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Chicken infectious anaemia virus (CIAV) causes severe anemia and immunosuppression through horizontal or vertical transmission in young chickens. Especially, vertical transmission of virus through the egg can lead to significantly economic losses due to the increased mortality in the broiler industry. Here, 28 CIAV complete sequences circulating in Korea were first characterized using the newly designed primers. Phylogenetic analysis based on the complete sequences revealed that CIAV isolates were divided into four groups, IIa (2/28, 7.1%), IIb (9/28, 32.1%), IIIa (8/28, 28.6%) and IIIb (9/28, 32.1%), and exhibited a close relationship to each other. The major groups were IIb, IIIa and IIIb, and no strains were clustered with a vaccine strain available in Korea. Also, for viral titration, we newly developed a quantitative PCR assay that is highly sensitive, reliable and simple. To investigate the pathogenicity of three major genotypes, 18R001(IIb), 08AQ017A(IIIa), and 17AD008(IIIb) isolates were challenged into one-day-old specific-pathogen-free (SPF) chicks. Each CIAV strain caused anaemia, severe growth retardation and immunosuppression in chickens regardless of CIAV genotypes. Notably, a 17AD008 strain showed stable cellular adaptability and higher virus titer in vitro as well as higher pathogenicity in vivo . Taken together, our study provides valuable information to understand molecular characterization, genetic diversity and pathogenicity of CIAV to improve management and control of CIA in poultry farm., Competing Interests: Two patent numbers, 1025563160000 (12 July 2023) for a method for determining the complete sequences of CIAV, and 1020210053458 (26 April 2021) for a method for determining viral titers, were approved by the Korean Intellectual Property Office (KIPO). The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Song, Kim, Kwon and Kim.)

Budgerigar fledgling disease (BFD) is a contagious disease caused by avian polyomavirus (APV) in psittacine birds and causes high mortality rates. Here, eight APV-positive cases were confirmed from dead parrots or parrot tissue samples by polymerase chain reaction (PCR). Full-length genome sequencing showed high nucleotide identity (98.84-100%) between the APV strains. Phylogenetic analysis revealed that two genogroups were cocirculating in South Korea. The nucleotide sequences of five strains, collected from different parrot species, were identical; however, pathological lesions were observed in only two parrots, both aged 2 months. Pathology included necrotic spots in the liver, subcutaneous haemorrhage, hepatomegaly, ascites, intranuclear inclusion bodies, hepatocyte karyomegaly, hepatic necrosis, and bile duct proliferation. This suggests that the pathogenicity of APV might be host age-dependent regardless of the host species. This study improves our understanding of APV pathogenicity and provides a more detailed genetic characterization of APV strains. RESEARCH HIGHLIGHTS Eight APV strains were identified in South Korea from 2019 to 2021.By phylogenetic analysis, South Korean APV strains were classified into two clades.

Cutibacterium acnes is a pathogen that can cause acne vulgaris, sarcoidosis, endodontic lesions, eye infections, prosthetic joint infections, and prostate cancer. Recently, bacteriophage (phage) therapy has been developed as an alternative to antibiotics. In this study, we attempted to isolate 15 phages specific to C. acnes from 64 clinical samples obtained from patients with acne vulgaris. Furthermore, we sequenced the genomes of these three phages. Bioinformatic analysis revealed that the capsid and tape measure proteins are strongly hydrophobic. To efficiently solubilize the phage particles, we measured the adsorption rate, one-step growth curve, and phage stability using an SMT2 buffer containing Tween 20. Here, we report the genotypic and phenotypic characteristics of the novel C. acnes-specific phages.

