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PubMedDate not supplied

Efficacy of a recombinant fowl pox-based Newcastle disease virus vaccine candidate against velogenic and respiratory challenge.

A fowl pox-based recombinant virus TROVAC-NDV (vFP96.5) was developed expressing the fusion and hemagglutinin-neuraminidase glycoproteins from a velogenic strain of Newcastle disease virus (NDV). Studies in specific-pathogen-free birds indicated that inoculation of a single dose of the recombinant led to the induction of significant levels of hemagglutination-inhibiting antibody that were maintained to 8 wk postinoculation. Further, the recombinant induced protective immunity against a combined intramuscular velogenic NDV challenge and respiratory NDV challenge. In commercial broiler chickens that were inoculated in the presence of maternally derived NDV immunity, the level of the NDV-specific humoral response was dampened, but significant levels of protection against both a lethal intramuscular NDV challenge and a fowl poxvirus challenge were obtained.

Animals↗
PubMedDate not supplied

An atypical fowl pox outbreak in broilers in southern Brazil.

An unusual fowl pox outbreak occurred in two integrated broiler operations. The uncommon characteristic of this outbreak was that the pox lesions were manifested in the feathered parts of the body, mainly in the posterior dorsal area and external part of the thigh. Diagnosis was made by means of histopathology and virus isolation. Severe losses were incurred at the processing plant as a consequence of condemnation due to dermatitis. Vaccination of day-old chicks with mild fowl pox vaccine combined with Marek's disease (HVT) vaccine in the area of the outbreak appeared to be important in controlling the disease.

Animals↗
PubMedDate not supplied

Protection and synergism by recombinant fowl pox vaccines expressing genes from Marek's disease virus.

Recombinant fowl poxviruses (rFPV) were constructed to express genes from serotype 1 Marek's disease virus (MDV) coding for glycoproteins B (gB1), C (gC), and D (gD) and tegument proteins UL47 and UL48, as well as genes from serotypes 2 and 3 MDV coding for glycoprotein B (gB2 and gB3). These rFPVs, alone and in various combinations, including combinations of fowl poxvirus (FPV)/gBs with turkey herpesvirus (HVT), were evaluated for ability to protect maternal antibody-positive (ab+) and -negative (ab-) chickens against challenge with highly virulent MDV isolates. The protective efficacy was also compared with that of prototype Marek's disease (MD) vaccines. No protection was induced in ab+ chickens by rFPV expressing gC, gD, UL47, or UL48. In contrast, the rFPV/gB1 construct protected about 23% of ab+ chickens against MDV challenge compared with 26% for cell-associated HVT. Levels of protection by rFPV/gBs of different MDV serotypes was highest for gB1, intermediate for gB2, and lowest for gB3. When rFPV/gB1 was combined with cell-associated HVT, protection was enhanced by an average of 138% compared with the best component monovalent vaccine, and the mean level of protection was 59% compared with 67% for the HVT+SB-1 bivalent vaccine. Relatively high protection (50%) and enhancement (200%) were also observed between rFPV/gB1 and cell-free HVT. These results suggest a specific synergistic interaction between rFPV/gB1 and HVT, possibly analogous to that previously described between serotypes 2 and 3 viruses. Levels of protection by rFPV/ gB1 alone or by bivalent rFPV/gB1+cell-associated HVT were similar to those of conventional cell-associated MD vaccines. However, the bivalent rFPV/gB1+cell-free HVT vaccine was clearly more protective than cell-free HVT alone and, thus, may be the most protective, entirely cell-free MD vaccine thus far described.

Animals↗
PubMedDate not supplied

[Effect of neuraminidase treatment of chick embryo fibroblasts on the adsorption and reproduction of the fowl plague virus].

