In vitro and in vivo antiviral effects of CLEVir-X against porcine reproductive and respiratory syndrome virus.

The aim of this study was to investigate the in vitro and in vivo antiviral effects of CLEVir-X, against porcine reproductive and respiratory syndrome virus (PRRSV). CLEVir-X is a nucleoside analogue and a dialdehyde form of xanthosine. CLEVir-X demonstrated antiviral action during the in vitro portion of this experiment with its inosine monophosphate dehydrogenase (IMPDH) inhibition against PRRSV. The anti-PRRSV effect of CLEVir-X was recovered through supplementation with guanosine. This suggests that PRRSV replication may be regulated through IMPDH and its guanosine biosynthetic pathway. CLEVir-X treatment in cultures resulted in mutation frequency increase of up to 7.8-fold within the viral genomes (e.g. ORF6) compared to their parallel, untreated cultures. The incorporation of CLEVir-X into the viral genome causes lethal mutagenesis and subsequent decrease in specific infectivity. During the in vivo antiviral experiment, 21-day-old pigs began oral administration of 5 mL of phosphate buffered saline containing CLEVir-X (with purity of 68 % and dosage of 40 mg/kg body weight). This treatment was provided twice daily at 9:00AM and 5:00PM for 14 days. Pigs were simultaneously intranasally inoculated with PRRSV at the beginning of CLEVir-X treatment (21 days of age). Several beneficial effects from the oral administration of CLEVir-X were observed including reduction of body temperature, alleviation of respiratory clinical signs, decreased PRRSV load in both blood and lung tissues, and mitigation of lung interstitial pneumonia lesions. The results of the present study demonstrated that CLEVir-X has mutagenic and nonmutagenic modes of antiviral action against PRRSV based on both in vitro and in vivo antiviral experiments.

The in vitro and in vivo anti-inflammatory and anti-oxidative effects of an amino acid blend supplemented feed on pigs experimentally challenged with Salmonella Typhimurium.

Background: The in vitro and in vivo anti-inflammatory and anti-oxidative effects of an amino acid (AA) blend (tryptophan, threonine, and methionine) in pigs. Objective: This study aimed to evaluate the in vitro anti-inflammatory and anti-oxidative effects of an AA blend on intestinal porcine epithelial cells (IPEC-J2) and the in vivo anti-inflammatory and anti-oxidative effects in pigs experimentally challenged with Salmonella Typhimurium. Methods: IPEC-J2 were pretreated with an AA blend for 25 h and then treated with lipopolysaccharide (LPS), deoxynivalenol (DON), or H2O2 for in vitro evaluation. A controlled standard diet supplemented with 0.3% of the AA blend was orally fed to the treated group pigs for 14 days, beginning at 21 days of age. At the end of the feeding period, pigs were orally inoculated with Salmonella Typhimurium. Results: Pre-treatment with the AA blend reduced LPS/DON-induced interleukin (IL)-8 mRNA as a measurement of the anti-inflammatory effect and H2O2-induced reactive oxygen species (ROS) as a measurement of the anti-oxidative effect on IPEC-J2. Feeding with an AA blend resulted in a reduction of proinflammatory (tumor necrosis factor-α, IL-6, and IL-8) cytokine levels, while treated pigs experienced an increase in anti-inflammatory IL-10 cytokine in their sera. The addition of an AA blend-supplemented pig feed resulted in significantly lower Salmonella-induced cecal lesion scores compared to untreated pigs. Discussion: Supplementation of feed with an AA blend reduced intestinal inflammation and pathology in pigs and may be applied for the control of Salmonella Typhimurium infection, as demonstrated in this study.

Divergent clinical outcomes depending on the sequential infection order of porcine circovirus type 2 and Mycoplasma hyopneumoniae.

