Host Switching of Zoonotic Broad Fish Tapeworm (Dibothriocephalus latus) to Salmonids, Patagonia

Diphyllobothriosis is a reemerging zoonotic disease because of global trade and increased popularity of eating raw fish. We present molecular evidence of host switching of a human-infecting broad fish tapeworm, Dibothriocephalus latus, and use of salmonids as intermediate or paratenic hosts and thus a source of human infection in South AmericaFil: Kuchta, Roman. Academy of Sciences of the Czech Republic. Biology Centre. Institute of Parasitology; República ChecaFil: Radačovská, Alžbeta. Biology Centre of the Academy of Sciences of the Czech Republic; República ChecaFil: Bazsalovicsová, Eva. Slovak Academy of Sciences. Institute of Parasitology; EslovaquiaFil: Viozzi, Gustavo Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Semenas, Liliana Graciela. Universidad Nacional del Comahue; ArgentinaFil: Arbetman, Marina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Scholz, Tomáš. Biology Centre of the Academy of Sciences of the Czech Republic; República Chec

Occurrence of Dibothriocephalus latus in European perch from Alpine lakes, an important focus of diphyllobothriosis in Europe

The broad fish tapeworm Dibothriocephalus latus (syn. Diphyllobothrium latum) is one of the most common causative agents of human diphyllobothriosis, a significant fish-borne parasitic zoonosis. In Europe, the occurrence of D. latus has been repeatedly reported in lakes of the Alps region, the Baltic region, Fennoscandia and Russia. Regular detection of D. latus plerocercoids in fish coming from different subalpine lakes linked with ongoing D. latus infection in humans indicates that Alpine region is a rather specific area from the medical, epidemiological and ecological point of view. Results from the examination of 688 European perch (Perca fluviatilis) from six subalpine lakes in Switzerland, France and northern Italy (Lakes Geneva, Neuchâtel, Biel, Como, Maggiore and Iseo) confirmed the ongoing occurrence of D. latus in the Alps region. The detected prevalence of D. latus in the studied Alpine lakes (2% in Lake Neuchâtel; 37.5% in Lake Biel; 6.4% in Lake Geneva; 22.8% in Lake Iseo [2018]; 12.8% in Lake Iseo [2017]; 15.2% in Lake Como; 16.7% in Lake Maggiore) was compared with previously published data. In addition, the importance of the Alpine lakes region and data on the epidemiology and ecology of D. latus related to subalpine lakes were discussed

Development of 14 microsatellite markers for zoonotic tapeworm dibothriocephalus dendriticus (Cestoda: Diphyllobothriidea)

Dibothriocephalus dendriticus is one of the causative agents of the fish-borne zoonosis diphyllobothriosis. Polymorphic microsatellite markers were originally developed for future genetic studies using microsatellite library screening and next-generation sequencing (NGS). Out of 128 microsatellite candidates selected after NGS analysis, 126 yielded PCR products of the expected size. A declared repetitive motif was confirmed in 92 loci by Sanger sequencing. The level of polymorphism was tested by fragment analysis. Statistical tests for observed and expected heterozygosities and deviations from Hardy–Weinberg equilibrium revealed 14 polymorphic microsatellite loci suitable for studies on the finer genetic structure of global populations of D. dendriticus

An examination of nervous system revealed unexpected immunoreactivity of both secretory apparatus and excretory canals in plerocercoids of two broad tapeworms (Cestoda: Diphyllobothriidea)

