Is it feasible to test if liver fluke (Fasciola hepatica) is associated with increased risk of verocytotoxin producing Escherichia coli O157 from an existing study?

Abstract

The liver fluke parasite, Fasciola hepatica, is a major cause of economic loss to cattle industries worldwide. Cattle are also the principle reservoir of Verocytotoxigenic Escherichia coli O157 (VTEC O157), an important cause of disease in humans. It is hypothesised that F. hepatica, which is known to suppress type 1 immune responses and induce an anti-inflammatory or regulatory immune environment in the host, may promote colonisation of the bovine intestine with VTEC O157. However, there has been little empirical research on the interaction between F. hepatica and VTEC O157 and the collection of suitable samples from representative field surveys is expensive. We assessed whether it would be statistically feasible to augment a planned study - to quantify the prevalence of VTEC O157 in cattle in Great Britain - with additional testing of samples for liver fluke, as a pilot study to test this hypothesis.