This study compared the different sequential order of infection of porcine circovirus type 2d (PCV2d) and Mycoplasma hyopneumoniae. Thirty-six pigs were allocated randomly across six different groups. Pigs underwent various inoculation sequences: M. hyopneumoniae administered 14 days before PCV2d, simultaneous PCV2d-M. hyopneumoniae, PCV2d given 14 days before M. hyopneumoniae, PCV2d only, M. hyopneumoniae only, or a mock inoculum. Overall, the pigs inoculated with M. hyopneumoniae 14 days prior to PCV2d (Mhyo-PCV2 group) and those inoculated simultaneously with PCV2d and M. hyopneumoniae (PCV2+Mhyo group) displayed notably higher clinical disease severity and experienced a significant decrease of their average daily weight gain than pigs inoculated with PCV2d 14 days prior to M. hyopneumoniae (PCV2-Mhyo group). M. hyopneumoniae infection potentiated PCV2 blood and lymph node viral loads, as well as PCV2-associated lesions, while the infection of PCV2d did not impact the intensity of M. hyopneumoniae infection. Tumor necrosis factor-α (TNF-α) sera levels were significantly increased in the Mhyo-PCV2 and PCV2+Mhyo groups as compared to the PCV2-Mhyo, PCV2, and Mhyo groups. The most important information was that the potentiation effect of M. hyopneumoniae on PCV2d was found only in pigs inoculated with either M. hyopneumoniae followed by PCV2d (Mhyo-PCV2 group) or a simultaneous inoculation of PCV2d and M. hyopneumoniae (PCV2+Mhyo group). The sequential infection order of PCV2d and M. hyopneumoniae resulted in divergent clinical outcomes.

Cross-protection of a porcine circovirus types 2a/b (PCV-2a/b) and Mycoplasma hyopneumoniae trivalent vaccine against a dual PCV-2e and Mycoplasma hyopneumoniae challenge.

The purpose of this experimental study was to determine the cross-protection of a new trivalent vaccine containing porcine circovirus types 2a/b (PCV-2a/b) and Mycoplasma hyopneumoniae. Pigs were vaccinated intramuscularly at 21 days of age, then challenged at 42 days of age with a dual PCV-2e and M. hyopneumoniae challenge. Growth performance was significantly improved during the experimental period (21 to 63 days of age) in vaccinated-challenged pigs compared to unvaccinated-challenged pigs. Pigs that were vaccinated and challenged elicited a significant amount of PCV-2e- and M. hyopneumoniae-specific interferon-γ secreting cells (IFN-γ-SC) and reduced the levels of PCV-2e viremia and laryngeal shedding. The results of the present study demonstrated that a trivalent vaccine provided cross-protection against a dual PCV-2e and M. hyopneumoniae challenge.

Le but de cette étude expérimentale était de déterminer la protection croisée d'un nouveau vaccin trivalent contenant le circovirus porcin de types 2a/b (PCV-2a/b) et Mycoplasma hyopneumoniae. Les porcs ont été vaccinés par voie intramusculaire à l'âge de 21 jours, puis provoqués à l'âge de 42 jours avec double provocation par PCV-2e et M. hyopneumoniae. Les performances de croissance ont été significativement améliorées au cours de la période expérimentale (21 à 63 jours) chez les porcs vaccinés-provoqués par rapport aux porcs non-vaccinés-provoqués. Les porcs qui ont été vaccinés et provoqués ont produit une quantité importante de cellules sécrétant de l'interféron-γ spécifiques au PCV-2e et à M. hyopneumoniae (IFN-γ-SC) et ont réduit les niveaux de virémie du PCV-2e et d'excrétion laryngée. Les résultats de la présente étude ont démontré qu'un vaccin trivalent offrait une protection croisée contre une double provocation par le PCV-2e et M. hyopneumoniae.(Traduit par Docteur Serge Messier).

Field evaluation of novel plant-derived porcine circovirus type 2 vaccine related to subclinical infection.

BACKGROUND: The objective of this field trial was to evaluate the efficacy of a new plant-based porcine circovirus type 2a (PCV2a) vaccine. This vaccine was a recombinant capsid subunit PCV2a vaccine based on the Nicotiana benthamiana expression system. METHODS: Three farms were selected for the study based on their history of subclinical PCV2 infection. A total of 40 18-day-old pigs were randomly allocated to either vaccinated or unvaccinated groups (20 pigs per group; 10 = male and 10 = female). Pigs received a 2.0-mL dose of the plant-based PCV2a vaccine intramuscularly at 21 days of age in accordance with the manufacturer's recommendations, whereas unvaccinated pigs were administered a single dose of phosphate buffered-saline at the same age. RESULTS: Vaccination had a positive effect on pig growth performance compared to that of unvaccinated pigs on all three of the farms. Vaccination of pigs with a plant-based PCV2a vaccine induced high levels of neutralizing antibodies titres against PCV2d and PCV2d-specific interferon-γ secreting cells which resulted in the reduction of PCV2d viral load and reduced lymphoid lesions severity. CONCLUSIONS: The results of this field trial demonstrated cross-protection of PCV2d by a plant-based PCV2a vaccine and a positive effect of pig growth performance with vaccination.

