Human-related microsporidia in the English urban environment: what we know so far?

The potential zoonotic transmission route of Enterocytozoon bieneusi and Encephalitozoon spp. (E. intestinalis, E. hellem and E. cuniculi) is under discussion. “Urban animals” could represent a risk to the population that should be carefully studied. Following the detection of human-related microsporidia in 2 out of 18 dog faecal samples collected in the city centre of Leicester (UK) in January 2016, 228 animal faecal samples were randomly sampled from different parks and recreational areas across the city from June 2016 to February 2017. The presence of microsporidia species were sought by real time polymerase chain reaction (RT-PCR) with melting curve analysis after extracting DNA by dysrupting the spores using Fast-Prep for soil following previous methodologies. 28 stool samples were positive for human-pathogenic microsporidia, as follows: Enterocytozoon bieneusi was detected in 2 waterfowl stool samples. A higher prevalence of Encephalitozoon spp. was identified. Thus, 26 faecal samples (14 deer, 7 avian [3 waterfowl, 2 songbird, 1 pigeon, 1 uncertain], 2 dog, 1 fox and 2 unidentified due to diarhoea) were positive for Encephalitozoon spp. Specifically, E. intestinalis/ E. hellem were detected in two samples from avian species (waterfowl and diarrhoeic sample) and E. cuniculi in 7 (6 deer and 1 fox). Our results indicate that human-related microsporidia would be present in urban parks and recreational areas in Leicester, which could represent a risk for humans. Interventions to tackle this potential risk should be applicable to a variety of animals, although more studies are needed to fully understand the potential zoonotic role of these pathogens.