Life history and biology of Fascioloides magna (Trematoda) and its native and exotic hosts

Abstract

Host–parasite interactions are model systems in a wide range of ecological and evolutionary fields and may be utilized for testing numerous theories and hypotheses in terms of both applied and fundamental research. For instance, they are important in terms of studying coevolutionary arms races, species invasions, and in economic terms the health of livestock and humans. Here, I present a comprehensive description of the life history, biogeography, and biology of the giant liver fluke, Fascioloides magna, and both its intermediate and definitive hosts. F. magna is native to North America where it uses several species of freshwater snails (Lymnaeidae) as intermediate hosts and four main species of ungulates as definitive hosts. The fluke has also been introduced into parts of Europe where it is now established in two lymnaeid snail species and three ungulate species. This study gives a comprehensive description of different developmental stages of the fluke in its two host classes, as well as detailed notes on historical and present distributions of F. magna in North America and Europe as well as in its snail and deer hosts (with range maps provided). Aberrant and dead-end hosts are also discussed in detail, and descriptive phylogenies are provided for all of the organisms. I briefly discuss how F. magna represents a model example of multiple-level ecological fitting, a phenomenon not yet described in the empirical literature. Lastly, I explore possible future scenarios for fluke invasion in Europe, where it is currently expanding its range.

Morphology and molecular study of Fascioloides magna – a growing threat to cervids (Cervidae) in Poland

“…Therefore, the authors of this study decided to use a molecular method to differentiate these two flukes. Environmental factors play a key role in the prevalence and intensity of the fluke infection (23) and are more important in its development than the density of the animal population (12). On the one hand, the most dangerous areas for wild game are floodplain and swamp habitats since infections are usually limited to these territories.…”

“…There has been an increase in the number of infections by this parasite in Central Europe in recent years. The giant liver fluke has established three permanent natural foci: La Mandria Regional Park in northern Italy, the Danube floodplain forests, including Austria, Slovakia, Hungary, Croatia, and Serbia, and lastly the Czech Republic and southwestern Poland (7,11,12,15,18,22). F. magna was first noted in red deer in Poland by Salomon in 1932 (19), followed by Ślusarski in 1953 (21).…”

Complete mitochondrial genome of the giant liver fluke Fascioloides magna (Digenea: Fasciolidae) and its comparison with selected trematodes

“…Fascioloides magna , known as the large American liver fluke, giant liver fluke or deer fluke, is an important digenetic trematode of the family Fasciolidae [ 3 , 4 ]. This species, which is of North America origin [ 5 , 6 ] and invasive in European countries [ 7 ], has high potential to colonize new geographic territories (a variety of wild and domestic ungulates [ 3 , 8 – 10 ]), and can establish expanding populations from a natural epidemic focus through translocated hosts [ 5 , 6 , 11 ]. Migration of F. magna immature flukes within the host body often leads to profound damage to the liver and other organ tissues [ 8 , 12 ], causing economic losses worldwide [ 13 ].…”

The spreading of parasites by human migratory activities

“…Probably proboscideans brought a fasciolid with them to the Nearctic in prehistoric times, where the parasite evolved into F. magna after adapting to cervids following the extinction of proboscideans in North America [53]. Fascioloides magna was at least twice introduced into Europe with imported game animals [55]. The parasite was introduced with wapiti (Cervus canadensis) brought from original habitats in North America to Italy in the nineteenth century and to Bohemia at the beginning of the twentieth century.…”