Efficacy of a novel bivalent vaccine containing porcine circovirus type 2d and Mycoplasma hyopneumoniae against a dual PCV2d and Mycoplasma hyopneumoniae challenge.

Background: Information on efficacy of a novel bivalent vaccine containing porcine circovirus type 2d (PCV2d) and Mycoplasma hyopneumoniae. Objective: To evaluate bivalent vaccine for efficacy under experimental conditions. Animals: Clinically healthy 35 weaned piglets at 18 days of age were used. Methods: A 2.0 mL dose of bivalent vaccine was administered intramuscularly to pigs at 21 days of age in accordance with the manufacturer's instructions. The pigs were challenged at 42 days of age either intranasally with PCV2d, or intratracheally with M. hyopneumoniae, or with both. Results: Vaccinated-challenged pigs improved the growth performance compared to pigs that were unvaccinated and then, challenged. Vaccinated-challenged pigs elicited a significant amount of protective immunity for PCV2d-specific neutralizing antibodies and interferon-γ secreting cells (IFN-γ-SC) as well as for M. hyopneumoniae-specific IFN-γ-SC compared to unvaccinated/challenged pigs. Induction of systemic cellular and humoral immune responses from bivalent vaccination reduced the viral and mycoplasmal loads in the blood and larynx. Vaccination and challenge simultaneously reduced both lung and lymphoid lesion severity when compared to unvaccinated-challenged pigs. Discussion: The results of this study demonstrated that the evaluated bivalent PCV2d and M. hyopneumoniae vaccine was efficacious in protecting pigs from the most predominant PCV2d genotype in the field today, as evaluated with a dual PCV2d and M. hyopneumoniae challenge under experimental conditions.

Virulence comparison of 4 porcine circovirus type 2 (PCV-2) genotypes: 2a, 2b, 2d, and 2e with a single infection and co-infection with PCV-2 and porcine reproductive and respiratory syndrome virus (PRRSV).

The objective of this study was to compare the virulence of 4 porcine circovirus type 2 (PCV-2) genotypes (2a, 2b, 2d, and 2e) in pigs singly infected with 1 of these 4 PCV-2 genotypes and pigs dually infected with a combination of 1 of the 4 PCV-2 genotypes and porcine reproductive and respiratory syndrome virus (PRRSV). Virulence was determined based on levels of PCV-2 loads in the blood and lymph nodes and the severity of lymphoid lesion. Within the singly infected groups, PCV-2a, PCV-2b, and PCV-2d resulted in a similar virulence to each other and all were more virulent than the PCV-2e groups. Within the dually infected groups, the combination of PCV-2d and PRRSV was more virulent than the other 3 PCV-2 genotypes (2a, 2b, and 2e), each in combination with PRRSV. Both PCV-2a+PRRSV and PCV-2b+PRRSV were more virulent than PCV-2e+PRRSV in dually infected pigs. This increased virulence of PCV-2d compared to the other 3 PCV-2 genotypes (2a, 2b, and 2e) may be attributed to an extra amino acid (lysine residue) found within open reading frame 2 (ORF2) of PCV-2d. In contrast, extra amino acids in ORF2 may decrease the virulence of PCV-2e when compared to the other 3 PCV-2 genotypes (2a, 2b, and 2d). The results of this study demonstrated that PCV-2d was the most virulent PCV-2 genotype in pigs co-infected with PRRSV. The results also suggest that genetic differences in the ORF2 of PCV-2 may affect the virulence of PCV-2 genotypes.

