• Korean Journal of Veterinary Service
• /
• v.37 no.2
• /
• pp.137-141
• /
• 2014

A captive mute swan (Cygnus olor) in the brooding period was found dead without any specific signs. On necropsy, the entire digestive tract was severely necrotized with loosely adherent pseudomembranes, and Clostridium perfringens (CP) colonies isolated from the intestinal contents were identified as CP type A by polymerase chain reaction. Microscopically, the intestine and the liver were necrotized and intralesional bacterial clusters were observed. In this case, there were no other mortalities, so the condition of a single bird, in particular, stress from incubation effort, could act as the predisposing factor for necrotic enteritis. In this study, we report a unique case of necrotic enteritis associated with incubation in a captive mute swan.

• Journal of Veterinary Science
• /
• v.24 no.1
• /
• pp.5.1-5.16
• /
• 2023

The H9N2 avian influenza (AI) has become endemic in poultry in many countries since the 1990s, which has caused considerable economic losses in the poultry industry. Considering the long history of the low pathogenicity H9N2 AI in many countries, once H9N2 AI is introduced, it is more difficult to eradicate than high pathogenicity AI. Various preventive measures and strategies, including vaccination and active national surveillance, have been used to control the Y439 lineage of H9N2 AI in South Korea, but it took a long time for the H9N2 virus to disappear from the fields. By contrast, the novel Y280 lineage of H9N2 AI was introduced in June 2020 and has spread nationwide. This study reviews the history, genetic and pathogenic characteristics, and control strategies for Korean H9N2 AI. This review may provide some clues for establishing control strategies for endemic AIV and a newly introduced Y280 lineage of H9N2 AI in South Korea.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.5
• /
• pp.630-636
• /
• 2013

Recently, there has been a growing body of evidence showing that cellular microRNAs (miRNAs) are involved in virus-host interactions. Numerous studies have focused on analyses of the expression profiles of cellular miRNAs, but the expression patterns of Dicer, which is responsible for the generation of miRNAs, have only rarely been explored in Gallus gallus. We developed a duplex real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay for the relative quantification of the mRNAs of Dicer and ${\beta}$-actin in G. gallus. To apply this method, the expression of Dicer in avian cells after infection with avian leukosis virus subgroup J (ALV-J) was detected using our established duplex real-time RT-PCR. The duplex real-time RT-PCR assay is sufficiently sensitive, specific, accurate, reproducible, and cost-effective for the detection of Dicer in G. gallus. Furthermore, this study, for the first time, demonstrated that ALV-J can induce differential expression of Dicer mRNA in the ALV-J-infected cells.

• Korean Journal of Poultry Science
• /
• v.40 no.4
• /
• pp.379-388
• /
• 2013

Avian paramyxovirus (APMV) type 4 and 6 were isolated during an avian influenza (AI) surveillance program of wild birds. This study also conducted experimental infection of wild-bird-origin APMV type 4 and 6 in specific pathogen free (SPF) chickens to study pathogenicity and transmission within domestic flocks. In addition, serological prevalence data of APMV type 4 and 6 in domestic fowls was conducted with chicken sera collected from 2007 to 2009 in order to understand infection status. The results of the animal experiment showed that APMV type 4 and 6 had the ability to infect chickens with sero-conversion and to transmit the virus from infected birds to contacted birds, but showed low pathogenicity. Serological tests revealed that APMV type 4 was widespread in the poultry industry, especially in layer flocks, but the positive rate for APMV type 6 was very low. This study concluded that wild bird-origin APMV type 4 and 6 could infect the chickens by inter-species transmission and the seroprevalence of APMV type 4 was quite high in Korean poultry. However, since almost all the chicken flocks had a high level of antibody titer against APMV type 1, there was possibility of cross reaction between APMV type 1 and 4, which made the interpretations more complicated. In order to understand infection status in the natural environment, additional study is necessary regarding the seroprevalence of APMV type 4 and 6 in the wild bird population.

• Korean Journal of Veterinary Service
• /
• v.27 no.1
• /
• pp.75-80
• /
• 2004

This survey was performed to investigate avian salmonellosis from broiler farms in Namwon area for 4 years. The whole samples from farms were 541 and chicken samples were 294. Out of 294, 83 cases were identified with avian salmonellosis for 4 years by various serological and biochemical tests. There was no outbreak of pullorum disease, but fowl typhoid occurred in 36 farms. The outbreak of avian salmonellosis occurred continuously regardless of seasons throughout the year. Avian salmonellosis mostly happened within 10 days of age which were 52 cases(63%). The selection of susceptible antibiotics has changed from Quinoline group in 2000 to amoxacillin + clavulanic acid(AmC).

