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1.
Article in Korean | WPRIM | ID: wpr-816641

ABSTRACT

Porcine respiratory disease complex (PRDC) continues to be a significant economic problem to the swine industry. Porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV), and Mycoplasma hyopneumoniae (MH) are considered to be the most important pathogens that cause PRDC. In this study, we investigated the prevalence of antibodies against PRRSV and MH in the serum of sows and piglets from 89 domestic commercial pig farms by ELISA, and the presence of viral nucleic acids of PRRSV, including North American and European PRRS, and PCV2 was also investigated in the serum of sows and piglets from 89 domestic commercial pig farms by real-time PCR. In case of PRRSV, 78.7% (70/89) of sows were positive for PRRSV antibody, and 96.6% (86/89) of piglets were positive for PRRSV antibody. For MH, 76.4% (68/89) of sows showed positive for MH antibody. In the PRRSV viral nucleic acid detection experiment, 36.0% (32/89) of sows were positive for PRRSV nucleic acids, and virus nucleic acid was detected in 83.1% (74/89) of piglets. In case of virus type, both North American and European types were detected. In case of PCV2, 15.7% (14/89) of sows were positive for PCV2 nucleic acids. Conclusively, PCV2, PRRSV, and MH were widely distributed in pig farms in Korea. These prevalence data related with PRDC provides clinical information for vaccination strategy and development for the control of PRDC.


Subject(s)
Agriculture , Antibodies , Circovirus , Enzyme-Linked Immunosorbent Assay , Korea , Mycoplasma hyopneumoniae , Mycoplasma , Nucleic Acids , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Prevalence , Real-Time Polymerase Chain Reaction , Swine , Vaccination
2.
Article in English | WPRIM | ID: wpr-758832

ABSTRACT

Porcine reproductive and respiratory syndrome (PRRS) is recognized as one of the most important infectious diseases causing serious economic loss in the swine industry worldwide. Due to its increasing genetic diversity, a rapid and accurate diagnosis is critical for PRRS control. The immunochromatographic strip test (ICST) is a rapid and convenient type of immunoassay. In this study, an on-site immunochromatographic assay-based diagnostic method was developed for detection of PRRS virus (PRRSV)-specific antibodies. The method utilized colloidal gold nanoparticle-labeled dual-type nucleocapsid proteins encoded by open reading frame 7. We evaluated 991 field samples from pig farms and 66 serum samples from experimentally PRRSV-inoculated pigs. Based on true PRRSV-specific antibody-positive or


Subject(s)
Agriculture , Antibodies , Colloids , Communicable Diseases , Diagnosis , Enzyme-Linked Immunosorbent Assay , Fluorescent Antibody Technique , Genetic Variation , Gold Colloid , Immunoassay , Chromatography, Affinity , Immunoglobulin M , Methods , Nucleocapsid Proteins , Open Reading Frames , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Sensitivity and Specificity , Swine
3.
Article in English | WPRIM | ID: wpr-758820

ABSTRACT

Two strains of porcine reproductive and respiratory syndrome virus (PRRSV) were isolated in 2006 and 2016 and designated as FZ06A and FZ16A, respectively. Inoculation experiments showed that FZ06A caused 100% morbidity and 60% mortality, while FZ16A caused 100% morbidity without death. By using genomic sequence and phylogenetic analyses, close relationships between a Chinese highly pathogenic PRRSV strain and the FZ06A and FZ16A strains were observed. Based on the achieved results, multiple genomic variations in Nsp2, a unique N-glycosylation site (N³³→K³³), and a K151 amino acid (AA) substitution for virulence in the GP5 of FZ16A were detected; except the 30 AA deletion in the Nsp2-coding region. Inoculation experiments were conducted and weaker virulence of FZ16A than FZ06A was observed. Based on our results, a 30 AA deletion in the Nsp2-coding region is an unreliable genomic indicator of a high virulence PRRSV strain. The Nsp2 and GP5 differences, in addition to the virulence difference between these two highly pathogenic PRRSV strains, have the potential to be used to establish a basis for further study of PRRSV virulence determinants and to provide data useful in the development of vaccines against this economically devastating disease.


