First record of chronic Fascioloides magna infection in roe deer (Capreolus capreolus)

Molecular uncovering of important helminth species in wild ruminants in the Czech Republic

Monitoring gastrointestinal helminth infections in wild ruminants poses significant challenges for managing wildlife health, particularly regarding invasive species. Traditional coprological methods are often limited by their labor-intensive nature and potential for erroneous identification due to morphological similarities among parasite species. This study employed advanced molecular techniques to assess the prevalence and distribution of several helminth taxa, including the invasive nematode Ashworthius sidemi and the trematode Fascioloides magna, in wild ruminant populations in the Czech Republic (CR). A comprehensive and extensive survey on parasite occurrence, unique in its nationwide scope, was conducted on 983 fecal samples collected from red deer (Cervus elaphus), roe deer (Capreolus capreolus), fallow deer (Dama dama), and mouflon (Ovis musimon) across various regions of the CR. The samples were analyzed using multiplex real-time PCR assays specifically designed to detect the DNA of six helminth representatives: the nematodes A. sidemi and Haemonchus spp., as well as the trematodes F. magna, Dicrocoelium dendriticum, Fasciola hepatica, and Calicophoron daubneyi (and representatives of the family Paramphistomidae, respectively). These assays targeted regions of ribosomal DNA (rDNA) and were designed to exhibit high sensitivity and specificity, enabling accurate detection of helminth parasites directly in fecal samples. The molecular assays revealed that invasive nematode A. sidemi was the most prevalent helminth species, detected in 15.8% of all samples (155/983), with the highest infection rate observed in red deer at 30.7% (124/404). Haemonchus spp. were also frequently detected, identified in 14.9% of samples (146/983), particularly in roe deer, with a prevalence of 23.2% (86/371). Spatial analysis of these nematodes across various regions of the CR revealed the extensive distribution of both A. sidemi and Haemonchus spp. in nearly all regions. In contrast, trematode infections were less common, with F. magna and D. dendriticum each found in only 1.5% of samples (15/983). Members of the family Paramphistomidae were detected in 0.2% of the samples (2/983) and were confirmed through sequencing as C. daubneyi. The geographical distribution patterns identified in this study indicate potential hotspots for specific helminth species. These findings are critical for planning health management and conservation strategies to mitigate the impacts of helminth infections, especially in areas affected by invasive species.

Endoparasites of Red Deer (Cervus elaphus L.) and Roe Deer (Capreolus capreolus L.) in Serbian Hunting Grounds

In this study, parasitological examinations were conducted from 2019 to 2023. Fecal samples were collected from 289 wild ruminants (158 red deer and 131 roe deer) from hunting grounds in Vojvodina, which belong to the public company Vojvodinašume. Using qualitative and quantitative coprological diagnostic methods, the presence of protozoa (coccidia and Buxtonella sulcata), nematodes (gastrointestinal strongyles, Trichuris spp., Capillaria spp., Dictyocaulus spp., and Muellerius spp.), cestodes (Moniezia spp.), and trematodes (Fasciola hepatica, Fascioloides magna, Paramphistomum spp., and Dicrocoelium dendriticum) in the form of single and mixed infections were confirmed. Coproculture was used to identify the infective larvae of gastrointestinal strongyles. The total prevalence of endoparasitic infections in hunting ground 1 was 89.77% in red deer and 92.85% in roe deer, while in hunting ground 2, it was 72.97% in red deer and 85.96% in roe deer. Knowledge of the prevalence and assessment of the intensity of parasitic infections in wild ruminants is necessary for designing health protection programs in hunting grounds and planning control strategies, which are significant for this branch of hunting and public health.

