A model for the dynamics of the free-living stages of equine cyathostomins.

摘要: Anthelmintic resistance in strongyle nematode parasites of horses is an expanding global problem and steps need to be taken slow its development before control becomes more problematic. A move away from traditional deworming programmes, involving frequent whole-herd treatments with broad spectrum anthelmintics, a strategic or targeted use chemicals required. However, anthelmintic management strategies which also maintain effective are invariably complicated often require greater understanding both epidemiology grazing management, than does the simple routine chemicals. Here, as first step applying modelling approach horses, model proposed describe dynamics on pasture free-living stages equine cyathostomins. Firstly, survival pre-infective considered single process driven by temperature, secondly, two populations infective stage larvae (L3) considered; those within faecal pat herbage. Both modelled using box-car train allows for variable rates cohort individuals full overlap generations. Uniquely, L3 ageing where progress through physiological age classes at rate determined temperature rainfall. Model output reflects under range environments. Under extreme cold, there no but eggs can survive long periods develop if conditions become favourable, while reduced repeated freeze-thaw cycles. tropical conditions, rapid large number produced short. In temperate climates tends slower, numbers over warmer months fewer winter, higher all year round. Although attempts validate against field studies were compromised lack published detail inability access specific weather records, outputs averaged multiple sets data was appropriate that location. Variation when started different days same week suggests day-to-day differences may affect developing optimisation minimise infectivity detailed effects previously thought.