Prevalence of #SFTS Virus in #Ticks Collected from National #Parks in #Korea (Vector Borne Zoo Dis., abstract)

[Source: Vector-Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

Prevalence of Severe Fever with Thrombocytopenia Syndrome Virus in Ticks Collected from National Parks in Korea

Young-Sun Jo, Jun-Gu Kang, Jeong-Byoung Chae, Yoon-Kyoung Cho, Jeong-Hwa Shin, Weon-Hwa Jheong, and Joon-Seok Chae

Published Online: 27 Nov 2018 / DOI: https://doi.org/10.1089/vbz.2018.2338

 

Abstract

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging viral disease in East Asian countries, including China, Japan, and the Republic of Korea (ROK). The causative agent of SFTS is the SFTS virus (SFTSV), which is transmitted by ticks. To investigate the prevalence of SFTSV in the ROK, a total of 9744 ticks were collected from vegetation in five national parks between July and November 2015. Of the collected adult and nymph ticks, Haemaphysalis longicornis (68.44%) was the most abundant, followed by Haemaphysalis flava (29.66%), Ixodes nipponensis (1.56%), and Amblyomma testudinarium(0.34%). Collected larval ticks were of the genera Haemaphysalis (99.61%) and Ixodes (0.39%). One-step RT-PCR and nested PCR were used to detect SFTSV-specific genes from each individual adult and nymph tick and pooled larval ticks. SFTSV was detected in 4.77% (48/1006) in H. longicornis, 1.15% (5/436) in H. flava, 0% (0/23) in I. nipponensis, and 20% (1/5) in A. testudinarium. The infection rate of SFTSV in adult and nymph ticks was 3.61%. The prevalence of SFTSV in adult and nymph ticks was relatively high, compared with previous reports. In larval ticks, the minimum infection rate was 0.31%. SFTSV was detected in ticks collected from both trail and nontrail areas in the national parks, and up to 800 meters above sea level. The sequences obtained showed 99.4–99.7% homology with SFTS virus S segment sequences from Chinese and Japanese ticks.

Keywords: SFTSV; South Korea; Ticks.

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#Pathogenesis and genetic characteristics of novel #reassortant low-pathogenic #avian #influenza #H7 viruses isolated from migratory #birds in the Republic of #Korea in the winter of 2016-2017 (Emerg Microbes Infect., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Emerg Microbes Infect. 2018 Nov 15;7(1):182. doi: 10.1038/s41426-018-0181-3.

Pathogenesis and genetic characteristics of novel reassortant low-pathogenic avian influenza H7 viruses isolated from migratory birds in the Republic of Korea in the winter of 2016-2017.

Lee YN1, Cheon SH1, Lee EK1, Heo GB1, Bae YC2, Joh SJ2, Lee MH1, Lee YJ3.

Author information: 1 Avian Influenza Research & Diagnostic Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon-si, Gyeongsangbuk-do, 39660, Republic of Korea. 2 Avian Disease Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon-si, Gyeongsangbuk-do, 39660, Republic of Korea. 3 Avian Influenza Research & Diagnostic Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon-si, Gyeongsangbuk-do, 39660, Republic of Korea. leeyj700@korea.kr.

 

Abstract

In this study, we characterized H7 subtype low-pathogenicity (LP) influenza A viruses (IAVs) isolated from wild bird habitats in the Republic of Korea from 2010 to early 2017. Through national surveillance, 104 H7 IAVs were isolated, accounting for an average of 14.9% of annual IAV isolations. In early 2017, H7 subtypes accounted for an unusually high prevalence (43.6%) of IAV detections in wild birds. Phylogenetic analysis revealed that all the viruses isolated in the winter of 2016-2017 fell within cluster II of group C, belonging to the Eurasian lineage of H7 IAVs. Notably, cluster II of group C included the H7 gene from the highly pathogenic H7N7 IAV that was detected in northeastern Italy in April of 2016. Through a gene-constellation analysis, the H7 LPIAVs that we isolated constituted ≥11 distinct genotypes. Because the viruses belonging to the genotypes G2.1 and G1 were observed most frequently, we compared the replication and transmission of representative viruses to these genotypes in specific-pathogen-free chickens. Notably, the representative G2.1 strain was capable of systemic replication and efficient transmission in chickens (as evidenced by virus isolation and histopathological examination) without any clinical signs except mortality (in one infected chicken). The efficient subclinical viral replication and shedding of the G2.1 virus in chickens may facilitate its silent spread among poultry after introduction. Given that wild birds harbor novel strains that could affect poultry, our results highlight the need for enhanced IAV surveillance in both wild birds and poultry in Eurasia.

PMID: 30442892 DOI: 10.1038/s41426-018-0181-3

Keywords: Avian Influenza; H7N7; Reassortant Strain; Wild Birds; Poultry; Italy; S. Korea.

