This study was carried out to determine the prevalence of rumen flukes on German cattle farms via the sedimentation technique, and to identify the rumen fluke species occurring in Germany. Additionally, the prevalence of patent Fasciola hepatica infections was determined. Furthermore, a short questionnaire was answered by the farmers. A prevalence of 5.5% and 9.5% was detected for rumen flukes and liver flukes, respectively. Coinfections occurred on 2.1% of farms. In northern Germany, the rumen fluke prevalence was higher than in southern Germany, while for liver fluke the distribution was reversed. Rumen flukes were mostly identified as Calicophoron daubneyi, but in four cases, sequencing revealed Paramphistomum leydeni for the first time in Germany. Grazing and feeding of fresh grass, as well as organic farming, were significantly associated with rumen and liver fluke occurrence. In contrast, suckler cow husbandry only had an influence on the occurrence of rumen flukes, but not liver flukes. Trematode eggs could be detected in both, farms with and without deworming. Since there were only a few studies about Paramphistomidosis in Germany, more attention should be paid to these parasitic diseases for animal welfare and animal health reasons.

Paramphistomidosis has recently been identified as an emerging parasitosis in Europe. This study estimated the prevalence of rumen flukes, Fasciola hepatica and Dicrocoelium dendriticum, in small ruminants in Germany and identified occurring rumen fluke species and potential predictors for fluke infections. Pooled fecal samples from 223 sheep farms and 143 goat farms in northern and southern Germany were examined by the sedimentation technique, and molecular species identification was performed on rumen-fluke-positive samples. In sheep, a flock prevalence of 2.2% was detected for rumen flukes. Calicophoron daubneyi was identified on four of five positive farms, while species identification failed in one flock. No rumen fluke eggs were detected in the examined goat herds. F. hepatica eggs were detected in 2.7% of the sheep flocks, while the herd prevalence was 5.6% in goats. Higher prevalence values of 21.1% (sheep) and 7.0% (goats) were observed for D. dendriticum. Mixed grazing with other ruminants and previously identified infections with rumen flukes and/or F. hepatica were identified as predictors for paramphistomidosis. The distribution of the three trematode species followed a geographical pattern associated with conditions favoring the relevant intermediate hosts. C. daubneyi is an established parasite in German sheep at a currently low prevalence.

