Pathological Evaluation of Natural Cases of a Highly Pathogenic Avian Influenza Virus, Subtype H5N8, in Broiler Breeders and Commercial Layers in South Korea.

Bae, Yeon-Ji,Lee, Seung-Baek,Min, Keong-Cheol,Mo, Jong-Suk,Jeon, Eun-Ok,Koo, Bon-Sang,Kwon, Hyeok-Il,Choi, Young Ki,Kim, Jeom-Joo,Kim, Jong-Nyeo,Mo, In-Pil American Association of Avian Pathologists [etc.] 2015 Avian diseases Vol.59 No.1

<P>Outbreaks of highly pathogenic avian influenza (HPAI) virus, subtype H5N8, were observed in two different flocks of local broiler breeder farms and a commercial layer farm in South Korea. Clinically, the cases were characterized by a gradual increase in mortality, slow transmission, and unrecognizable clinical signs of HPAI. Gross observations in both cases included hemorrhagic or necrotic lesions in internal organs, such as serosal and mucosal membranes, spleen, and pancreas. Both cases exhibited similar histopathologic lesions, including multifocal malacia in the brain and multifocal or diffuse necrosis in the spleen and pancreas. Immunohistochemical results indicated that neurons and glial cells in the brain, myocytes in the heart, acinar cells in the pancreas, and mononuclear phagocytic cells in several visceral organs were immunopositive for avian influenza viral antigen. To experimentally reproduce the low pathogenicity and the mortality observed in these two cases, 18 specific-pathogen-free chickens and 18 commercial layers were divided into an H5N8 virus-inoculated group and a contact-exposed group. The mortality of the chickens in the inoculation group was 50%-100%, whereas the mean time to death was delayed or death did not occur in the contact-exposed group. The distributions of the viral antigens and histopathologic lesions in the experimental study were similar to those observed in the field cases. These findings suggest that the H5N8 virus induces a different pattern of pathobiology, including slow transmission and low mortality, compared with that of other HPAI viruses. This is the first pathologic description of natural cases of H5N8 in South Korea, and it may be helpful in understanding the pathobiology of novel H5N8 HPAI viruses.</P>

Antiviral efficacy of oseltamivir against avian influenza virus in avian species.

Lee, Dong-Hun,Lee, Yu-Na,Park, Jae-Keun,Yuk, Seong-Su,Lee, Jae-Won,Kim, Jong-In,Han, Jin Soo,Lee, Joong-Bok,Park, Seung-Yong,Choi, In-Soo,Song, Chang-Seon American Association of Avian Pathologists [etc.] 2011 Avian diseases Vol.55 No.4

<P>Avian influenza is one of the most contagious viral diseases in bird species and, increasingly, interspecies transmission to mammalian species has been reported. Prevention and eradication of avian influenza virus (AIV) infection in birds may require vaccines as part of a comprehensive program including biosecurity, culling, diagnostics, and surveillance. However, for valuable bird species in zoos, novel eradication strategies are needed, including antiviral treatments. The present study evaluated the anti-influenza efficacy of the potent neuraminidase inhibitor oseltamivir in avian species using the orders Galliformes (chickens) and Anseriformes (ducks). Viral replication of low pathogenic AIV was significantly reduced in the chicken model and completely reduced in the duck model. Anti-influenza drug administration to valuable bird species with an appropriate extrapolation approach could be useful for control of AIV in combination with active surveillance and vaccination strategies. Further, evaluation of oseltamivir against highly pathogenic avian influenza (HPAI) using avian models would be needed to optimize the oseltamivir application guideline for HPAI control.</P>

Occurrence of avian botulism in Korea during the period from June to September 2012.

