Showing papers in "Avian Pathology in 2002"
TL;DR: Advances in understanding of epidemiological factors and recent improvements of administration methods that have helped to allay fears and to make the use of anticoccidial vaccines in broilers technically achievable are described.
Abstract: The use of live vaccines, either attenuated or non-attenuated, for the control of coccidiosis due to Eimeria infections in broiler breeder or layer chickens is well established. Use in broilers, however, has been slow to gain acceptance. This has been partly for economic reasons, but also because of perceived adverse effects on early chick growth, particularly with non-attenuated vaccines, and concerns about timely onset of protective immunity in such short-lived birds. This review describes advances in understanding of epidemiological factors and recent improvements of administration methods that have helped to allay these fears and to make the use of anticoccidial vaccines in broilers technically achievable. Topics discussed include: (1) types of commercially available vaccine, (2) vaccines in development, (3) vaccination methods and equipment, (4) basis of vaccine efficacy and immunogenic variation of parasites, (5) key factors in the survival, sporulation and dissemination of vaccinal oocysts, (6) descriptions and significance of patterns of litter oocyst accumulation and occurrence of intestinal lesions in vaccinated flocks, (7) rotation of anticoccidial vaccination and chemotherapy to restore drug sensitivity to resistant wild-type coccidia, (8) combinations of anticoccidial vaccination and chemotherapy, (9) interactions between coccidiosis and clostridiosis in broilers and compatibilities of potential control methods, (10) published performance data for live anticoccidial vaccines in broilers, (11) possible further developments of live vaccines.
321 citations
TL;DR: The HCC and diets supplemented with MOS or PKM affected the birds intestinal microflora by increasing the Bifidobacterium spp.
Abstract: This study first investigates the effects of mash diet, or mash supplemented with either 2.5% mannose-oligosaccharide (MOS) or palm kernel meal (PKM), on the microflora of the hen caecal contents. Second, it investigates the effect of caecal contents of hens (HCC) fed mash or mash supplemented with MOS or PKM on the major microflora groups of chicks, and their inhibitory effect on Salmonella enterica serovar Enteritidis (PT4) colonization. Finally, this study investigates the effect over time of diets supplemented with MOS or PKM on S. Enteritidis colonization and the microflora of chicks. In hens, supplemented diets increased Bifidobacterium spp., while decreasing members of Enterobacteriaceae and Enterococcus spp., compared with the mash diet. Chicks dosed with the HCC showed, on average, increased numbers of anaerobes, while the numbers of aerobes decreased including coliforms and S. Enteritidis compared with controls without HCC. In chicks fed the MOS-supplemented or PKM-supplemented diets, S. Enteritidis colonization decreased over time, compared with mash alone. Four-week-old PKM birds showed an increase in Bifidobacterium spp. and Lactobacillus spp., with a decrease in S. Enteritidis compared with week 2. Generally, the HCC and diets supplemented with MOS or PKM affected the birds intestinal microflora by increasing the Bifidobacterium spp. and Lactobacillus spp., while decreasing the Enterobacteriaceae groups. They also reduced susceptibility in young chickens to colonization by S. Enteritidis.
268 citations
TL;DR: The circulation of the virus and mixed infection with other respiratory pathogens were incriminated in the high mortality on poultry farms and resulting great economic losses and an inactivated H9N2 avian influenza vaccine prevented mortality in experimentally challenged chickens.
Abstract: Since 1998, an epidemic of avian influenza has occurred in the Iranian poultry industry. The agent was pathotyped as non-highly pathogenic and subtyped as an H9N2 avian influenza virus. Therefore it did not require eradication. However, frequent incidences of high mortality were observed commonly on broiler farms. No other species of bird were affected. The circulation of the virus and mixed infection with other respiratory pathogens, particularly infectious bronchitis virus and Mycoplasma gallisepticum , were incriminated in the high mortality on poultry farms and resulting great economic losses. Clinical signs in both field and experimental studies included swelling of the periorbital tissues and sinuses, nasal and ocular discharge, and severe respiratory distress. However, in the experimental study, the mortality rate was much lower than in the natural outbreak. Gross lesions identified included extensive congestion of the respiratory tissues, and exudation with cast formation in the tracheal bifurcati...
230 citations
TL;DR: It is confirmed that coronaviruses are present in pheasants and demonstrated that their genomes are IBV-like in their organization, and it is shown that there is sequence heterogeneity within the group of pheasant coronviruses, especially within the spike protein gene.
