Interactions in vitro between plant secondary metabolites and benzimidazoles on the egg development of Parascaris equorum.

The livestock sectors are under intense pressure from parasitic nematode infections. These include the gastrointestinal nematodes, lungworm and ascarids. A particularly harmful species to young foals is Parascaris equorum. This species of nematode has been traditionally treated with anthelmintic. Recently resistance has arisen to this treatment and the investigation of alternatives has begun. One such alternative is the plant secondary metabolite, tannin. It is unclear how tannin and benzimidazole interact in the same system as each other for the nematode species such as P. equorum. The egg development plates used in the current study aims to investigate this interaction at different development stages of P. equorum eggs, utilising thiabendazole, sainfoin and wormwood as treatments. The presence of plants increased mortality in the egg stage but more eggs still larvated. When combined with anthelmintic sainfoin saw increased mortality but eggs where still able to reach full larvation. Wormwood combination had a lower level of mortality, but no eggs reached larvation. The current study indicates a difference in interaction between plants and thiabendazole combinations. This is a promising start, but further work should include field trials within horses. This would allow the analysis of tannin structures present in natural faeces and could also shed light on the internal cycle of P. equorum, and how combination impacts metabolic uptake in the horse alongside the migratory and adult stages.