Park entrances may be hotspots for infective dog roundworm eggs

In an analysis of soil samples from twelve parks in Dublin, Ireland, park entrances were more heavily contaminated with infective roundworm eggs than any other tested park location. Jason Keegan of Trinity College in Dublin, Ireland, and colleagues present these findings in the open-access journal PLOS Neglected Tropical Diseases.

Dogs and cats are often infected with parasitic roundworms in the Toxocara genus. Infected animals can release the roundworm eggs into the environment, and humans can become infected after accidental ingestion of the eggs. Many infected humans never experience symptoms, but some may experience mild or severe symptoms such as eye infection. Infection with Toxocara is one of the most widespread parasitic infections in the world.

While prior studies have shown that soils in public parks are commonly contaminated with Toxocara roundworm eggs, few have explored whether certain areas within parks are more contaminated than others. To address that question, Keegan and colleagues collected and analyzed soil samples from within 12 parks in Dublin, Ireland, focusing on park entrances, playgrounds, the sidelines of sports fields, and popular areas for sitting on grass.

The analysis showed that park entrances were more heavily contaminated with roundworm eggs than the other park locations. The second-most contaminated areas were playgrounds. Closer examination of the detected eggs found that most were potentially infective, and most were of the species Toxocara canis—the common dog roundworm.

On the basis of these findings, the researchers call for increased preventive efforts focused on encouraging dog owners to properly dispose of dog feces at park entrances and playgrounds. They note that the success of such efforts should be monitored with regular measurements of Toxocara eggs at these sites. They specifically designed the analytical method used for this study to be accessible and affordable, so it could serve as a standardized monitoring strategy, easing comparison between sites and over time.

The authors add: "Park entrances had the most Toxocara eggs, and most of these eggs likely came from dogs. By providing signage, bins and a means to clean up after your dog in these locations, we could reduce the level of contamination. That’s the next step in the research." 

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In your coverage please use this URL to provide access to the freely available article in PLOS Neglected Tropical Diseases: https://plos.io/3E7WEYK

Citation: Keegan JD, Airs PM, Brown C, Dingley AR, Courtney C, Morgan ER, et al. (2025) Park entrances, commonly contaminated with infective Toxocara canis eggs, present a risk of zoonotic infection and an opportunity for focused intervention. PLoS Negl Trop Dis 19(3): e0012917. https://doi.org/10.1371/journal.pntd.0012917

Author Countries: Ireland, United Kingdom

Funding: This research was funded by The Irish Research Council's Postdoctoral Fellowship programme (GOIPD/2020/510 to JDK and CVH). https://research.ie/ The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.