Human infection with Candidatus Rickettsia jingxinensis: First identification and clinical characteristics

New tick-borne pathogens are being discovered worldwide, and recognized tick-borne diseases are becoming increasingly diverse. Candidatus R. jingxinensis is endemic in Asia, but its potential to cause clinical infection in humans remains unclear. This study was designed to elucidate the prevalence and delineate the clinical profile of Candidatus Rickettsia jingxinensis infection in Liaoning Province, China.

The subjects of this study were suspected cases of tick-borne infectious diseases admitted to the First Affiliated Hospital of China Medical University or reported to the Liaoning Provincial Center for Disease Control and Prevention in 2018-2022. Epidemiological and clinical data were collected. Tick-borne pathogens were detected with a microfluidic chip detection system, and specific gene fragments of the screened pathogens were amplified, sequenced, and compared. Evolutionary and phylogenetic trees were constructed and analyzed.

In total, 398 infected subjects from 14 cities were included in the study, and 255 tick-borne pathogens were detected. Among these, 11 subjects were found to be infected with Candidatus Rickettsia jingxinensis. This is the first time this strain has been shown to cause infection and illness in humans. The main clinical features of subjects infected with Candidatus R. jingxinensis included fever, fatigue, dizziness, headache, nausea, diarrhea, general pain or muscle and joint pain, reduced leukocytes and platelets, abnormal coagulation function and liver function.

This study documents the first human infections with Candidatus R. jingxinensis, confirms its prevalence in Liaoning Province, and delineates the primary clinical manifestations of the disease.