Infectious laryngotracheitis (ILT), fowlpox (FP), and reticuloendotheliosis are important poultry diseases caused by gallid herpesvirus 1 (ILTV), fowlpox virus (FWPV), and reticuloendotheliosis virus (REV), respectively. Coinfections with ILTV and FWPV occur naturally in chickens, and FP in its more virulent wet form is characterized by diphtheritic lesions and easily confused with ILT. Moreover, the insertion of only partial REV-LTR or a nearly full-length REV into the FWPV genome, located between the ORF 201 and ORF 203, has increased recently in wild-type field FWPV isolates. Therefore, it is critical to detect ILTV, FWPV, REV-integrated FWPV, and REV early and accurately. In this study, we successfully developed a multiplex PCR assay for the simultaneous detection of ILTV, FWPV, REV-integrated FWPV, and REV, and the detection limits was 1 × 5 4 copies/tube. When used to test clinical samples, the results of the multiplex PCR were in 100% agreement with singleplex PCRs and sequencing. This new multiplex PCR is a simple, rapid, sensitive, specific, and cost-effective method for detection of 4 viruses in clinical specimens., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Enterococcus spp. are opportunistic pathogens that cause lameness in broiler chickens, resulting in serious economic losses worldwide. Virulence of Enterococcus spp. is associated with several putative virulence genes including fsr , efm , esp , cylA , cad1 , ace , gelE , and asa1 . In this study, multiplex polymerase chain reaction (PCR) for the simultaneous detection of these virulence genes in Enterococcus spp. was developed, and detection limits for E. faecium , E. faecalis , and E. hirae were 64.0 pg/μL, 320.0 pg/μL, and 1.6 ng/μL DNA, respectively. Among 80 Enterococcus isolates tested, efm and cad1 were detected in all 26 E. faecium samples, and only cad1 was observed in E. hirae . Additionally, the presence of virulence genes in 25 E. faecalis isolates were 100% for cad1 , 88.0% for gelE , 64.0% for fsr , 44.0% for asa1 , 16.0% for cylA , and 4.0% for esp . No virulence genes were found in E. gallinarum isolates. A total of 49 isolates were resistant to tigecycline and to at least 2 different classes of antibiotics. The most prevalent resistance was to ciprofloxacin (73.5%), quinupristin/dalfopristin (55.1%), and tetracycline (49.0%). No strains were resistant to vancomycin or linezolid. This is the first multiplex PCR assay to simultaneously detect eight virulence genes in Enterococcus spp., and the method provides diagnostic value for accurate, rapid, and convenient detection of virulence genes. Additionally, we report the prevalence of virulence genes and antimicrobial resistance in Enterococcus isolates from commercial broiler chickens suffering lameness., Competing Interests: The authors declare no conflicts of interest., (© 2019 The Korean Society of Veterinary Science.)

Bacterial chondronecrosis with osteomyelitis (BCO) is a major cause of lameness in broiler chicken, and results in serious economic losses worldwide. Although the pathogenesis mechanism leading to lameness is not entirely understood, some strains of Enterococcussp., avian pathogenic Escherichia coli or Staphylococcus aureus have been long recognized as important causative pathogens. To prevent the progression of Enterococcussp., avian pathogenic E. coli or S. aureus infections, we developed rapid, sensitive and convenient diagnostic assays using loop-mediated isothermal amplification (LAMP). Entero-Common-LAMP assays were developed for simultaneous detection of eight Enterococcus species. To target specific microorganisms, seven Entero-Specific-LAMP assays for E. faecalis, E. faecium, E. hirae, E. gallinarum, E. avium, E. duransand E. cecorum were developed, as well as E. coli-LAMP and S. aureus-LAMP assays. Considering the prevalence and economic impact of Enterococcussp., E. coli and S. aureus, the 10 different LAMP assays which were developed have considerable potential as routine diagnostic methods in the field or in resource-limited environments., (© FEMS 2019.)

Loop-mediated isothermal amplification (LAMP) methods to detect chicken infectious anemia virus (CIAV), reticuloendotheliosis virus (REV), and Marek's disease virus (MDV), and a reverse transcription (RT)-LAMP assay to detect infectious bursal disease virus (IBDV), were developed. The CIAV-LAMP, REV-LAMP, MDV-LAMP, and IBDV-RT-LAMP methods were performed using four sets of six primers targeting the VP1 gene of CIAV, the gp90 gene of REV, the Meq gene of MDV, and the VP2 gene of IBDV. The results (a change in color) were observed visually. The methods showed high specificity and sensitivity. The detection limits were 50 genomic copies of CIAV, 16 genomic copies of REV, 20 genomic copies of MDV, and 250 genomic copies of IBDV. When used to test clinical samples, the results of the LAMP assays were in 100% agreement with a previously described PCR. Therefore, the LAMP assays are simple, rapid, highly sensitive, and specific methods for detecting four immune-suppressive viruses., (Copyright © 2018 Elsevier B.V. All rights reserved.)