The Seroprevalence and Risk Factors for Spotted Fever Group and Typhus Group Rickettsia Along the Texas–Mexico Border

Rickettsial pathogens are an endemic and emergent source of disease in Texas, with a historically high rate of transmission along the United States–Mexico border. To better understand the prevalence and risk factors for spotted fever group Rickettsia (SFGR) and typhus group Rickettsia (TGR) along the Texas–Mexico border, we conducted a seroprevalence study of adults residing in Starr County, Texas ( N = 616). Plasma samples were screened for IgG reactivity to SFGR and TGR using commercially available ELISA. ELISA-positive samples were confirmed using a dual spot IgG indirect immunofluorescent assay. Seropositivity was defined as having a ≥1:128 titer. Analysis was conducted to assess risk factors associated with seropositivity. A higher seroprevalence of TGR (10.9%) was identified compared with SFGR (4.6%) and Rickettsia unspecified (2.0%). These findings add to the growing body of evidence suggesting that both SFGR and TGR are endemic along the Texas–Mexico border.