Porcine circovirus type 2 (PCV2) is the primary causative agent for post-weaning, multisystemic, wasting syndrome. Consequently, serologic detection of and vaccination against PCV2 are important for the swine industry. Among several serological tests, the enzyme-linked immunosorbent assay (ELISA) is commonly used to measure anti-PCV2 antibody levels. In the present study, we used two commercial ELISA systems to comparatively evaluate anti-PCV2 antibodies in field pigs treated with three different PCV2 vaccines. Among a total of 517 serum samples, the results of the two ELISAs were fully concordant for 365 positive and 42 negative samples, indicating 78.7% agreement. In addition, the Pearson coefficient (0.636) indicated a moderate correlation between data from the two ELISAs. Results from the farms with pigs vaccinated with the three different PCV2 vaccines demonstrated that most of the vaccinated animals underwent seroconversion. However, the increase and duration of antibody titers varied depending on the vaccine, the presence of maternal antibodies, and the vaccination program. PCV2 serologic status and anti-PCV2 antibody levels of herds from this study could be utilized to determine the best timing for vaccination and assessing vaccination compliance.
Aging ; Animals ; Antibodies, Viral/*blood ; Circovirus/*classification/immunology ; Enzyme-Linked Immunosorbent Assay/methods/*veterinary ; Female ; Porcine Postweaning Multisystemic Wasting Syndrome/blood/immunology/*prevention & control ; Republic of Korea/epidemiology ; Swine ; Swine Diseases/*prevention & control/virology ; Viral Vaccines/*immunology

In early 2011, the serious outbreak of porcine pseudorabies virus (PRV) infection suddenly recurred in Henan and neighboring Provinces. To investigate the etiology of massive infection with PRV, 16 800 serum samples, 905 porcine epidemic diarrhea virus (PEDV) back-feeding tissues, and 56 PR gene deleted live vaccines were colleted from January 2011 to May 2013 to detect PRV field infection using a PRV gE antibody test kit. The gE and TK genes of 11 new epidemic PRV strains were sequenced by PCR, and their molecular characteristics were analyzed. Moreover, virus titer determination, protective test against PRV, and vaccine potency testing were performed. The results showed that the detection rate of PRV field infection-positive pig farms was 68.06%, and the overall positive rate of PRV field infection in serum was 38.47%; the positive rates in breeding sows, breeding boars, reserve pigs, and commercial pigs were 40.12%, 30.88%, 54.67%, and 26.52%, respectively. The new epidemic strains were in the same evolutionary branch and belonged to the virulent strain group. Compared with the classical PRV strain, the virulence of new epidemic strains changed a little. The length of gE gene was 1 787 bp, and the length of TK gene was 963 bp. The nucleotide homologies of gE and TK genes to Chinese reference strains were 98.2%-99.8% and 98.90%-99.6%, respectively, and the amino acid homologies were 97.1%-99.8% and 97.5%-99.4%, respectively. Commercial vaccine had a 100% protective effect against the new epidemic strains. The positive rate of PRV field infection was 0% in vaccine and 40.44% in back-feeding tissues. The results confirmed that PRV field infection rates were rising sharply among pigs in Henan and neighboring Provinces after 2011. The main virulence genes of new epidemic PRV strains did not change significantly over the years. PR gene deleted live vaccines had no PRV field infection and could completely resist the attack of new strains. The virus carriage of breeding boars and reserve pigs and the serious PRV field infection in PEDV back-feeding tissues were the main causative factors for massive infection with PRV and epidemic outbreak in Henan and neighboring Provinces from 2011 to 2013.
Amino Acid Sequence ; Animal Feed ; analysis ; virology ; Animals ; China ; epidemiology ; Epidemics ; Female ; Herpesvirus 1, Suid ; chemistry ; classification ; genetics ; isolation & purification ; Male ; Molecular Sequence Data ; Phylogeny ; Pseudorabies ; epidemiology ; virology ; Sequence Alignment ; Sequence Homology, Amino Acid ; Sus scrofa ; Swine ; Swine Diseases ; epidemiology ; virology ; Viral Proteins ; chemistry ; genetics

