Diagnosing and reintegrating traceability of infectious diseases via metagenomic next-generation sequencing:Study of a severe case of Rickettsia japonica infection

Background:In this study,we present a case of Japanese spotted fever(JSF)caused by Rickettsia japonica and use this case to investigate the process of diagnosing and reintegrating traceability of infectious diseases via metagenomic next-generation sequencing(mNGS).Methods:From data relating to epidemiological history,clinical and laboratory examinations,and mNGS se-quencing,a diagnosis of severe JSF was concluded.Results:A detailed field epidemiological investigation discovered parasitic Haemaphysalis longicornis from a host animal(dog)in the domicile of the patient,within which R.japonica was detected,along with a diverse array of other potentially pathogenic microorganisms that could cause other infectious diseases.Conclusion:The mNGS provided an efficient method to diagnose JSF infection.This methodology could also be applied to field epidemiological investigations to establish the traceability of infectious diseases.