Family Cluster Analysis of Severe Fever with Thrombocytopenia Syndrome Virus Infection in Korea

Abstract

Severe fever with thrombocytopenia syndrome (SFTS) is tick-borne viral disease that was first suspected in China in 2009. The causative virus (SFTSV) was isolated in 2009 and reported in 2011, and SFTSV expanded its geographic distribution in 2012–2013, from China to South Korea and Japan. Most SFTSV infections occur through Haemaphysalis longicornis. However, SFTSV infection can also occur between family members, and nosocomial transmission of SFTSV is also possible through close contact with a patient. In this study, we first analyzed clinical, epidemiological, and laboratory data for SFTS patients and family members of an index patient in Korea. The S segment of SFTSV was amplified from the sera of three patients, and the S segment of SFTSV and IgG specific to SFTSV were detected in the serum from one family member; although this individual had no history of exposure to H. longicornis, she frequently had close contact with the index patient. In Korea, SFTSV infection among family members does not have to be reported, and we suggest that person-to-person transmission of SFTSV among family members is possible in Korea.

A Cluster of Symptomatic and Asymptomatic Infections of Severe Fever with Thrombocytopenia Syndrome Caused by Person-to-Person Transmission

“…In recent years, a few cases of asymptomatic infections have been noted in the clusters of person-to-person transmission. 10,12,13 They had close contact with SFTS patients and presented no symptoms, however, viral RNA or IgG could be detected in their sera samples. The reasons and mechanisms that SFTSV caused asymptomatic infections remained unclear.…”

“…3,4 Additionally, clusters caused by the transmission of SFTSV among humans has been described from 2007 to 2015 in the epidemic provinces in China, including Henan, 5 Jiangsu, 6 Liaoning, 7 Shandong, 2,8,9 Anhui, 10 and Hubei, 11 as well as in South Korea. 12,13 It is important to investigate the symptomatic SFTSV infections of both fatal and nonfatal patients in the clusters which provided better understanding of the clinical course of SFTS disease and thus guide the treatment of SFTS. Furthermore, the potential contacts responsible for person-to-person transmission of SFTSV among the patients were evaluated.…”

“…The major risk factor was direct blood exposure without personal protection equipment. 2,[5][6][7][8][9][10][11]13 Other possible contacts such as urine, feces, and respiratory secretions were evaluated to be not associated significantly with person-to-person transmission. 2,5 In recent years, asymptomatic infections have been noted in a few cluster reports of SFTSV infection, 10,12,13 suggesting that SFTSV infection could be asymptomatic via person-to-person transmission, which, however, needs additional attention.…”

The Emergence of Severe Fever with Thrombocytopenia Syndrome Virus

“…33,34 Although tick to human is believed to be the main route of SFTS virus transmission, evidence supporting possible person-to-person transmission of SFTS virus has also been documented. 10,[35][36][37] Given the fact that SFTS virus RNA is found in bodily secretions, this further supports the potential for human-to-human SFTS virus transmission without the involvement of the tick vector; nevertheless, risk factor analyses did not detect being in close contact with SFTS patient as one of the main risk factor for infection. 38 SFTS pathogenesis.…”

Surveillance results for family members of patients with severe fever with thrombocytopenia syndrome

“…In addition, transmission to healthcare workers was identified via blood and respiratory secretions in nosocomial conditions (Kim et al, ). However, it was also found that in a secondary SFTS case, no contact occurred with infected blood or other body fluids of a patient who died in the community (Yoo et al, ). The SFTSV threat posed to public health worldwide is significant because the infectious organism has been detected in various bodily fluids such as blood, respiratory secretions and urine and therefore has many possible transmission modalities (Jeong et al, ).…”