Treatment with neuraminidase (100 units/ml) of chick embryo fibroblasts in vitro only partially inhibits adsorption of fowl plague virus on these cells. Cultivation of chick embryo fibroblasts in the presence of 50 units/ml neuraminidase had no effect on the sensitivity of these cells to fowl plague virus and on the extent of virus reproductions. It is suggested that neuraminic acid which is a component of the external cell membrane is not only substance responsible for adsorption of orthomyxoviruses.

Adsorption↗
PubMed1997

Interrelationship between tumour virus receptors, A and C, coded by host cell genes in fowl.

Bryan Standard strain of Rous Sarcoma Virus (BS-RSV) of subgroup A and pseudotype of Bryan high titre RSV(RAV-49) of subgroup C and an equal mixture of subgroup A and subgroup C virus were inoculated to 11-day old embryos of white leghorn (WL), Australorp (AL) and f1 and f2 generations of crosses between WL and AL breeds of fowl to detect and estimate the interrelationship between tumour virus receptor coding host cell genes of tva and tvc loci. Linkage values estimated on a pooled sex basis were 0.08 +/- 0.03 and 0.10 +/- 0.03 for WL and AL breeds respectively and 0.09 on pooled breed basis. This clearly indicates that the tva and tvc loci are indeed closely linked in WL and AL breeds of fowl and supports the concept of using subgroup C virus to raise stocks resistant to subgroup A virus infection.

Animals↗
PubMed1997

New treatment regimens in organophosphate (diazinon) and carbamate (methomyl) insecticide-induced toxicosis in fowl.

The objective of this work was to determine optimal treatment regimens for organophosphate (OP) or carbamate insecticide toxicoses in fowl using the antidotes atropine sulfate and pralidoxime chloride (2-PAM). Broiler chicks in treatment groups, each comprising 3 replicates of 6-7 birds/replicate, were gavaged on a body weight (BW) basis with the OP and carbamate insecticides, diazinon and methomyl, respectively, at lethal dosages. Treatment groups were injected with either or both of the antidotes at various dosages as soon as clinical signs appeared. Birds appearing healthy 24 h thereafter were regarded as having been treated successfully. At a dosage of 100 mg/kg BW, atropine was mildly toxic and at 200 mg/kg 2-PAM was severely toxic (but not lethal), whereas at dosages of 50 and 100 mg/kg BW, respectively, the antidotes were at their most effective. With diazinon, atropine alone was only partially effective (12/20 survivors), whereas 2-PAM was extremely efficacious. (20/20 survivors); the combination of the 2 antidotes at 2 dosages was slightly less effective (19/20 survivors) than 2-PAM alone. For methomyl toxicity, atropine was largely successful (18/20 survivors), whereas 2-PAM was mostly unsuccessful (10/20 survivors); the combination at high dosage was less effective (15/20 survivors) than atropine alone, but at a low dosage the combination was the most successful (20/20 survivors). The results indicate that anticholinesterase insecticide toxicoses in fowl should not be treated according to textbook recommendations, and antidotal dosage with atropine should be up to 100 times greater than is commonly recommended. The specific cause of the toxicoses should ideally be determined before treatment is given, but as this is often unknown, a combination of antidotes may be the optimal treatment protocol.

Animals↗
PubMedDate not supplied

Efficacy of recombinant fowl poxvirus vaccine in protecting chickens against a highly pathogenic Mexican-origin H5N2 avian influenza virus.