Abstract: Reverse-transcriptase polymerase chain reactions (RT-PCRs) were used to examine RNA extracted from mouth/nasal swabs from pheasants exhibiting signs of respiratory disease. The oligonucleotides used were based on sequences of infectious bronchitis virus (IBV), the coronavirus of domestic fowl. A RT-PCR for the highly conserved region II of the 3' untranslated region of the IBV genome detected a coronavirus in swabs from 18/21 estates. Sequence identity with the corresponding region of IBVs and coronaviruses from turkeys was > 95%. A RT-PCR for part of the S1 region of the spike protein gene was positive with 13/21 of the samples. Sequence analysis of the RT-PCR products derived from nine of the pheasant viruses revealed that some of the viruses differed from each other by approximately 24%, similar to the degree of difference exhibited by different serotypes of IBV. Further analysis of the genome of one of the viruses revealed that it contained genes 3 and 5 that are typical of IBV but absent in both the transmissible gastroenteritis virus and murine hepatitis virus groups of mammalian coronaviruses. The nucleotide sequences of genes 3 and 5 of the pheasant virus had a similar degree of identity (approximately 90%) with those of coronaviruses from turkeys and chickens, as is observed when different serotypes of IBV are compared. This work: (a) confirms that coronaviruses are present in pheasants (indeed, commonly present in pheasants with respiratory disease); (b) demonstrates that their genomes are IBV-like in their organization; and (c) shows that there is sequence heterogeneity within the group of pheasant coronaviruses, especially within the spike protein gene. Furthermore, the gene sequences of the pheasant viruses differed from those of IBV to similar extents as the sequence of one serotype of IBV differs from another. On the genetic evidence to date, there is a remarkably high degree of genetic similarity between the coronaviruses of chickens, turkeys and pheasants.
166 citations
TL;DR: It is suggested that the increased incidence of necrotic enteritis in broilers fed barley and wheat diets compared with those fed a corn diet may be due in part to increased clostridial proliferation associated with the wheat and barley diets, or to decreased proliferationassociated with the corn diet.
Abstract: Necrotic enteritis, caused by Clostridium perfringens type A, is more prevalent in broilers fed wheat or barley diets than in those fed a corn diet. We compared the effects of wheat, barley and corn diets on in vitro proliferation of C. perfringens type A. Bacteria were inoculated into the supernatants delivered from either digested or non-digested barley, wheat and corn diets mixed with thioglycollate medium (1:3). Colony forming units were counted following incubation for 6 h at 40°C. There were no significant differences in clostridial proliferation among non-digested diets. Bacterial proliferation in the digested wheat and barley diets was significantly higher than in the digested corn diet. These findings suggest that the increased incidence of necrotic enteritis in broilers fed barley and wheat diets compared with those fed a corn diet may be due in part to increased clostridial proliferation associated with the wheat and barley diets, or to decreased proliferation associated with the corn diet.
160 citations
TL;DR: A strong probability is revealed that the vaccination had lead to the spread of the vaccine virus, causing various disease manifestations and a confusing epizootiological situation in the poultry population.
Abstract: To improve the detection and molecular identification of infectious bronchitis virus (avian coronavirus), two reverse transcriptase-polymerase chain reaction (PCR) assays were developed. As 'diagnostic PCR', a set of consensus nested primers was selected from highly conserved stretches of the nucleocapsid (N) gene. As 'phylogeny' PCR, a fragment of the spike protein gene (S1) was amplified and the PCR products were directly sequenced. To study the phylogenetic relationships of the viruses from various outbreaks, studies of molecular epizootiology were performed in Sweden, a Nordic region, where the occurrence of natural cases of the disease is relatively low and the occasional use of live vaccine(s) is well recorded and monitored. The disease appeared in the region in 1994, associated with production problems among layers of various ages. During outbreaks in 1995 and 1997, both layers and broilers were affected. To reduce losses, a live attenuated vaccine has been applied since 1997. By examining 12 cases...
111 citations
TL;DR: The protective effect of two vaccination regimes using Salenvac, a commercially available iron-restricted Salmonella enterica subsp.
Abstract: The protective effect of two vaccination regimes using Salenvac, a commercially available iron-restricted Salmonella enterica subsp. Enterica serotype Enteritidis PT4 bacterin vaccine, was verified in laying birds. Immunization was intramuscular at 1 day old and again at 4 weeks of age (V2), or at 1 day and 4 weeks with a third dose at 18 weeks of age (V3). Challenge S. Enteritidis (5 to 7.5); x 10(7) colony forming units) was given intravenously at 8, 17, 23, 30 and 59 weeks of age. For all age groups, both vaccination regimes reduced significantly the number of tissues and faecal samples that were culture positive for the challenge strain. For laying birds, fewer eggs (P < 0.001) were culture positive for S. Enteritidis after challenge from vaccinated laying birds (56/439 batches of eggs) than unvaccinated birds (99/252 batches). The data give compelling evidence that the vaccine is efficacious and may contribute to the reduction of layer infection and egg contamination.
