Geographical distribution of the giant liver fluke (Fascioloides magna) in the Czech Republic and potential risk of its further spread

Abstract

  The giant liver fluke, Fascioloides magna, is of interest to wild-life managers, veterinarians and researchers, due to its unusual body size (3–10 cm), high pathogenic potential and because it is continuously spreading to new areas, especially in Europe. Annually, the number of cases of animal infections (mainly cervids and bovids) caused by this fluke is monitored in many European countries, including the Czech Republic (with some foci of prevalence over 90%). During the years 2009 and 2010, 1622 survey forms focused on monitoring of fascioloidosis were distributed in the community of “Czech Inspectors of Hunted Game” (CIHG), and 21.3% of forms containing positive or negative response about F. magna occurrence were returned. The administrative units monitored by particular CIHG, who answered the forms, were geographically equally distributed and therefore we believe that also the recorded distribution of F. magna in wild-life animals reflects the real situation in the Czech Republic. A significant number of cases of F. magna infection were repeatedly reported from areas in the south-west part of the Czech Republic. Moreover, our report contains also some unique records of several new F. magna foci in the western (close to the German border), northern (close to the Polish border) and central parts of the Czech Republic, supporting the assumption that the parasite is spreading further throughout Europe. In five game administrative units F. magna infection was directly confirmed by examination of dissected deer livers or by microscopic examination of coprological samples, followed by isolation of DNA from adults and eggs and further molecular analyses. Fascioloides magna intermediate host snails (Galba truncatula and Radix spp.) were collected during 2009 and 2010 from different localities of the Czech Republic, kept in aquaria, examined for shedding of F. magna cercariae, dissected and parasite/snail DNA was isolated. After PCR with specific primers for parasite/snail internal transcribed region number two (ITS-2) the obtained sequences confirmed identification of the following species: F. magna, G. truncatula, R. peregra, R. lagotis, R. labiata and R. auricularia. Although it has been demonstrated that the number of areas with positive cases of fascioloidosis is still growing, the risk of pathogenic impact of F. magna on populations of free-living animals and farming cervids/bovids is generally underestimated.

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

“…Molecular studies have shown that the Czech fluke haplotype is convergent with that found in other Danube countries, suggesting the parasite was transported from the Czech Republic to Hungary, Austria, and Croatia (9,20). Further studies in the Czech Republic have shown the spread of F. magna foci not only in the south-western parts of the country but also in the west, near the German border and in the north, near the Polish border (7). Recent molecular research on giant liver fluke specimens from southwestern Poland based on mitochondrial markers (cox1 and nad1) revealed the genetic uniformity of F. magna specimens from Poland with certain specimens from a Czech natural focus (8).…”

“…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).…”

AN EXPANDING POPULATION OF THE GIANT LIVER FLUKE (FASCIOLOIDES MAGNA) IN ELK (CERVUS CANADENSIS) AND OTHER UNGULATES IN CANADA

“…Within 10 yr, extensive fluke-related mortality of elk occurred and outbreaks continue (Balbo et al 1987). Molecular evaluation confirmed multiple introductions of F. magna into Europe from translocated elk and white-tailed deer (Odocoileus virginianus) (Kralova-Hromadova et al 2011), and the distribution continues to expand (Novobilský et al 2007;Rajkovic-Janje et al 2008;Kasny et al 2012). …”

“…Giant liver flukes apparently contribute to mortality of heavily infected individuals (Kermode 1916;Fenstermacher and Olsen 1942;Cheatum 1951;Murray et al 2006) and are a serious concern for wildlife managers in North America (Pybus 2001) and Europe (Kasny et al 2012). We examined the interplay of giant liver fluke among sympatric, free-ranging ungulates in various habitats within Banff and Kootenay national parks in the Rocky Mountains of AB and BC (Fig.…”

The role of hepatic myofibroblasts in liver cirrhosis in fallow deer (Dama dama) naturally infected with giant liver fluke (Fascioloides magna)

“…The finding of this parasite in the fallow deer population represents a threat as the giant liver fluke could spread to domestic ruminants which reside in close proximity to hunting grounds [1,4,5,7-9]. …”