Social determinants of health and temporospatial trends associated with Giardia duodenalis infection in Texas canines

Giardia duodenalis is a protozoal parasite that infects a wide range of animal hosts and poses a zoonotic risk to humans. Although social determinants of health (SDOH) are well characterized in human disease, their role in shaping animal health outcomes remains poorly understood. Using a One Health framework, this ecological study evaluated temporospatial trends in canine Giardia infection in Texas and assessed associations with county-level socioeconomic indicators. Veterinary diagnostic laboratory test results from 2012–2022 were analyzed to characterize temporal trends and geographic variation in test positivity. Negative binomial regression models were used to examine associations between Giardia positivity and county-level measures of poverty, unemployment, income, educational attainment, and veterinary care accessibility scores (VCAS). Overall, 4.61% of canine tests were positive, with substantial county-level variation (median 4.61%, range 0.59–12.06%). Higher positivity was associated with limited veterinary care access (PR 2.06 [1.39–3.05], p < 0.001) and a lower proportion of college graduates (PR 1.61 [1.24–2.08], p < 0.001). Temporal increases in positivity were observed in Cameron County and Lubbock County, whereas decreases were noted in El Paso County and Parker County. These findings suggest that socioeconomic factors related to veterinary access and education are associated with canine Giardia infection risk and may help identify regions where targeted interventions are warranted. However, further studies are needed to elucidate the underlying mechanisms and zoonotic implications.