Spatial patterns of Fasciola hepatica and Calicophoron daubneyi infections in ruminants in Ireland and modelling of C. daubneyi infection

Amalia Naranjo-Lucena,Annetta Zintl,Mícheál Casey,Grace Mulcahy,María Pía Munita Corbalán,Guy Mcgrath,Riona Sayers,Ana María Martínez-Ibeas,Barbara Good,Gerard Murray

doi:10.1186/s13071-018-3114-z

Amalia Naranjo-Lucena, Annetta Zintl + Show 8 more

Open Access

https://doi.org/10.1186/s13071-018-3114-z

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Abstract

BackgroundFasciola hepatica has always represented a threat to Irish livestock because the Irish climate is highly suitable for the main local intermediate host of the parasite, the snail Galba truncatula. The recent clinical emergence of infections due to Calicophoron daubneyi has raised the question of whether the two parasites, which share a niche during part of their life-cycles, interact in some way. Here, we used geographical information systems (GIS) to analyse the distribution of both parasites in cattle and sheep. We also developed the first predictive model of paramphistomosis in Ireland.ResultsOur results indicated that, in cattle, liver fluke infection is less common than rumen fluke infection and does not exhibit the same seasonal fluctuations. Overall, we found that cattle had a higher likelihood of being infected with rumen fluke than sheep (OR = 3.134, P < 0.01). In addition, infection with one parasite increased the odds of infection with the other in both host species. Rumen fluke in cattle showed the highest spatial density of infection. Environmental variables such as soil drainage, land cover and habitat appeared to be the most important risk factors for C. daubneyi infection, followed by rainfall and vegetation. Overall the risk of infection with this parasite was predicted to be higher in the west of the country.ConclusionsThis study shows differences between the infection rates and spatial patterns of bovine and ovine infections with F. hepatica and C. daubneyi in Ireland. Whether the reasons for this are due to susceptibility, exposure and/or management factors is yet to be determined. Furthermore, the rumen fluke model indicates distinct risk factors and predicted distribution to those of F. hepatica, suggesting potential biological differences between both parasite species.

Highlights

Fasciola hepatica has always represented a threat to Irish livestock because the Irish climate is highly suitable for the main local intermediate host of the parasite, the snail Galba truncatula
At any given time of year, rumen fluke infection was more common in cattle than in sheep and generally more frequent than liver fluke infection
The frequency of co-infection with both parasites was similar in cattle and sheep (≤ 10%), and the seasonal pattern resembled that of the liver fluke in each host species

Summary

Introduction

Fasciola hepatica has always represented a threat to Irish livestock because the Irish climate is highly suitable for the main local intermediate host of the parasite, the snail Galba truncatula. The helminth parasite Fasciola hepatica (the liver fluke) is the causative agent of fasciolosis, which is of high economic importance in ruminants. Fasciolosis causes annual losses estimated at around €2.5 billion to livestock and food industries worldwide and losses of about €90 million every year in Ireland [1]. Increasing prevalence of the rumen fluke, Calicophoron daubneyi, and sporadic clinical cases of paramphistomosis have been reported since the late 2000s in Ireland and the UK [6,7,8,9,10,11], leading to the suggestion that C. daubneyi is the dominant rumen fluke species in Europe [12,13,14,15,16] with significant clinical importance in ruminants in Europe [17]. Even heavy infections with adult rumen flukes are generally benign

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