Japanese encephalitis (JE) is a mosquito-borne disease caused by the Japanese encephalitis virus (JEV). The disease is mainly an epidemic in Asia and has been studied for nearly 90 years. To evaluate the research trends of JE, 3,023 English publications between 1934 and 2020 were retrieved and analyzed from the Web of Science database using indicators for publication, country or territory, citation, journal, author and affiliation, keyword co-occurrence cluster, and strongest citation bursts detection. The results of the bibliometric analysis and the visualization tools show that the number of annual publications on JE has been increasing. JE has been continuously studied in the USA and also many Asian countries, such as Japan, China, India, and South Korea; however, only a few publications have high citations. The main research groups of JE in the last 5 years were in China, Japan, and the UK. The keyword co-occurrence analysis and the strongest citation bursts detection revealed that most studies focused on the pathogenic mechanism of JEV, control of outbreaks, and immunization with JE vaccine. The research maps on JE obtained by our analysis are expected to help researchers effectively explore the disease.

Japanese encephalitis (JE) is an important viral encephalitis with epidemic status in Asia, which is caused by Japanese encephalitis virus (JEV), a member of the genus Flavivirus. JEV is divided into five genotypes. Genotype 5 (G5) is relatively neglected because of the limited number of cases and strains isolated. The first strain of G5 JEV (Muar strain) was isolated in Singapore in 1952 in a patient from Muar, Malaysia. The second strain (XZ0934) was isolated 57 years later in China, thus indicating the re-emergence of G5 JEV. A female patient who had been vaccinated against JE was infected with G5 JEV in Korea in 2015. JE is a vaccine-preventable disease, and its incidence has decreased with vaccination in many Asian countries. G3 JEV is the main candidate for current JE vaccines, which include attenuated, inactivated and chimeric type vaccines. However, the available vaccines do not provide adequate protection against the older G5 JEV lineage. Therefore, more research on this genotype is crucial for developing better detection methods, expanding surveillance to determine the possible chains of viral transmission for this new threat and developing a polyvalent JEV vaccine.

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