Wherefrom and whereabouts of an alien: the American liver fluke Fascioloides magna in Austria: an overview.

Helmut Sattmann,Anna Sophia Feix,Larissa Gaub,Heinrich Prosl,Michaela Haider,Wolfgang Rabitsch,Christoph Hörweg,Julia Walochnik

doi:10.1007/s00508-014-0499-3

Abstract

SummaryThe giant liver fluke Fascioloides magna, an invasive species originating from North America, was recorded in Austria in the wild for the first time in 2000. Since then, various data concerning the epidemiology in snail intermediate hosts and cervid final hosts have been reported. Galba truncatula acts as snail intermediate host, and red deer, roe deer and fallow deer act as final hosts. G. truncatula is abundant throughout the region, especially along muddy shores of slow-flowing branches of the river system. Prevalence in deer (20–100 %) is much higher than in snails (0.03–0.2 %). Despite medical treatment of parts of the deer population, the parasite has successfully established itself on both sides of the Danube floodplain environments southeast of Vienna. Genetic analysis revealed that the infection of Austrian deer populations apparently originated from foci in the Czech Republic or from populations of Danube tributaries. Areas adjacent southwards, which will soon be joined through wildlife crossings, have not yet evidenced F. magna. Nonetheless, these environments are inhabited by host snails and deer and therefore constitute suitable habitats for F. magna. Invading alien parasites not only threaten native individual hosts but also influence host populations, thus potentially also modifying parasite communities and interactions. The host range of F. magna includes a variety of potential hosts, notably other Lymnaeidae as potential intermediate hosts and various ungulates, including sheep and cattle, as final hosts. Because eradication after medical treatment was unsuccessful, and due to the risk of further spread of the parasite into unaffected regions, enhanced control strategies need to be developed. We recommend assessment of introduction pathways and dispersal, continuous monitoring of host abundance and distribution and the prevalence of flukes in intermediate and final hosts, as well as coordinated and concerted actions with neighbouring countries. This strategy could help to reduce potential negative impacts of this and other invasive parasites on host populations in Europe.

Highlights

The giant liver fluke Fascioloides magna (Bassi 1875) is a parasite in the liver of ungulates, preferentially cervids
Infection of final hosts occurs via ingestion of metacercariae, similar as in the European common liver fluke Fasciola hepatica (L) [1, 2] (life cycle, main hosts and larval stages see (Fig. 1, 2, 3, 4 and 5)
F. magna was discovered and first described in Italy by Bassi [6], and it was only later determined that this species originates from North America [7, 8]

Summary

Introduction

The giant liver fluke Fascioloides magna (Bassi 1875) is a parasite in the liver of ungulates, preferentially cervids. F. magna proved to be moderately to severely pathogenic, depending on intensity of infection and host species [3,4,5]. The native distribution range of F. magna is North America [5]. F. magna was discovered and first described in Italy by Bassi [6], and it was only later determined that this species originates from North America [7, 8]. The dispersal downstream of the Danube River seems to originate from well-established and stable populations in the Czech Republic, repeated introductions via introduced and infected hosts must be assumed [24]. Several studies have described the epidemiology, pathology and ecological hot spots of infection of this Austrian population

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