Interactions and epidemiology of nematode worm control in livestock

Abstract

The livestock industry relies heavily upon anthelmintics for the treatment of parasitic nematode diseases. This has resulted in widespread resistance to multiple anthelmintic classes across several parasitic genera. In response to this spread in resistance and subsequent decrease in efficacy there has been increased interest in the use of combined treatment. It is hoped that this combined treatment approach will reduce resistance and increase overall efficacy. However there is little known on how treatments interact with one another and how this impacts implementation. The systematic review (chapter 1) shows a distinct lack of knowledge into large livestock species such as the equines and bovines. Certain combinations such as anthelmintic and plants have a small body of research with conflicting information on how the treatments interact with one another. The current research shows the interaction between anthelmintic and plants to be positive for gastro-intestinal nematodes (chapter 2) and negative for ascarids (chapter 3), specifically Parascaris equorum. The direct impact between treatments has also been investigated, with a negative direct interaction being found between condensed tannins and Duddingtonia flagrans (chapter 4). The GLOWORM-FL model was adapted to predict the larval burdens for plant and D. flagrans in various European regions (chapter 5), this study found there to be clear differences in how combined treatments are targeted which can change dependent on both geographical region and temporally dependent on abiotic factors. The current body of work tries to determine interaction between nematode control but relies heavily on in vitro experimentation. These results may not transfer directly to in vivo field trials of these interactions. There is clear evidence that the treatment interactions need to be considered and optimum application may change dependent on region, time of year and presence or absence of interaction.

Date of Award	Jul 2022
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Northern Ireland Department for the Economy
Supervisor	Nikki Marks (Supervisor) & Eric Morgan (Supervisor)