Subject(s)
Asian Continental Ancestry Group , China , Genomics , Humans , Mortality , Phylogeny , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Vaccines , Virulence
4.
Article in English | WPRIM | ID: wpr-758818

ABSTRACT

The porcine reproductive and respiratory syndrome virus (PRRSV) is a globally ubiquitous swine viral pathogen that causes major economic losses worldwide. We previously reported an over-attenuated phenotype of cell-adapted PRRSV strain CA-2-P100 in vivo. In the present study, CA-2-P100 was serially propagated in cultured porcine alveolar macrophage (PAM) cells for up to 20 passages to obtain the derivative strain CA-2-MP120. Animal inoculation studies revealed that both CA-2-P100 and CA-2-MP120 had decreased virulence, eliciting weight gains, body temperatures, and histopathologic lesions similar to those in the negative control group. However, compared to CA-2-P100 infection, CA-2-MP120 yielded consistently higher viremia kinetics and enhanced antibody responses in pigs. All pigs inoculated with CA-2-MP120 developed viremia and seroconverted to PRRSV. During 20 passages in PAM cells, CA-2-MP120 acquired 15 amino acid changes that were mostly distributed in nsp2 and minor structural protein-coding regions. Among these changes, 6 mutations represented reversions to the sequences of the reference CA-2 and parental CA-2-P20 strains. These genetic drifts may be hypothetical molecular markers associated with PRRSV macrophage tropism and virulence. Our results indicate that the PAM-passaged CA-2-MP120 strain is a potential candidate for developing a live, attenuated PRRSV vaccine.


Subject(s)
Animals , Antibody Formation , Body Temperature , Genetic Drift , Humans , Kinetics , Macrophages , Macrophages, Alveolar , Parents , Phenotype , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Swine , Tropism , Vaccines, Attenuated , Viremia , Virulence , Weight Gain
5.
Article in English | WPRIM | ID: wpr-758775

ABSTRACT

Porcine reproductive and respiratory syndrome (PRRS) is one of the most important swine diseases worldwide. In the present study, a new virulent strain of PRRS virus (PRRSV), GDsg, was isolated in Guangdong province, China, and caused high fever, high morbidity, and high mortality in sows and piglets. The genome of this new strain was 15,413 nucleotides (nt) long, and comparative analysis revealed that GDsg shared 82.4% to 94% identity with type 2 PRRSV strains, but only 61.5% identity with type 1 PRRSV Lelystad virus strain. Phylogenetic analysis indicated that type 2 PRRSV isolates include five subgenotypes (I, II, III, IV, and V), which are represented by NADC30, VR-2332, GM2, CH-1a, and HuN4, respectively. Moreover, GDsg belongs to a newly emerging type 2 PRRSV subgenotype III. More interestingly, the newly isolated GDsg strain has multiple discontinuous nt deletions, 131 (19 + 18 + 94) at position 1404–1540 and a 107 nt insertion in the NSP2 region. Most importantly, the GDsg strain was identified as a virus recombined between low pathogenic field strain QYYZ and vaccine strain JXA1-P80. In conclusion, a new independent subgenotype and recombinant PRRSV strain has emerged in China and could be a new threat to the swine industry of China.


Subject(s)
China , Fever , Genome , Mortality , Nucleotides , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Swine , Swine Diseases
6.
Article in English | WPRIM | ID: wpr-741511

ABSTRACT

The efficacy of the CA-2-MP120 vaccine, a cell culture-attenuated strain of virulent porcine reproductive and respiratory syndrome virus (PRRSV), was assessed in pigs. Despite the persistence of viremia in all vaccinated animals during the immunization period, the virus was not detected in vaccinated pigs following challenge. Furthermore, no pigs in the vaccinated group shed PRRSV nasally, orally or rectally throughout the experiment. Moreover, histopathological lung and lymph node lesions in the immunized group were much milder than those in the unimmunized and challenged group. These results indicated that CA-2-MP120 can provide effective protection against virulent wildtype PRRSV-2.