Internationally and nationally, governments and the poultry industries have used various strategies to control avian influenza (AI), ranging from a minimum of living with mildly pathogenic AI virus (AIV) infections to the other extreme of implementing a total quarantine-slaughter approach for eradication of highly pathogenic (HP) forms of the disease. However, recent economic considerations in various countries have prompted a broader reevaluation of vaccination as one of several tools to be used in AI control programs, including H5 and H7 HP AI. In the current study, 1-day-old chickens were immunized with a recombinant fowl poxvirus vaccine containing a hemagglutinin gene insert (Vector-HA) from an H5 AIV. Vector-HA- and negative control (vector-control)-vaccinated chicks were challenged with a HP H5N2 AIV isolated from chickens in Mexico. All immunized chickens were antibody negative on the agar gel precipitin test, indicating that vaccination would not interfere with routine AI serologic surveillance programs in the United States. However, in the hemagglutinin-inhibition test, a few immunized chickens (8%) had low serologic titers. Protection against illness (90-100%) and death (90-100%) was provided by the vector-HA vaccine from 3 wk of age to the end of the 20-wk study. The number of chickens shedding the challenge AIV from their enteric tracts was significantly reduced (50-75%) and the quantity of challenge AIV shed from respiratory and enteric tracts was significantly reduced (10(1)-10(2.1) mean embryo lethal dose/ml) in most vector-HA vaccine groups when compared with vector-control groups. Furthermore, vector-HA vaccination reduced in contact transmission of HP AI challenge virus to both vector-HA- and vector-control-vaccinated chickens. These findings indicate the recombinant fowl poxvirus vaccine can be a useful tool in an AI control program by preventing illness and death in chickens and reducing intestinal and respiratory shedding of H5 AIV. However, for an AI control program to be successful, enhanced biosecurity and surveillance must be practiced, and the vaccine's use must be controlled by an industry and/or government task force.

Animals↗
PubMed1976

Fractionation of fowl immunoglobulins.

Serum, Na2SO4-precipitated serum immunoglobulins and bile from 12-week-old fowls, and serum from day-old chicks, were fractionated by Sephadex G-200 gel filtration, DEAE Sephadex A-50 ion exchange chromatography and ultracentrifugation through 10-40 per cent sucrose gradients. Elution of IgM, IgG, IgA and albumin was monitored by examination of fractions in agar gel diffusion against antisera specific to these proteins. Serum and bile from 12-week-old fowls contained IgM and IgA in two molecular sizes and a single molecular size of IgG. Day-old chick serum contained IgM estimated to be 7S, a polymerised form of IgG in addition to the normal 7S component, and a small molecular weight protein antigenically related to IgA. Most of the albumin in bile was of lower molecular weight than serum albumin, while heavy forms of albumin were detected in ultracentrifugation of bile and day-old chick serum.

Animals↗
PubMedDate not supplied

Isolation of adenoviruses and reoviruses from avian species other than domestic fowl.

Adenoviruses and reoviruses were isolated from pigeons and mallard ducks. In addition, adenoviruses were isolated from budgerigars and a bantam and a reovirus was isolated from a turkey. Primary identification of these viruses was by electron-microscope examination. It was further possible to assign the 4 adenoviruses to recognized fowl serotypes, and the reoviruses shared a common antigen with fowl reoviruses. These viruses were isolated from a variety of clinical conditions.

Adenoviridae↗
PubMedDate not supplied

Bacterin-induced protection of turkeys against fowl cholera following infection with Bordetella avium.

Groups of Beltsville small white turkeys, passively immunized and not passively immunized against Bordetella avium, were challenged with live B. avium at 2 days of age. Birds not passively immunized developed severe bordetellosis with early onset, whereas passively immunized birds developed mild bordetellosis with late onset. Following convalescence, birds with and without exposure to B. avium were vaccinated against fowl cholera with a water-in-oil bacterin. The birds were given a homologous challenge with serotype A: 3 Pasteurella multocida. Although no difference in protection against fowl cholera was seen between vaccinated birds that were previously infected with B. avium and those that were not, survivability was better in birds given two doses rather than 1 dose of bacterin.

Animals↗
PubMed2006

Sequence analysis of the left end of fowl adenovirus genomes.