Development of a qPCR Duplex Assay for simultaneous detection of Fascioloides magna and Galba truncatula in eDNA samples: Monitoring beyond boundaries

Parasites constitute a significant economic burden and highly impact environmental, public, and animal health. The emergence of many parasitic diseases is environmentally mediated and they share the same biogeography with humans and both domestic and wild animals. American liver fluke, Fascioloides magna - a trematode parasite of domestic and wild ungulates - is an example of the anthropogenic introduction of an "invasive alien species" in Italy and Europe. Multiple introductions to Europe have led to the biogeographical expansion of the parasite across the Danube region mainly provided by the presence of suitable habitats for all hosts involved in the parasite's life cycle, human-assisted transport, and drastic environmental events such as flooding. In Italy, it was introduced and established in La Mandria Regional Park (LMRP) near Turin in 1865 along with imported wapitis (Cervus elaphus canadensis) from North America (Bassi, 1875), but with no reported expansion to the surrounding areas. LMRP isolated F. magna focus, poses an important threat of possible expansion since the enclosed area is vulnerable to occasional bidirectional passage of roe deer. Additionally, tributary rivers to the Po river system, traversing the enclosed area, could further bolster the possibility of such spread. In this study, we developed a duplex qPCR assay for F. magna and its principal intermediate host Galba truncatula optimized for testing eDNA samples to meet the needs for surveillance of the parasite. Moreover, we validated the developed assay in natura by testing samples derived from filtered water and sediments collected inside and outside LMRP's fenced-off area. Our findings for the first time demonstrate the presence of F. magna's eDNA outside the park's internal fenced-off area.

First Molecular Data of Gongylonema pulchrum (Rhabditida: Gongylonematidae) in European Fallow Deer Dama dama from Romania

Due to its adaptive versatility to numerous types of habitats, extremely diverse both in terms of composition and specificity, developed in various areas of the Western Plains of Romania, the European fallow deer (Dama dama) is a species with high ecological plasticity. In this area, the D. dama interacts with other species of wild fauna but also with numerous domestic animals, an important aspect in terms of the sanitary-veterinary status of animal populations, as well as the existence of a potential risk of infection with various species of parasites that can cause the D. dama specimens to obtain certain diseases and even zoonoses. A total of 133 esophagi from D. dama have been examined for helminths. Of the 133 esophagus samples from D. dama, nematodes of the genus Gongylonema were identified in 25 (18.80%). Sequencing revealed that the nematode identified in the samples was 99% similar to the sequence of Gongylonema pulchrum (GenBank no. LC026018.1, LC388754.1, AB646061). The present research is the first report of the nematode G. pulchrum from D. dama in Romania.

Hatchability of Fascioloides magna Eggs in Cervids

The giant liver fluke (Fascioloides magna) is an invasive parasite found permanently in three foci in Europe. The fluke has an indirect life cycle involving a final and an intermediate host. The currently accepted terminology determines three types of final hosts: definitive, dead-end, and aberrant hosts. Recently, roe deer (Capreolus capreolus) has been classified as an aberrant host, which cannot contribute to the reproduction of F. magna. This study investigated the hatchability of F. magna eggs of red deer (Cervus elaphus) and roe deer origin to compare the suitability of the two host species for the maintenance of the parasite. The study was carried out on a newly invaded area, two years after the first reported observation of F. magna. The prevalence of the parasite proved to be 68.4% (CI95% 44.6-85.3%) in red deer and 36.7% (CI95% 24.8-50.0%) in roe deer. The difference between the two species was confirmed to be significant (p = 0.02). The mean intensity proved to be 10.0 (CI95% 4.9-22.6) and 7.59 (CI95% 2.7-24.2) in the red deer and the roe deer, respectively. The difference of the mean intensities did not prove to be significant (p = 0.72). Of the 70 observed pseudocysts, 67 originated from red deer and 3 from roe deer. Most of the pseudocysts contained two flukes, while a few pseudocysts contained one or three parasites. Egg production was observed in all three types of pseudocysts. We did not find more than three flukes in any pseudocyst. The apparent proportion of self-fertilisation in flukes without mating partners was 23.5% and 100% in red deer and roe deer, respectively. The survival of single-parent eggs was not confirmed to be worse than that of gregarious parents. The viability of offspring originating from roe and red deer differed significantly. Our findings suggest that F. magna adapted to the new populations of susceptible hosts rather than vice versa.