Subject(s)
Animals , Immunization , Lung , Lymph Nodes , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Swine , Treatment Outcome , Vaccination , Vaccines, Attenuated , Viremia
7.
Article in English | WPRIM | ID: wpr-741503

ABSTRACT

Outbreaks of porcine reproductive and respiratory syndrome virus (PRRSV) in vaccinated sow herds from occurrence to stabilization were monitored and analyzed in terms of serology and reproductive performance. Three different conventional pig farms experienced severe reproductive failures with the introduction of a type 1 PRRSV. These farms had adopted mass vaccination of sows using a type 2 PRRSV modified live vaccine (MLV). Therefore, to control the type 1 PRRSV, an alternative vaccination program utilizing both type 1 and type 2 MLV was undertaken. Following whole herd vaccinations with both types of MLV, successful stabilization of PRRS outbreaks was identified based on serological data (no viremia and downward trends in ELISA antibody titers in both sows and suckling piglets) and recovery of reproductive performance. Additionally, through comparison of the reproductive parameters between outbreak and non-outbreak periods, it was identified that PRRSV significantly affected the farrowing rate and the number of suckling piglets per litter at all three pig farms. Comparison of reproductive parameters between periods when the different vaccination strategies were applied revealed that the number of piglets born in total and born dead per litter were significantly increased after the introduction of the type 1 PRRS MLV.


Subject(s)
Agriculture , Disease Outbreaks , Enzyme-Linked Immunosorbent Assay , Immunity, Herd , Immunity, Heterologous , Mass Vaccination , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Vaccination , Viremia
8.
Article in English | WPRIM | ID: wpr-741493

ABSTRACT

A preliminary study into the protective mechanisms of adaptive immunity against porcine reproductive and respiratory syndrome virus (PRRSV) in piglets (n = 9) born to a gilt challenged intranasally with a type-2 PRRSV. Immune parameters (neutralizing antibodies, CD3⁺CD4⁺, CD3⁺CD8⁺, CD3⁺CD4⁺CD8⁺ T-lymphocytes, and PRRSV-specific interferon (IFN)-γ secreting T-lymphocytes) were compared with infection parameters (macro- and microscopic lung lesion, and PRRSV-infected porcine alveolar macrophages (CD172α⁺PRRSV-N⁺ PAM) as well as with plasma and lymphoid tissue viral loads. Percentages of three T-lymphocyte phenotypes in 14-days post-birth (dpb) peripheral blood mononuclear cell (PBMC) had significant negative correlations with percentages of CD172α⁺PRRSV-N⁺ PAM (p 0.1) with infection parameters. The results indicate that T-lymphocytes contribute to controlling PRRSV replication in young piglets born after in-utero infection.


Subject(s)
Adaptive Immunity , Antibodies , Antibodies, Neutralizing , Interferons , Lung , Lymph Nodes , Lymphoid Tissue , Macrophages, Alveolar , Phenotype , Plasma , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , T-Lymphocytes , Viral Load
9.
Article in Korean | WPRIM | ID: wpr-111256

ABSTRACT

Porcine ear necrosis syndrome is characterized by erosive and ulcerative lesions at the margin or tip of the pinna. Three growing pigs of different ages exhibited retarded growth accompanied by reddening and necrosis of ear prior to death. Gross examination showed reddening, swelling, black discoloration, scaling, and variable-sized yellowish materials and edema in ear cross section. Microscopically, thrombosis, abscess, ulceration, epidermal hyperplasia, and dermal pyogranulomatous inflammation with an intralesional bacterial colony were observed. Staphylococcus hyicus was isolated in all pigs' ears and porcine reproductive and respiratory syndrome virus was detected by PCR and immunohistochemistry.