110 citations
TL;DR: Eighty isolates of Riemerella anatipestifer representing 71 outbreaks of riemerellosis in Thailand between 1994 and 1999 were serotyped using the gel diffusion precipitin test, demonstrating that the untypable strain probably represents a new serotype.
Abstract: Eighty isolates of Riemerella anatipestifer representing 71 outbreaks of riemerellosis in Thailand between 1994 and 1999 were serotyped using the gel diffusion precipitin test. Based on the precipitation patterns, 25 serological profiles containing one to three antigenic determinants were recognized. Heat-stable antigens of the organism reacted with antisera raised against 16 known serotypes and an untypable strain 698/95. The most prevalent serotype appeared to be serotype 7, followed by serotypes 5, 10, 21 and 1. Further study demonstrated that the untypable strain probably represents a new serotype. Analysis of the polymerase chain reaction-amplified rrs genes for restriction fragment length polymorphisms verified the inclusion of strain 698/95 within the species R. anatipestifer and supported earlier work excluding strain 670/89, which had originally been designated the reference strain of serotype 20. Therefore, it is suggested that the strain 698/95 could be adopted as a replacement for the referenc...
108 citations
TL;DR: The development and application of a one-step RT-PCR test coupled with REA as a fast, specific method for both the detection and typing of APMV-1 from field samples is reported.
Abstract: Amplification of avian paramyxovirus serotype 1 (APMV-1)-specific nucleic acid fragments, followed by restriction endonuclease analysis (REA) using BglI, was carried out to type strains according to their virulence. Primer sequences were used to amplify a 202 base pair fragment, encompassing the fusion protein cleavage site, in a one-step reverse transcriptase-polymerase chain reaction (RT-PCR) test for detection of a range of field cases and reference strains of APMV-1. Subsequent REA of the amplified fragments enabled differentiation of low virulent lentogenic field and vaccine strains from more virulent mesogenic and velogenic field strains of APMV-1, including pigeon PMV-1. In the present paper, we report the development and application of a one-step RT-PCR test coupled with REA as a fast, specific method for both the detection and typing of APMV-1 from field samples.
90 citations
TL;DR: Twenty-seven Newcastle disease virus isolates obtained during the years 1998 and 1999 from racing pigeons were shown to be antigenically indistinguishable from the pigeon paramyxovirus type 1 (PPMV-1) viruses isolated in the years 1983 and 1984.
Abstract: Twenty-seven Newcastle disease virus isolates obtained during the years 1998 and 1999 from racing pigeons were shown to be antigenically indistinguishable from the pigeon paramyxovirus type 1 (PPMV-1) viruses isolated in the years 1983 and 1984. Partial sequencing of 240 base pairs of the F gene demonstrated at least 94.7% identity at the nucleotide level between isolates from 1983 and 1984, and more recent viruses isolated in 1998 and 1999. Most of the nucleotide changes observed were silent mutations as only six amino acid changes were observed. Three amino acid substitutions were observed in the F2/F1 cleavage site. The sequence of the F2/F1 cleavage site of all isolates was typical for pathogenic paramyxovirus 1 viruses. Amino acids at the F2/F1 cleavage site changed from (112)GRQKRF(117) to (112)RRQKRF(117), (112)RRKKRF(117) or (112)RRRKRF(117). The motif (112)RRQKRF(117) was present in the majority of the isolates but the intracerebral pathogenicity indexes of PPMV-1 isolates having this motif was highly variable but largely lower (mean, 0.69) than that reported for PPMV-1 viruses isolated in the years 1983 and 1984 (mean, 1.44).
90 citations
TL;DR: The current regulations preventing vaccination against H5 or H7 MPAI have had the effect of promoting circulation of M PAI virus in commercial poultry and live poultry markets and there is no justification for forbidding the use of inactivated vaccine.
Abstract: Biosecurity is the first line of defence in the prevention and control of mildly pathogenic avian influenza (MPAI). Its use has been highly successful in keeping avian influenza (AI) out of commercial poultry worldwide. However, sometimes AI becomes introduced into poultry populations and, when that occurs, biosecurity again is the primary means of controlling the disease. There is agreement that routine serological monitoring, disease reporting, isolation or quarantine of affected flocks, application of strict measures to prevent the contamination of and movement of people and equipment, and changing flock schedules are necessities for controlling AI. There is disagreement as to the disposition of MPAI-infected flocks: some advocate their destruction and others advocate controlled marketing. Sometimes biosecurity is not enough to stop the spread of MPAI. In general, influenza virus requires a dense population of susceptible hosts to maintain itself. When there is a large population of susceptible poultry...
