Presence of coccidian human parasites in animal faecal samples from an English urban environment.

Cryptosporidium spp. and Cyclospora cayetanensis are protozoan emerging human parasites that can severely affect immunocompromised patients worldwide for which an early stage diagnosis is critical for appropriate prognosis. They can also affect immunocompetent individuals and have been related with serious outbreaks. Zoonotic transmission has been suggested for different human-pathogenic species of Cryptosporidium but remains unclear for Cyclospora cayetanensis. Despite humans becoming more exposed to biological hazards in urban environments due to exponential urbanisation and human population expansion, there is little understanding of the presence and distribution of these emerging pathogens in urban areas. Additionally, “urban” animals could act as reservoirs of these parasites that also require to be fully understood. A preliminary investigation carried out by our group reported the presence of Cryptosporidum spp. in a dog faecal sample collected in a highly frequented public park in Leicester city centre (UK), after screening 9 topsoil and 18 faecal samples in New Walk (LE1 6TE) and Abbey Park (LE4 5AQ). We performed a more comprehensive study in November 2017 in which we collected 62 animal faecal samples in the same two locations in Leicester. Animal species stool samples collected were: 57 avian (20 pigeon, 20 waterfowl, 11 songbird, 2 bird, 4 uncertain), 4 cat and 1 dog. Detection of these coccidian parasites was performed with Kinyoun's acid-fast staining. Structures related to Cryptosporidium spp. and Cyclospora were not found in any of the samples after appropiate screening. However, these results should be considered inconclusive as further monitoring of other public parks and recreational areas within Leicester are needed to ensure the negligible presence and distribution of these parasites in this urban environment. This information is crucial to assess the public risks of these pathogens in the urban media and develop/implement possible interventions to protect the public health.