A pediatric case of severe fever with thrombocytopenia syndrome in Zhejiang Province, China

Infection of Severe Fever with Thrombocytopenia Syndrome Virus as a Cause of a Child's Fever of Unknown Origin: A Case Report

Background

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne disease resulted from SFTSV. It is found in Japan, South Korea, Central, and Eastern China. With the increasing prevalence of SFTS and the rapid spread of the SFTS virus (SFTSV) vector, it is obvious that this virus has pandemic potential and poses an imminent public health concern.

Case Presentation

We depict SFTS in a child from Anhui Province and conduct a review of all reported pediatric cases in China, which is an endemic area for SFTS. From 2011 to 2021, ten SFTS pediatric cases confirmed by RT-PCR were reported, with no child dying. Although SFTS cases in adolescents and children are uncommon, the reported literature showed that clinical symptoms in adolescents and children were milder than in adults.

Conclusion

To better understand this emerging disease, we described the clinical and epidemiological attributes of SFTS. We suggest that the possibility of SFTSV infection in children with seasonal and virus-related acute febrile diseases should be considered in major endemic areas.

Estimation of the incidence of severe fever with thrombocytopenia syndrome in high endemic areas in China: an inpatient-based retrospective study

BACKGROUND

Severe fever with thrombocytopenia syndrome (SFTS) is a severe viral disease caused by SFTSV. It is important to estimate the rate of missed SFTS diagnosis and to further understand the actual incidence in high endemic areas in China.

METHODS

This study was conducted in two high SFTS endemic provinces in 2015. Patients hospitalized in 2014 or within 1 year before investigation were selected after considering their clinical manifestations, specifically, fever, platelet, and white blood cell. During retrospective investigation, sera were collected to detect SFTSV antibodies to assess SFTSV infection. To further understand SFTSV infection, acute phase sera were detected; SFTSV infection rate among a healthy population was also investigated to determine the basic infection level.

RESULTS

In total, 246 hospitalized cases were included, including 83 cases (33.7%) with fever, thrombocytopenia and leukopenia, 38 cases (15.4%) with fever and thrombocytopenia but without leukopenia, and 125 cases (50.8%) without fever but with thrombocytopenia and leukopenia. In total, 13 patients (5.3%) were SFTSV IgM antibody-positive, 48 (19.5%) were IgG-positive. Of the 13 IgM-positive cases, 11 (84.6%) were IgG-positive (9 with titres ≥1:400). Seropositive rates of antibodies were high (8.4% for IgM and 30.1% for IgG) in patients with fever, thrombocytopenia and leukopenia. Furthermore, among IgG-positive cases in this group, 76% (19/25) of patients' IgG antibody titres were ≥1:400. Additionally, 28 of 246 cases were initially diagnosed with suspected SFTS and were then excluded, and 218 patients were never diagnosed with SFTS; the seropositive rates of IgM and IgG in these two groups were 25% and 67.9% and 2.8% and 13.3%, respectively. These rates were 64.3% and 21.4% in 14 sera collected during acute phase of the 28 cases mentioned above. Seropositive rate of SFTSV IgG was only 1.3% in the patient-matched healthy group, and no IgM antibody was detected. A preliminary estimate of 8.3% of SFTS cases were missed in SFTS high endemic provinces.

CONCLUSIONS

The actual SFTS incidence was underestimated. Effective measures such as adding a new SFTS case category - "SFTS clinical diagnosis cases" or using serological detection methods during acute phase should be considered to avoid missed diagnoses.

Pediatric huaiyangshan virus infection: A case report with literature review

To define the clinical manifestations and laboratory characteristics of pediatric severe fever with thrombocytopenia syndrome (SFTS) case caused by a novel bunyavirus. we retrospectively analyzed a pediatric case of viral SFTS in a 13 year old successfully managed and confirmed to be due to the novel bunyavirus now referred to as Huaiyangshan virus. A literature review of related cases was performed.Our pediatric case was a 13.3-year-old middle school student no underlying disease. Major clinical features included a fever with chills, headache, and dizziness. The patient's epidemiology showed he had close contact with his grandfather who had a confirmed, novel bunyavirus infection. Symptomatic theraphy were given at admission. The patient's temperature and platelet count returned to normal by days 7 and 10, respectively, and he was discharged from the hospital with an improved condition. A literature search was performed using "severe fever with thrombocytopenia syndrome" and "bunyavirus" as keywords, but few relevant reports were found. Novel bunyavirus infection can be transmitted through close contact. Confirmed cases should be kept in isolation. Clinical manifestations were characterized by aspecific symptoms, such as fever and chills. In some cases, platelet counts may remain normal in the early phase of the disease, and fever may not present throughout the entire illness period. Thus, misdiagnosis is possible. Surveillance and vigorous follow-up should be carried out in children with tick bites or in close contact with an index patient in high-risk areas during peak season.

A Pediatric Case of Severe Fever with Thrombocytopenia Syndrome in Korea

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease and elderly people living in rural areas have the greatest risk of infection. We report the first pediatric case of SFTS in Korea and the clinical characteristics and disease progression in children. A 10-year-old child from Chonnam province visited the hospital with myalgia and a history of fever over the previous 8 days. Her father noticed a tick on her head and removed it before fever developed. Because the symptoms continued, her father consulted the community health center and SFTS virus was detected both from the tick (Haemaphysalis longicornis) and the patient's blood. On hospitalization, fever and severe myalgia were improved and no gastrointestinal and hemorrhagic symptoms were observed. The patient was successfully treated with a combination of steroids, IVIG, and ribavirin. In this report, a pediatric case of SFTS presents a mild clinical course but close attention must be paid to the screening of children with mild symptoms consisting of SFTS.

Current status of severe fever with thrombocytopenia syndrome in China

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by SFTS virus (SFTSV). SFTSV is associated with a high mortality rate and has been reported in China, South Korea and Japan. SFTSV undergoes rapid changes owing to evolution, gene mutations, and reassortment between different strains of SFTSV. In this review, we summarize the recent cases and general properties of SFTS, focusing on the epidemiology, genetic diversity, clinical features, and diagnostics of SFTSV in China. From 2010 to October 2016, SFTS cases were reported in 23 provinces of China, with increased numbers yearly. Infection and death cases are mainly found in central China, where the Haemaphysalis longicornis ticks are spread. The national average mortality rate of SFTS infection was 5.3%, with higher risk to elder people. The main epidemic period was from May to July, with a peak in May. Thus, SFTS reminds a significant public health problem, and development of prophylactic vaccines and effective antiviral drugs will be highly needed.