Detection and molecular characterization of virulent Newcastle disease virus (subgenotype VII.2) in broiler chickens in Northern Vietnam.

Background And Aim: Newcastle disease (ND) is a major viral disease of poultry worldwide. However, data on the molecular characterization of Newcastle disease virus (NDV) in Vietnam are limited. This study aimed to identify the molecular characteristics of NDV strains from the vaccinated chickens farmed in Northern Vietnam.

A Cell-Adapted Live-Attenuated Vaccine Candidate Protects Pigs against the Homologous Strain VNUA-ASFV-05L1, a Representative Strain of the Contemporary Pandemic African Swine Fever Virus.

African swine fever (ASF) is a lethal and highly contagious transboundary animal disease with the potential for rapid international spread. Currently, there is no ASF vaccine commercially available. All infected animals must be isolated and culled immediately upon the confirmation of the presence of the virus.

PCR-Based Detection and Genetic Characterization of Parainfluenza Virus 5 Detected in Pigs in Korea from 2016 to 2018.

This study applied a molecular-based method to detect parainfluenza virus 5 (PIV5) collected from 2016 to 2018 in nine provinces of Republic of Korea. We demonstrated that PIV5 was detectable in both serum and pooled organs at an average positive rate of 1.78% (99/5566).

A Multiplex PCR Method for Simultaneous Detection of Infectious Laryngotracheitis Virus and .

To date, many fluorescence- and gel-based multiplex polymerase chain reaction (PCR) assays have been developed for the simultaneous detection of multiple infectious agents of respiratory disease in poultry. However, PCR assays are not available for other important emerging respiratory bacteria, such as (ORT). We aimed to fill this gap by establishing a new duplex PCR method for the simultaneous detection of infectious laryngotracheitis virus (ILTV) and ORT.

Development of a highly sensitive point-of-care test for African swine fever that combines EZ-Fast DNA extraction with LAMP detection: Evaluation using naturally infected swine whole blood samples from Vietnam.

Background: While early detection and early containment are key to controlling the African swine fever (ASF) pandemic, the lack of practical testing methods for use in the field are a major barrier to achieving this feat.

Objectives: To describe the development of a rapid and sensitive point-of-care test (POCT) for ASF, and its evaluation using swine whole blood samples for field settings.

Methods: In total, 89 swine whole blood samples were collected from Vietnamese swine farms and were performed the POCT using a combination of crude DNA extraction and LAMP (loop-mediated isothermal amplification) amplification.

Estimation of the herd-level basic reproduction number for African swine fever in Vietnam, 2019.

Background And Aim: African swine fever (ASF) is a notifiable viral disease of pigs and wild boars that causes severe economic losses to the swine industry. The pig industry in Vietnam was recently attacked by the ASF virus (ASFV) for the first time in history. However, we lack information regarding the transmissibility of ASF within indoor production systems communities, such as those in Vietnam.

Magnetic-bead-based DNA-capture-assisted real-time polymerase chain reaction and recombinase polymerase amplification for the detection of African swine fever virus.

African swine fever (ASF) is a deadly disease in swine caused by African swine fever virus (ASFV). The global spread of ASFV has resulted in significant economic losses worldwide. Improved early detection has been the most important first line of defense for preventing ASF outbreaks and for activating control measures.

Polymerase chain reaction-based detection of coinfecting DNA viruses in Vietnamese pigs in 2017 and 2021.

Background And Aim: Many studies have reported on the phenomenon of co-infections involving two or more pathogens (bacteria or viruses) over the past few years. However, very few studies on this issue were conducted in Vietnam. Therefore, this study aimed to determine the circulation of single and multiple porcine parvovirus (PPV) (e.

Dynamic Models of Within-Herd Transmission and Recommendation for Vaccination Coverage Requirement in the Case of African Swine Fever in Vietnam.

African swine fever (ASF) is a highly contagious disease that is caused by the ASF virus (ASFV) with a high fatality rate in domestic pigs resulting in a high socio-economic impact. The pig business in Vietnam was recently affected by ASF for the first time. This study thus aimed to develop a disease dynamic model to explain how ASFV spreads in Vietnamese pig populations and suggest a protective vaccine coverage level required to prevent future outbreaks.

Serological and Molecular Characterization of Avian Metapneumovirus in Chickens in Northern Vietnam.

Avian Metapneumovirus (aMPV) is a causative agent of respiratory disease complex in turkeys and chickens that has recently been detected in Vietnam. Due to its novelty, this study was conducted to elucidate the distribution of aMPV in several provinces in northern Vietnam. By the application of Enzyme-Linked Immunosorbent Assay (ELISA) and nested Reverse Transcription-Polymerase Chain Reaction (RT-PCR), this study demonstrated the circulation of aMPV in 12 out of 14 cities/provinces with positive rates of 37.