Subject(s)
Abscess , Coinfection , Ear , Edema , Hyperplasia , Immunohistochemistry , Inflammation , Necrosis , Polymerase Chain Reaction , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Staphylococcus hyicus , Swine , Thrombosis , Ulcer
10.
Article in English | WPRIM | ID: wpr-109772

ABSTRACT

There are high levels of co-incidence of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) in porcine tissue. This study established a duplex nested reverse transcriptase polymerase chain reaction (RT-PCR) method that targets the genomic RNA of type 2 PRRSV and the mRNA of PCV2 in infected tissues. The method amplified discriminative bands of 347 bp and 265 bp specific for type 2 PRRSV and PCV2, respectively. The limits of detection of the duplex nested RT-PCR were 10(1.5) TCID₅₀/mL for type 2 PRRSV and 10² infected cells/mL for PCV2. The kappa statistic, which measures agreement between methods, was 0.867, indicating a good level of agreement. This RNA-based duplex RT-PCR approach can be another way to detect type 2 PRRSV and PCV2 simultaneously and with improved convenience.


Subject(s)
Circovirus , Limit of Detection , Methods , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Reverse Transcriptase Polymerase Chain Reaction , RNA , RNA, Messenger , RNA-Directed DNA Polymerase
11.
Article in Korean | WPRIM | ID: wpr-90021

ABSTRACT

Salmonella (S.) Typhimurium is highly contagious, and its infection may rapidly spread within pig populations of herd. According to the survey (1,191 pigs) from 2003 to 2012, 155 pigs (13.0%) were diagnosed as salmonellosis in Jeju. Major porcine salmonellosis cases (88.4%) were concentrated in 4- to 12-week-old weaned pigs, but 6 pigs (3.9%) under 4 weeks old were also diagnosed. Based on the histopathologic examinations, ulcerative enteritis (63.9%) in the large intestine and/or paratyphoid nodules formation (57.4%) in the liver were most prevalent lesions in porcine salmonellosis. Single infection of S. Typhimurium and mixed infection with more than 2 pathogens were detected in 38 (24.5%) and 117 (75.5%) in pigs, respectively. Co-infections of Porcine reproductive and respiratory syndrome virus and Porcine circovirus type 2 were very common in porcine salmonellosis in Jeju and detected in 84 (54.2%) and 59 (38.1%) pigs, respectively. Based on the serotyping tests using 41 bacterial isolates, S. Typhimurium and S. Rissen were confirmed in 39 (95.1%) and 2 (4.9%) cases, respectively.


Subject(s)
Circovirus , Coinfection , Enteritis , Intestine, Large , Liver , Porcine respiratory and reproductive syndrome virus , Prevalence , Salmonella , Salmonella Infections , Salmonella typhimurium , Serotyping , Swine , Ulcer
12.
Article in English | WPRIM | ID: wpr-57419

ABSTRACT

Oral fluid analysis for herd monitoring is of interest to the commercial pig production in Korea. The aim of this study was to investigate pathogen-positive rates and correlations among eight pathogens associated with porcine respiratory disease complex by analyzing oral fluid samples from 214 pig groups from 56 commercial farms. Samples collected by a rope-chewing method underwent reverse-transcriptase polymerase chain reaction (RT-PCR) or standard polymerase chain reaction (PCR) analysis, depending on the microorganism. Pathogens were divided into virus and bacteria groups. The former consisted of porcine reproductive and respiratory syndrome virus and porcine circovirus type 2 (PCV2), and the latter Pasteurella multocida, Haemophilus parasuis, Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae (MHP), Mycoplasma hyorhinis, and Streptococcus suis (SS). All pathogens were detected more than once by PCR. Age-based analysis showed the PCR-positive rate increased with increasing age for PCV2 and MHP, whereas SS showed the opposite. Correlations between pathogens were assessed among 36 different pair combinations; only seven pairs showed statistically significant correlations. In conclusion, the oral fluid method could be a feasible way to detect various swine respiratory disease pathogens and, therefore, could complement current monitoring systems for respiratory diseases in the swine industry.


