Serological and molecular epidemiological investigation of Mediterranean spotted fever in Yunnan Province, China

Given the limited research and its potential hazards, the study aimed to determine the prevalence of Mediterranean spotted fever (MSF) caused by Rickettsia conorii (R. conorii), a tick-borne disease, in Yunnan Province, China. Through stratified sampling across five distinct regions in Yunnan, 5358 blood samples were obtained from the general healthy population. Enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay (IFA), and Polymerase chain reaction (PCR) were employed for analysis. IFA identified 27 (0.50%) subjects with immunoglobulin G (IgG) positivity; none were positive for immunoglobulin M (IgM) via ELISA. PCR detected one individual with R. conorii outer membrane protein A (ompA). Significant seroprevalence variation was observed, particularly in Southern Yunnan (P = 0.032), with R. conorii subsp. conorii confirmed in the PCR-positive sample. This research reveals a correlation between MSF prevalence, geography, and climate in Yunnan. The paucity of prior studies underscores MSF's potential diagnostic challenges in the region. Comprehensive understanding of the pathogen's distribution is pivotal for intervention. Given the study's scope and Yunnan's unique setting, additional research is advocated.