Ethical approval

Signed individual written informed consent was obtained from each patient at the time of sample collection. All adult human subjects provided informed consent, and a parent or guardian of any child participant provided informed consent on the child’s behalf (less than 18 years old). Collecting human serum samples from patients was reviewed and approved by the ethics committees of the National Institute for Communicable Disease Control and Prevention, China CDC. All methods were performed in accordance with the relevant guidelines and regulations. Animal experiments were performed according to Guidance for Experimental Animal Welfare and Ethical Treatment by the Ministry of Science and Technology of China (www.most.gov.cn/fggw/zfwj/zfwj2006/zf06yw/zf06qt/200612/t20061226_39235.htm). These protocols were approved by the National Institute for Communicable Disease Control and Prevention of the China CDC (Permit number: ICDC20170616-001). All mammals were euthanized used the ether anesthetic chamber, and all tissue samples were taken during necropsy. Tissue samples of liver, spleen, lung, and kidney were collected from small mammals for detecting Rickettsiales bacteria. Field Research was also approved by the ethics committee of National Institute of Communicable Disease Control and Prevention of the China CDC, and the field permit number is 201710082.