L'objectif de cette étude était de comparer la virulence de quatre génotypes de circovirus porcin de type 2 (PCV-2) (2a, 2b, 2d et 2e) chez des porcs infectés individuellement par un de ces quatre génotypes de PCV-2 et des porcs doublement infectés par une combinaison d'un des quatre génotypes PCV-2 et du virus du syndrome reproducteur et respiratoire porcin (PRRSV). La virulence a été déterminée en fonction des niveaux de charges de PCV-2 dans le sang et les ganglions lymphatiques et de la gravité des lésions lymphoïdes. Au sein des groupes infectés individuellement, PCV-2a, PCV-2b et PCV-2d ont entraîné une virulence similaire les uns aux autres et tous étaient plus virulents que les groupes PCV-2e. Au sein des groupes doublement infectés, la combinaison du PCV-2d et du PRRSV était plus virulente que les trois autres génotypes du PCV-2 (2a, 2b et 2e), chacun en combinaison avec le PRRSV. Le PCV-2a+PRRSV et le PCV-2b+PRRSV étaient plus virulents que le PCV-2e+PRRSV chez les porcs doublement infectés. Cette virulence accrue du PCV-2d par rapport aux trois autres génotypes du PCV-2 (2a, 2b et 2e) peut être attribuée à un acide aminé supplémentaire (résidu lysine) trouvé dans le cadre de lecture ouvert 2 (ORF2) de PCV-2d. En revanche, des acides aminés supplémentaires dans ORF2 peuvent diminuer la virulence du PCV-2e par rapport aux trois autres génotypes PCV-2 (2a, 2b et 2d). Les résultats de cette étude ont démontré que le PCV-2d était le génotype PCV-2 le plus virulent chez les porcs co-infectés par le PRRSV. Les résultats suggèrent également que des différences génétiques dans l'ORF2 du PCV-2 peuvent affecter la virulence des génotypes du PCV-2.(Traduit par Docteur Serge Messier).

Comparison of pathogenicity of 4 porcine circovirus type 2 (PCV2) genotypes (2a, 2b, 2d, and 2e) in experimentally infected pigs.

The objective of the current study was to compare the virulence of four porcine circovirus type 2 (PCV2) genotypes (PCV2a, 2b, 2d, and 2e) in pigs. Pigs were inoculated at 42 days of age with one of four PCV2 genotypes, then necropsied at 63 days of age. PCV2 genotype groups were evaluated through a comparison of clinical outcomes, antibody titers, level of PCV2 loads in blood and lymph nodes, and lymphoid lesion severity. Statistical differences did not occur between the evaluated genotype groups. Pigs inoculated with PCV2a, PCV2b, or PCV2d had a significantly (P<0.05) higher levels of PCV2 loads in blood and lymph node compared to pigs inoculated with PCV2e. The results of this study indicated that the PCV2a, PCV2b, and PCV2d are more virulent than PCV2e based on blood and lymphoid viral load of PCV2.

An evaluation of intradermal all-in-one vaccine based on an inactivated recombinant Mycoplasma hyopneumoniae strain expressing porcine circovirus type 2 (PCV2) capsid protein against Korean stains of PCV2d and M. hyopneumoniae challenge.

This study evaluates the efficacy of intradermal all-in-one vaccine (MHYOSPHERE® PCV ID, Laboratorios Hipra S.A. Amer, Spain) based on the strain Nexhyon, an inactivated recombinant M. hyopneumoniae strain with an embedded/integrated PCV2a capsid protein thereof, as the single active substance. Pigs were administered the vaccine intradermally at 21 days of age with 0.2 mL, then challenged at 49 days of age with either M. hyopneumoniae (intratracheal route), PCV2d (intranasal route), or both. Upon dual challenge, growth performance was improved when the intradermal all in one vaccine was administered compared to the unvaccinated group. In pigs receiving single or dual challenge, vaccination increased neutralizing antibodies against PCV2d and specific interferon-γ secreting cells for each pathogen. In contrast, viral load of PCV2d in the blood, M. hyopneumoniae load in the larynx, and the severity of pulmonary and lymphoid lesions were decreased. Vaccination provided good protection against challenge with M. hyopneumoniae and PCV2d.

Virulence Comparison of Four Porcine Circovirus Type 2 (PCV2) Genotypes (2a, 2b, 2d and 2e) in Pigs Single-Infected with PCV2 and Pigs Dual-Infected with PCV2 and Mycoplasma hyopneumoniae.

