Virulence Genes, Antimicrobial Resistance, and Genotypes of Isolated from Chicken Slaughterhouses in South Korea.

represents one of the leading causes of bacterial gastroenteritis in humans and is primarily linked to chicken meat contamination. In the present study, we analyzed the virulence and survival genes, antimicrobial resistance, and the clonal distribution of 50 isolates obtained from various sources in 14 chicken slaughterhouses across 8 provinces in South Korea from 2019 to 2022. Furthermore, we determined their genetic relatedness to human-derived isolates registered in PubMLST using multilocus sequence typing (MLST).

Intrahepatic Cholangiocarcinoma Identified in a Zoo-Housed Sandhill Crane (): An Anatomopathological and Metagenomic Study.

Tumors in birds can be caused by a variety of factors such as species, age, sex, virus, chemicals, and environment. In particular, tumors are a major cause of death in long-lived birds such as parrots and zoo birds. A male sandhill crane that was bred for 8 years in a zoo was diagnosed with intrahepatic cholangiocarcinoma (ICC).

The Development of Novel Reverse Transcription Loop-Mediated Isothermal Amplification Assays for the Detection and Differentiation of Virulent Newcastle Disease Virus.

Newcastle disease (ND) is a highly pathogenic viral infection of poultry with significant economic impacts worldwide. Despite the widespread use of vaccines, ND outbreaks continue to occur even within vaccinated poultry farms. Furthermore, novel Newcastle disease virus (NDV) genotypes are emerging in poultry, increasing the need for the development of rapid, accurate, and simple diagnostic methods.

In Vivo Evaluation of an Ivermectin and Allicin Combination Treatment for Eradicating Poultry Red Mite.

A safe and effective method for eradicating poultry red mite (PRM; ) is urgently needed, as existing treatments show a low efficacy or hazardous effects on chickens. We evaluated the efficacy of a combined treatment with ivermectin and allicin (IA) against PRMs in chickens and drug residues in non-target samples. The efficiency of PRM eradication by IA was compared with those of natural acaricides in vitro.

Prevalence of asymptomatic infections of Chlamydia psittaci in psittacine birds in Korea.

Avian chlamydiosis is an acute or chronic bacterial disease of birds. Chlamydia psittaci is the primary agent of the disease. It is also an important zoonotic pathogen.

A Multiplex PCR Assay for Differential Identification of Wild-type and Vaccine Strains of .

(MG) can cause respiratory disease in chickens and result in serious economic losses in the chicken industry. The use of live vaccines has been a favorable option for the control of MG infection in multi-age commercial layers and broiler breeders. There are three live vaccines, including ts-11, 6/85, and F strain, that have been commonly used in various parts of the world, including South Korea.

Dynamics of the Emerging Genogroup of Infectious Bursal Disease Virus Infection in Broiler Farms in South Korea: A Nationwide Study.

Infectious bursal disease (IBD), caused by IBD virus (IBDV), threatens the health of the poultry industry. Recently, a subtype of genogroup (G) 2 IBDV named G2d has brought a new threat to the poultry industry. To determine the current status of IBDV prevalence in South Korea, active IBDV surveillance on 167 randomly selected broiler farms in South Korea from August 2020 to July 2021 was conducted.

Histopathological Findings and Metagenomic Analysis of Esophageal Papillary Proliferation Identified in Laying Broiler Breeders.

White or pale-yellow nodules 2-7 mm in length were observed in the esophageal lumen in a number of laying broiler breeders with reduced laying rates. Metaplasia of the mucosal epithelial layer and mucous gland, as well as lymphocyte infiltration under the esophageal mucous gland and epithelial cell layer, were observed, which we found were caused by vitamin A deficiency. In one chicken, however, the stratified squamous epithelial cells of the esophagus were completely replaced by increased numbers of ducts/ductules, lymphocytes, and connective tissue, resulting in a papillary morphology.

Nationwide Surveillance for Infectious Bronchitis Virus in South Korea from 2020 to 2021.

Infectious bronchitis virus (IBV) is a major pathogen in poultry. The genotypes of IBV vary considerably, and their antigenicity may differ. Nationwide surveillance in South Korea was performed to determine the prevalence and distribution of IBV and its genotypes.

