Studying complexes of cryptic or pseudocryptic species opens new horizons for the understanding of speciation processes, an important yet vague issue for the digeneans. We investigated a hemiuroidean trematode Lecithaster salmonis across a wide geographic range including the northern European seas (White, Barents, and Pechora), East Siberian Sea, and the Pacific Northwest (Sea of Okhotsk and Sea of Japan). The goals were to explore the genetic diversity within L. salmonis through mitochondrial (cox1 and nad5 genes) and ribosomal (ITS1, ITS2, 28S rDNA) marker sequences, to study morphometry of maritae, and to revise the life cycle data. Mitochondrial markers showed that L. salmonis is likely divided into six lineages (referred to as operational taxonomic units, OTUs), which often occur in sympatry, sometimes in a single host specimen. Variation in rDNA was not consistent with that in the mitochondrial markers. Morphometric analysis of maritae was performed for four out of six OTUs; it showed that some OTUs had significant differences from the others, but some did not. The effect of host species on the morphometric characteristics cannot be excluded. Intramolluscan stages were identified for two OTUs; they differed clearly by the structure of cercariae and also by the species of the first intermediate host. The case of L. salmonis is instructive in how different criteria for species delimitation can contradict each other. We regard this as a sign of recent or ongoing speciation and suggest using the name Lecithaster cf. salmonis. The most promising criteria to differentiate genetic lineages within L. cf. salmonis are first intermediate hosts and morphological characteristics of the cercariae: shape of the delivery tube and caudal cyst, and length of the filamentous appendage.

Cystic Echinococcosis (CE) is a zoonotic disease caused by Echinococcus granulosus sensu lato. Diagnosing CE primarily relies on imaging techniques, and there is a crucial need for an objective laboratory test to enhance the diagnostic process. Today, cell-free DNAs (cfDNAs) have gained importance regarding their biomarker potential. This study aims to investigate the diagnostic capabilities of different cfDNA targets (Echinococcus-specific repeat sequences (mgs-4 and mgs-12) and partial fragment of repetitive sequence (EG1 Hae III)) and evaluate their diagnostic effectiveness when compared to a frequently used commercial E.granulosus-specific IgG ELISA. Seventy-six confirmed hepatic CE patients and healthy controls were included in the study. The EG1 Hae III region was assessed using nested PCR, whereas real-time PCR was employed to investigate other cfDNA targets. Analysis of the cfDNA-targeted tests indicated that mgs-4 demonstrated the highest diagnostic efficacy in distinguishing CE patients from healthy controls, achieving a sensitivity of 60.5% (p = 0.002). Combining ELISA with the mgs-4 target led to an increased sensitivity of 72.4% for distinguishing between CE patients and the control group. The sensitivity rates for ELISA and the three cfDNA targets varied among the groups. Active CE patients showed sensitivity rates of 52.9%, 52.9%, 23.5%, and 52.9% for ELISA, mgs-4, mgs-12, and EG1 Hae III assays, respectively. In contrast, inactive cyst patients displayed sensitivity rates of 21.4%, 66.7%, 19%, and 42.9% for the corresponding assays. The mgs-4, either alone or in combination with ELISA, demonstrated notably higher sensitivity values for CE diagnosis in all group comparisons compared to serology.

Currently, there is limited available information on the epidemiology of parasitic infections in captive non-human primates (NHPs) and their zoonotic potential. However, numerous cases of helminth infections in NHPs have been documented in several zoos around the world, with one of the most prevalent being those of the genus Trichuris. The main objective of this study is to investigate the occurrence of infection by Trichuris spp. in primates from zoological gardens in Spain and to ascertain, at the species level, the specific Trichuris species harbored by these hosts by using mitochondrial and ribosomal markers. A total of 315 stools collected from NPHs (n = 47) in the 13 zoological gardens analyzed yielded a prevalence rate of 19.05%. Nevertheless, not all the zoos exhibited parasitic infections; this was observed in only 53.85% of the zoos. Moreover, 15 host groups of 12 different species were found to be infected by Trichuris species, among which the identified species included Trichuris trichiura, Trichuris colobae, and Trichuris sp. Our findings suggest a substantial exposure of primates to zoonotic Trichuris species, suggesting that NHPs could potentially act as reservoirs capable of transmitting this parasite to humans. Hence, it is crucial to implement additional control and prevention measures and explore ways to eradicate parasitic infections in these areas. Further examination is warranted to minimize the risk of spreading drug-resistant parasite strains.