The objective of this study was to compare the virulence of four porcine circovirus type 2 (PCV2) genotypes (2a, 2b, 2d and 2e). Pigs were infected with one of these four genotypes. Pigs were also dually infected with Mycoplasma hyopneumoniae and one of the four PCV2 genotypes. Virulence was determined based on the amount of PCV2 loads in the blood and lymph nodes and the severity of lymphoid lesions. Marked differences in virulence were found among the four genotypes. Within the single infection model, PCV2a, PCV2b and PCV2d were more virulent than PCV2e, while significant differences in virulence were not found among the PCV2a, PCV2b and PCV2d groups. Within the dual infection model, PCV2d was more virulent than the other three PCV2 genotypes. Mycoplasma hyopneumoniae potentiated the severity of PCV2-associated lymphoid lesions and increased the amount of PCV2 loads in the blood and lymph nodes, regardless of the PCV2 genotype. By contrast, PCV2 was not able to potentiate the severity of mycoplasmal-induced lung lesions or the level of M. hyopneumoniae laryngeal load. The results of this study demonstrate that PCV2d is of major clinical importance, while PCV2e is of minor clinical importance.

Pathogenicity of Porcine Circovirus Type 2e in Experimentally Infected Pigs.

A 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.

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.

The 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-γ 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.

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.

The 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.

Pharmacokinetics and toxicity evaluation following oral exposure to bisphenol F.

Bisphenol 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.

Comparative growth performance of 3 types of combination vaccines containing porcine circovirus 2 and Mycoplasma hyopneumoniae under field conditions.

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.

L'objectif de cet essai de terrain était de comparer l'effet 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 l'emploi contenant le PCV-2a et M. hyopneumoniae. Deux fermes ont été sélectionnées sur la base de leurs antécédents d'infection 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 d'engraissement (70 à 175 jours d'âge) dans le groupe vacciné bivalent mélangeable par rapport au groupe vacciné bivalent prêt à l'emploi sur une ferme. Le groupe vacciné par trivalent a suscité des niveaux plus élevés d'anticorps neutralisants et de cellules sécrétant de l'interféron-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 l'emploi. Le groupe vacciné trivalent a également provoqué des niveaux plus élevés d'IFN-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 l'emploi. Les résultats de la présente étude ont démontré qu'un 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 l'emploi malgré la présence d'une infection subclinique par le PCV-2d et d'une pneumonie enzootique dans les élevages.(Traduit par Docteur Serge Messier).

Multiplex polymerase chain reaction for the detection and differentiation of 4 porcine circovirus 2 genotypes (PCV-2a, -2b, -2d, and -2e) in clinical samples.

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).

L'objectif 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 l'extraction de l'ADN 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 d'infections 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).

Non-Inferiority Field Study Comparing the Administrations by Conventional Needle-Syringe and Needle-Free Injectors of a Trivalent Vaccine Containing Porcine Circovirus Types 2a/2b and Mycoplasma hyopneumoniae.

The objective of this study was to assess the clinical, immunological, microbiological, and pathological evaluation of trivalent vaccine containing porcine circovirus types 2a/b (PCV2a/b) and Mycoplasma hyopneumoniae given by two different needle-free injection devices compared with conventional needle-syringe injection in a herd with subclinical PCV2d infection and enzootic pneumonia. A total of 240 21-day-old pigs, which weighed between 5 to 6 kg, were randomly divided into four groups (60 pigs per group, 30 = male and 30 = female per group). Injection site reactions in the pigs were minimal for the two needle-free injection devices and needle-syringe injection. Trivalent vaccination of pigs with two needle-free injection devices was not inferior to conventional needle-syringe injection for growth performance. Trivalent vaccination of pigs with two different needle-free injection devices reduced levels of PCV2d loads in serum and M. hyopneumoniae loads in the larynx equally compared to the conventional needle-syringe injection. The amount of PCV2d load in serum from the needle-free Pulse FX injection device at 49 days post vaccination showed non-inferiority to conventional needle-syringe injection. The immune response against PCV2 and M. hyopneumoniae to trivalent vaccine given with the needle-free Pulse FX injection device was non-inferior to conventional needle-syringe injection. The pigs from the two needle-free injection device and conventional needle-syringe injection had significantly (p < 0.05) lower macroscopic and microscopic lung lesion scores, and microscopic lymphoid lesions than from unvaccinated. The results of this study demonstrated that vaccination of trivalent vaccine by the two needle-free Pulse injection devices used in the study was non-inferior to that by conventional needle-syringe injection for growth performance, immune response against PCV2 and M. hyopneumoniae, and reduction of PCV2 viremia.