Application of chitosan as a natural disinfectant against porcine epidemic diarrhoea virus.

Porcine epidemic diarrhoea virus (PEDV) is one of the major pathogens causing acute enteritis, which is characterised by vomiting and watery diarrhoea and commonly leads to high rates of mortality and morbidity in suckling piglets. Chitosan has been regarded as a promising natural disinfectant. In this study, the disinfectant effect and mammalian-cell toxicity of chitosan were evaluated against PEDV using Vero cells.

Molecular-based detection, genetic characterization and phylogenetic analysis of porcine circovirus 4 from Korean domestic swine farms.

Porcine circovirus 4 (PCV4), a novel and unclassified member of the genus Circovirus, was first reported in China in 2019. Aiming to provide more evidence about the active circulation of PCV4, this study screened 335 pooled internal organs and detected the virus (i) at a rate of 3.28%, (ii) from both clinically healthy and clinically sick pigs of various age groups, and (iii) in six out of nine provinces of Korea.

A descriptive survey of porcine epidemic diarrhea in pig populations in northern Vietnam.

Porcine epidemic diarrhea (PED) virus (PEDV) is a globally emerging and re-emerging epizootic swine virus that causes massive economic losses in the swine industry, with high mortality in piglets. In Vietnam, PED first emerged in 2009 and has now developed to an endemic stage. This is the first cross-sectional survey performed to evaluate the proportion of PEDV-positive swine farms in Vietnam from January 2018 to February 2019.

Evaluating the Risk Factors for Infection in an Endemic Area of Vietnam.

(PEDV) causes enteritis, vomiting, watery diarrhea, and high mortality in suckling pigs, threatening the swine industry. Porcine epidemic diarrhea (PED) re-emerged globally in 2013 in many important swine-producing countries in Asia and the Americas. Several studies have identified the risk factors for the spread of PEDV in acute outbreaks.

Molecular Characterization of Porcine Epidemic Diarrhea Virus and Its New Genetic Classification Based on the Nucleocapsid Gene.

() causes continuous, significant damage to the swine industry worldwide. By RT-PCR-based methods, this study demonstrated the ongoing presence of in pigs of all ages in Korea at the average detection rate of 9.92%.

PCR-based detection and genetic characterization of porcine parvoviruses in South Korea in 2018.

Background: with the advantage of sequencing technology, many novel porcine parvoviruses (PPV) rather than PPV1 has been reported. This study ultilized specific PCR- based method and gene- based analysis to study the presence and genetic diversity of porcine parvoviruses in South Korea in 2018.

Results: The present study was conducted in 2018 and found PPV1 and PPV7 in nine out of 151 field samples (organs and semen) by the PCR method.

Molecular-based investigation and genetic characterization of porcine stool-associated RNA virus (posavirus) lineages 1 to 3 in pigs in South Korea from 2017 to 2019.

Recent results on the detection and genetic characterization of stool-associated RNA viruses from different species have increased the knowledge about the extreme genetic diversity of picornaviruses. This study aimed to investigate the presence of unclassified porcine stool-associated RNA viruses (posaviruses) in South Korea and to elucidate the molecular evolution of the viruses. By RT-PCR, posaviruses 1 and 3 were exclusively found in fecal samples and consistently detected in three consecutive years in six of eight provinces, with 148/697 (21.

Molecular characterization of a Korean porcine epidemic diarrhea virus strain NB1.

In Korea, for the past 30 years (1987-present), porcine epidemic diarrhea (PED) has been established as an endemic situation in which multiple genogroups of classical G1 and G2b, and the recently introduced pandemic G2a, coexisted. Because of the dynamic nature of the virus, continuous field monitoring for PEDV strains is required. This study is the first to reveal prevalence of PEDV in 9 sampling provinces, with an overall detection rate of 6.

Duplex nested reverse transcriptase polymerase chain reaction for simultaneous detection of type 2 porcine reproductive and respiratory syndrome virus and porcine circovirus type 2 from tissue samples.

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.

New emergence pattern with variant porcine epidemic diarrhea viruses, South Korea, 2012-2015.

Since outbreaks of porcine epidemic diarrhea virus (PEDV) in the United States in 2013, explosive outbreaks of PED in South Korea have infected all age groups of pigs in 2014-2015year. This study analyzed a large collection of the Spike protein coding gene to infer the spatial-temporal diffusion history of PEDV. The studying results suggested that PEDVs in Korea belonged to different genogroups.