Severe Fever with Thrombocytopenia Syndrome Virus, South Korea, 2013

Sun-Whan Park, Myung-Guk Han, Seok-Min Yun, Chan Park, Won-Ja Lee, and Jungsang Ryou

Author affiliations: Korea Centers for Disease Control and Prevention, Cheongwon-gun, South Korea

Abstract

During 2013, severe fever with thrombocytopenia syndrome was diagnosed in 35 persons in South Korea. Environmental temperature probably affected the monthly and regional distribution of case-patients within the country. Phylogenetic analysis indicated that the isolates from Korea were closely related to isolates from China and Japan.

Severe fever with thrombocytopenia syndrome (SFTS) is a newly emerging infectious disease. Symptoms and laboratory abnormalities are fever, thrombocytopenia, leukocytopenia, and elevated serum enzyme levels. Multiorgan failure occurs in severe cases, and 6%–30% of case-patients die. The syndrome is caused by the SFTS virus (SFTSV) (genus Phlebovirus, family Bunyaviridae). SFTS case-patients were first reported in China (1) and more recently were reported in Japan (2) and South Korea (3). Two case-patients with symptoms consistent with a similar virus, Heartland virus, were reported in the United States (4).

Ixodid tick species are implicated as vectors of SFTSV (1,5,6). One study described a SFTSV prevalence in Haemaphysalis longicornis ticks, a major vector of SFTSV, of 0.46% minimum infection rate in South Korea (7); in another study, SFTSV was detected in ticks that had bitten humans (6). From these studies, we realized that SFTSV was common throughout the country. We aimed to evaluate the prevalence of SFTS in South Korea and isolate the SFTSV to analyze its phylogenetic properties.

Thumbnail of Isolation of severe fever with thrombocytopenia syndrome virus (SFTSV) from case-patients, South Korea, 2013. A) Indirect immunofluorescent features of Vero E6 cells primed with SFTSV N protein monoclonal antibody and reacted with fluoresce in isothiocyanate-conjugated anti-mouse IgG. B) A transmission electron microscopy image of Vero E6 cells infected with SFTSV. Scale bar indicates 500 nm. C and D) Phylogenetic analysis of SFTSV Korea isolates based on the partial medium (M) and

Figure 1. Isolation of severe fever with thrombocytopenia syndrome virus (SFTSV) from case-patients, South Korea, 2013. A) Indirect immunofluorescent features of Vero E6 cells primed with SFTSV N protein monoclonal antibody and reacted...

Dr. Sun-Whan Park is a senior researcher at the Division of Arboviruses, National Institute of Health, Korea Centers for Disease Control and Prevention. His research focuses on bunyaviruses, including SFTSV and hantavirus.

Acknowledgments

We thank all involved in SFTS diagnosis in 2013, especially the staff in 17 regional Institutes of Health and Environment. We also thank Young Eui Jeong and Ki Ju Choi for technical support with molecular evolution and the electron microscope.

This study was financially supported by the Korea National Institute of Health, Korea Centers for Disease Control and Prevention (program no. ******************** and 4800-4861-304-210-13 [grant no. 2014-NG53002-00]).

References

Yu XJ, Liang MF, Zhang SY, Liu Y, Li JD, Sun YL, Fever with thrombocytopenia associated with a novel bunyavirus in China. N Engl J Med.2011;364:1523–32. DOI PubMed
Takahashi T, Maeda K, Suzuki T, Ishido A, Shigeoka T, Tominaga T, The first identification and retrospective study of severe fever with thrombocytopenia syndrome in Japan. J Infect Dis. 2014;209:816–27. DOI PubMed
Kim KH, Yi J, Kim G, Choi SJ, Jun KI, Kim NH, Severe fever with thrombocytopenia syndrome, South Korea, 2012. Emerg Infect Dis. 2013;19:1892–4.DOI PubMed
McMullan LK, Folk SM, Kelly AJ, MacNeil A, Goldsmith CS, Metcalfe MG, A new phlebovirus associated with severe febrile illness in Missouri. N Engl J Med. 2012;367:834–41. DOI PubMed
Zhang YZ, Zhou DJ, Qin XC, Tian JH, Xiong Y, Wang JB, The ecology, genetic diversity, and phylogeny of Huaiyangshan virus in China. J Virol.2012;86:2864–8. DOI PubMed
Yun SM, Lee WG, Ryou JS, Yang SC, Park SW, Roh JY, Severe fever with thrombocytopenia syndrome virus in ticks collected from humans, South Korea, 2013. Emerg Infect Dis. 2014;20:1350–3. DOI PubMed
Park SW, Song BG, Shin EH, Yun SM, Han MG, Park MY, Prevalence of severe fever with thrombocytopenia syndrome virus in Haemaphysalis longicornis ticks in South Korea. Ticks Tick Borne Dis. 2014. In press.
Lee HW. Virus isolation. In: Lee HW, Calisher CC. Schmaljohn CS, editors. Manual of hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome. Seoul (South Korea): WHO Collaborating Centre for Virus Reference and Research (Hantavirus), Asian Institute for Life Sciences; 1999. p. 74–9.
Shin JS, Park JH, Kwon DH. Epidemiologic and clinical characteristics of severe fever with thrombocytopenia syndrome in the Republic of Korea.Public Health Weekly Report, KCDC. 2014;7:493–8.
Ding F, Zhang W, Wang L, Hu W, Soares Magalhaes RJ, Sun H, Epidemiologic features of severe fever with thrombocytopenia syndrome in China, 2011–2012. Clin Infect Dis. 2013;56:1682–3. DOI PubMed

Figures

Suggested citation for this article: Park S-W, Han M-G, Yun S-M, Park C, Lee W-J, Ryou J. Severe fever with thrombocytopenia syndrome virus, South Korea, 2013. Emerg Infect Dis [Internet]. 2014 Nov [date cited]. http://dx.doi.org/10.3201/eid2011.140888

DOI: 10.3201/eid2011.140888