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• Isolation and Identification Biochemical Characteristics of Porcine Circovirus Type 2 (PCV2) from pigs in Some Northern Provinces of Vietnam

  Huynh Thi My Le, Nguyen Van Giap

  Date Received: 15-04-2013 / Date Accepted: 15-06-2013

   Abstract PDF (VIETNAMESE)

  The aim of this study was to isolate and identify biochemichal characteristics of PCV2formpigs with PCVAD in 4 nothern provinces of Vietnam (Hanoi, Hoa Binh, Bac Giang and Hai Duong). Isolation of PCV2 would be a conclusive evidence to confirm the circulation of PCV2 and PCVAD in pigs of Vietnam. 8 of PCV2 were isolated from 38 samples collected from pigs with suspected PCVAD. PCV2 isolates were PCV2b genotype. The result of identification biochemical characteristics of isolated PCV2 shown that PCV2 could multiply in PK15 cell culture from the first or second passage, but no CPE was observed. TCID50of all ranging from 102,7to104,2 /ml.

• Gene Expresssion of Cytokine and Toll-like Receptor Signaling molecule mRNA in Peripheral Blood Mononuclear Cells (PBMCs) from Pigs Co-infected with Porcine Reproductive and Respiratory Syndrome Virus and Porcine Circovirus

  Dong Van Hieu, Phan Hong Dien, Tran Thi Huong Giang, Wen Bin Chung

  Date Received: 18-03-2015 / Date Accepted: 18-05-2015

   Abstract PDF (VIETNAMESE)

  Field and experimental studies have shown that co-infection of PRRSV and PCV2 in pigs were quite common and thus the interactions between both viruses in the host might be critical to the pathogenesis of the disease. The exact interaction mechanisms are unknown and remained to be elucidated. In this study, the expression of cytokine mRNA as well as Toll like receptor signaling molecules associated with innate immunity in peripheral blood mononuclear cells (PBMCs) from pigs infected with PRRSV and/or PCV2 were investigated. Cytokine mRNA and TLR signaling molecule expression were determined by quantitative real-time polymerase chain reaction. Co-infection of pigs with PRRSV and PCV2 led to up-regulated expression of IL-1β and IL-10 mRNA and down-regulated expression of TNF-α and IL-6, IFN-α and IFN-β in PBMCs of pigs co-infected with PRRSV and PCV2. An increased expression of CD14 mRNA was noticed in pigs co-infected with PRRSV and PCV2. A down-regulated expression of IRF-1 and IRF-3 mRNA might also suppress the expression of IFNs that leads to the enhanced replication of PCV2 in pigs co-infected with PRRSV and PCV2.

• Selection of Porcine Circovirus Type 2(PCV2) Isolates for Development ofVaccine against Postweaning Multisystemic Wasting Syndrome

  Huynh Thi My Le, Le Van Phan, Nguyen Van Giap, Trinh Dinh Thau

  Date Received: 28-01-2015 / Date Accepted: 18-04-2015

   Abstract PDF (VIETNAMESE)

  This study aimed to build up a collection of field isolates ofPorcine circovirus type 2 (PCV2) circulating in pigs of Viet Nam.This is the first study for development of vaccine against post-weaning multi-systemic wasting syndrome, one of the most important Porcine circovirus type 2-associated diseases. Seven isolates of PCV2 were selected as candidates for subsequent evaluations. The purity test showed that 100% of PCV2 isolates were free of CSFV, PRRSV, PPV, PEDV, TGEV, PRV, PAdV and Mycoplasma. However, there were two out of sevenisolates were contaminated with PCV1, and thus were not eligible for the production of master seed. The titers of fivepurePCV2 isolates were in the rangefrom 102.00TCID50/ 0.1 ml to 105.75TCID50/ 0.1 ml, of which the titers of threeisolates werehigher than 105.00TCID50/ 0.1 ml.

