Serological Investigation into the Infected Genotypes of Patients with Japanese Encephalitis in the Coastal Provinces of China.

Objective: Genotypes (G) 1, 3, and 5 of the Japanese encephalitis virus (JEV) have been isolated in China, but the dominant genotype circulating in Chinese coastal areas remains unknown. We searched for G5 JEV-infected cases and attempted to elucidate which JEV genotype was most closely related to human Japanese encephalitis (JE) in the coastal provinces of China.

Methods: In this study, we collected serum specimens from patients with JE in three coastal provinces of China (Guangdong, Zhejiang, and Shandong) from 2018 to 2020 and conducted JEV cross-neutralization tests against G1, G3, and G5.

Results: Acute serum specimens from clinically reported JE cases were obtained for laboratory confirmation from hospitals in Shandong (92 patients), Zhejiang (192 patients), and Guangdong (77 patients), China, from 2018 to 2020. Seventy of the 361 serum specimens were laboratory-confirmed to be infected with JEV. Two cases were confirmed to be infected with G1 JEV, 32 with G3 JEV, and two with G5 JEV.

Conclusion: G3 was the primary infection genotype among JE cases with a definite infection genotype, and the infection caused by G5 JEV was confirmed serologically in China.