Subject(s)
Actinobacillus pleuropneumoniae , Agriculture , Bacteria , Circovirus , Complement System Proteins , Haemophilus parasuis , Korea , Methods , Mycoplasma hyopneumoniae , Mycoplasma hyorhinis , Pasteurella multocida , Polymerase Chain Reaction , Porcine respiratory and reproductive syndrome virus , Streptococcus suis , Swine
13.
Article in English | WPRIM | ID: wpr-57417

ABSTRACT

A simple and rapid immunochromatographic test strip incorporating a colloidal gold-labeled recombinant Nsp7 antigen probe was successfully developed for the detection of anti-porcine reproductive and respiratory syndrome virus (PRRSV) antibodies in swine. Recombinant Nsp7 protein of PRRSV labeled with colloidal gold was dispensed on a conjugate pad for use as the detector. Staphylococcal protein A and purified porcine anti-Nsp7 antibodies were blotted on a nitrocellulose membrane to form test and control lines, respectively. A comparison of the strip with standard diagnostic tests, enzyme-linked immunosorbent assays and immunoperoxidase monolayer assay, was also performed. The immunochromatographic test strip was shown to be of high specificity and sensitivity. Furthermore, the strip assay is rapid and easy to perform with no requirement for professional-level skills or equipment. It is suggested that the immunochromatographic test strip can be used to quickly and accurately detect PRRSV antibody and to be suitable for diagnostic purposes in the field.


Subject(s)
Antibodies , Collodion , Colloids , Diagnostic Tests, Routine , Enzyme-Linked Immunosorbent Assay , Gold Colloid , Chromatography, Affinity , Membranes , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Sensitivity and Specificity , Staphylococcal Protein A , Swine
14.
Article in English | WPRIM | ID: wpr-57416

ABSTRACT

Porcine reproductive and respiratory syndrome virus (PRRSV) has a high degree of genetic variation. In this study, we characterized the genetic variation and evolutionary relationships among circulating PRRSV strains in southern China. We analyzed 29 NSP2 strains and 150 ORF5 strains from clinical samples collected in southern China during 2007–2014. The alignment results showed that the nucleotide identity similarities of the two genes among these strains were 80.5%–99.7% and 80.9%–100%, respectively. Phylogenetic analysis based on the NSP2 gene showed that highly pathogenic (HP)-PRRSV was still the dominant virus in southern China from 2013 to 2014. Compared with reference strains CH-1a and VR-2332, the field strain 131101-GD-SHC, which shared high homology with JXA1-P170, had a novel 12 amino acid deletion at position 499–510. Phylogenetic analysis based on the ORF5 gene showed that HP-PRRSV, VR2332-like strains, and QYYZ-like strains were simultaneously circulating in southern China from 2007 to 2014, suggesting that, in recent years, the type 2 PRRSV was more diverse in southern China. In conclusion, mutations in the decoy epitope and primary neutralizing epitope could be markers of viral evolution and used to study evolutionary relationships among PRRSV strains in China.


Subject(s)
China , Genetic Variation , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus
15.
Article in English | WPRIM | ID: wpr-8371

ABSTRACT

PURPOSE: Porcine reproductive and respiratory syndrome virus (PRRSV) leads to major economic losses in the swine industry. Vaccination is the most effective method to control the disease by PRRSV. MATERIALS AND METHODS: In this study, the efficacy of a glycoprotein (GP) 5-modified inactivated vaccine was investigated in pigs. The study was performed in three farms: farm A, which was porcine reproductive and respiratory syndrome (PRRS)-negative, farm B (PRRS-active), which showed clinical signs of PRRS but had not used vaccines, and farm C (PRRS-stable), which had a history of endemic PRRS over the past years, but showed no more clinical signs after periodic administration of modified live virus vaccine. RESULTS: The inactivated vaccine induced great enhancement in serum neutralizing antibody titer, which was sufficient to protect pigs from further infections of PRRSV in a farm where pre-existing virus was circulating. CONCLUSION: These results indicated that vaccination with the inactivated vaccine composed of viruses possessing deglycosylated GP5 would provide enhanced protection to pigs from farms suffering from endemic PRRSV.