This study aimed to amplify major genome segments (VP7, VP4, VP6, VP2 and NSP2-5) of porcine G3 group A rotavirus (GARV) LLZ212 isolated in our laboratory, determine their genotypes, and explore the evolutionary relationships between G3 GARV strains isolated from humans and pigs in Lulong County, Hebei Province, China. Major genome segments of seven GARV strains were amplified by reverse transcription-polymerase chain reaction (RT-PCR) and the segments were sequenced. The genome segments of seven GARV strains were determined by the online RotaC genotyping tool (RotaC v2.0). The reference sequences of each GARV genome segment were downloaded from GenBank. Homology and phylogenetic evolutionary analyses were conducted using the MEGA 5.0 and DNAStar software packages. LLZ212 isolated from pigs in Lulong had the following genotype: G3-P[8]-I5-C1-N1-T1-E1-H1. All human GARV strains had the following genotype: G3-P[8]-I1-C1-N1-T1-E1-H1. The VP7, VP4, NSP4 and NSP5 genes of the LLZ212 strain had the highest nucleotide identities with the human GARV E885, CMH014/07, Wa and RMC321 strains, respectively, and these clustered together in a sublineage. The VP6, NSP4 and NSP5 genes of the LLZ212 strain shared the highest nucleotide identities with the porcine GARV PRG921 strain, while VP2 associated most closely with porcine GARV OSU strain, and these also clustered in a sublineage. A rare porcine G3-P[8]-I5-C1-N1-T1-E1-H1 GARV strain was identified, which may represent a reassortment between porcine and human viruses. In conclusion, the VP7, VP4, NSP4 and NSP5 genes of LLZ212 share high levels of sequence identity with human GARV, while VP2, VP6, NSP2 and NSP3 cluster with porcine GARV.
Animals ; Capsid Proteins ; genetics ; Child, Preschool ; China ; epidemiology ; Evolution, Molecular ; Genotype ; Humans ; Infant ; Male ; Molecular Sequence Data ; Phylogeny ; Rotavirus ; classification ; genetics ; isolation & purification ; Rotavirus Infections ; epidemiology ; veterinary ; virology ; Swine ; Swine Diseases ; epidemiology ; virology ; Viral Nonstructural Proteins ; genetics

Since late 2010, porcine epidemic diarrhea virus (PEDV) has been re-emerging in central China. To explore the possible reason of the PEDV outbreaks, twelve PEDV field strains were isolated from different swine breeding farms in central China during 2010-2012, and molecular diversity, phylogenetic relationships of these strains with other PEDV reference strains were investigated. Sequence analysis of S, M and ORE3 genes revealed that the central China PEDV isolates had several specific nucleotides and amino acids which were different from PEDV reference strains. In addition, the entire S genes of eleven central China PEDV isolates were found to be nine nucleotides longer in length than CV777 and large number of amino acid variations was accumulated in the N-terminal region of S gene. Phylogenetic analysis showed that the central China PEDV isolates had close relationship with Korea strains (2007-2009), Thailand strains (2007-2008), Vietnam strains (2009-2010), Japan strains (2010), and other prevailing strains from other parts of China (2010-2012). However, they differed genetically from European strains (CV777, Brl/87), China strains (2003-2007) and the vaccine strains (CV777) used in China. These results imply that a rapid variation and evolution of central China PEDV strains has occurred in recent years, and a more efficient vaccine strain should be selected to prevent and control outbreaks of PEDV in China.
Animals ; China ; epidemiology ; Disease Outbreaks ; Feces ; virology ; Molecular Sequence Data ; Open Reading Frames ; Phylogeny ; Porcine epidemic diarrhea virus ; classification ; genetics ; isolation & purification ; Swine ; Swine Diseases ; epidemiology ; virology ; Viral Proteins ; genetics

Porcine Torovirus (PToV) is widely distributed in the world with high prevalence rate in swinery. Due to the high detection rate in diarrhea pigs, PToV is thought to be a potential pathogen of swine diarrhea. In recent years, epidemic outbreaks of diarrhea with high morbidity and mortality in China have caused great economic losses. Intertypic recombination events and antigenic cross-reactivity among toroviruses implies potential zoonotic transmission of PToV. The review represented the development history of PToV and made a brief summary of the features in genome and protein epidemiology and laboratory diagnosis of the PToV, and so on.
Animals ; China ; epidemiology ; Swine ; Swine Diseases ; epidemiology ; virology ; Torovirus ; genetics ; physiology ; Torovirus Infections ; epidemiology ; veterinary ; virology

Since the first report of a swine influenza virus (SIV) infection in humans in 1958, cases have occurred continuously and increased significantly after the 2009 H1N1 pandemic. Although exposure to swine is thought to be a risk factor for human SIVs infections, approximately half of the reported cases had no known exposure to pigs. Besides, epidemiological investigation showed that several cases had limited human-to-human transmission. Based on the analyses of data on swine influenza virus infection in humans in this review, both the improved SIVs surveillance in humans and swine population and wider vaccination coverage among occupational workers are critical strategies in pandemic preparedness and response.
Animals ; Humans ; Influenza A virus ; genetics ; isolation & purification ; physiology ; Influenza, Human ; diagnosis ; epidemiology ; transmission ; virology ; Orthomyxoviridae Infections ; diagnosis ; epidemiology ; veterinary ; virology ; Swine ; Swine Diseases ; diagnosis ; epidemiology ; transmission ; virology ; Zoonoses ; diagnosis ; epidemiology ; transmission ; virology

