Molecular surveillance of intestinal parasites and Acanthamoeba species in soils from outdoor built environments in rural northwestern Argentina.

Abstract

Background: Soil-transmitted helminths (STHs) and other enteric parasites remain endemic in rural communities of northwestern Argentina. Environmental surveillance may provide additional information on transmission dynamics and community exposure.

Results: We analyzed 116 soil samples collected from 28 sites, including 27 households in Solazuti and one rural school in El Cedral (Orán Department, Salta Province, Argentina), using multi-parallel real-time quantitative PCR targeting intestinal protozoa, STHs, zoonotic nematodes, and Acanthamoeba spp. Parasites were detected in outdoor built environments, with 44% of Solazuti households showing at least one positive sample. Ascaris lumbricoides and Toxocara canis were the most frequently detected helminths and showed distinct spatial patterns. Detection of A. lumbricoides was strongly associated with the presence of other parasites (OR 18.11, 95% CI 8.30-38.6; p < 0.0001). Additionally, A. lumbricoides-positive households harbored significantly more parasite species than A. lumbricoides-negative households (p = 0.0343), and A. lumbricoides frequency correlated with parasite richness (Spearman r = 0.4145, p = 0.0316). Acanthamoeba spp. was nearly ubiquitous (96.4% of sites), including the school environment, with a 75% contamination rate.

Conclusions: Molecular analysis of soil samples revealed spatially heterogeneous but sustained exposure to multiple pathogens in rural outdoor environments. Soil-based qPCR may complement traditional surveillance by providing community-level data independent of human sampling.