Construction and Characterization of an Infectious Clone of the Asian Genotype Chikungunya Virus from Yunnan, China

Chikungunya fever (CHIKF) is caused by the Chikungunya virus (CHIKV). In recent years, it has rapidly spread globally and has been listed as a public health concern by the World Health Organization. In 2019, the first local outbreak of Asian-type CHIKF was reported in Xishuangbanna, Yunnan Province, China, with 88 CHIKV nucleic acid-positive cases detected from clinical specimens. To further investigate the biological characteristics of the virus strain responsible for this outbreak, we rescued the 625D6h strain using reverse genetics and tested its growth kinetics in different cell lines. The results showed that the 625D6h strain had strong replication capacity in the Aedes albopictus C6/36 insect cell line but weaker replication capacity in mammalian cell lines. Its high replication capacity under high mosquito vector adaptability may have contributed to the outbreak in 2019. The study also found that two DHODH inhibitors, ML390 and vidofludimus, could effectively inhibit CHIKV replication. The infectious clone created in this study provides a useful tool for studying the recently prevalent Asian-type strain in China and supports the subsequent development of prevention and treatment methods.