A peer-reviewed study of 87 cats trapped through New York City's TNR program found 57.5% infected with zoonotic parasites — including a soil-persisting roundworm that poses risks for children in parks and playgrounds — and recommends the city add parasite treatment to its current trapping protocol.

A study published July 8 in PLOS One examined blood and fecal samples from 87 cats trapped through New York City's Trap Neuter Return program between May and July 2023, and found that more than half — 57.5% — carried at least one parasite species transmissible to humans.

Researchers from Rowan University's Shreiber School of Veterinary Medicine and Long Island University's Lewyt College of Veterinary Medicine identified Toxocara roundworms in 54% of sampled animals. Toxocara eggs shed in cat feces can survive in soil for months; ingestion — a particular risk for children playing in contaminated parks or sandboxes — can cause toxocariasis, a disease that in severe cases affects the eyes or liver. Hookworms (Ancylostoma spp.) appeared in 13.8% of cats, Giardia in 11.6% of a subset tested by coproantigen assay, and antibodies to Toxoplasma gondii in 8.9% of blood samples. About one in five cats carried multiple parasites simultaneously.

The authors identified juvenile male cats as high-intensity "super-shedders": statistically more likely to carry Toxocara and to do so in larger concentrations than adult or female animals, amplifying environmental contamination across the parks, alleys, and vacant lots where colonies settle.

The study's corresponding author, Pratap Kafle of Rowan University, and the team recommend integrating parasite surveillance and antiparasitic treatment into TNR programs citywide — steps not currently standard in New York's program. The city runs TNR operations through community partners and NYC Animal Care Centers; the standard protocol covers spay/neuter and basic vaccination but does not include routine deworming. Without that addition, the authors argue, the program leaves a public-health gap that no amount of trapping and neutering closes on its own.