Rickettsia2024 is a multicenter, tissue observational, retrospective and prospective cohort study. Enrollment will take place within the outpatient clinics of the Infectious Diseases and Dermatology Unit of the IRCCS AOUBO and, following an infectious disease consultation in the Bologna Metropolitan area, at the Hospitals and CAUs of the Bologna Local Health Authority. Within these UUOOs, biopsy samples from normal clinical practice are performed on patients with strong clinical suspicion of Rickettsia infection: therefore, it will not be necessary to perform any additional samples for the conduct of this study. Samples from the normal diagnostic process are sent to the Microbiology UOC, where they are subjected to various analyses. RT-PCR analyses (commercial or in-house kit) and assay of species-specific IgG antibodies will be performed according to clinical practice. Additional tests will be performed with a commercial kit for retrospective samples and with a home-made method for prospective samples.

It is estimated that a total of approximately 800 patients can be recruited, 400 for the retrospective part and the same number for the prospective part (estimated using data collected from requests received to date). For the retrospective cohort: from January 2023 until approval by the ethics committee; For the prospective cohort: from ethics committee approval until December 2027.

Inclusion Criteria:

• pazienti che presentano escara
• pazienti con richiesta del dosaggio degli anticorpi anti-Rickettsia conorii

Exclusion Criteria:

• None

The study population will consist of patients belonging to the UUOOs involved in the study, for whom serum samples, whole blood, skin biopsy, eschar, vesicle buffer underlying the eschar collected through withdrawals that meet the inclusion criteria, performed according to clinical practice, are available:

• For the retrospective cohort: from January 2023 until approval by the ethics committee;
• For the prospective cohort: from ethics committee approval until December 2027. The Microbiology Unit is the operational reference unit. The Infectious Diseases and Dermatology Unit of the IRCCS AOUBO is involved in patient enrollment, as are the Hospitals and CAUs of the Bologna Local Health Authority, following requests for infectious disease counseling in the Bologna Metropolitan Area.