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#Mutations in the #spike protein of #MERS-CoV transmitted in #Korea increase #resistance towards #antibody-mediated neutralization (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

Mutations in the spike protein of MERS-CoV transmitted in Korea increase resistance towards antibody-mediated neutralization

Hannah Kleine-Weber, Mahmoud Tarek Elzayat, Lingshu Wang, Barney S. Graham, Marcel A. Müller, Christian Drosten, Stefan Pöhlmann, Markus Hoffmann

DOI: 10.1128/JVI.01381-18

 

ABSTRACT

The Middle East respiratory syndrome coronavirus (MERS-CoV) poses a threat to public health. The virus is endemic in the Middle East but can be transmitted to other countries by travel activity. The introduction of MERS-CoV into the Republic of Korea by an infected traveler resulted in a hospital outbreak of MERS that entailed 186 cases and 38 deaths. The MERS-CoV spike (S) protein binds to the cellular protein DPP4 via its receptor binding domain (RBD) and mediates viral entry into target cells. During the MERS outbreak in Korea emergence and spread of viral variants was observed that harbored mutations in the RBD, D510G and I529T. Counterintuitively, these mutations were found to reduce DPP4 binding and viral entry into target cells. Here, we investigated whether they also exerted pro-viral effects. We confirm that changes D510G and I529T reduce S protein binding to DPP4 but show that this reduction only translates into diminished viral entry when expression of DPP4 on target cells is low. Both mutations did not modulate S protein binding to sialic acids, S protein activation by host cell proteases and inhibition of S protein-driven entry by interferon-induced transmembrane proteins. In contrast, changes D510G and I529T increased resistance of S protein-driven entry to neutralization by monoclonal antibodies and serum from a convalescent MERS patient. These findings indicate that MERS-CoV variants with reduced neutralization sensitivity were transmitted during the Korean outbreak and that the responsible mutations were compatible with robust infection of cells expressing high levels of DPP4.

 

IMPORTANCE

MERS-CoV has pandemic potential and it is important to identify mutations in viral proteins that might augment viral spread. In the course of a large hospital outbreak of MERS in the Republic of Korea in 2015 the spread of a viral variant was observed that contained mutations in the viral spike protein. These mutations were found to reduce receptor binding and viral infectivity. However, it remained unclear whether they also exerted pro-viral effects. We demonstrate that these mutations reduce sensitivity to antibody-mediated neutralization and are compatible with robust infection of target cells expressing high amounts of the viral receptor DPP4.

Copyright © 2018 American Society for Microbiology. All Rights Reserved.

Keywords: MERS-CoV; Human.

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Agent-Based #Modeling for #SuperSpreading #Events: A Case Study of #MERS-CoV #Transmission Dynamics in the Republic of #Korea (Int J Environ Res Public Health, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Int J Environ Res Public Health. 2018 Oct 26;15(11). pii: E2369. doi: 10.3390/ijerph15112369.

Agent-Based Modeling for Super-Spreading Events: A Case Study of MERS-CoV Transmission Dynamics in the Republic of Korea.

Kim Y1, Ryu H2, Lee S3,4.

Author information: 1 Division of Media Communication, Hankuk University of Foreign Studies, Seoul 02450, Korea. yunhwankim2@gmail.com. 2 Department of Applied Mathematics, Kyung Hee University, Yongin 446-701, Korea. kyinr108@gmail.com. 3 Department of Applied Mathematics, Kyung Hee University, Yongin 446-701, Korea. sunmilee@khu.ac.kr. 4 Institute of Natural Sciences, Kyung Hee University, Yongin 446-701, Korea. sunmilee@khu.ac.kr.

 

Abstract

Super-spreading events have been observed in the transmission dynamics of many infectious diseases. The 2015 MERS-CoV outbreak in the Republic of Korea has also shown super-spreading events with a significantly high level of heterogeneity in generating secondary cases. It becomes critical to understand the mechanism for this high level of heterogeneity to develop effective intervention strategies and preventive plans for future emerging infectious diseases. In this regard, agent-based modeling is a useful tool for incorporating individual heterogeneity into the epidemic model. In the present work, a stochastic agent-based framework is developed in order to understand the underlying mechanism of heterogeneity. Clinical (i.e., an infectivity level) and social or environmental (i.e., a contact level) heterogeneity are modeled. These factors are incorporated in the transmission rate functions under assumptions that super-spreaders have stronger transmission and/or higher links. Our agent-based model has employed real MERS-CoV epidemic features based on the 2015 MERS-CoV epidemiological data. Monte Carlo simulations are carried out under various epidemic scenarios. Our findings highlight the roles of super-spreaders in a high level of heterogeneity, underscoring that the number of contacts combined with a higher level of infectivity are the most critical factors for substantial heterogeneity in generating secondary cases of the 2015 MERS-CoV transmission.

KEYWORDS: 2015 MERS-CoV; agent-based models; basic reproduction number; isolation interventions; super-spreading events

PMID: 30373151 DOI: 10.3390/ijerph15112369

Keywords: MERS-CoV; S. Korea; Nosocomial Outbreaks.

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Highly Pathogenic #Avian #Influenza A(#H5N6) in Domestic #Cats, South #Korea (Emerg Infect Dis., abstract)

[Source: US Centers for Disease Control and Prevention (CDC), Emerging Infectious Diseases Journal, full page: (LINK). Abstract, edited.]

