Background: Toxocara canis and Toxocara cati are intestinal parasites of dogs, cats and foxes, with infected animals shedding eggs of the parasite in their faeces. If humans accidentally ingest embryonated Toxocara spp. eggs from the environment, severe clinical consequences, including blindness and brain damage, can occur. Previous work has demonstrated the presence of Toxocara spp. eggs on vegetable produce grown in the UK, but only in small-scale community gardens. The aim of this study was to determine whether Toxocara spp. eggs are also present on vegetables grown on commercial farms in the UK, which supply produce to a greater number of people.

Methods: A total of 120 samples (300 g each) of spinach (Spinacia oleracea) were collected across four farms in the south of England, UK. The samples were processed using a sieving approach followed by multiplex quantitative polymerase chain reaction analysis.

Results: Overall, 23.0% of samples were positive for T. canis (28/120; 95% confidence interval 16.7-31.7%) and 1.7% for T. cati (2/120; 95% confidence interval 0.5-5.9%). There was a statistically significant difference in the number of positive samples between farms (P = 0.0064). To our knowledge, this is the first report of the isolation of Toxocara spp. from vegetables grown on commercial farms in the UK.

Conclusions: The results of this study highlight the requirement for the thorough washing of vegetables prior to their consumption, especially those such as spinach which may be eaten without first peeling or cooking, and effective farm biosecurity measures to minimise access to farmland by definitive host species of Toxocara spp.