Confirmation of spotted-fever group and typhus group rickettsiosis cases through a three-month hospital-based sentinel surveillance of acute undifferentiated febrile illness in the municipality of Santander de Quilichao, Cauca, Colombia

Introduction: Spotted fever group (SFG) and typhus group (TG) rickettsioses are important causes of acute undifferentiated febrile illness (AUFI). Its diagnosis is not routinely performed; thus, surveillance studies that attempt to identify active cases are highly important. The objective of this study was to conduct an AUFI sentinel surveillance in a region with high seropositivity rates in the Cauca Department, Colombia. Materials and Methods: Patients with AUFI were recruited over three months in a local hospital in Santander de Quilichao municipality. Demographic and epidemiological data were also collected. Acute and convalescent blood simples were collected from each patient. Complete hemograms, liver function tests, and C-reactive protein (CRP) measurements were conducted. SFG and TG rickettsiosis was screened using an indirect immunofluorescence assay. Results: A total of 22 febrile patients were included in this study. In six of them (27.3%), SFG rickettsiosis was detected; TG rickettsiosis was detected in four (18.2%) and three (13.6%) patients seroconverted to both Rickettsia spp. groups. Additionally, in fourteen patients (93.3%) and eleven patients (73.3%) patients had previous exposure to SFG and TG Rickettsia spp., respectively. Discussion: Active circulation of SFG and TG rickettsioses cases was identified in rural areas of Santander de Quilichao, as well as previous exposure to Rickettsia spp., shedding light on a possible important novel endemic región for rickettsioses in Cauca.