1,720,989 research outputs found
Pathogenicity of Porcine Circovirus Type 2e in Experimentally Infected Pigs
No full text© 2022 Elsevier LtdA new porcine circovirus type 2e (PCV2e) genotype was recently isolated from diseased pigs. To investigate the pathogenicity of PCV2e, groups of conventional pigs were inoculated in one of three ways: with PCV2e only, with Mycoplasma hyopneumoniae and PCV2e, or with PCV2e and porcine reproductive and respiratory syndrome virus (PRRSV). Pigs were examined post mortem at 21 days post inoculation. Pigs in the M. hyopeumoniae/PCV2e group were inoculated intratracheally with M. hyopneumoniae at 4 weeks of age followed by an intranasal inoculation with PCV2e at 6 weeks of age. Pigs in the PCV2e/PRRSV group were inoculated intranasally with PCV2e and PRRSV at 6 weeks of age. Significant differences in PCV2e loads in blood or lymph nodes, or in the severity of lymphoid lesions, were not detected between the M. hyopneumoniae/PCV2e and PCV2e/PRRSV groups. All pigs co-infected with either M. hyopneumoniae/PCV2e or PCV2e/PRRSV developed mild porcine circovirus-associated disease (PCVAD), whereas none of the pigs infected with PCV2e alone developed PCVAD. Production of PCVAD in pigs therefore appears to require PCV2e infection simultaneously with an additional infectious agent such as M. hyopneumoniae or PRRSV for full disease expression in pigs. These results demonstrate that PCV2e is not associated with significant clinical disease as assessed by levels of PCV2e viraemia and severity of lymphoid lesions.N
A Comparative Field Evaluation of the Effect of Growth Performance Between Porcine Circovirus Type 2a (PCV2a)- and PCV2b-Based Bivalent Vaccines Containing PCV2 and Mycoplasma hyopneumoniae
No full textThe objective of this study was to compare two different bivalent vaccines containing porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae. One vaccine contained PCV2a and the other contained PCV2b, and both were administered on a farm suffering from subclinical PCV2d infection and enzootic pneumonia. A total of 180 pigs were randomly divided into 3 groups (60 pigs per group; male pigs = 30 and female pigs = 30). Bivalent vaccination significantly improved growth performance in both vaccinated groups as compared to the unvaccinated (UnVac) group. Growth performance measured by body weight and average daily weight gain (ADWG) was not significantly different between the two bivalent-vaccinated groups (VacA and VacB). Both bivalent vaccines elicited high levels of neutralizing antibodies and interferon-γ secreting cells (IFN-γ-SC) against PCV2d, leading to a reduction in the levels of PCV2d blood viral load as compared to unvaccinated animals. Similarly, both bivalent vaccines elicited high levels of IFN-γ-SC against M. hyopneumoniae that reduced the level of M. hyopneumoniae laryngeal viral loads as compared to unvaccinated animals. Significant differences in severity of lung and lymphoid lesions were observed in both vaccinated groups as compared to the UnVac group. These comparative field data demonstrated that both bivalent vaccines are good candidates for controlling subclinical PCV2d infection and enzootic pneumonia in swine farms suffering from an existing infection
Evaluation of the new commercial recombinant chimeric subunit vaccine PRRSFREE in challenge with heterologous types 1 and 2 porcine reproductive and respiratory syndrome virus
No full textThe objective of this study was to evaluate a new recombinant chimeric vaccine against porcine reproductive and respiratory syndrome virus (PRRSV). The subunit vaccine, PRRSFREE, from Reber Genetics, Taiwan, Republic of China, is based on a plasmid containing a detoxified Pseudomonas exotoxin carrying open reading frame (ORF) 7, 1b, and 5 and 6 chimeric subunits of types 1 and 2 PRRSV. Pigs were injected intramuscularly with 2.0 mL of the vaccine at 21 and 42 d of age, according to the manufacturer's recommendation. At the age of 63 d the pigs were inoculated intranasally with either type 1 or type 2 PRRSV. Regardless of the genotype of the challenging PRRSV, the vaccinated challenged pigs had significantly lower (P < 0.05) mean rectal temperature, respiratory score, lung lesion score, and amount of PRRSV antigen within areas of interstitial pneumonia, along with overall lower levels of viremia due to type 1 or type 2 PRRSV compared with the unvaccinated challenged pigs. The vaccinated challenged pigs also had significantly higher (P < 0.05) numbers of interferon-g secreting cells compared with the unvaccinated challenged pigs. This study demonstrated that the new vaccine provides protection against respiratory disease from heterologous types 1 and 2 PRRSV challenge in growing pigs.OAIID:RECH_ACHV_DSTSH_NO:T201716295RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A004714CITE_RATE:.804FILENAME:2016-08 Evaluation of the new commercial recombinant chimeric subunit vaccine PRRSFREE in challenge with heterologous types 1 and 2 porcine reproductive and respiratory syndrome virus.pdfDEPT_NM:수의학과EMAIL:[email protected]_YN:YFILEURL:https://srnd.snu.ac.kr/eXrepEIR/fws/file/fe36de2e-cef6-4b2c-97df-dfa50374ad7a/linkN
