WormWatch: Park soil surveillance reveals extensive Toxocara contamination across the UK and Ireland.

BACKGROUND: Toxocarosis is a globally distributed zoonotic disease, but sources of infection are not well documented over large geographical scales. To determine levels of environmental contamination, soil from 142 parks and recreational areas across the UK and Ireland was assessed for the presence of Toxocara. METHODS: Toxocara ova (eggs) were isolated from soil samples by sieving and flotation and then enumerated. Individual eggs were isolated and imaged, and a subset was characterised by species-specific PCR and Sanger sequencing. RESULTS: Characteristic Toxocara-type eggs were found in 86.6% of parks, with an average of 2.1 eggs per 50 g of topsoil. Representative eggs were confirmed as Toxocara canis by Sanger sequencing, with many eggs containing developed larvae, hence being viable and potentially infective. Positive samples were more common, and egg density was higher, in parks with greater perceived levels of dog fouling. LIMITATIONS: Samples were collected at a single timepoint and with limited spatial mapping within parks. Further study is needed to discern spatiotemporal differences within parks and recreational areas. CONCLUSION: Toxocara is widespread in soil in public parks, indicating a need for further efforts to reduce egg shedding from pet dogs. Standardised methods and large-scale surveys are required to evaluate risk factors for egg presence and the impact of interventions.

Toxocara: time to let cati 'out of the bag'.

Zoonotic toxocariasis is increasingly prominent as knowledge of its insidious impact on human health accumulates. Toxocara canis dominates research attention, with Toxocara cati relegated to the periphery. We argue that there are few grounds to support this bias, and that differences in life history and epidemiology between T. canis and T. cati could have implications for disease impacts and control. Research on T. cati should be cognisant of its unique characteristics and not extrapolate uncritically from knowledge about T. canis. Key research gaps identified long ago remain largely unfilled. We set challenges for future research to better understand the biology of T. cati and its role in zoonotic disease - essential for guiding urgently needed actions in support of public health.