Die Paramphistomidose ist eine weltweit auftretende parasitäre Erkrankung bei diversen Wiederkäuern, ausgelöst durch verschiedene Pansenegelarten (u. a. Paramphistomum cervi, Calicophoron daubneyi und Paramphistomum leydeni). In Europa sind lokale Vorkommen von Pansenegelinfektionen bei Haus- und Wildwiederkäuern seit Jahrzehnten beschrieben. Mittlerweile gibt es Hinweise, dass die Paramphistomidose an Bedeutung gewinnt, denn in Großbritannien, Irland, Frankreich, Spanien, Belgien und den Niederlanden wurden teilweise hohe Prävalenzen festgestellt. Aktuelle Prävalenzdaten aus Deutschland liegen nicht vor. In neueren Untersuchungen in Norddeutschland, Hessen und Bayern konnte Calicophoron daubneyi, die auch in Europa aktuell am häufigsten vorkommende Pansenegelart, nachgewiesen werden. Die Entwicklung des Pansenegels ist an Zwischenwirte aus der Familie der Wasserlungenschnecken gebunden. Calicophoron daubneyi und der Große Leberegel Fasciola hepatica teilen im Laufe ihrer Entwicklung den gleichen Zwischenwirt, die Zwergschlammschnecke Galba truncatula. Der Endwirt nimmt die infektiösen Metazerkarien auf. Im Dünndarm schlüpfen die jungen Pansenegel und heften sich im Duodenum an. Danach wandern sie in den Pansen ein, wo sie als Adulte anfangen, Eier auszuscheiden. Die Infektion kann während der intestinalen Phase zu schwerem Durchfall und bei hoher Befallsintensität zum Tod führen. Die ruminale Paramphistomidose verläuft in den meisten Fällen subklinisch. Aktuell steht zur Diagnostik der koproskopische Einachweis mittels Sedimentationsverfahren zur Verfügung. Aufgrund der Ähnlichkeit besteht die Gefahr der Verwechslung mit Eiern des Großen Leberegels. Die Paramphistomidose kann mit Oxyclozanid behandelt werden. Über die Wirksamkeit anderer Wirkstoffe liegen widersprüchliche Ergebnisse vor. Umso wichtiger erscheint die Prophylaxe dieser Parasitose. Bekämpfungsvorschläge richten sich aufgrund der ähnlichen Epidemiologie nach den Empfehlungen, die zur Vorbeugung der Fasziolose abgegeben werden. Ob es sich bei der Paramphistomidose auch in Deutschland um eine sich ausbreitende Infektionskrankheit handelt, kann aktuell noch nicht beurteilt werden. Paramphistosis is a globally occurring parasitic disease in various ruminants caused by a range of rumen flukes (including Paramphistomum cervi, Calicophoron daubneyi and Paramphistomum leydeni). In Europe, local occurrences of rumen fluke infection in domestic and wild ruminants have been described for decades. There is now evidence that paramphistomidosis is gaining in importance, because high prevalence rates were reported in the United Kingdom, Ireland, France, Spain, Belgium and The Netherlands. Current prevalence data from Germany are lacking. In recent investigations in northern Germany, Hesse and Bavaria, C. daubneyi was detected, which is currently the most prevalent rumen fluke in Europe. The development of therumen fluke is linked to aquatic snails as intermediate hosts. C. daubneyi and the liver fluke Fasciola hepatica share in the course of their development the same intermediate snail host, Galba truncatula. The definitive ruminant host takes up infective metacercaria. In the small intestine, the young flukes excyst and attach to the duodenum. Subsequently, they migrate to the rumen, where, as adults, they begin to release eggs. The infection can lead to severe diarrhea during the intestinal phase and death at high infection intensity. Ruminal paramphistomidosis is subclinical in most cases. Currently, coproscopic detection by the sedimentation method is the available diagnostic tool. Because of similar morphology, there is a risk of confusion with the eggs of the liver fluke F. hepatica. Paramphistomidosis can be treated with oxyclozanide. There are conflicting results regarding the effectiveness of other drugs. Therefore, prophylaxis of this parasitosis is important. Because of the similar epidemiology, control recommendations are based on those for the prevention of fasciolosis. Whether paramphistomidosis is also an emerging infectious disease in Germany cannot be currently assessed.

The complex life cycle of the rumen fluke Calicophoron daubneyi is similar to that of the liver fluke Fasciola hepatica. Interestingly, C. daubneyi and F. hepatica share the same intermediate host, Galba truncatula. However, in contrast to its relative, experimental production of metacercariae is a major challenge for C. daubneyi, hampering a detailed analysis of its life cycle, especially in the definitive host. G. truncatula snails collected from natural habitats were bred in glass Petri dishes and fed dried organic lettuce leaves. C. daubneyi eggs were obtained from feces of naturally infected cattle and incubated until miracidia were hatching. Subsequently, these miracidia were allowed to infect snails, which were kept under specific laboratory conditions to monitor the shedding of metacercariae. In total, 177 G. truncatula snails were exposed to C. daubneyi miracidia during eleven snail infection trials. Sixty-eight of these snails survived for longer than 30 days post-infection (p.i.). From day 35 p.i., seven snails from five trials started shedding an average number of 106 metacercariae (range: 38-186) per snail. Three ewe lambs (aged 7-10 months) were inoculated orally with 150 metacercariae each. A different batch of metacercariae (obtained from three different snail trials) was used for each lamb. Another two lambs served as controls. All animals were regularly examined clinically, hematologically and coproscopically, using sedimentation techniques for the detection of trematode eggs. Low numbers of C. daubneyi eggs were detected in fecal samples of two of the three inoculated lambs on day 86 post-inoculation (yielding ≤ 2 epg), but only one lamb continued to shed eggs (up to 6 epg) until the end of the experiment (day 104 post-inoculation). None of the animals showed any abnormal clinical findings or blood parameters throughout the course of the study. Production of C. daubneyi metacercariae under laboratory conditions is reported, followed by experimental infection of the definitive host, thus completing the full life cycle of this parasite under experimental conditions. However, neither the survival rate of the snails nor the amount of metacercariae produced were comparable to previously published experiments using F. hepatica, necessitating further optimization of the laboratory protocols. Nevertheless, the results can serve as a starting point for more in-depth studies of this increasingly important trematode.