Concurrent vaccination of boars with type 1 and type 2 porcine reproductive and respiratory syndrome virus (PRRSV) reduces seminal shedding of type 1 and type 2 PRRSV
No full textThe objective of the present study was to determine the effect of concurrent vaccination of boars with type 1 and type 2 porcine reproductive and respiratory syndrome virus (PRRSV) on seminal shedding of both genotypes. The boars tolerated well concurrent administration of 2 commercial PRRSV vaccines, and no adverse reactions were observed. No interference in the humoral immune response (measured as the level of anti-PRRSV antibodies) or the cell-mediated immune response (measured as the level of PRRSV-specific interferon-g-secreting cells) was observed after concurrent administration compared with single administration of the same vaccines. Concurrent vaccination significantly reduced the load of type 1 and type 2 PRRSV in blood and semen after singular (type 1 or type 2) and dual (type 1 and type 2) PRRSV challenge, and it did not significantly affect the efficacy of each vaccine. The results demonstrate that concurrent vaccination of boars with type 1 and type 2 PRRSV reduces shedding of both genotypes in semen.OAIID:RECH_ACHV_DSTSH_NO:T201716289RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A004714CITE_RATE:.804FILENAME:2016-10 Concurrent vaccination of boars with type 1 and type 2 porcine reproductive and respiratory syndrome virus (PRRSV) reduces seminal shedding of type 1 and type 2 PRRSV.pdfDEPT_NM:수의학과EMAIL:[email protected]_YN:YFILEURL:https://srnd.snu.ac.kr/eXrepEIR/fws/file/ddd306a5-bd19-44c7-80c8-e49aee68c3ab/linkN
Multiplex polymerase chain reaction for the detection and differentiation of 4 porcine circovirus 2 genotypes (PCV-2a, -2b, -2d, and -2e) in clinical samples
No full textCopyright and/or publishing rights held by the Canadian Veterinary Medical Association.The objective of this study was to develop multiplex polymerase chain reaction (PCR) for the simultaneous detection of porcine circovirus 2 (PCV-2) and differentiation among 4 PCV-2 genotypes (2a, 2b, 2d, and 2e) in collected clinical lymph node samples. The multiplex PCR detected each of 4 PCV-2 genotypes (2a, 2b, 2d, and 2e) to a dilution of 2 × 101 copies/μL. PCV-2a, PCV-2b, PCV-2d, and PCV-2e were propagated in tissues prior to DNA extraction for use in multiplex PCR for the simultaneous detection and differentiation of 4 PCV-2 genotypes. The designed multiplex PCR effectively detected and differentiated various combinations of multiple infection, such as PCV-2a+2b, PCV-2a+2d, PCV-2b+2d, PCV-2a+2e, and PCV-2a+2b+2d, in clinical lymph node samples. The results of this study demonstrated that multiplex PCR testing of clinical samples developed herein was able to simultaneously detect and differentiate among the 4 PCV-2 genotypes (PCV-2a, 2b, 2d, and 2e). Lobjectif de cette étude était de développer une réaction en chaîne par la polymérase multiplex (PCR) pour la détection simultanée du circovirus porcin 2 (PCV-2) et la différenciation entre quatre génotypes PCV-2 (2a, 2b, 2d et 2e) dans des échantillons cliniques de noeuds lymphatique. La PCR multiplex a détecté chacun des quatre génotypes PCV-2 (2a, 2b, 2d et 2e) à une dilution de 2 × 101 copies/μL. Le PCV-2a, le PCV-2b, le PCV-2d et le PCV-2e ont été propagés dans les tissus avant lextraction de lADN pour être utilisés dans la PCR multiplex pour la détection et la différenciation simultanées de quatre génotypes du PCV-2. La PCR multiplex conçue a efficacement détecté et différencié diverses combinaisons dinfections multiples, telles que PCV-2a+2b, PCV-2a+2d, PCV-2b+2d, PCV-2a+2e et PCV-2a+2b+2d, dans les échantillons cliniques de ganglions lymphatiques. Les résultats de cette étude ont démontré que le test PCR multiplex des échantillons cliniques développés ici était capable de détecter et de différencier simultanément les quatre génotypes PCV-2 (PCV-2a, 2b, 2d et 2e).(Traduit par Docteur Serge Messier).N
Development of porcine circovirus 2 (PCV2) open reading frame 2 DNA vaccine with different adjuvants and comparison with commercial PCV2 subunit vaccine in an experimental challenge