Nucleotide sequence analysis of the left end of the genome of fowl adenoviruses (FAdV) representing species group C (FAdV-4 and -10), D (FAdV-2) and E (FAdV-8) were carried out, and the sequence data was compared to those of FAdV-1 (FAdV-A) and FAdV-9 (FAdV-D). The viruses were propagated in chicken hepatoma cell line for viral DNA isolation. Restriction endonuclease analysis was performed followed by hybridization with two DNA probes representing the left end of FAdV-9. The identified fragments were sequenced, and the generated data were compared with the GenBank database. Nucleotide sequence homology and amino acid sequence identities were high between members of the same species group, FAdV-2 and -9, and FAdV-4 and -10, whereas different degrees of variations were observed among all FAdVs. Gene arrangement and position of ORFs at the left end of FAdV genomes were largely conserved suggesting similar gene functions. All previously characterized left end ORFs in CELO virus and FAdV-9 were found in all analyzed FAdVs. However, ORF 1C was absent in FAdV-4 and -10, but additional ORFs, most likely corresponding to duplicates of ORF 14, were observed in these viruses.

Amino Acid Sequence↗
PubMed2006

Effect of fowl adenovirus-1 (IBH isolate) on humoral and cellular immune competency of broiler chicks.

Fowl adenovirus-1 (FAV-1), isolated from field outbreaks of inclusion body hepatitis (IBH), was administered orally to 3-week-old disease-free broiler chicks. Humoral immune competency was evaluated by determining the antibody response of infected chicks to sheep red blood cells (SRBC) and Brucella abortus. FAV-1 infection significantly decreased the antibody response of chicks to B. abortus (T-cell-independent antigen) by decreasing IgM responses, however, the decreased antibody response to SRBC (T-cell-dependent antigen) was statistically non-significant. Bursal index was also found lowered in infected chicks as compared to the control chicks. A significant decrease was seen in blastogenesis response of peripheral blood lymphocytes to phytohaemagglutinin (PHA-P) in FAV-1-infected chicks on 2 and 3 weeks post-infection (WPI). These results indicated that FAV-1 affects humoral as well as cellular immune competency of infected chicks.

Animals↗
PubMed2002

Characterization of fowl adenovirus serotype-4 associated with hydropericardium syndrome in chicken.

The polypeptides of three fowl adenovirus-4 (FAV-4) field isolates of hydropericardium syndrome from various geographical areas of the country and the standard FAV-1 (CELO virus) were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis and analysed by protein immunoblotting with polyclonal antibodies to FAV-4 and FAV-1. Protein profile analysis of FAV-4 isolates revealed similarity of all the eight polypeptides with molecular weight ranging from 20 to 107 kDa but differed from CELO, particularly in their 24.2 kDa protein. Subsequent immunoblotting showed relatedness of at least five protein fractions of FAV-4 to CELO virus.

Adenoviridae Infections↗
PubMed2003

Antibody response and virus tissue distribution in chickens inoculated with wild-type and recombinant fowl adenoviruses.

We demonstrated that the long tandemly repeated region (TR-2) is dispensable for in vitro replication of fowl adenovirus 9 (FAdV-9). The TR-2-deleted recombinant FAdV-9 expressing the enhanced green fluorescence protein was further characterized for in vivo effects. Groups of chickens were exposed to recombinant or wild-type FAdV-9 by intramuscular injection, through the feed or drinking water and one group served as a negative control. The antibody (Ab) response, evaluated by ELISA and a plaque reduction test depended on the virus, dosage and the route of inoculation. Although the highest levels of anti-viral Ab were detected in chickens inoculated intramuscularly (i.m.) with wild-type FAdV-9, the deletion of TR-2 did not have a significant effect on the immune response. The tissue distribution of the virus was examined by the polymerase chain reaction (PCR) and was similar for both wild-type and recombinant viruses. Based on these results the TR-2 was dispensable for viral replication in vivo and did not influence virus distribution, and the recombinant FAdV-9 induced the same immune response as the wild-type virus.

Adenoviridae Infections↗
PubMed2006

Relaxed template specificity in fowl adenovirus 1 DNA replication initiation.