TL;DR: The available detection methods for avian pneumoviruses (turkey rhinotracheitis virus; genus Metapneumovirus) in turkeys, domestic fowl and other species are reviewed and the problems likely to be encountered are considered.
Abstract: The available detection methods for avian pneumoviruses (turkey rhinotracheitis virus; genus Metapneumovirus ) in turkeys, domestic fowl and other species are reviewed. The advantages and disadvantages of virus isolation techniques, virus or genome (polymerase chain reaction) detection and serology are discussed. Some of the problems likely to be encountered are considered, including the detection of yet to be discovered subtypes, as are the factors that are likely to influence the outcome of the work
TL;DR: Vaccination with HVT provided good protection against most of the immunosuppressive effects of MDV but not against MDV-induced growth impairment and reduced responsiveness to IB vaccination, suggesting that recent Australian strains ofMDV may be evolving in virulence to overcome the protective effects of HVT.
Abstract: Much of the impact of Marek's disease in broiler chickens is considered to be due to immunosuppression induced by Marek's disease virus (MDV). The present study evaluates the effects of an Australian isolate of pathogenic MDV (strain MPF 57) and a non-pathogenic vaccinal strain of herpesvirus of turkeys (HVT) (strain FC 126) on the immune system of commercial broiler chickens for 35 days following challenge at days 0 or 3 of age. It also investigates the extent of protection provided by HVT vaccine against MDV-induced immunosuppression. Immune system variables, including relative lymphoid organ weight, blood lymphocyte phenotype (CD45+/CD3+, putatively T, and CD45+/LC+, putatively B) and antibody production following vaccination against infectious bronchitis (IB) at hatch, were used to assess the immune status of chickens. Immunosuppression was also assessed by susceptibility to secondary challenge with pathogenic Escherichia coli on day 29 post-MDV challenge. MDV infection reduced the weight of the thymu...
TL;DR: This study confirms that B. pilosicoli can cause serious egg production losses in adult chickens, while B. innocens is not obviously pathogenic.
Abstract: The pathogenic potential of the anaerobic intestinal spirochaetes Brachyspira (Serpulina) pilosicoli and Brachyspira innocens was evaluated in adult chickens. Thirty 17-week-old Cobb broiler breeder hens were individually caged in three groups of 10 birds. Control birds (group A) were sham inoculated with sterile broth medium. Birds in the other two groups (groups B and C) were inoculated, respectively, with an isolate of B. innocens or of B. pilosicoli. Birds were monitored daily, and killed at 41 weeks of age. Infection had no consistent effect on body weight gain, but inoculation with B. pilosicoli resulted in a transient increase in faecal water content. B. innocens infection had no effect on egg production, but B. pilosicoli infection caused a delayed onset of laying, and a highly significant reduction in egg production over the first 11 weeks of lay. This study confirms that B. pilosicoli can cause serious egg production losses in adult chickens, while B. innocens is not obviously pathogenic.
TL;DR: The findings indicate that the dose applied causes subclinical tissue lesions and measurable tissue residues, which may impair animal health and may lead to residues in edible tissues of slaughter animals.
Abstract: Ochratoxin A is a common feed contaminant, which may impair animal health and may lead to residues in edible tissues of slaughter animals To simulate field conditions, broiler chicks were exposed to a total of 05 mg ochratoxin A per week for each of 4 weeks Plasma toxin levels and tissue residues were measured by high-performance liquid chromatography (HPLC) and microplate enzyme-linked immunosorbent assay (ELISA) Results indicate an accumulation in plasma and wide distribution into all organs, with high levels in the liver and the kidney Microscopical changes that could primarily be associated with toxin exposure were glomerulonephrosis, tubulonephrosis, focal tubular epithelial cell proliferation and multiple, adenoma-like structures in the renal parenchyma The HPLC and ELISA methods gave similar results for both tissue distribution and depletion Differences in absolute tissue toxin concentrations obtained by the two methods might be attributed to the different extraction and clean-up procedures,
TL;DR: Salmonella enterica serovar Pullorum requires SPI 2 for virulence and persistence but SPI 1 appears to contribute to, but is not essential for, the virulence of S .
Abstract: Functional mutations were made in the type III secretion systems encoded by Salmonella pathogenicity island 1 (SPI 1) and Salmonella pathogenicity island 2 (SPI 2) of Salmonella enterica serovar Pullorum, the cause of pullorum disease in poultry. Their role in cell invasion in vitro, and in virulence in vivo was determined. The SPI 1 mutant showed decreased invasiveness for chicken cells but was capable of causing disease in orally infected 1-day-old chicks, although it showed some reduction in virulence. The SPI 2 mutant showed no reduction in invasiveness, but was fully attenuated for virulence in 1-day-old chicks, and was not detected following oral infection in 1-week-old chickens. Following intravenous infection, the SPI 2 mutant was also attenuated and cleared more rapidly than the parent strain. This indicates that S. Pullorum requires SPI 2 for virulence and persistence but SPI 1 appears to contribute to, but is not essential for, the virulence of S. Pullorum.