No full textThe objective of this study was to compare the protection against challenge with porcine circovirus 2 (PCV2) induced by an experimental vaccine based on open reading frame (ORF) 2 of PCV2 DNA plus an adjuvant (aluminum hydroxide, cobalt oxide, or liposome) and a commercial PCV2 subunit vaccine. A total of 35 colostrum-fed, cross-bred, conventional piglets were randomly divided into 7 groups. The commercial vaccine was more efficacious against PCV2 challenge than the 4 experimental vaccines according to immunologic, virologic, and pathological outcomes. The pigs inoculated with the experimental vaccine containing the liposome adjuvant had significantly higher levels (P < 0.05) of neutralizing antibodies and interferon-g-secreting cells, and significantly lower levels (P < 0.05) of PCV2 viremia than the pigs inoculated with the other experimental vaccines. The pigs inoculated with the experimental vaccines containing either the liposome adjuvant or the cobalt oxide adjuvant had significantly lower lymphoid lesion scores (P < 0.05) than the pigs in the group inoculated with the PCV2 DNA vaccine dissolved in phosphate-buffered saline. Liposome proved to be a potent adjuvant that efficiently enhanced both humoral and cellular immune responses induced by the PCV2 DNA vaccine.N
Efficacy test of a plant-based porcine circovirus type 2 (PCV2) virus-like particle vaccine against four PCV2 genotypes (2a, 2b, 2d, and 2e) in pigs
No full textThe objective of this study was to evaluate the efficacy of a recombinant porcine circovirus type 2 (PCV2) vaccine based from a Nicotiana benthamiana expression system against four different co-challenges with PCV2 genotypes (2a, 2b, 2d, and 2e) and porcine reproductive and respiratory syndrome virus (PRRSV). Pigs in the vaccinated groups each received a 1.0 mL intramuscularly of plant-based PCV2a vaccine in the neck muscle at 21 days of age. Vaccinates were then co-challenged with a combination of one of four PCV2 genotypes (2a, 2b, 2d, and 2e) and PRRSV at 42 days of age. Regardless of the PCV2 genotype used for challenge, vaccination significantly reduced clinical signs, reduced the level of PCV2 load in both blood and lymph nodes, and reduced the severity of lymphoid lesions in pigs. Vaccination resulted in significantly higher titers of neutralizing antibody against the corresponding PCV2 genotype evaluated and increased the frequency of PCV2-specific interferon-gamma secreting cells. The results of this study demonstrated that a plant-based PCV2 vaccine conferred protection against a dual challenge with four different PCV2 genotypes when combined with PRRSV based on clinical, virological, immunological and pathological evaluation.N
Pharmacokinetics and toxicity evaluation following oral exposure to bisphenol F
No full textBisphenol F is a substitute material for bisphenol A and is widely used in household products as a raw material for polycarbonate resin, epoxy resin, and plastic reinforcement. It is known to be mainly used in food containers, thermal paper for receipts, and coatings for water pipes. In some countries, bisphenol F has been detected in drinking water and human urine samples. However, due to the lack of safety evaluation data on bisphenol F, it is difficult to establish appropriate guidelines for the proper use of the substance, and social anxiety is increasing accordingly. This study investigated the use, exposure route, and distribution flow of bisphenol F, a household chemical. To determine the no-observed-adverse-effect level (NOAEL) and target organ of bisphenol F after exposure, a single-dose oral toxicity, dose-range finding (28 day oral), repeated dose toxicity (90 day oral), and genotoxicity (reverse mutation, chromosomal abnormality, in vivo micronucleus test) tests were performed. The pharmacokinetic profile was also obtained. The test results are as follows: in the pharmacokinetic study, it was confirmed that single oral exposure to BPF resulted in systemic exposure; in single oral dose toxicity test, the approximate lethal dose was found to be 4000 mg/kg and confusion and convulsion was shown in the test animals; NOAEL was determined to be 2 mg/kg/day for male and 5 mg/kg/day for female, and the no-observed-effect level (NOEL) was determined to be 2 mg/kg/day for males and 1 mg/kg/day for females, and the target organ was the small intestine; genotoxicity tests confirmed that BPF does not induce genotoxicity.N
Comparison of growth performance under field conditions in growing pigs each vaccinated with one of two commercial modified-live porcine reproductive and respiratory syndrome vaccines
