Diphyllobothriosis is a parasitic infection of humans caused by the broad fish tapeworm (Dibothriocephalus latus; synonym Diphyllobothrium latum). This disease is widespread in the Northern Hemisphere including Europe. Popular sport fish such as perch (Perca fluviatilis) and pike (Esox lucius) are the source of human infection. Here we document the first autochthonous case of diphyllobothriosis linked to the consumption of raw pike roe (caviar) originating from a popular tourist destination in South Bohemia. This is probably a recent introduction of the parasite into the Lipno Reservoir, which may represent a new focus of diphyllobothriosis, a zoonotic, fish-borne disease.

• Klíčová slova
• Central Europe, Freshwater fish, Lipno Reservoir, broad fish tapeworm, pike, roe, zoonosis,
• MeSH
• difylobotriáza * diagnóza   parazitologie   MeSH
• Diphyllobothrium * izolace a purifikace   MeSH
• lidé MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Geografické názvy
• Česká republika MeSH

The broad fish tapeworm, Dibothriocephalus latus (Diphyllobothriidea), is the most frequent causative agent of diphyllobothriosis, a fish-borne zoonosis, in Europe. Diphyllobothriosis is characterized by the transmission of D. latus larvae to humans via the consumption of raw, marinated, smoked or inadequately cooked fish products. The most important European foci of diphyllobothriosis have been Fennoscandia, the Baltic region, the Alpine lakes region, the Danube River region, and several endemic regions in Russia. This review provides basic data on the biology, life cycle, host specificity, methods of identification of D. latus, and a detailed summary of its occurrence in intermediate and definitive hosts in Fennoscandia and the Baltic, Alpine, and Danube regions during the last 120 years (1900-2020). Deeper insight into the unique pattern of distribution of D. latus in endemic regions is provided. The numbers of records are associated with several milestones of particular time periods. The first milestone (historical), which influenced studies on D. latus in Europe, was the period during and after World War II (1941-1950). The second milestone (epidemiological) was the decade 1981-1990, when previous massive health campaigns led to a marked decline of diphyllobothriosis in Europe and less published data on D. latus. Based on recent data, the broad fish tapeworm is either absent or present at very low prevalences in Fennoscandia and the Baltic and Danube regions, but the Alpine lakes region represents a continuous ongoing circulation of the parasite in the natural environment and humans.

• Klíčová slova
• Cestoda, Diphyllobothriidea, Diphyllobothriosis, Fish tapeworms, Fish-borne zoonosis, Food-borne diseases, Geographic distribution, Human parasites,
• MeSH
• Cestoda * MeSH
• difylobotriáza * MeSH
• Diphyllobothrium * MeSH
• lidé MeSH
• zoonózy MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Geografické názvy
• Evropa epidemiologie   MeSH

The Asian fish tapeworm (AFT), Schyzocotyle acheilognathi, is a notorious and highly successful invasive parasite reported in a wide spectrum of freshwater fishes, and new reports of its spread continue to emerge. To date, no thorough review of its worldwide distribution and host associations is available. In the present work, we collected information from 651 articles up until 2017, from which we updated the number of the hosts to 312 fish species and 11 non-fish species, which is quite unusual among helminths. The AFT has spread to all but one continent (Antarctica). The highest number of records are from North America, followed by Asia and Europe. A key feature of its invasive success is its broad environmental tolerance.

• Klíčová slova
• Bothriocephalidea, Schyzocotyle acheilognathi, biogeography, extreme euryxeny, primary data,
• MeSH
• Cestoda klasifikace   fyziologie   MeSH
• cestodózy parazitologie   MeSH
• hostitelská specificita fyziologie   MeSH
• nemoci ryb parazitologie   MeSH
• rozšíření zvířat * MeSH
• ryby MeSH
• sladká voda MeSH
• zavlečené druhy * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Geografické názvy
• Asie MeSH
• Evropa MeSH
• Severní Amerika MeSH

The large-sized tapeworm Dibothriocephalus latus is known as the broad or fish-borne cestode of mammals that is capable to infect humans and cause diphyllobothriosis. Recently, molecular data on D. latus has been accumulating in the literature and a complete genome sequence has been published; however, little is known about the karyotype and chromosome architecture. In this study, an in-depth karyological analysis of 2 D. latus specimens was carried out. The plerocercoids originated from a perch caught in subalpine Lake Iseo (Italy) and the tapeworms were reared in hamsters. Both specimens contained cells with a highly variable number of chromosomes ranging from18 to 27. Nevertheless, the largest portion of mitotic figures (47%) showed a number corresponding to the triploid set, 3n = 27. Accordingly, the karyotype of the analyzed specimens consisted of 9 triplets of metacentric chromosomes. Fluorescence in situ hybridization (FISH) with the 18S rDNA probe clearly demonstrated the presence of 3 clusters of hybridization signals on the triplet of chromosome 7, thus confirming the triploid status of the specimens. FISH with a telomeric (TTAGGG)n probe confined hybridization signals exclusively to the terminal chromosomal regions, supporting the earlier findings that this repetitive motif is a conserved feature of tapeworm telomeres.