TL;DR: Dietary ochratoxin, in the presence or absence of aluminosilicate, reduced their humoral immune response and the number of mitotic cells in the bursa and did not ameliorate the deleterious effects of the ochRatoxin.
Abstract: This study aimed to evaluate the effect of dietary ochratoxin, in the presence or absence of aluminosilicate, on the histology of the bursa of Fabricius, liver and kidneys, and on the humoral immune response of broilers vaccinated against Newcastle disease virus. The exposure of birds to 2 p.p.m. ochratoxin, in the presence or absence of aluminosilicate, reduced their humoral immune response and the number of mitotic cells in the bursa. The relative weight of the livers of the birds exposed to this toxin was increased and, microscopically, there was hepatocyte vacuolation and megalocytosis with accompanying hyperplasia of the biliary epithelium. The kidneys showed hypertrophy of the renal proximal tubular epithelium, with thickening of the glomerular basement membrane. Aluminosilicate did not ameliorate the deleterious effects of the ochratoxin.
TL;DR: Advances in the molecular characterization of M. gallisepticum (pMGA, pvpA ) and M. synoviae ( vlhA ) genes and their sequencing in numerous strains is likely to enable significantly improved epidemiological studies and improved tracing of M.'sSynoviae strains in different flocks.
Abstract: The pathogenic avian mycoplasmas, Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis, Mycoplasma iowae and Mycoplasma imitans, synthesize haemagglutinins that are immunogenic, variably expressed, surface proteins. The haemagglutinins of M. gallisepticum (pMGA), M. synoviae (VlhA) and M. imitans are lipoproteins, encoded by related multigene families that appear to have arisen by horizontal gene transfer. M. gallisepticum also has genes encoding cytadhesins in its genome but these are present as a single copies, while the pMGA gene family contains 30 to 70 genes. The switch in expression of distinct pMGA genes (e.g. pMGA1.1 to pMGA1.9) generates antigenic variation, which is thought to be important in immune evasion but also has significance in the preparation of M. gallisepticum antigens for serological diagnosis. In the majority of M. synoviae strains, post-translational cleavage of the VlhA protein generates an amino-terminal part (the lipoprotein MSPB) and a carboxyl-terminal part (MSPA), which mediates binding to erythrocytes. The 5'vlhA gene region, which encodes proline-rich repeats in the amino-terminal part of MSPB, is highly polymorphic among M. synoviae strains. Insertions or deletions in the part of vlhA encoding the proline-rich repeats cause MSPB length variation in different M. synoviae strains. Recombination between the 5'vlhA gene and pseudogenes in the genome generates changes in antigenic determinants in the carboxyl two-thirds of the MSPB molecule, and in MSPA, resulting in changes in the domains involved in the binding of M. synoviae to erythrocytes. Variant haemagglutinins of M. gallisepticum (pMGA1.7) and M. synoviae (diverse VlhA forms) share sequences that may be responsible for antigenic cross-reactions between M. gallisepticum and M. synoviae. Shared epitopes have been demonstrated using specific antibodies against MSPB that also recognize proteins of M. gallisepticum and of M. iowae (serotype N). Size and antigenic variants have also been reported for M. meleagridis and M. iowae proteins, but it is not known if these are their haemagglutinins. Advances in the molecular characterization of M. gallisepticum (pMGA, pvpA) and M. synoviae (vlhA) genes and their sequencing in numerous strains is likely to enable significantly improved epidemiological studies and improved tracing of M. gallisepticum and M. synoviae strains in different flocks.
TL;DR: It was shown that the E. faecalis isolates involved in these outbreaks of unilateral amyloid arthropathy in broiler breeders belonged to the same clone as that responsible for outbreaks in brown layers.