Swine influenza viruses (SIVs) are respiratory pathogens of pigs. They cause both economic bur den in livestock-dependent industries and serious global public health concerns in humans. Because of their dual susceptibility to human and avian influenza viruses, pigs are recognized as intermediate hosts for genetic reassortment and interspecies transmission. Subtypes H1N1, H1N2, and H3N2 circulate in swine populations around the world, with varied origin and genetic characteristics among different continents and regions. In this review, the role of pigs in evolution of influenza A viruses, the genetic evolution of SIVs and interspecies transmission of SIVs are described. Considering the possibility that pigs might produce novel influenza viruses causing more outbreaks and pandemics, routine epidemiological surveillance of influenza viruses in pig populations is highly recommended.
Animals ; Humans ; Influenza A virus ; genetics ; isolation & purification ; physiology ; Influenza, Human ; epidemiology ; transmission ; virology ; Orthomyxoviridae Infections ; epidemiology ; transmission ; veterinary ; virology ; Swine ; Swine Diseases ; epidemiology ; transmission ; virology

Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in Asia and domestic pigs serve as the amplifying hosts. In the present study, the full genomic sequences of two JEV strains (HEN0701 and SH0601) isolated from pigs in China were determined and compared with other 12 JEV strains deposited in GenBank. These two strains had an 88.8% nucleotide sequence similarity and 97.9% deduced amino acid sequence homology. HEN0701 had high nucleotide sequence and high amino acid sequence identity with genotype I (GI) strains, while SH0601 had high nucleotide sequence and high amino acid sequence identity with GIII strains at both the gene and full genome levels. Further phylogenetic analysis showed that HEN0701 belonged to the JEV GI group and SH0601 was classified as a GIII strain. Analysis of codon usage showed there were a few differences between the GI and GIII strains in nucleotide composition and codon usage for the open reading frames.
Animals ; Cell Line ; Cricetinae ; Encephalitis Virus, Japanese/classification/*genetics ; Encephalitis, Japanese/epidemiology/*veterinary/virology ; Gene Expression Regulation, Viral/physiology ; Genome, Viral ; Molecular Epidemiology ; Phylogeny ; Swine ; Swine Diseases/epidemiology/*virology

Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in Asia and domestic pigs serve as the amplifying hosts. In the present study, the full genomic sequences of two JEV strains (HEN0701 and SH0601) isolated from pigs in China were determined and compared with other 12 JEV strains deposited in GenBank. These two strains had an 88.8% nucleotide sequence similarity and 97.9% deduced amino acid sequence homology. HEN0701 had high nucleotide sequence and high amino acid sequence identity with genotype I (GI) strains, while SH0601 had high nucleotide sequence and high amino acid sequence identity with GIII strains at both the gene and full genome levels. Further phylogenetic analysis showed that HEN0701 belonged to the JEV GI group and SH0601 was classified as a GIII strain. Analysis of codon usage showed there were a few differences between the GI and GIII strains in nucleotide composition and codon usage for the open reading frames.
Animals ; Cell Line ; Cricetinae ; Encephalitis Virus, Japanese/classification/*genetics ; Encephalitis, Japanese/epidemiology/*veterinary/virology ; Gene Expression Regulation, Viral/physiology ; Genome, Viral ; Molecular Epidemiology ; Phylogeny ; Swine ; Swine Diseases/epidemiology/*virology

Our investigation was conducted in order to verify a recent severe epidemic at several swine farms in northern China that indicated a newly emerging disease. Evidence confirmed that the epidemic was caused by a virulent Pseudorabies virus infection in swine herds.
Animals ; China/epidemiology ; Enzyme-Linked Immunosorbent Assay/veterinary ; Epidemics/*veterinary ; Herpesvirus 1, Suid/classification/*isolation & purification/*pathogenicity ; Pseudorabies/*epidemiology/mortality/pathology/virology ; Reverse Transcriptase Polymerase Chain Reaction/veterinary ; Sequence Analysis, DNA/veterinary ; Swine ; Swine Diseases/*epidemiology/mortality/pathology/virology ; Vaccination/adverse effects/veterinary ; Virulence