A new insight into genetic structure of Danube and Italian foci of fascioloidosis

Human induced translocation and introduction of species have reshaped parasite fauna on a global scale. The introduction of the large American liver fluke Fascioloides magna from North America to Europe is an example of an invasive alien parasite causing significant ecological and economic damage. Recent genetic studies have shown that F. magna was introduced to Europe on multiple occasions forming three permanent foci of infection. This study primarily focuses on the poorly researched genetic structuring of F. magna flukes originating from Croatia and Serbia. Additional samples from USA and Italy are also included, thereby providing novel insights into F. magna's biogeography. Partial cox1 and nad1 genes were amplified from 216 F. magna flukes extracted from red deer, roe deer, fallow deer, white-tailed deer and wild boar. Seven cox1 and nine nad1 haplotypes were identified, of which two cox1 and four nad1 haplotypes have not been not previously found. Our analysis has expanded the knowledge about possible sources of F. magna introduction to Europe, by identifying a cox1 haplotype shared by flukes from the north-eastern parts of the USA and Italy and another cox1 haplotype shared by flukes also from north eastern parts of the USA and the Danube floodplains.

The giant liver fluke in Europe: A review of Fascioloides magna within cervids and livestock with considerations on an expanding snail-fluke transmission risk

The giant liver fluke, Fascioloides magna, common in North America and introduced into Europe in the 19th century, is an underappreciated model system for epidemiological studies on biological invasions, interactions with other native parasites and for health impact assessments within both definitive and intermediate snail host populations. Owing to its first contemporary appearance in Europe and then its subsequent spread, fascioloidosis has become a fluke-livestock/wildlife-snail combination of increasing interest for veterinarians, parasitologists and population geneticists. Here, we present a description of its recent epidemiology, biogeography and biology, inclusive of host species lists. Special emphasis is placed upon known definitive hosts of F. magna within Europe and considerations upon this fluke's local intermediate snail hosts. This helps us envisage plausible future epidemiological scenarios for further expansion across Europe, potentially even invasion into the UK. In line with others who draw attention upon needs for better systematic monitoring of putative risk-areas of fluke transmission, we close by highlighting why better surveillance of F. magna across continental Europe, and neighbouring territories, is justified.

The occurrence of Fascioloides magna (Bassi, 1875) in the wild cervid population in the Lower Silesian Wilderness – epidemiological and pathological aspects

Introduction

Fascioloides magna is a parasite of high veterinary importance due to its pathogenicity for wild and domestic ruminants. The aim of our study was to describe the presence of trematode infection in the red deer population in the Lower Silesian Wilderness, one of the established fascioloidosis foci in Central Europe, and to assess the overall prevalence of F. magna in the studied area. In order to achieve this, a coprological study of different cervid species was performed.

Material and Methods

The livers of 99 red deer were collected over three years and examined for the presence of trematodes. Prevalence and infection intensity was estimated and a histopathological analysis was performed. In addition, 172 faecal samples from red deer, fallow deer and roe deer were examined.

Results

By year, Fascioloides magna was isolated from the livers of 2/30 (6.7%), 9/34 (26.5%) and 10/35 (28.6%) red deer. Severe hepatic lesions, including massive tissue damage, extensive fibrosis, and cirrhotic changes in the liver parenchyma were observed. Faecal examination revealed the presence of F. magna eggs, with a prevalence of approximately 40%, 50% and 53% in roe deer, fallow deer and red deer, respectively.

Conclusion

The eggs of F. magna may be commonly excreted in the faeces of roe deer, as well as those of red deer and fallow deer. The presence of F. magna throughout the cervid population in the Lower Silesian Wilderness favours the risk of the trematode’s transmission to livestock or farmed deer.