• Immunogenicity of Porcine Circovirus Type 2 (PCV2) Strains Isolated from Pigsin Vietnam

  Huynh Thi My Le, Ta Thi Kim Chung, Mai Thi Ngan, Tran Thi Huong Giang, Vu Thi Ngoc, Cao Thi Bich Phuong

  Date Received: 15-01-2016 / Date Accepted: 03-05-2016

   Abstract PDF (VIETNAMESE)

  This study was conducted to determine the immunogenicity of several porcine circovirus type 2 (PCV2) strains which are chosen as candidates for selection of master seed. The results showed that 3 strains of PCV2 equally invoked the immune response of pigs with measurable level of humoral antibodies within 14 to 21 days and prolonged at least until day 56 post immunization. Sera of pigs immunized by PCV2 strains of different passaging levels all contained neutralizing antibodies against homologous virus.

• A Molecular Based Study on The Spatio-Temporal Dynamics of Porcine Circovirus Genotype 2d (PCV2d) Circulating in Vietnam

  Pham Hong Quan, Pham Cong Hoat, Huynh Thi My Le

  Date Received: 04-05-2017 / Date Accepted: 09-06-2017

   Abstract PDF (VIETNAMESE)

  This study aimed at providing an up-to-date information on the molecular epidemiology of porcine circovirus type 2 (PCV2) circulating in Vietnam with a focus on the spatio-temporal dynamics of a newly defined PCV2d genotype. The results revealed a presence of multiple genotypes/clusters of PCV2, such as 1A/1B, circulating recombinant form (CRF) of PCV2b, and PCV2d. In northern, central and southern Vietnam, a co-circulation of multiple genetic clusters of PCV2 was observed in each sampling location at the same time period. All field strains of PCV2d circulating in Vietnam from 2004- 2017 were predicted to have the most common recent ancestor originated from China, however, they located at different branches of the PCV2d- phylogenetic tree.

• Investigating ThePrevalence of Novel Porcine Circovirus 3 (PCV3) in Pig Populations in The North of Vietnam

  Pham Hong Quan, Nguyen Van Giap, Nguyen Thi Thanh Thuy, Pham Cong Hoat, Huynh Thi My Le

  Date Received: 02-11-2017 / Date Accepted: 28-11-2017

   Abstract PDF (VIETNAMESE)

  Circoviruses has been detected in diverse animal species, including sus scrofa. To date, only PCV2 is demonstrated as a causalagent of porcine circovirus associated diseases. In 2015, a novel circovirus (Porcine circovirus 3, PCV3) was detected for the first time from pigs suffered from porcine dermatitis and nephropathy syndrome and reproductive failure. Since then, PCV3 has been reported in several pig producing countries. This study was carriedout to investigate the presence and the prevalence of PCV3 in the pig populations in northern Vietnam. The PCR screening detected the presence of PCV3 in 6 out of 135 samples (4.44%) collected from7 Northern provinces in 2011 and 2016-2017and fivestrains were successfully sequenced. The capsid coding gene (ORF2) of 5 strains were 642 bases in length, containing39 point nucleotide mutations and 9 mutations were non-synonymous. The phylogenetic analysis on the basisof ORF2 gene suggested that 5 Vietnamese PCV3 strains belonged to PCV3bgenetic cluster, of which, 4 out of 5 strains were clustered closely with Chinese PCV3 strains.

• Evaluation of Efficacy of Circovac Vaccine in Pig of Thanh Long Company, Luong Son, Hoa Binh

  Pham Thi Kieu Anh, Ta Thi Kim Chung, Huynh Thi My Le

  Date Received: 06-07-2014 / Date Accepted: 13-08-2014

   Abstract PDF (VIETNAMESE)

  Our study was conducted for evaluating the efficacy of Circovac vaccine in preventing diseases caused by Porcine Circovirus type 2 (PCV) in pigs of Thanh Long company, Luong Son, Hoa Binh. The experiments were carried out in two trials. In each trial, there were 10 sows divided into 2 groups with and without vaccination. The results showed that Circovac vaccinated sows had better titers of antibodies against PCV2 than the unvaccinated sows. The percentage of PCV2 antibody positive samples collected from vaccination group were 100% with ≥3log2 titer, whereas only 9/20 (45%) samples collected from nonvaccination group had PCV2 antibody with low titer (<3log2). Comparison with the control group, using Circovac had shown to be highly efficacious in terms of reduced mortality, number of culls, and improved growth performance (p<0.05).