and “Juan De La Cierva Fellowship” (IJC2019-040468-I/25A04100). MO thanks Spanish Ministry of Science [PID2021-122478NB-I00]; BioExcel-3: Centre of Excellence for Computational Biomolecular Research [European Union: 101093290; Ministerio de Ciencia e Innovación: PCI2022-134976-2]; Instituto de Salud Carlos III − Instituto Nacional de Bioinformatica, Fondo Europeo de Desarrollo Regional [ISCIII PT 17/0009/0007]; European Regional Development Fund, ERFD Operative Programme for Catalunya, the Catalan Government AGAUR [SGR2021 00863]. The IRB Barcelona is the recipient of a Severo Ochoa Award of Excellence from the MINECO.The authors thankfully acknowledge the NMR resources and the technical support provided by the LRB and LMR of the Spanish ICTS Red de Laboratorios de RMN de Biomoléculas (R-LRB).
Author contributions: Conceptualization: MT, IBH, MO; Data curation: AS, GP; Formal Analysis: VG, GP, AS, ISC, PA, IBH; Funding acquisition: MO; Investigation: VG, GP, AS, MT, ISC, JG, NV, LM, CC, ML, AA, AH, AG, PA, IBH, CG, RE; Methodology: GP, MT; Project administration: IBH, MO; Resources: MO; Software: GP, AS, AH; Supervision: IBH, CG, RE, MO; Visualization: GP, MT, ISC, IBH; Writing – original draft: VG, MT, MO; Writing – review & editing: AS, ISC, IBH, MO.Peer reviewe
Adaptation and attenuation of fowl adenovirus in mammalian cell line
No full textHighly pathogenic Fowl Adenoviruses (FAdVs) have been recognised as the primary pathogen of inclusion body hepatitis (IBH) in many poultry producing areas and thus, there is a need to develop vaccine for the control and prevention of the disease. It was the objective of the study to determine the adaptation and attenuation of FAdV (UPM1137) isolated from chickens with IBH in mammalian cell line (Vero cells). Confluent monolayer of Vero cells were inoculated with 0.1mL FAdV inoculum and monitored daily until day 7 post inoculation (pi) for cytopathic effect (CPE). CPE was recorded on day 6 pi on the first (P1) and subsequent passages up to passage 5 (P5). It was further confirmed that the CPE belong to FAdV by polymerase chain reaction (PCR) and sequence analysis. The virus successfully adapted and attenuated up to P5 with presence of amino acids changes. Phylogenetic trees revealed both samples from original homogenate embryo liver (P0) and P1 infected Vero cells (P1) were classified under FAdV group E strain (serotype 8). However, the FAdV at P5 could not be assigned to any clusters within groups as it might be due to a new strain of FAdV
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