A Surfeit of Snails

A Surfeit of Snails

News from the SAC: A Surfeit of Snails

Galba truncatula appear to be thriving this Spring.  Should we be worried?  Who knows what our changing climate will throw at us next.  To quote the Met.office perhaps we should considered this a yellow “Be Aware” warning.  These snails have massive reproductive potential and will happily survive through any dry spell to re-emerge when wet conditions return.  Large numbers of snails will make it easier for larvae hatching from Fasciola hepatica eggs to successfully locate one of these snails.

The Met. Office have confirmed that winter rainfall in both the Scotland West and England NW/N Wales regions was the highest since records began, with temperatures of 4.46 and 5.81°C.  Local records from SRUC’s Crichton Royal farm show that there were 19 days in November and 20 in December when the maximum temperature exceeded 10°C.  Nevertheless, at these temperatures, any development of F. hepatica stages outwith the final host (the suprapopulation) should be extremely slow, if it happens at all.

Nothing can be done about the overwintered F. hepatica suprapopulation.  As we move towards late spring/early summer, and the temperatures increase, focus must move to reducing the numbers of F. hepatica eggs being deposited.  This is particularly important on holdings where triclabendazole inefficacy has been confirmed.  Summer infection of snails is key as it leads to the autumn peak of larvae on pasture.  The following should be considered before deciding if and when any treatment is required:

  • When were stock last treated?
  • What product was used?
  • How have they been managed since and is reinfection likely?

The numbers of overwintered larvae will continue to fall due to ingestion, trampling and natural mortality.  If it is not clear whether treatment is required monitor faeces for coproantigen or fluke eggs.

Related SEV Branch