Jang, Il,Kang, Min-Su,Kim, Hye-Ryoung,Oh, Jae-Young,Lee, Jae-Il,Lee, Hee-Soo,Kwon, Yong-Kuk American Association of Avian Pathologists [etc.] 2014 Avian diseases Vol.58 No.4

<P>Botulism is a paralytic disease caused by the botulinum neurotoxin produced by Clostridium botulinum. In the summer season in Korea, intensive outbreaks of avian botulism were reported in both poultry and wild birds, including five Korean native chicken farms (HanHyup NO.3), one pheasant (Phasianus colchicus karpowi) farm, and one community of spot-billed ducks (Anas poecilorhyncha). The affected domestic birds showed 24.5% to 58.3% mortality, with specific clinical signs including ataxia, limber neck, and diarrhea. To confirm the botulinum toxin, neutralization tests were performed on sera (four Korean native chicken farms and one pheasant farm) or culture supernatant (spot-billed ducks). Additionally, the contents of the cecum and liver from poultry presenting signs suggestive of botulism were inoculated to isolate the pathogen. The toxin genes were then detected by polymerase chain reaction (PCR). Through the neutralization tests, it was possible to diagnose the botulism and, except in the case of one Korean native chicken farm, to identify the type of pathogen. Using detection by PCR, except in two cases of the Korean native chicken farms, the botulinum toxin gene was found. Additionally, in four cases, it was possible to identify the C/D mosaic type using PCR. This paper reports the first occurrence of avian botulism in domestic birds and the first detection of botulism caused by this mosaic type in Korea.</P>

Different routes of inoculation impact infectivity and pathogenesis of H5N1 high pathogenicity avian influenza virus infection in chickens and domestic ducks.

Kwon, Y K,Swayne, D E American Association of Avian Pathologists [etc.] 2010 Avian diseases Vol.54 No.4

<P>The H5N1 type A influenza viruses classified as Qinghai-like virus (clade 2.2) are a unique lineage of type A influenza viruses with the capacity to produce significant disease and mortality in gallinaceous and anseriform birds, including domestic and wild ducks. The objective of this study was to determine the susceptibility and pathogenesis of chickens and domestic ducks to A/Whooper Swan/Mongolia/224/05 (H5N1) high pathogenicity avian influenza (HPAI) virus when administered through respiratory or alimentary routes of exposure. The chickens and ducks were more susceptible to the H5N1 HPAI virus, as evidenced by low infectious and lethal viral doses, when exposed by intranasal as compared to alimentary routes of inoculation (intragastric or oral-fed infected chicken meat). In the alimentary exposure pathogenesis study, pathologic changes included hemorrhage, necrosis, and inflammation in association with virus detection. These changes were generally observed in most of the visceral organs of chickens, between 2 and 4 days postinoculation (DPI), and are similar to lesions and virus localization seen in birds in natural cases or in experimental studies using the intranasal route. Alimentary exposure to the virus caused systemic infection in the ducks, characterized by moderate lymphocytic encephalitis, necrotized hepatitis, and pancreatitis with a corresponding demonstration of virus within the lesions. In both chickens and ducks with alimentary exposure, lesions, virus, or both were first demonstrated in the upper alimentary tract on 1 DPI, suggesting that the alimentary tract was the initial site affected upon consumption of infected meat or on gavage of virus in liquid medium. However, as demonstrated in the infectivity study in chickens, alimentary infection required higher exposure doses to produce infection as compared to intranasal exposure in chickens. These data suggest that upper respiratory exposure to H5N1 HPAI virus in birds is more likely to result in virus infection and transmission than will consumption of infected meat, unless the latter contains high doses of virus, as found in cannibalized infected carcasses.</P>

Development of One-Step Reverse Transcriptase-Polymerase Chain Reaction to Detect Duck Hepatitis Virus Type 1

Kim, Min-Chul,Kwon, Yong-Kuk,Joh, Seong-Joon,Kwon, Jun-Hun,Kim, Jae-Hong,Kim, Sun-Joong American Association of Avian Pathologists [etc.] 2007 Avian diseases Vol.51 No.2