Subject(s)
Antibodies, Neutralizing , Glycoproteins , Neutralization Tests , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Swine , Vaccination , Vaccines , Vaccines, Inactivated
16.
Chinese Journal of Virology ; (6): 585-592, 2015.
Article in Chinese | WPRIM | ID: wpr-296243

ABSTRACT

The porcine reproductive and respiratory syndrome virus (PRRSV) can cause reproductive barriers in breeding pigs and respiratory symptoms in piglets. In this review, we summarize research progress of the infection and replication mechanisms of the PRRSV. We also review the virulence determinants of the PRRSV. All these fundamental studies are important for the control and elimination of the PRRSV.


Subject(s)
Animals , Porcine Reproductive and Respiratory Syndrome , Virology , Porcine respiratory and reproductive syndrome virus , Genetics , Virulence , Physiology , Swine , Virulence , Virus Replication
17.
Chinese Journal of Virology ; (6): 65-73, 2015.
Article in Chinese | WPRIM | ID: wpr-280293

ABSTRACT

Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) are very two important pathogens that have coursed huge economic losses in swine production in worldwide. In this study,a vector pCMV-TJM containing the full-length cDNA clone of PRRSV attenuated strain TJM-F92 was firstly constructed by PCR method. Then a gene sequence containing Afl II/Mlu I e restriction enzyme sites and a transcription regulatory sequence for ORF6 (TRS6) was inserted be- tween ORF7 and 3'UTR, yielding a expression vector pCMV-TJM-TRS. Subsequently, a plasmid pCMV-TJM-Cap was constructed by cloning of PCV2 ORF2 gene into the unique sites Afl II /Mlu I of pCMV- TJM-TRS plasmid DNA. Then three recombinant PRRSV, rTJM, rTJM/TRS and rTJM/Cap, were rescued by transfection of pCMV-TJM, pCMV-TJM-TRS and pCMV-TJM-Cap into Marc-145 cells, respectively,and confirmed by the genome sequence, restriction enzyme digestion, Western Blot and IFA. They all had the molecular markers which was different from the parent virus. The growth characteristics of the rescued viruses were similar to that of parent virus. rTJM/Cap could also express efficiently PCV2 Cap protein in Marc-145 cells. At passage 8, it still had PCV2 ORF2 gene which examined by RT-PCR. It indicated that the full-length cDNA clone of PRRSV attenuated strain TJM-F92 and recombinant PRRSV rTJM/Cap expressing PCV2 Cap protein were successfully constructed. It made an important foundation for studying on the pathogenic mechanisms of PRRSV and PRRSV-PCV2 vaccine in the future.


Subject(s)
Animals , Capsid Proteins , Genetics , Allergy and Immunology , Cell Line , Circoviridae Infections , Virology , Circovirus , Classification , Genetics , Metabolism , Gene Expression , Open Reading Frames , Porcine Reproductive and Respiratory Syndrome , Virology , Porcine respiratory and reproductive syndrome virus , Genetics , Metabolism , Recombination, Genetic , Swine , Swine Diseases , Virology , Viral Vaccines , Genetics , Allergy and Immunology
18.
Article in English | WPRIM | ID: wpr-22784

ABSTRACT

All vaccines are developed to elicit an effective immune response in vaccinated animals such as innate, humoral and cell mediated response to protect animal health. Quality and intensity of the immune responses are differing by characteristics of the vaccine formulation and nature of the infectious agent. Modified live virus vaccines showed advantages over killed vaccines in terms of rapid immune response, duration of the immunity and better cell mediated protection mechanism. The porcine reproductive and respiratory syndrome virus (PRRSV) is relatively newly emerging (1986 in United States, 1990 in Europe) viral pathogen in pigs and tremendous effort has been made to protect pigs from this economically devastating disease such as developing killed, modified live, recombinant protein based and DNA vaccines. However, only cell culture attenuated virus vaccine is practiced with arguably limited efficacy. The PRRSV vaccine did not clear virus from infected pigs nor prevent re-infection of the virus. The vaccine showed very limited innate immune response, low anamnestic immune response and negligible cell mediated immune response. Despite of the current developed scientific technology, there still remain many questions to solve a most important pig disease worldwide.


