Severe Fever with Thrombocytopenia Syndrome (SFTS) viruses

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1 7 th ASIA PACIFIC WORKSHOP ON MULTISECTORAL COLLABORATION FOR THE PREVENTINO AND CONTROL OF ZOONOSES 21 September 2017 Manila Phlippines Severe Fever with Thrombocytopenia Syndrome (SFTS) viruses Hideki Hasegawa M.D., Ph.D. Dept. of Pathology National institute of infectious diseases

2 SFTS (Severe Fever with Thrombocytopenia Syndrome) SFTS is a newly emerged infectious disease caused by tick-borne virus infection first reported in China. Severe febrile illness with gastrointestinal symptoms, leukopenia and thrombocytopenia are the characteristics. SFTSV is a Phlebovirus in the family Bunyaviridae that was first isolated in China and reported in High Case fatality rate: 6-30% (Average: 17%). Human-to-human transmission has been described and attributed to close contact with infected blood. At first, SFTS was reported to be unique to China. N Engl J Med 2011;364: Clin Infect Dis 2013; 57:

3 Distribution of SFTSV-related viruses SFTS virus complex SFTS virus complex and Bhanja virus complex are not serologically cross-rective.

4 Pathological characteristics of SFTS Rt Axillary LN Disruption of the basic architecture of LN BM (1)Necrotizing lymphadenitis / Splenitis with large lymphoid cells infiltration. (2) Large lymphoid cells infiltration into the extranodal parenchymal organs. (3)Prominent hemophagocytosis.

5 Number of cases Confirmed SFTS patients in Japan < 2013/2014/2015 (42/61/>54cases) SFTS in Japan (as of 30 May 2017) SFTS cases may be underestimated since CFR of 26.4 % is significantly higher than that in China (10%).

6 Phylogenetic relationship of SFTSV based on M-seg seq C1 C2 C3 China C5 C4 J1 SFTSVs in China, Japan and ROK belong to different genetic clades. In Japan, a majority of SFTSVs belong to J1 clade. No correlation between virus clade and its distribution in Japan. SFTSV isolated in China Japan Korea J2 J3/ K1 Japan/Korea

7 SFTSV infected animals and their distribution in Japan

8 SFTSV Ab prevalence in wild Japanese deer 0 % 1 5 % 6 10 % % % ( 年 ) Prefecture AB- pos samples Positive (%) Hokkaido Iwate Miyagi Fukushima Tochigi Gunma Chiba Yamanashi SFTS non-endemic region : 9.9%(85/860) SFTS endemic region : 37.0%(360/973) (Fisher s exact test P<0.0001) Nagano Gifu Shizuoka Mie Wakayama Kyoto Shiga Hyogo Hiroshima Tottori Shimane Yamaguchi Ehime Tokushima Kochi Fukuoka Oita Miyazaki Kumamoto Kagoshima total

9 Distribution of SFTSV in Japan SFTSV patients SFTSV Ab+ animals SFTSV+ ticks

10 Life cycle of ticks and SFTSV SFTS virus Eggs laid eggs hatch reservoir? amplifier? incidental host? feed feed adult SFTSV Animal,human SFTSV larva SFTSV feed moult moult nymph SFTS virus infects horizontally and vertically among ticks Ticks infest and feed three times during their life cycle Ticks infest and feed mainly between spring to autumn

11 Summary & Conclusion SFTS is a recently emerged disease caused by a novel Phlebovirus in China, Japan and South Korea. (1) Necrotizing lymphadenitis / Splenitis with large lymphoid cells infiltration, (2) Large lymphoid cells infiltration into the extranodal parenchymal organs, and (3) Prominent hemophagocytosis are the histopathological characteristics of SFTSV infection. SFTSV antibody positive animals are distributed in endemic and non-endemic regions in Japan, but its prevalence is significantly higher in the endemic region. SFTSV antibody positive rates in some wild animals are recently increasing in some regions indicating a risk of human infection with SFTS virus is increasing in the regions. Control of wild animals in the region at risk may be necessary to reduce a risk to contract SFTS.

12 One Health deepen the cooperation Experts in human health (American Veterinary Medical Association, ) Work together Experts in animal health Human health and animal health are inextricably linked One Health is collaboration Dept.Vet.Sci, Lab.Res.Cont.Zoonoses Experts in environmental health Endorsed by American Medical Association American Society for Microbiology CDC The American Society of Tropical Medicine and Hygiene 12