The infection of cattle with the rumen fluke Calicophoron daubneyi has been detected with increasing frequency in Europe in recent decades. The question of the importance of this parasitic infection for milk production has come to the fore. While the influence on beef cattle has already been investigated in a few studies with contradictory results, there is hardly any knowledge about an influence on milk yield and fertility. Therefore, in a case control field study, we aimed to determine the monthly excretion of C. daubneyi eggs in the feces of dual-purpose dairy cows on two farms in southern Germany over a period of one year, and to compare milk yield and fertility parameters between infected and non-infected cows within the herds. For this purpose, the cows were divided into groups depending on egg excretion (1 = negative; 2 = rumen fluke-positive; 3 = rumen fluke- and liver fluke-positive). To be able to investigate seasonal influences, the data was analysed in three time-intervals (entire study period, summer half-year, winter half-year). A total of 117 cows from the two farms were examined in this study. The in-herd-prevalence for rumen fluke was 57.0 % and 64.0 %, respectively. The median egg excretion was low in both farms (< 6 epg), the maximum excretion reached 92.3 epg. Cows coinfected with F. hepatica showed the highest rumen fluke egg excretion rate. Calicophoron daubneyi infection had no significant effect on milk production parameters (milk yield, milk fat, milk protein, and somatic cell count). Remarkably, all infected cows showed higher values of milk fat content than non-infected cows. The metabolic parameter β-hydroxybutyrate (BHB), determined using Fourier-transform mid-infrared (FT-MIR) spectroscopy, was within the normal range on both farms and did not differ between infected and uninfected cows. The fertility parameters (CTFS - calving to first service, CIV - calving interval, SFI - success in first insemination, and 56-NRR - 56-day non-return rate) tended to be worse in C. daubneyi infected cows but without significant difference to non-infected cows. No influence on the consistency of feces was observed in rumen fluke-infected cows. In summary, this study showed that low-level infections with C. daubneyi had no influence on milk yield or metabolic status in dual-purpose dairy cows, while C. daubneyi infected cows tended to perform unfavourable in some parameters compared to uninfected cows.

Water buffalo are ideal for grazing in restored wetlands due to their anatomical and behavioural adaptations. Unlike cattle or sheep, the water buffalo thrive in such habitats, feeding on rushes and reeds while helping maintain open landscapes. However, these moist environments also harbor risks, particularly parasitic infections by liver flukes ( Fasciola hepatica ) and the recently widespread rumen flukes, which require aquatic snails as intermediate hosts. For the present study faecal samples were taken once a year from 2016 to 2024 and monthly in two 12-month periods (2019/20 and 2022/23) from a water buffalo herd established in 2014 on a southern German farm and examined for fluke eggs with a sedimentation technique. In addition, climate data were obtained from a nearby weather station to analyse the impact of rainfall and sunshine hours on the fluke prevalence. To test whether blood samples can be used to detect infection with F. hepatica , residual quantities of blood samples from disease surveillance were tested for F. hepatica antibodies using a commercially available ELISA test. Copromicroscopical results showed that fluke prevalence rose significantly within a few years, with F. hepatica prevalence being always higher than C. daubneyi prevalence. Co-infections were common and seasonal patterns inconsistent. Fluke prevalence increased with rainfall and sunshine hours. In the herd, older water buffalo were more prone to liver flukes. The ELISA test for fascioliasis failed even though F. hepatica eggs were present in the faeces. The findings of the study highlight that extensively reared water buffalo are at high risk of trematode infection, which spreads rapidly throughout the herd and reaches high prevalence rates. The specific wallowing behaviour of water buffalo and favourable climatic conditions for parasite development may contribute to this development.