Dibothriocephalus ditremus and Dibothriocephalus latus are diphyllobothriidean tapeworms autochthonous to Europe. Their larval stages (plerocercoids) may seriously alter health of their intermediate fish hosts (D. ditremus) or cause intestinal diphyllobothriosis of the final human host (D. latus). Despite numerous data on the internal structure of broad tapeworms, many aspects of the morphology and physiology related to host–parasite co-existence remain unclear for these 2 species. The main objective of this work was to elucidate functional morphology of the frontal part (scolex) of plerocercoids, which is crucial for their establishment in fish tissues and for an early attachment in final hosts. The whole-mount specimens were labelled with different antibodies and examined by confocal microscope to capture their complex 3-dimensional microanatomy. Both species exhibited similar general pattern of immunofluorescent signal, although some differences were observed. In the nervous system, FMRF amide-like immunoreactivity (IR) occurred in the bi-lobed brain, 2 main nerve cords and surrounding nerve plexuses. Differences between the species were found in the structure of the brain commissures and the size of the sensilla. Synapsin IR examined in D. ditremus occurred mainly around FMRF amide-like IR brain lobes and main cords. The unexpected finding was an occurrence of FMRF amide-like IR in terminal reservoirs of secretory gland ducts and excretory canals, which has not been observed previously in any tapeworm species. This may indicate that secretory/excretory products, which play a key role in host–parasite relationships, are likely to contain FMRF amide-related peptide/s

Genetic interrelationships of North American populations of giant liver fluke Fascioloides magna

Abstract Background Population structure and genetic interrelationships of giant liver fluke Fascioloides magna from all enzootic North American regions were revealed in close relation with geographical distribution of its obligate definitive cervid hosts for the first time. Methods Variable fragments of the mitochondrial cytochrome c oxidase subunit I (cox1; 384 bp) and nicotinamide dehydrogenase subunit I (nad1; 405 bp) were applied as a tool. The concatenated data set of both cox1 and nad1 sequences (789 bp) contained 222 sequences that resulted in 50 haplotypes. Genetic data were analysed using Bayesian Inference (BI), Maximum Likelihood (ML) and Analysis of Molecular Variance (AMOVA). Results Phylogenetic analysis revealed two major clades of F. magna, which separated the parasite into western and eastern populations. Western populations included samples from Rocky Mountain trench (Alberta) and northern Pacific coast (British Columbia and Oregon), whereas, the eastern populations were represented by individuals from the Great Lakes region (Minnesota), Gulf coast, lower Mississippi, and southern Atlantic seaboard region (Mississippi, Louisiana, South Carolina, Georgia, Florida) and northern Quebec and Labrador. Haplotype network and results of AMOVA analysis confirmed explicit genetic separation of western and eastern populations of the parasite that suggests long term historical isolation of F. magna populations. Conclusion The genetic makeup of the parasite’s populations correlates with data on historical distribution of its hosts. Based on the mitochondrial data there are no signs of host specificity of F. magna adults towards any definitive host species; the detected haplotypes of giant liver fluke are shared amongst several host species in adjacent populations

Development of 14 Microsatellite Markers for Zoonotic Tapeworm Dibothriocephalus dendriticus (Cestoda: Diphyllobothriidea)

Dibothriocephalus dendriticus is one of the causative agents of the fish-borne zoonosis diphyllobothriosis. Polymorphic microsatellite markers were originally developed for future genetic studies using microsatellite library screening and next-generation sequencing (NGS). Out of 128 microsatellite candidates selected after NGS analysis, 126 yielded PCR products of the expected size. A declared repetitive motif was confirmed in 92 loci by Sanger sequencing. The level of polymorphism was tested by fragment analysis. Statistical tests for observed and expected heterozygosities and deviations from Hardy–Weinberg equilibrium revealed 14 polymorphic microsatellite loci suitable for studies on the finer genetic structure of global populations of D. dendriticus

Additional file 5: Figure S1. of Population structure and dispersal routes of an invasive parasite, Fascioloides magna, in North America and Europe

Implementation of delta K statistic and determination of number of genetic clusters using STRUCTURE HARVESTER. (DOCX 35 kb

Additional file 1: Table S1. of Population structure and dispersal routes of an invasive parasite, Fascioloides magna, in North America and Europe

Primer pairs and multiplex panels for 11 microsatellite loci applied in Fascioloides magna genotyping (modified according to Minárik et al. 2014). (DOCX 19 kb