Presence of Giardia in urban parks from Leicester, UK

Giardia duodenalis (syn. G. lamblia and G. intestinalis) is a worldwide leading diarrheagenic human protozoan parasite with potential to contaminate water, food or fomites. Animal-to‑animal and animal‑to‑human transmissions are major concerns, however human giardiasis in the United Kingdom (UK) are underdiagnosed. The main aim of this study was to evaluate if Giardia is present in an English urban environment to determine if public health interventions were necessary to protect human health. Thus, 21 fresh animal faecal samples were collected from Humberstone Park in Leicester (UK) in August 2017, when there had been no precipitation for at least the preceding 48 h. A veterinarian identified the possible animal species as: 7 avian (2 songbird, 1 pigeon, 4 uncertain) and 14 canine (dog). Smears were stained with Trichrome as described elsewhere. Giardia spp. cysts were observed in three faecal samples from dogs (21.4%), confirming our previous results in which we detected the presence of G. duodenalis in one dog faecal sample collected in the Leicester’s Castle Park (central Leicester) in a pilot study performed in winter 2016 using the immunoassay ImmunoCard STAT!®. Our results, although preliminary, indicate the presence of Giardia spp. in Leicester’s urban environment. Moreover, dogs could act as reservoirs and might play a potential role in the transmission of these pathogens in Leicester. Thus, public parks could be an important source of infection, particularly for children, as they can accidentally ingest this parasite from soil contaminated with dog faeces. This pilot study has provided critical insight for performing a more comprehensive study to determine the size of this risk and the necessity of enhancing public health awareness to reduce canine faecal pollution in Leicester to protect human health.