TaqMan qPCR and IgM Detection in Samples of Patients with Tick-Borne Encephalitis Virus Infection in Northeast China

Menghan Yu,1 Xiaoshu Fu,1 Yanli Zhu,2 Miao Li,3 Min Wu,1 Entong Zhou,1 Hanwen Dong,1 Likun Wang,1 Ruoxi Wang,4 Fang Liu,2 Chunlai Jiang,1 Xiangwei Kong,5 Weiheng Su1,6 1National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun, People’s Republic of China; 2People’s Hospital of Jiangyuan District, Baishan, Jilin Province, People’s Republic of China; 3Department of Neurosurgery, China-Japan Union Hospital, Jilin University, Changchun, People’s Republic of China; 4School of Public Health, Capital Medical University, Beijing, People’s Republic of China; 5Changchun University of Science and Technology, Changchun, People’s Republic of China; 6Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, School of Life Sciences, Jilin University, Changchun, People’s Republic of ChinaCorrespondence: Weiheng Su, National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun, People’s Republic of China, Email suweiheng@jlu.edu.cn Xiangwei Kong, Changchun University of Science and Technology, Changchun, People’s Republic of China, Email tenbpro@163.comPurpose: Tick-borne encephalitis virus (TBEV) infections result in severe central nervous system diseases in humans across Asia and Europe. In China, cases of tick-borne encephalitis are primarily caused by the Far East subtype of TBEV, which exhibits a distinct disease course compared to other extensively studied subtypes. However, there is limited knowledge regarding the nucleic acid and serological diagnostic characteristics of patients infected with the TBEV in China, which is the focus of investigation in the present study.Methods: This study established a TaqMan qPCR approach to detect TBEV RNA in the serum with optimal specificity, sensitivity, and precision. Using TaqMan qPCR and ELISA assay for TBEV IgM detection, serum samples from 63 hospitalized patients bitten by ticks in Northeast China were investigated for diagnostic characteristics.Results: Twenty-five patients were positive for viral RNA; nineteen patients were positive for IgM, and nine were positive for both viral RNA and IgM. Through comparative analysis, TBEV RNA copies were negatively correlated with the virus incubation period. IgM levels were positively correlated with the clinical symptom scores of patients. The severity of clinical symptoms and the length after the tick bite could be used to predict the IgM occurrence. Furthermore, IgM levels and viral RNA copies were not correlated in double-positive patients.Conclusion: Both nucleic acid and serological detection methods exhibited distinct windows for detecting TBEV infection, with some overlap, and were associated with specific correlated factors. This study provided novel insights into the diagnosis and course of TBEV-induced tick-borne encephalitis in China.Keywords: tick-borne encephalitis, TBE, tick-borne encephalitis virus, TBEV, TaqMan qPCR, IgM