The fowl adenovirus 1 (FAdV-1) isolates PHELPS and OTE are highly similar, but have striking differences in the repeat region of the inverted terminal repeat (ITR). Whilst the repeat region in OTE conforms to the conventional human adenovirus repeat region (5'-CATCATC), that of PHELPS contains guanidine residues at positions 1, 4 and 7 (5'-GATGATG). This implies that the FAdV-1 isolates PHELPS and OTE have either distinct template specificity at replication initiation or, alternatively, a relaxed specificity for replication initiation. In this study, the distinct sequence variation at the origin of DNA replication in the ITRs of the FAdV-1 PHELPS and OTE isolates was confirmed. Sequence analyses of the pTP and Pol genes of both PHELPS and OTE did not reveal differences that could explain the distinct template specificity. Replication assays demonstrated that linear DNA fragments flanked by either 5'-CATCATC or 5'-GATGATG termini replicated in cells upon infection with FAdV-1 OTE and FAdV-1 PHELPS. This was evident from the appearance of DpnI-resistant fragments in a minireplicon assay. From these data, it is concluded that FAdV-1 has relaxed, rather than changed, its template specificity at replication initiation.

Amino Acid Sequence↗
PubMed2006

Comparison of the polymerase chain reaction-restriction fragment length polymorphism pattern of the fiber gene and pathogenicity of serotype-1 fowl adenovirus isolates from gizzard erosions and from feces of clinically healthy chickens in Japan.

The fiber gene sequence and pathogenicity of the serotype-1 fowl adenovirus (FAdV-1) isolated from gizzard erosions and from clinically normal chickens were compared among isolates. The FAdV-99ZH strain, which induced gizzard erosions, had a nucleotide sequence of the long fiber gene that was different from that of the Ote strain, which did not induce gizzard erosions. The differences could be distinguished by use of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The long fiber gene of 16 FAdV-1 isolates from gizzard erosions and 10 FAdV-1 isolates from the feces of clinically normal chickens was examined by use of PCR-RFLP analysis. All 16 FAdV-1 isolates from gizzard erosions had the same restriction patterns as those of strain 99ZH; however, 10 FAdV-1 isolates from normal chickens were classified into 3 groups. Specific-pathogen-free (SPF) chickens were inoculated orally with 2 FAdV-1 isolates from gizzard erosions or 3 FAdV-1 isolates from clinically normal chickens to determine the pathogenicity of each strain. Two of 2 FAdV-1 isolates from gizzard erosions induced gizzard erosions. Two of 3 FAdV-1 isolates from normal chickens had the same PCR-RFLP patterns as those of the Ote strain, but did not induce any gizzard erosions. However, 1 FAdV-1 isolate from clinically normal chickens had the same PCR-RFLP pattern as that of strain 99ZH and induced gizzard erosions. These results indicate that there are FAdV-1 strains that have different pathogenicity; one strain induces gizzard erosions, and the other does not. Use of PCR-RFLP analysis of long fiber genes may be able to distinguish between these two strains.

Adenoviridae Infections↗
PubMed2006

Pathogenicity of fowl adenovirus isolated from gizzard erosions to immuno-suppressed chickens.

Pathogenicity of a fowl adenovirus (FAV), JM1/1 strain of serotype 1 derived from gizzard erosions of a broiler chicken, was examined to specific pathogen-free (SPF) chickens pre-treated with infectious bursal disease viruses (IBDVs) or cyclophosphamide (CY). Virulent IBDVs, classical type, were inoculated orally at 3 days of age of SPF chickens. CY was treated subcutaneously for 3 days after hatch. FAV was given orally at 30 days of age. At 40 days of age, all chickens were bled and autopsied for serology and gross observation. Gizzard lesions were ranked by the scores depending on their severities. IBDV- or CY-treated chickens showed significantly higher gizzard lesion scores than non treated birds. There were no gross lesions in any other organs except for bursal atrophy. Serologically, antibody production against FAV was highly suppressed by IBDV infection or CY treatment.

Adenoviridae Infections↗