Abstract: Although symmetrical polyarticular amyloidosis has been described extensively in brown layers, spontaneous unilateral amyloid arthropathy has not been described previously in chickens. Birds from nine flocks of broiler parent stock (PS) had unilateral lameness associated with severe swelling of the left hock joint and the caudal aspect of the metatarsus. Gross pathology was restricted to the left hock joint and the left digital flexor tendons in almost all cases, suggesting an association with administration of Marek's disease vaccine. Amyloid deposits were found in 83% (25/30) of affected joints by histological examination of Congo red stained sections. Systemic amyloidosis, involving mainly the liver and spleen, was found in 59% (10/17) of birds. Enterococcus faecalis was isolated from joints in 77% (23/30) of cases and Staphylococcus aureus was isolated from the joint in one case (1/30). Thirty-five E. faecalis isolates from joints, tendons and blood samples from birds in five affected PS flocks were compared using pulsed-field gel electrophoresis (PFGE) to separate genomic fragments after digestion with SmaI. All but one isolate had identical or closely related restriction endonuclease digestion (RED) patterns that were very similar to a known arthropathic and amyloidogenic E. faecalis isolate. A further 30 E. faecalis isolates from seven grandparent stock (GPS) flocks and two isolates from two unaffected PS flocks of the same genetic background were analysed by PFGE. Among these isolates, 11 originating from four GPS flocks had RED patterns identical to or closely related to the reference amyloid-inducing strain. Moreover, one E. faecalis isolate from amyloidotic joints of brown layers housed in California, USA was included in the analysis and appeared to be identical to the reference strain. This study showed that the E. faecalis isolates involved in these outbreaks of unilateral amyloid arthropathy in broiler breeders belonged to the same clone as that responsible for outbreaks in brown layers.
TL;DR: It is shown that the polymerase chain reaction for MDV and ALV-J env using DNA from feather tips was more effective for diagnosis of naturally infected commercial chickens than using the liver and spleen.
Abstract: Marek's disease virus (MDV), a herpesvirus, and avian leukosis virus, subgroup J (ALV-J), a retrovirus, are oncogenic viruses of poultry. The present report describes a case-report study aimed at examining the efficacy of amplifying MDV and/or ALV-J from feather-tip DNA as compared with DNA purified from liver and spleen. We show that the polymerase chain reaction for MDV and ALV-J env using DNA from feather tips was more effective for diagnosis of naturally infected commercial chickens than using the liver and spleen.
TL;DR: The overall results of this study indicate that the 63rd passage of APV was sufficiently attenuated and offered protection against challenge with virulent virus.
Abstract: The attenuation of an avian pneumovirus (APV) isolate (APV/MN/turkey/1-a/97) by 63 serial passages in cell culture (seven in chicken embryo fibroblasts and 56 in Vero cells) and its evaluation as a live attenuated vaccine in turkey poults is described. The birds were vaccinated with two different doses of attenuated virus (10 4.5 median tissue culture infectious dose (TCID 50 )/ml and 10 2.5 TCID 50 /ml) at 2 weeks of age, and were challenged 2 weeks later with virulent APV. No clinical signs were seen in vaccinated, challenged birds, whereas severe clinical signs were observed in the mock-vaccinated, challenged group. Vaccinated birds developed anti-APV antibodies, which increased in titre following challenge with virulent virus. On challenge, none of the vaccinates was found to shed viral nucleic acid as detected by reverse transcriptase-polymerase chain reaction, but non-vaccinated, challenged birds did. The vaccine virus was also evaluated under field conditions in two farms. At one farm, the 'seeder ...
TL;DR: The use of this vaccine is likely to enable the replacement of anticoccidial drug shuttle programmes in broilers reared under conditions similar to those used in these Italian flocks, and growth curves showed that there was no post-vaccinal growth check in the vaccinated birds and no intolerance of the anticoccids.
Abstract: A live attenuated anticoccidial vaccine (Paracox) was compared with a nicarbazin-monensin anticoccidial drug shuttle programme in three crops of Italian broilers, comprising a total of 290,405 chickens. All birds received the antibiotic growth promoter avilamycin. No coccidiosis was evident during the trials, but the occurrence of oocysts in the litter demonstrated that a natural challenge was present. Vaccinated birds consistently performed at least as well as those treated with the anticoccidial drug shuttle. The final mean weights of vaccinated birds were significantly greater (P < 0.001) than those of birds treated with anticoccidial drugs, both for females at 36/37 days and males at 56 days. Feed conversion ratios, total mortality including culls, the proportion of rejects at the processing plant, and the moisture content of the litter were not significantly different between the two control methods. Growth curves showed that there was no post-vaccinal growth check in the vaccinated birds and no intolerance of the anticoccidial drug treatment. There was no overall seasonal effect, regardless of treatment, on the performance of the three crops reared from November 1997 to July 1998. These findings suggest that the use of this vaccine is likely to enable the replacement of anticoccidial drug shuttle programmes in broilers reared under conditions similar to those used in these Italian flocks.
TL;DR: Rapid serum agglutination, haemagglutination inhibition and enzyme-linked immunosorbent assays were used to screen Swiss fancy breed chicken flocks for antibodies against 12 avian infectious agents.
