Seroprevalence of spotted fever rickettsiosis and ehrlichiosis among food processing workers and their families in Latino communities in North Carolina

Workers in food processing industries are subject to many occupational health risks and disparities, but little is known about their risk of tickborne diseases. We examined a cohort of Latino individuals working in the meat packing, produce processing, and farming industries and their family members in central North Carolina, where incidence of tickborne infections is high. Blood samples were tested for IgG antibodies against Spotted Fever Group Rickettsiosis (SFGR) and Ehrlichia chaffeensis. Covariates of interest included age, sex, primary language, work industry, indoor vs. outdoor work, home characteristics, medical comorbidities, and travel history. Among 201 Latino food processing workers and their family members, the seroprevalence of SFGR and Ehrlichia was 14.9% and 19.9%, respectively. Almost a third of participants were seropositive for at least one infection. SFGR seropositive individuals were significantly older than seronegative individuals (median 45 [interquartile range 35–55] vs. 33 [14–45] years, p < 0.001), while Ehrlichia seropositivity appeared to have a bimodal distribution by age, with peaks in children under age 10 and adults in their forties and fifties. Farm workers had higher seroprevalence of SFGR (25.0%) than other workers (13.5%), although this did not reach statistical significance (p = 0.13). Having a seropositive household member for either infection was a risk factor for seropositivity for the same infection, adjusted for age and household clustering (adjusted OR [aOR] 8.26, 95% CI [confidence interval] 3.27-20.90 for SFGR; aOR 11.24, 95% CI 4.24-29.80 for Ehrlichia). Seroprevalence for SFGR and Ehrlichia was similar between index workers and household members when adjusted for age. Our findings indicate that Latino food processing communities in North Carolina have high exposure to tickborne disease, and older age and having seropositive household members are key risk factors.