A multiplex real-time PCR assay for differential identification of avian .

Avian chlamydiosis is an acute or chronic disease of birds after infection by . Although is the primary agent of the disease, two additional species, and , have also been recognized as potential disease agents. Therefore, the diagnosis of avian chlamydiosis requires differential identification of these avian species.

Identification of Campylobacter jejuni and Chlamydia psittaci from cockatiel (Nymphicus hollandicus) using metagenomics.

Background: In July 2015, the carcasses of 11 cockatiels were submitted for disease diagnosis to the Avian Disease Division of the Animal and Plant Quarantine Agency of Korea. The cockatiels, which appeared dehydrated and underweight, had exhibited severe diarrhea and 22 % mortality over 2 weeks. Traditional diagnosis did not reveal the causes of these symptoms.

Viral Metagenomic Analysis of Japanese Quail () with Enteritis in the Republic of Korea.

We performed viral metagenomics analysis of Japanese quail affected with enteritis to elucidate the viral etiology. Metagenomics generated 21,066,442 sequence reads via high-throughput sequencing, with a mean length of 136 nt. Enrichment in viral sequences suggested that at least three viruses were present in quail samples.

Comparative Characteristics and Zoonotic Potential of Avian Pathogenic (APEC) Isolates from Chicken and Duck in South Korea.

Avian pathogenic (APEC) causes colibacillosis, which is an economically important disease in the poultry industry worldwide. The present study investigated O-serogroups, phylogenetic groups, antimicrobial resistance, and the existence of virulence-associated genes (VAGs) and antimicrobial resistance genes in 125 APEC isolates between 2018 and 2019 in Korea. The phylogenetic group B2 isolates were confirmed for human-related sequence types (STs) through multi-locus sequence typing (MLST).

High prevalence of a gene cluster conferring resistance to streptomycin, sulfonamide, and tetracycline in Escherichia coli isolated from indigenous wild birds.

A total of 116 Escherichia coli isolates from cecal contents of 81 indigenous wild birds in Korea were tested for antimicrobial susceptibility. Seventy-one isolates from sparrows (Passer montanus) and one isolate from doves (Columba livia) were resistant to three antimicrobials, including streptomycin, sulfonamide, and tetracycline (SSuT). PCR and subsequent sequence analysis revealed the SSuT gene cluster region (approximately 13 kb) harboring genes encoding resistance to streptomycin (strA and strB), sulfonamide (sul2), and tetracycline (tetB, tetC, tetD, and tetR).

Characterization of antigenic variant infectious bursal disease virus strains identified in South Korea.

Infectious bursal disease (IBD) is one of the most important immunosuppressive diseases of young chickens, causing considerable economic losses to the poultry industry. More than 30 years ago, an antigenic variant (av) pathotype of the IBD virus (IBDV) was reported to originate in, and subsequently spread among, poultry farms in the USA. Recently, a novel avIBDV lineage was identified in China and was shown to exhibit clear differences in its pathogenicity as well as molecular characteristics compared with the previously isolated variant strains.

Impact of Dermanyssus gallinae infestation on persistent outbreaks of fowl typhoid in commercial layer chicken farms.

Although it has rapidly decreased since the early 2000s, fowl typhoid still occurs in commercial layer chickens, causing a significant economic loss in Korea. There is growing concern about the emergence of new pathogenic strains of the causative agent, Salmonella Gallinarum, which is able to overcome vaccine immunity. It has also been suspected that the poultry red mite, Dermanyssus gallinae, which is commonly found in layer chicken farms, may be an important cause of the recurrence of fowl typhoid in the farms.

High prevalence and variable fitness of fluoroquinolone-resistant avian pathogenic isolated from chickens in Korea.

Colibacillosis caused by avian pathogenic (APEC) is the most common bacterial disease in poultry, resulting in significant economic losses. Resistance to fluoroquinolones has been found to be high in APEC worldwide, which has increased concerns about risks to human health as well as poultry production. In the present study, we determined the prevalence, genetic traits, and fitness traits of fluoroquinolone-resistant APEC isolated from chickens in Korea using a total of 286 APEC isolates collected between 2014 and 2017.