Abstract: Rapid serum agglutination, haemagglutination inhibition and enzyme-linked immunosorbent assays were used to screen Swiss fancy breed chicken flocks for antibodies against 12 avian infectious agents. For this purpose, 1002 blood samples from 40 flocks were collected and tested. Ten percent of the samples were positive for Salmonella gallinarum-pullorum and 62.5% of the flocks were affected. More than 75% of the flocks had antibodies against Mycoplasma gallisepticum/Mycoplasma synoviae , infectious bronchitis, infectious bursal disease, avian encephalomyelitis, infectious chicken anaemia and reoviral arthritis. Low prevalence of antibodies was recorded for Salmonella enteritidis , avian influenza, avian leukosis and Newcastle disease (2.0 to 4.0%).
TL;DR: The data support the important role of the β -adrenergic receptor in the cardiovascular system for cardiac output, and secondary to pulmonary hypertension syndrome.
Abstract: The present study was carried out to determine, first, the cardiac β -adrenergic receptor characteristics of broiler chick embryos exposed to two different CO 2 levels during the last stage of embryonic development, and second, the prophylactic effect of β 1 -adrenoceptor blocker on right ventricular hypertrophy in broiler chickens. High CO 2 embryos showed significantly higher haematocrit values, higher partial pressure of CO 2 levels and lower partial pressure of O 2 levels than those of normal CO 2 embryos. Exposure of chick embryos to high CO 2 levels reduced the binding capacity of myocardial β -adrenergic receptors compared with those embryos incubated at the normal CO 2 level. Atenolol-supplemented diet numerically reduced ascites incidence in broiler chickens (7%) compared with birds fed the control diet (15%). In conclusion, these data support the important role of the β -adrenergic receptor in the cardiovascular system for cardiac output, and secondary to pulmonary hypertension syndrome.
TL;DR: Serological, bacteriological and PCR examinations were carried out concerning microbes that are known to cause swollen heads in birds and suggest that the high levels of ammonia fumes promoted infection and multiplication of M. gallisepticum and Cryptosporidium sp.
Abstract: On a farm raising approximately 75,000 Japanese quail (Coturnix coturnix japonica) for egg production, the diseased quail showed clinical signs of swelling of the head, nasal discharge, increased lacrimation, and decreased egg production. The flock experienced a mortality rate of 5.7% per day. Macroscopic observation revealed large, gelatinous masses of caseous exudate in the sinuses, egg peritonitis, and airsacculitis. Microscopically, non-purulent or purulent inflammation accompanied by lymphoid hyperplastic tissue with germinal centers was observed in the oculofacial respiratory mucosa. The developing stage of the lesions was abscess formation. In the investigation of pathogens, antigens to Mycoplasma gallisepticum and Pasteurella multocida serotype D were immunolabeled on and demonstrated in the mucosal membranes. In addition, P. multocida, Escherichia coli, Staphylococcus sp., and Streptococcus sp. were isolated from the infraorbital sinuses, and Mycoplasma isolated from a diseased bird was confirmed as M. gallisepticum by polymerase chain reaction (PCR). Furthermore, Cryptosporidium sp. was frequently found in the brush border. Serological, bacteriological and PCR examinations, some with negative outcomes, were carried out concerning microbes that are known to cause swollen heads in birds (Haemophilus paragallinarum, Newcastle disease virus and turkey rhinotracheitis virus). The average concentration of ammonia fumes in the cages was 30.6 parts/106, which suggests that the high levels of ammonia fumes promoted infection and multiplication of M. gallisepticum in the quail, and that the clinical disease then worsened due to mixed infection with M. gallisepticum and Cryptosporidium sp. or other bacteria.
TL;DR: Interestingly, non-neutralizing, cross-reactive, conformation-dependent and confirmation-independent epitopes also changed on VP 2, which demonstrates that different host systems may play an important role in the antigenicity of IBDV.
Abstract: In vitro and in ovo virus neutralization assays were conducted to assess the role of different host systems in infectious bursal disease virus (IBDV) antigenic and immunogenic variation. Four different strains, two variant (1084 E and GLS) and two standard (Edgar and STC), were propagated separately in the bursa of Fabricius and embryos, and were compared with cell culture-adapted preparations of the homologous strains. Chicken polyclonal antisera were prepared against each IBDV and neutralizing antibody titres were determined. Normalized IBDV antibody concentrations were used in neutralization assays against homologous and heterologous IBDVs in 10-day-old specific pathogen free embryos. Both antigenic and immunogenic changes occurred in IBDVs evaluated, as evidenced by differences in the ability of normalized antibody to neutralize IBDV propagated in different host systems. Antibody induced by bursal-derived IBDV neutralized all isolates equally well, whereas antibody induced by cell culture-derived virus neutralized bursal-derived IBDV much less effectively.