Subject(s)
Animals , Cell Culture Techniques , Immunity, Innate , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Swine , United States , Vaccines , Vaccines, DNA , Vaccines, Inactivated
19.
Article in English | WPRIM | ID: wpr-194862

ABSTRACT

The objectives of the present study were to evaluate the anatomic localization of porcine reproductive and respiratory syndrome virus (PRRSV) in naturally infected pigs and to determine whether oral fluid could be used to detect the virus in infected animals. Two sows, seven 2-month-old grower pigs, and 70 6-month-old gilts were included in this study. PRRSV in sera and oral fluid were identified by nested reverse transcription PCR (nRT-PCR) while lung, tonsil, and tissue associated with oral cavity were subjected to nRT-PCR, immunohistochemistry, and in situ hybridization. In sows, PRRSV was identified in oral fluid and tonsils. PRRSV was also detected in oral fluid, tonsils, salivary glands, oral mucosa, and lungs of all seven grower pigs. However, viremia was observed in only two grower pigs. Double staining revealed that PRRSV was distributed in macrophages within and adjacent to the tonsillar crypt epithelium. In gilts, the North American type PRRSV field strain was detected 3 to 8 weeks after introducing these animals onto the farm. These results confirm previous findings that PRRSV primarily replicates in tonsils and is then shed into oral fluid. Therefore, oral fluid sampling may be effective for the surveillance of PRRSV in breeding herds.


Subject(s)
Animals , Female , In Situ Hybridization/veterinary , Lung/virology , Male , Palatine Tonsil/virology , Polymerase Chain Reaction/veterinary , Porcine Reproductive and Respiratory Syndrome/virology , Porcine respiratory and reproductive syndrome virus/physiology , Saliva/virology , Salivary Glands/virology , Swine/virology , Virus Replication/physiology
20.
Article in English | WPRIM | ID: wpr-191849

ABSTRACT

Currently, killed-virus and modified-live porcine reproductive and respiratory syndrome virus (PRRSV) vaccines are used to control porcine reproductive and respiratory syndrome. However, both types of vaccines have inherent drawbacks; accordingly, the development of novel PRRSV vaccines is urgently needed. Previous studies have suggested that yeast possesses adjuvant activities, and it has been used as an expression vehicle to elicit immune responses to foreign antigens. In this report, recombinant Kluyveromyces lactis expressing GP5 of HP-PRRSV (Yeast-GP5) was generated and immune responses to this construct were analyzed in mice. Intestinal mucosal PRRSV-specific sIgA antibody and higher levels of IFN-gamma in spleen CD4+ and CD8+ T cells were induced by oral administration of Yeast-GP5. Additionally, Yeast-GP5 administered subcutaneously evoked vigorous cell-mediated immunity, and PRRSV-specific lymphocyte proliferation and IFN-gamma secretion were detected in the splenocytes of mice. These results suggest that Yeast-GP5 has the potential for use as a vaccine for PRRSV in the future.


Subject(s)
Administration, Oral , Animals , Antibodies, Viral/immunology , B-Lymphocytes/immunology , Enzyme-Linked Immunosorbent Assay , Immunity, Cellular , Immunity, Mucosal , Injections, Subcutaneous , Kluyveromyces/genetics , Mice , Mice, Inbred BALB C , Porcine respiratory and reproductive syndrome virus/immunology , Recombinant Proteins/genetics , T-Lymphocytes/immunology , Viral Envelope Proteins/genetics , Viral Vaccines/administration & dosage
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