Volume 24, Number 12—December 2018 / Dispatch

Highly Pathogenic Avian Influenza A(H5N6) in Domestic Cats, South Korea

KyungHyun Lee1, Eun-Kyoung Lee1, HyunKyoung Lee, Gyeong-Beom Heo, Yu-Na Lee, Ji-Youl Jung, You-chan Bae, ByungJae So, Youn-Jeong Lee  , and Eun-Jin Choi

Author affiliations: Author affiliation: Animal and Plant Quarantine Agency, Gimcheon, South Korea

 

Abstract

In December 2016, highly pathogenic avian influenza (HPAI) infection with systemic pathological lesions was found in cats in South Korea. Genetic analyses indicated that the feline isolates were similar to HPAI H5N6 viruses isolated in chicken farms nearby. This finding highlights the need for monitoring of domestic mammals during HPAI outbreaks.

Keywords: Avian Influenza; H5N6; Poultry; Cats; South Korea.

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#Clinical implication of #radiographic scores in acute #MERS #coronavirus #pneumonia: Report from a single tertiary-referral center of South #Korea (Eur J Radiol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Eur J Radiol. 2018 Oct;107:196-202. doi: 10.1016/j.ejrad.2018.09.008. Epub 2018 Sep 11.

Clinical implication of radiographic scores in acute Middle East respiratory syndrome coronavirus pneumonia: Report from a single tertiary-referral center of South Korea.

Cha MJ1, Chung MJ2, Kim K3, Lee KS1, Kim TJ1, Kim TS1.

Author information: 1 Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea. 2 Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea. Electronic address: mj1.chung@samsung.com. 3 Statistics and Data Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul 06351, Republic of Korea; Department of Digital Health, SAIHST, Sungkyunkwan University, Seoul 06351, Republic of Korea.

 

Abstract

The aim of this study is to determine the earliest cutoff of radiographic score as a potential prognostic indicator of fatal outcomes in patients with acute Middle East respiratory syndrome coronavirus (MERS-CoV) pneumonia. The institutional review board approved this retrospective study. Serial chest radiographies (CXRs) were obtained from viral exposure until death or discharge in 35 patients with laboratory confirmed MERS-CoV infection. Radiographic scores were calculated by multiplying a four-point scale of involved lung area and three-point scale of abnormal opacification, in each of the six lung zones. Receiver operating characteristics (ROC) analyses were performed to identify optimal day and radiographic score for the prediction of respiratory distress, and univariate and multivariate logistic regression analyses were performed to assess significant predictive factors for intubation or tracheostomy. Among 35 patients (22 men, 13 women; median age: 48 years), 25 demonstrated abnormal opacity on CXR (MERS pneumonia), whereas no abnormality was detected in 10 patients (MERS upper respiratory tract infection). Seven patients required ventilator support (intubation group) and three of them eventually expired. The average incubation period was 5.4 days (standard deviation, ±2.8; range, 2-11). Patients in the intubation group had a higher incidence of diffuse lung involvement, higher radiographic scores, and fibrosing sequela on follow up study compared with those in the non-intubation group. However, patients’ age and comorbidity did not differ significantly between the two groups. The ROC analysis revealed an area under curve of 0.726 for the radiographic score on day 10 with an optimal cutoff score of 10 for prediction of intubation, with a sensitivity of 71% and specificity of 67%. Our study suggest that MERS patients with radiographic score > 10 on day 10 from viral exposure require aggressive therapy with careful surveillance and follow-up evaluation.

KEYWORDS: Chest radiograph; Chest radiographic score; Middle East respiratory syndrome coronavirus (MERS-CoV); Prognostic indicator

PMID: 30292266 DOI: 10.1016/j.ejrad.2018.09.008

Keywords: Radiology; MERS-CoV; Pneumonia; S. Korea.

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#SFTS Virus #Infection, South #Korea, 2010 (Emerg Infect Dis., abstract)

[Source: US Centers for Disease Control and Prevention (CDC), Emerging Infectious Diseases Journal, full page: (LINK). Abstract, edited.]

Volume 24, Number 11—November 2018 / Research Letter

Severe Fever with Thrombocytopenia Syndrome Virus Infection, South Korea, 2010

Young Ree Kim1, Yeojun Yun1, Seung Geon Bae, Dahee Park, Suhyun Kim, Jae Myun Lee, Nam-Hyuk Cho, Yang Soo Kim, and Keun Hwa Lee

Author affiliations: Jeju National University College of Medicine, Jeju, South Korea (Y.R. Kim, S.G. Bae, D. Park, S. Kim, K.H. Lee); Ewha Womans University, Seoul, South Korea (Y. Yun); Yonsei University College of Medicine, Seoul (J.M. Lee); Seoul National University College of Medicine, Seoul (N.-H. Cho); University of Ulsan College of Medicine, Seoul (Y.S. Kim).

 

Abstract

Severe fever with thrombocytopenia syndrome (SFTS) was reported in China in 2009 and in South Korea in 2012. We found retrospective evidence of SFTS virus infection in South Korea in 2010, suggesting that infections in South Korea occurred before previously reported and were more concurrent with those in China.

Keywords: SFTS; South Korea; Human; Emerging Diseases.

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