<P>A one-step reverse transcriptase-polymerase chain reaction (RT-PCR) method was developed and optimized for the detection of duck hepatitis virus type 1 (DHV-1) using the Viral Gene-spin viral DNA/RNA extraction kit. A pair of DHV-1-specific primers was designed against the gene encoding RNA-dependent RNA polymerase (3D gene). Using RNA prepared from duckling liver samples infected with two reference and seven Korean field isolates of DHV-1, one-step RT-PCR with DHV1-specific primers amplified a 467-bp fragment. Under the same conditions, no amplification was observed for 14 other avian pathogenic viruses and bacteria. Using RNA prepared from serial dilutions of the DHV-1 with the supernatant of the uninfected duckling liver homogenate (10% w/v), the one-step RT-PCR assay was found to be sensitive to 10 50% egg lethal dose (ELD50) 0.1 ml(-1) of DHV-1. Furthermore, this method detected DHV-1 from the livers and allantoic fluid of duck embryos dying before 3 days postinoculation (PI) and of chicken embryos that were chilled at 3 days PI. Therefore, this one-step RT-PCR method is rapid, sensitive, and reliable, and can be readily adapted for detection of DHV-1 from other clinical samples.</P>

Efficacy of Bacteriophage Therapy on Horizontal Transmission of Salmonella Gallinarum on Commercial Layer Chickens

Lim, T.-H.,Lee, D.-H.,Lee, Y.-N.,Park, J.-K.,Youn, H.-N.,Kim, M.-S.,Lee, H.-J.,Yang, S.-Y.,Cho, Y.-W.,Lee, J.-B. AMERICAN ASSOCIATION OF AVIAN PATHOLOGISTS 2011 Avian diseases Vol.55 No.3

Experimental Infection of Chickens with Intercontinental Reassortant H9N2 Influenza Viruses from Wild Birds

Lee, Dong-Hun,Kwon, Jung-Hoon,Park, Jae-Keun,Yuk, Seong-Su,Tseren-Ochir, Erdene-Ochir,Noh, Jin-Yong,Lee, Joong-Bok,Park, Seung-Yong,Choi, In-Soo,Song, Chang-Seon AMERICAN ASSOCIATION OF AVIAN PATHOLOGISTS 2016 Avian diseases Vol.60 No.2

<P>The H9N2 subtype of low pathogenic avian influenza (LPAI) virus is the most prevalent LPAI in domestic poultry. We previously reported the natural reassortant H9N2 viruses between North American and Eurasian lineages isolated from wild birds in Korea. These viruses were identified in China and Alaska, providing evidence of intercontinental dispersal. In this study, we evaluated the infectivity, transmissibility, and pathogenic potential of these H9N2 viruses and Eurasian H9N2 virus identified from wild birds using specific-pathogen-free chickens. Three-week-old chickens were infected intranasally. All of these reassortant H9N2 viruses could not be replicated and transmitted in chickens. On the other hand, three out of eight chickens inoculated with the Eurasian H9N2 virus shed detectable levels of virus and showed seroconversion but did not show contact transmission of the virus. Although all reassortant H9N2 viruses could not be replicated and transmitted in chickens, and although there are no reports on reassortant H9N2 virus infection in poultry farms until now, monitoring of reassortant H9N2 viruses should be continued to prepare for the advent and evolution of these viruses.</P>

Pemphigus-Like Immune-Mediated Dermatosis in a Korean Native Black-Bone Fowl

Han, Jae-Ik,Mo, In-Pil,Na, Ki-Jeong BioOne (American Association of Avian Pathologists 2008 Avian diseases Vol.52 No.4

<P>A 3-yr-old female Korean native black-bone fowl weighing 1 kg presented with refractory dermatosis characterized by hyperkeratosis and alopecia on the head, neck, and scapular region. Antibiotic therapy before referral had not reduced the severity of lesions. Histopathologic findings revealed hyperkeratosis, acantholysis, heterophil infiltration, and ballooning degeneration in the epidermis. Immunohistochemical analysis showed immunoglobulin G deposits in the intercellular spaces of the intermediate layer of the epidermis. Based on these observations, this case was diagnosed as a pemphigus-like immune-mediated dermatosis. The administration of prednisolone eliminated the lesions, and the feathers grew back partially.</P>

Isolation and characterization of a novel H9N2 influenza virus in Korean native chicken farm.

