A High Viral Load in Urine Correlates with Acute Kidney Injury and Poor Outcomes in Hospitalized Patients with Severe Fever with Thrombocytopenia Syndrome: A Noninvasive and Convenient Prognostic Marker

Background Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with an extensive geographical distribution and high mortality rate. To date, the role of SFTS virus (SFTSV) in urine is still elusive. We aimed to explore the relationship between urinary bunyavirus and acute kidney injury (AKI) and mortality in patients with SFTS. Methods Urine samples were collected from 102 patients to quantify SFTSV load in urine (U-SFTSV). Patient renal function was evaluated on admission. Receiver operating characteristic (ROC) curve and logistic regression analysis were performed to evaluate the predictive value of U-SFTSV. Viral infectivity assays in Vero cells were performed from 10 urine samples. Results The U-SFTSV level was positively correlated with SFTSV load in plasma (r = 0.624) and indicators of renal damage. The U-SFTSV level was identified as an independent risk factor for SFTS-associated AKI (odds ratio, 3.631; P = .019). The U-SFTSV showed great value in predicting the fatal outcome of SFTS patients with high area under curve (0.881). The Kaplan-Meier survival comparison showed that patients with U-SFTSV levels greater than 6379 copies/mL were at a higher risk of death within 28 days after onset. In addition, 4 urine samples with high U-SFTSV levels were infectious. Conclusions Our large cohort study identified that the U-SFTSV level is a novel convenient and noninvasive predictive biomarker for incidence of AKI and poor outcome of patients with SFTS. Urine specimens could be a source of SFTSV infection in humans.