Deer in public parks in Leicesthershire (UK): is there any risk to human health?

Deer may act as reservoirs of various parasites that can infect humans and livestock, which can be a concern for public health and the economy. Bradgate Park, a public park in Leicestershire (UK), houses numerous herds of red and fallow deer and is highly frequented by the public due to it’s proximity to Leicester city. Thirty fresh deer faecal samples were collected in February 2019 and concentrated by formalin-ethyl acetate sedimentation technique. Fifty topsoil samples were also collected to determine the physicochemical properties of the monitored faecally contaminated soils to fully characterise risks. Eggs of hookworms-like (n=18), Capillaria spp. (n=9) and Trichuris spp. (n=2) were detected in the monitored samples; larvae of nematodes were observed in 7 samples and oocysts of Eimeriidae in 4. No parasitic structures were observed in just two of the samples. Monitored soils presented slight levels of moisture (3.1%) but high levels of organic matter (10.30%), which would favour survival of soil transmitted helminths (hookworms). However, the pH was slightly acidic (5.38), which was much lower than the ideal reported range of pH for development of helminths (8 to 10). Bradgate Park’s topsoils were characterised as silty loam, with a low sand content (23% sand, 23% clay, 54% silt), which in turn would facilitate retention of water and survival of eggs. Despite exact identification of these parasites needed at species level to detect human-pathogenic species or freeliving nematodes, a high parasitic load was detected. Thus, monitoring the health of over the 400 red and fallow deer that live in Bradgate Park will be necessary to control the potential risk of infections to humans, livestock/other wild animals and dogs. This monitoring should be done long-term and environmental influential factors, such as physicochemical and soil properties, should be taken into consideration, to appropriately interpret the potential public risk.