Lee, Yu-Na,Lee, Dong-Hun,Park, Jae-Keun,Lim, Tae-Hyun,Youn, Ha-Na,Yuk, Seong-Su,Lee, Youn-Jeong,Mo, In-phil,Sung, Haan-Woo,Lee, Joong-Bok,Park, Seung-Yong,Choi, In-Soo,Song, Chang-Seon American Association of Avian Pathologists [etc.] 2011 Avian diseases Vol.55 No.4

<P>An outbreak of avian influenza, caused by an H9N2 low-pathogenic avian influenza virus (AIV), occurred in a chicken farm and caused severe economic losses due to mortality and diarrhea. AIV was isolated and identified in a sample from an affected native Korean chicken. Genetic analysis of the isolate revealed a high sequence similarity to genes of novel reassortant H9N2 viruses isolated from slaughterhouses and live bird markets in Korea in 2008 and 2009. Animal challenge studies demonstrated that the replication kinetics and pathogenicity of the isolate were considerably altered due to adaptation in chickens. Vaccine protection studies indicated that commercial vaccine was not able to prevent virus shedding and clinical disease when chickens were challenged with the isolate. These results suggest that the novel H9N2 virus possesses the capacity to replicate efficiently in the respiratory system against vaccination and to cause severe disease in domestic chickens. The results also highlight the importance of appropriate updating of vaccine strains, based on continuous surveillance data, to prevent the possibility of a new H9N2 epidemic in Korea.</P>

Continuing evolution and interspecies transmission of influenza viruses in live bird markets in Korea.

Lee, Hyun-Jeong,Kwon, Ji-Sun,Lee, Dong-Hun,Lee, Yu-Na,Youn, Ha-Na,Lee, Youn-Jeong,Kim, Min-Chul,Jeong, Ok-Mi,Kang, Hyun-Mi,Kwon, Jun-Hun,Lee, Joong-Bok,Park, Seung-Yong,Choi, In-Soo,Song, Chang-Seon American Association of Avian Pathologists [etc.] 2010 Avian diseases Vol.54 No.1

<P>Live bird markets (LBMs) provide an ideal environment for the evolution and interspecies transfer of avian influenza viruses (AIVs). In this study, we analyzed AIVs present in LBMs in Korea during the winter seasons of 2006-08. Sixty-five AIVs that belong to four hemagglutination (HA) subtypes ofAIV (H3, H4, H6, and H9) were isolated from 644 pooled tissue or swab samples collected in LBMs. Most H9 subtypes of AIVs were isolated from Galliformes (chickens, silky fowls, pheasants, and guinea fowls), and other subtypes were isolated from Anseriformes (Pekin ducks and mallards). In addition, we obtained a single H3N2 virus from nasal swabs of dogs sold in LBMs, and the virus was genetically identical to the canine influenza virus (CIV) isolated from pet dogs in Korea. Phylogenetic analysis suggests that the Korean H9N2 viruses prevalent in chickens have provided their gene segments to AIVs circulating in ducks. These gene transfers facilitated reassortment events among AIVs and likely generated the ancestors of CIV in Korea. An animal challenge study using chickens, quail, mice, and dogs had shown that the H4 and H6 subtypes could replicate in mice and that some H4 and H6 viruses could replicate in chickens without preadaptation. In addition, two H3 subtype viruses (H3N2 and H3N8) induced interstitial pneumonia that accompanied clinical signs and seroconversion in dogs. Our findings indicate that the newly evolved AIVs have been continuously generated by reassortment in ducks, and these reassortments could result in expanding the host range of AIVs.</P>