Exploring spotted-fever and typhus group rickettsiae seroprevalence and associated risk factors among rural inhabitants from Cauca department, Colombia

Rickettsia species are vector-borne bacteria, some of which cause rickettsioses, an underrecognized cause of acute undifferentiated febrile illness. While several regions of Colombia are considered endemic for rickettsial infections, information from other areas such as the Cauca department remains limited. Human serum samples and epidemiological data were collected from 506 rural inhabitants in eight rural localities across four municipalities of Cauca department, Colombia, between August and November 2017. Antibodies against SFG (spotted-fever group) and TG (typhus group) rickettsiae were detected using indirect immunofluorescence assay (IFA), and potential risk factors were evaluated using survey data and simple logistic regression analyses. Overall, 65.6% of individuals showed seropositivity for rickettsiae, including 58.3% for SFG, 22.3% for TG rickettsiae, and 15% for both groups. Cattle ownership was identified as a risk factor associated with rickettsial exposure, whereas some regions and housing conditions were associated with lower seropositivity, suggesting possible protective factors. These findings reveal a high level of exposure to SFG and TG rickettsiae among rural inhabitants of the Cauca department and highlight the need for increased surveillance and public health attention in this region.