No full textUnder field conditions, in groups of pigs each vaccinated with one of two modified live virus porcine reproductive and respiratory syndrome vaccines, growth performance was better and lung lesions were fewer than in nonvaccinated controls. Growth performance and number of lung lesions did not differ between the two vaccinated groups.N
Comparative growth performance of 3 types of combination vaccines containing porcine circovirus 2 and Mycoplasma hyopneumoniae under field conditions
No full textCopyright and/or publishing rights held by the Canadian Veterinary Medical Association.The objective of this field trial was to compare the effect of 3 different types of combination vaccines on growth performance in pigs under field conditions. The vaccines compared were: a trivalent vaccine containing porcine circovirus type 2a and 2b (PCV-2a/b); and Mycoplasma hyopneumoniae; a mixable bivalent vaccine containing PCV-2a and M. hyopneumoniae; and a ready-to-use bivalent vaccine containing PCV-2a and M. hyopneumoniae. Two farms were selected on the basis of their history of subclinical PCV-2d infection and enzootic pneumonia. A total of 120 pigs on each farm was randomly divided into 4 groups of 30 pigs each. The trivalent-vaccinated group from both farms outperformed each bivalent-vaccinated group in terms of growth performance. Growth performance was significantly improved during the fattening period (70 to 175 d of age) in the mixable bivalent-vaccinated group compared with the ready-to-use bivalent-vaccinated group on 1 farm. The trivalent-vaccinated group elicited higher levels of neutralizing antibodies and interferon-γ secreting cells (IFN-γ-SC) against PCV-2d, while simultaneously decreasing the levels of PCV-2d load in blood when compared with the mixable and ready-to-use bivalent-vaccinated groups. The trivalent-vaccinated group also elicited higher levels of IFN-γ-SC against M. hyopneumoniae and lower levels of M. hyopneumoniae load in the larynx when compared with the mixable and ready-to-use bivalent-vaccinated groups. The results of the present study demonstrated that a trivalent vaccine containing PCV-2a/b and M. hyopneumoniae resulted in a more productive parameter, higher immune responses, and less blood-viral and mycoplasmal larynx-loads when compared with the mixable and ready-to-use bivalent vaccines despite the presence of ongoing subclinical PCV-2d infection and enzootic pneumonia on the farms. Lobjectif de cet essai de terrain était de comparer leffet de trois différents types de vaccins combinés sur les performances de croissance chez les porcs dans des conditions de terrain. Les vaccins comparés étaient : un vaccin trivalent contenant des circovirus porcins de type 2a et 2b (PCV-2a/b) et Mycoplasma hyopneumoniae; un vaccin bivalent mélangeable contenant PCV-2a et M. hyopneumoniae; et un vaccin bivalent prêt à lemploi contenant le PCV-2a et M. hyopneumoniae. Deux fermes ont été sélectionnées sur la base de leurs antécédents dinfection subclinique par le PCV-2d et de pneumonie enzootique. Un total de 120 porcs dans chaque ferme a été divisé au hasard en quatre groupes de 30 porcs chacun. Le groupe vacciné par les trivalents des deux fermes a surpassé chaque groupe vacciné par les bivalents en termes de performances de croissance. Les performances de croissance ont été significativement améliorées pendant la période dengraissement (70 à 175 jours dâge) dans le groupe vacciné bivalent mélangeable par rapport au groupe vacciné bivalent prêt à lemploi sur une ferme. Le groupe vacciné par trivalent a suscité des niveaux plus élevés danticorps neutralisants et de cellules sécrétant de linterféron-γ (IFN-γ-SC) contre le PCV-2d, tout en diminuant simultanément les niveaux de charge de PCV-2d dans le sang par rapport aux vaccins mélangeables et prêts à lemploi. Le groupe vacciné trivalent a également provoqué des niveaux plus élevés dIFN-γ-SC contre M. hyopneumoniae et des niveaux inférieurs de charge de M. hyopneumoniae dans le larynx par rapport aux groupes vaccinés bivalents mélangeables et prêts à lemploi. Les résultats de la présente étude ont démontré quun vaccin trivalent contenant du PCV-2a/b et M. hyopneumoniae entraînait un paramètre plus productif, des réponses immunitaires plus élevées et moins de charges sanguines virales et mycoplasmiques dans le larynx par rapport aux vaccins mélangeables et prêts à lemploi malgré la présence dune infection subclinique par le PCV-2d et dune pneumonie enzootique dans les élevages.(Traduit par Docteur Serge Messier).N
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