Is Parasitic Contamination of Soil in the Southern United States Related to Poverty and Does It Represent a Human Health Threat? A Perspective

In recent years, multiple reports have emerged describing real-time quantitative polymerase chain reaction (qPCR) detection of DNA derived from human parasite species in environmental soil samples. In one such report, sampling was focused in impoverished areas of the southeastern United States, and a link between poverty and the presence of parasite DNA in soil was proposed. Whether transmission of certain parasitic diseases persists in the United States in association with poverty remains an important question. However, we emphasize caution when reviewing interpretations drawn solely from qPCR detection of parasite-derived environmental DNA without further verification. We discuss here the limitations of using qPCR to test environmental DNA samples, the need for sampling strategies that are unbiased and repeatable, and the importance of selecting appropriate control areas and statistical tests to draw meaningful conclusions.