The dynamics of gastrointestinal nematodes present in grazing animals kept in a Scottish zoological collection.

Abstract
Aims: Grazing animal species kept in zoological collections can be at risk of significant gastrointestinal nematodes (GIN) infections, due to life-cycle maintenance in confined grazing areas and proximity to other susceptible hosts. Yet little work has been undertaken to understand the GIN species dynamic within co-grazed host-species. This pilot study aimed to describe the species diversity of nematode species found in faeces of grazing animals in a Scottish zoological collection.
Methods: At a single time-point, fresh faecal samples were collected randomly from the ground of the studied animals’ enclosures including horses, sheep, alpacas, deer, and tapirs. The presence of nematode eggs was detected and quantified using a saturated saline centrifugal flotation cuvette technique. The nematode species profile was estimated using deep-amplicon sequencing.
Results: There was a 95% prevalence of gastrointestinal nematode infection. Magnitude in faecal worm egg counts varied between individual host-species (p<0.01). Apart from goats who had an egg count of 460epg, all other animal groups had egg counts < 200epg. There was various gastrointestinal parasite species found across the hosts including the potentially pathogenic species Haemonchus contortus.
Conclusion: The variation in egg counts and parasite species across the studied animals suggest how different host species and management factors could influence transmission. A high prevalence of gastrointestinal parasites was found across host-species. In particular, the increased egg count found in goats and the presence of potential pathogenic species (H. contortus) indicates the importance of regularly monitoring levels of parasitic infections in zoological collections to influence approaches to preventative and sustainable control methods.