The Prevalence of and -Like Diseases in Patients with Undifferentiated Febrile Illness - Hainan Province, China, 2018-2021.

Introduction: and -like diseases, resulting from obligate intracellular Gram-negative bacteria, pose a growing public health threat in China. To assess the current prevalence of these diseases on Hainan Island, a study was conducted on 9 bacterial pathogens found in patients with undifferentiated febrile illness (UFI) treated in Haikou between 2018 and 2021 using a TaqMan Polymerase Chain Reaction (TaqMan PCR) array.

Methods: Blood samples (=503) were collected from patients with UFI between 2018 and 2021. The samples were screened for spp., (), (), , , , spp., , and using a TaqMan PCR array. Positive samples (Ct<35) underwent confirmation through nested PCR, sequencing, and phylogenetic analysis.

Results: and were detected in the patients at positive rates of 14.51% (73/503) and 5.57% (28/503), respectively. Co-infection of and was identified in scrub typhus (ST) positive populations from Hainan (10.96%, 8/73), Guangxi (61.54%, 8/13), and Yunnan (5.36%, 3/56) provincial-level administrative divisions (PLADs) of China.

Conclusion: An increased prevalence rate of ST and a decreased prevalence of rickettsioses were observed in patients with UFI in Hainan compared to a decade ago. The co-infection of and poses a current public health threat in China.