TL;DR: The results indicate the disseminating capacity of this mycoplasma and the possible use of PCR methods for epidemiological analyses and control of farm decontamination before the introduction of new birds.
Abstract: The polymerase chain reaction (PCR) was used to detect Mycoplasma gallisepticum in samples collected from the environment of experimentally or naturally infected poultry. Culture was also used in the experimental infections. Of 160 samples of food, drinking water, feathers, droppings or dust collected during experimental infection, 103 were positive using a M. gallisepticum-specific PCR (MG-PCR) and 68 were positive using a PCR (mycoplasma-PCR) that detects all species of the genera Mycoplasma, Spiroplasma, Acholeplasma and Ureaplasma. Six of these samples were also positive by culture. In environmental samples collected on a depopulated M. gallisepticum-positive turkey farm, three and two out of a total of 12 were positive by mycoplasma-PCR and MG-PCR, respectively. These results indicate the disseminating capacity of this mycoplasma and the possible use of PCR methods for epidemiological analyses and control of farm decontamination before the introduction of new birds.
TL;DR: Copenhagen strains isolated from homing pigeons were tested for susceptibility to the antimicrobials most commonly used to treat pigeons, and none showed extended spectrum β -lactamase activity, implying that the cephalosporins (ceftiofur) remained active.
Abstract: Thirty-three Streptococcus gallolyticus , 60 Escherichia coli and 18 Salmonella enterica serotype Typhimurium var. Copenhagen strains isolated from homing pigeons ( Columba livia ) were tested for susceptibility to the antimicrobials most commonly used to treat pigeons. Minimal inhibitory concentrations were determined using the agar dilution technique. Aminoglycosides (gentamicin and kanamycin), trimethoprim and flumequine were relatively inactive against the streptococci tested. Acquired tetracycline resistance amounted to 85%, and lincomycin and macrolide (erythromycin) resistance to 48 and 45%, respectively. Fluoroquinolone (enrofloxacin) resistance was found in four S. gallolyticus strains . All strains were susceptible to ampicillin. With the E. coli strains, resistance was found to all antibiotics tested. Over one-half of them were resistant to tetracycline and to broad-spectrum penicillins (ampicillin); however, none showed extended spectrum β -lactamase activity, implying that the cephalosporins ...
TL;DR: A sensitive and specific nested polymerase chain reaction (PCR) protocol was developed that could amplify a 419 base pair DNA fragment of fowlpox virus with a detection limit of less than one infectious unit, and this finding is discussed.
Abstract: Dermal squamous cell carcinoma (DSCC; avian keratoacanthoma) is a neoplastic skin lesion of broiler chickens of unknown aetiology. In previous studies, the possibility of the involvement of pox viruses in the cause of DSCC was considered. In this work, a sensitive and specific nested polymerase chain reaction (PCR) protocol was developed that could amplify a 419 base pair DNA fragment of fowlpox virus with a detection limit of less than one infectious unit. Fowlpox virus DNA was always detected in skin samples with fowlpox lesions while it was not detected in samples of unrelated diseases such as cowpox, Marek's disease or infectious laryngotracheitis. Some macroscopically normal skin samples from vaccinated and non-vaccinated birds also produced PCR-positive results, corroborating previous studies on the possibility that a latent or chronic form of fowlpox occurs. Fowlpox virus DNA was consistently detected from DSCC skin lesions, and this finding is discussed.
TL;DR: Compared the invasion of selected zoonotic Salmonella serotypes of poultry in an in vivo chicken intestinal loop model and also in vitro in epithelial cell cultures, a group of serotypes showed significantly higher intracellular counts than the reference strain.
Abstract: The aim of the present study was to compare the invasion of selected zoonotic Salmonella serotypes of poultry in an in vivo chicken intestinal loop model and also in vitro in epithelial cell cultures. Invasion was measured relative to a reference strain, Salmonella Typhimurium 4/74 inv H201::Tn phoA . Two serotypes demonstrated intracellular log 10 counts that differed significantly from all other serotypes tested: Salmonella Enteritidis PT4 being 1.5 log 10 colony forming units (CFU) (31-fold) higher, and Salmonella Tennessee being 0.7 log 10 CFU (fivefold) lower than the reference strain ( P h 0.0001). A group of serotypes, which can be vertically transmitted, showed significantly higher intracellular counts (fourfold to eightfold) than the reference strain. The group included S. Typhimurium 4/74, S. Typhimurium DT104 (poultry and porcine isolates), S. Enteritidis PT1, S. Enteritidis PT6, S. Enteritidis PT8, and Salmonella Berta. The serotypes Salmonella Hadar, Salmonella Virchow, S. 4,12:b:-, S. Typhim...