Fascioloides

Abstract: Lymnaeid snails of the genus Radix serve as intermediate hosts of some schistosomes and fasciolids. In Europe, delineation of species within the genus Radix is unresolved and, therefore, spectrum of snail hosts susceptible to trematode infections is under discussion. We used and compared three criteria for species delineation using snails collected at 43 localities. (a) Sequence analysis of ITS-2 rDNA disclosed that the collected snails belong to four species — R. auricularia (Linnaeus, 1758), R. peregra (Muller, 1774), R. lagotis (Schrank, 1803) and R. labiata (Rossmaessler, 1835) (criteria and names are based on the work of Bargues et al. 2001). Occurrence of R. peregra in the Czech Republic was confirmed by molecular data for the first time. (b) Characterization of reproductive system disclosed differences in location, size and shape of bursa copulatrix and its ductus. Unfortunately, some R. labiata specimens shared morphological features of reproductive organs with R. lagotis. (c) Statistical analysis of shell morphology proved that significant differences exist among particular species. One prediction model showed that correct classification of species may be achieved in 82-84% of cases. However, identification of individual snails in the field (without knowledge of respective snail population and use of statistical tools) still remains a complicated issue due to overlaps of shell characteristics. Concerning the role in trematode transmission, R. lagotis, R. labiata and R. peregra are susceptible to Trichobilharzia regenti. Also, successful experimental infections of R. lagotis and R. labiata by Fascioloides magna were accomplished.

Abstract: Fascioloides magna,the giant liver fluke, is an introduced parasite imported to Europe with infected game which is endemic in the Austrian wetlands of the Danube from Vienna to the Slovakian border. Due to its pathogenicity (especially in roe deer) and its potential of transmission to domestic ruminants a project on the epidemiology and control of this parasite was carried out between 2000 and 2005. To assess distribution faecal droppings from red deer were collected in an area along the Danube and livers of red and roe deer shot or found dead were examined. Simultaneously, triclabendazole-medicated feed was offered repeatedly in several areas of known fluke presence from 2001. The average prevalence of infection as demonstrated by Fascioloides eggs in droppings (n = 145) was 6.3%, with > 50% in some areas. Infection rates decreased from 11.3% (01/2001) to 1.5% (04/2002) in the whole area. In Fischamend, a highly endemic area, prevalences in monthly samples (n = 25) decreased from 70% (01/2001) to less than 1% (01/2005). Similarly, the number of eggs per gram of faeces was significantly reduced. Of 457 red deer livers 15.8% were positive. In the Fischamend area, a reduction of positive livers was also found (2000:100%; 2005:13%), as well as a reduction of the numbers of flukes/liver. Control of F. magna in the Danubian wetlands by anthelmintic treatment proved to be successful although eradication was not achieved.

Abstract: After initial observations of suspicious cases in 2009, the occurrence of Fascioloides (F.) magna in deer of a deer farm located in northeastern Bavaria, Germany, at the border to the Czech Republic was confirmed in autumn 2011. In March 2012, the deer were treated for fascioloidosis with triclabendazole. To monitor the epizootiology of fascioloidosis in the farm, 80-100 faecal samples were examined for Fascioloides eggs at monthly intervals from June 2012 to June 2013 inclusive. In addition, livers of 27 red deer and one sika deer collected during winter 2012/2013 were examined for gross lesions suspicious for F. magna infection and 21 of the 28 livers were dissected for F. magna recovery. Fascioloides eggs were recorded in 63 (4.9%) of 1280 faecal samples (range 0.4 to 355 eggs per gram). Both, number of Fascioloides-egg positive samples and egg counts were low during the first eight months of the study but increased notably since February 2013. While Fascioloides egg-positive faecal samples were obtained from red deer (46/948,4.9%) and fallow deer (17/166, 10.2%), no Fascioloides eggs were demonstrated in the 166 samples obtained from sika deer. Livers of five red deer and the sika deer showed gross lesions characteristic for fascioloidosis, and F. magna were recovered from three of the five affected red deer livers (range, five to seven flukes). Results of this study confirm that F. magna is endemic in the deer farm, and measures should be implemented to minimize the transmission of the parasite.