Chronological expression and distribution of African swine fever virus p30 and p72 proteins in experimentally infected pigs.

African swine fever virus (ASFV), the causative agent of contagious hemorrhagic disease in domestic pigs and wild boars, has temporally regulated gene expression kinetics. The p30 and p72 major structural proteins are involved in viral entry each with different expression kinetics, but neither of their chronological expressions and distribution have been identified in virus-infected animals. Here, we found that both transcription and translation levels of p30 were significantly higher than those of p72 in target organs during the earlier infection-phase. Lymphocyte apoptosis/necrosis and angiectasia were observed as signs of early infection with acute African swine fever. These results show that the chronologically differential expression of ASFV structural proteins tends to be prominent in infected animals, and the p30 protein could play a role in the indication of acute lesions during early infection compared to the late-expressed p72 protein. In conclusion, we propose to consider the chronological expression dynamics of ASFV structural proteins in infected animals to understand virus pathogenesis and antigen targeting for vaccine development.

A field efficacy trial of a trivalent vaccine containing porcine circovirus type 2a and 2b, and Mycoplasma hyopneumoniae in three herds.

BACKGROUND: This field trial was designed to evaluate the efficacy of a new trivalent vaccine containing porcine circovirus type 2a and 2b (PCV2a/b), and Mycoplasma hyopneumoniae at three independent locations. METHODS: Three farms were selected based on their history of PCV2 and M. hyopneumoniae co-infection. Each farm housed a total of 60, 3-day-old pigs that were randomly allocated to one of three treatment groups. Pigs were administered the trivalent vaccine intramuscularly with either a 1.0 ml dose at 3 and 24 days of age or a 2.0 ml dose at 21 days of age in accordance with the manufacturer's recommendations. RESULTS: Clinically, the average daily weight gain of the one-dose and two-dose vaccinated groups within all three farms was significantly higher (p < 0.05) than those of unvaccinated animals during the growing (70-112 days of age), finishing (112-175 days of age) and overall (3-175 days of age) stages of production. One-dose and two-dose vaccinated animals elicited neutralizing antibodies and interferon-γ-secreting cells (IFN-γ-SC), which reduced the amount of PCV2 in terms of blood load and reduced the severity of lymphoid lesions when compared with unvaccinated animals. Similarly, one-dose and two-dose vaccinated animals elicited IFN-γ-SC, which reduced the amount of M. hyopneumoniae in terms of laryngeal load and reduced the severity of lung lesions. CONCLUSIONS: The intramuscular administration of either one or two doses of trivalent vaccine was not significantly different in any of the evaluated parameters. The results of field trial demonstrated that the trivalent vaccine was efficacious in the protection of swine herds where PCV2d and M. hyopneumoniae were in active circulation.

Age-related viral load and severity of systemic pathological lesions in acute naturally occurring African swine fever virus genotype II infections.

African swine fever (ASF) causes a contagious hemorrhagic disease in all ages of pigs without sex predilections. The objective of this study was to determine the age-related viral loads and severity of systemic pathological lesions among three different swine group ages (weaned pigs, fattening pigs, and sows) during a recent outbreak of acute ASF in Vietnam. Age-related viral loads were determined in 5 major organs (lung, liver, spleen, kidney, and lymph node) by immunohistochemistry as well as in the blood by real-time polymerase chain reaction (PCR). Age-related systemic pathological lesions were analyzed in the listed organs among three age groups. Weaned pigs had significantly (p < 0.05) higher levels of viral loads in their lung, liver, lymph nodes and blood than in those of fattening pigs and sows. Fattening pigs had significantly (p < 0.05) higher scores of macroscopic lung and lymphoid lesions, and microscopic liver lesions compared with those of weaned pigs and sows. The results of this study demonstrated that viral loads were age-related in acute naturally occurring ASF but the severity of pathological lesions was not correlated with the level of viral loads in the five major organs.