• Korean Journal of Veterinary Service
• /
• v.36 no.1
• /
• pp.23-30
• /
• 2013

An avian rotavirus (AvRV-2) was isolated from feces of broilers suffering from acute gastroenteritis in 2011. It was the first avian rotavirus isolated in Korea. To investigate the molecular characteristics of AvRV-2, the VP4, VP6, VP7 and NSP4 gene nucleotide sequences were determined and compared with those of rotavirus strains available in the GenBank database. The phylogenetic tree of VP7 gene showed that AvRV-2 had a high degree of nucleotide sequence homology (93.4% to 94.7%) with those of rotaviruses belonging to genotype G19 cluster. The phylogenetic tree of the VP4 gene revealed a high degree of nucleotide sequence homology (95.8% to 95.9%) with genotype P[30] rotaviruses isolated from chickens. The VP6 and NSP4 gene nucleotide sequences showed the highest identities with those of avian strains with 95.3% to 96.4% and 90.3% to 92.2%, respectively. Genetic characterization of the VP4, VP6, VP7 and NSP4 showed that AvRV-2 strain was most closely related to chicken rotavirus strains from Germany and Japan. Comparative nucleotide sequences and phylogenetic analysis indicated that avian rotavirus isolated from broilers belonged to genotype G19P[30] and it was the first report on avian rotavirus infection in Korea.

• Korean Journal of Veterinary Service
• /
• v.34 no.1
• /
• pp.19-29
• /
• 2011

Prevalence of major legal communicable diseases in chickens and ducks, which had occurred in Jeonbuk province from year 2004 to 2008. Total 283 farms 1,419,244 chickens and ducks have been affected by avian diseases. Specifically, fowl typhoid (FT) occurred in 92 farms 416,600 chickens, Marek's disease (MD) in 45 farms 145,563, duck virus hepatitis (DVH) in 31 farms 199,200, infectious bursal disease (IBD) in 27 farms 113,220, infectious bronchitis (IB) in 27 farms 280,300, low pathogenic avian influenza (LPAI) in 26 farms 78,495, avian mycoplasmosis in 16 farms 103,774, Newcastle disease (ND) occurred in 11 farms 61,052, avian encephalomyelitis (AE) in 7 farms 21,000, Pullorum disease (PD) occurred in 1 farm 40. According to total analysis about major legal communicable diseases, 1 species of first-class legal communicable diseases have occurred, 3 species of second-class and 6 species of third-class all adding up to 10 species. In the first-class diseases, Newcastle disease have occurred. Pullorum and fowl typhoid, duck virus hepatitis in the second-class have occurred and as third-class diseases, Marek's disease, Infectious bursal disease, Infectious bronchitis, avian mycoplasmosis, avian encephalomyelitis, low pathogenic avian influenza have occurred.

• Korean Journal of Veterinary Research
• /
• v.58 no.1
• /
• pp.45-49
• /
• 2018

The helicase genes and hypervariable regions (HVRs) of three avian hepatitis E viruses (HEVs) detected at three different farms were sequenced and characterized. Two isolates (DW-L and GI-B2) were classified as genotype 2 and one isolate (GR-B) was classified as genotype 1. A phylogenetic tree, based on the helicase gene and HVR nucleotide sequences, revealed the newly detected viruses and other avian HEVs were classified similarly. Unlike previously reported avian HEVs, the DW-L isolate detected in broiler breeders with characteristic lesions of avian HEV had no proline-rich motif in its HVR, suggesting that the proline-rich motif is non-essential for viral replication and infection.

• Korean Journal of Veterinary Service
• /
• v.40 no.2
• /
• pp.149-153
• /
• 2017

The present study was carried out to evaluate the effect of avian pox on wild bird population by investigating the avian pox infection in migratory birds of a stopover site. 3,565 birds in 116 species were examined for avian pox in migratory birds at the Heuksando island in South Korea during the spring and fall of 2011. 20 birds in 12 species were found pox-like lesions and 5 birds were diagnosed by avian pox using PCR: Pale Thrush (Turdus pallidus), Yellow-breasted Bunting (Emberiza aureola), Yellow-throated Bunting (Emberiza elegans), Rustic Bunting (Emberiza rustica), Black-faced Bunting (Emberiza spodocephala). To our knowledge, this is the first report of avian pox detected in these 5 species of the world.

• Journal of Preventive Medicine and Public Health
• /
• v.40 no.2
• /
• pp.185-190
• /
• 2007

Objectives : Since the first human infection from avian influenza was reported in Hong Kong in 1997, many Asian countries have confirmed outbreaks of highly pathogenic H5N1 avian influenza viruses. In addition to Asian countries, the EU authorities also held an urgent meeting in February 2006 at which it was agreed that Europe could also become the next target for H5N1 avian influenza in the near future. In this paper, we provide the general and applicable information on the avian influenza in the bioinformatics field to assist future studies in preventive medicine. Methods : We introduced some up-to-date analytical tools in bioinformatics research, and discussed the current trends of avian influenza outbreaks. Among the bioinformatics methods, we focused our interests on two topics: pattern analysis using the secondary database of avian influenza, and structural analysis using the molecular dynamics simulations in vaccine design. Results : Use of the public genome databases available in the bioinformatics field enabled intensive analysis of the genetic patterns. Moreover, molecular dynamic simulations have also undergone remarkable development on the basis of the high performance supercomputing infrastructure these days. Conclusions : The bioinformatics techniques we introduced in this study may be useful in preventive medicine, especially in vaccine and drug discovery.