• Klíčová slova
• 18S rDNA, parthenogenesis, polyploidization, telomeres, triploid,
• MeSH
• chromozomy genetika   MeSH
• cytogenetické vyšetření MeSH
• difylobotriáza parazitologie   MeSH
• Diphyllobothrium genetika   metabolismus   MeSH
• hybridizace in situ fluorescenční MeSH
• karyotyp MeSH
• RNA helmintů analýza   MeSH
• RNA ribozomální 18S analýza   MeSH
• triploidie * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• RNA helmintů MeSH
• RNA ribozomální 18S MeSH

The broad fish tapeworm, Dibothriocephalus latus (Diphyllobothriidea), is the most important causative agent of diphyllobothriosis, a fish-borne zoonosis, in Europe. Part I of this review focused on the occurrence of D. latus in northwestern and central Europe, particularly in Fennoscandia, the Baltic, the Alpine lakes and Danube River regions during 1900-2020. Part II summarises data on D. latus from the European and Asian parts of Russia and from Asian countries. The tapeworm has occurred throughout Russia, with the most important foci in (i) the Republic of Karelia in the northwest of European Russia, (ii) the Volga River basin in the central and southern parts of European Russia, (iii) the Ob-Irtysh rivers region in the Ural region, (iv) the Yenisei-Lena rivers region in Siberia, and (v) the Lake Baikal basin in Siberia. The incidence of diphyllobothriosis has declined in recent decades, especially in European Russia, but zoonosis is still prevalent in some regions of Siberia. Cases reported from Arctic regions, the region around Lake Baikal, and the Pacific coast, including the Amur basin, however, were probably misidentifications with D. dendriticus and/or D. nihonkaiensis. No other Asian country where D. latus findings represented either imported cases or misidentifications had natural focus of diphyllobothriosis. Patterns of distribution of D. latus occurrence were similar in all Eurasian foci between 1900 and 2020. The numbers of records were associated with historical and epidemiological milestones of particular time periods.

• Klíčová slova
• Asia, Cestoda, Diphyllobothriidea, Diphyllobothriosis, Diphyllobothrium latum, Fish tapeworms, Fish-borne zoonosis, Food-borne diseases, Human parasites, Russia,
• Publikační typ
• časopisecké články MeSH

Using ITS2 gene sequences, the validity of the tapeworm Diphyllobothrium pacificum (Nybelin, 1931), infecting humans on the Pacific coast of South America and in Japan, was assessed. ITS2 sequences of this cestode differed markedly (sequence similarity 79.0-80.2%) from those of the most common human-infecting cestode, the broad fish tapeworm Diphyllobothrium latum (L.), as well as other four species of Diphyllobothrium, including potential human parasites (D. cordatum, D. dendriticum, and D. lanceolatum) and two species of Spirometra (sequence similarity 77.5-81.9%). Interspecific sequence similarity between all but one (D. pacificum) species was 86.1-99.6%, whereas individual isolates of D. dendriticum and D. ditremum exhibited intraspecific sequence similarity of 97.0-98.0% and 98.2-99.9%, respectively. Phylogenetic trees constructed from ITS2 sequences show a markedly distant position of D. pacificum from other species analyzed and also indicate the possible paraphyly of Spirometra.

• MeSH
• difylobotriáza parazitologie   MeSH
• Diphyllobothrium klasifikace   genetika   MeSH
• fylogeneze MeSH
• Herpestidae MeSH
• lachtani rodu Arctocephalus a Callorhinus MeSH
• lidé MeSH
• mezerníky ribozomální DNA genetika   MeSH
• molekulární sekvence - údaje MeSH
• mroži MeSH
• Puma MeSH
• ryby MeSH
• sekvenční homologie nukleových kyselin MeSH
• zeměpis MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Geografické názvy
• Jižní Amerika MeSH
• Názvy látek
• mezerníky ribozomální DNA MeSH

In the present study, the process of vitellogenesis of one of the most prolific organisms, the broad tapeworm, Diphyllobothrium latum, the causative agent of human diphyllobothriosis, was studied for the first time using transmission electron microscopy. Cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate for detection of glycogen was applied. Starting from the periphery toward the center of the vitelline follicle four stages of vitellocytes are differentiated: immature vitellocytes, early maturing vitellocytes, advanced maturing and mature vitellocytes. Differentiation into mature vitellocytes involves the formation of shell globule clusters containing shell globules, large amount of saturated lipid droplets and glycogen. A peculiar ultrastructural feature of D. latum vitellogenesis is the presence of lamellar bodies in the cytoplasm of mature vitellocytes. This feature is similar to that present in the closely related caryophyllideans and spathebothriideans. Despite the great similarity observed in the embryonic development of diphylobothriideans, caryophyllideans and spathebothriideans, and the fact that their vitellocytes share a feature not reported from other cestode groups, there are substantial differences in the morphology of vitelline clusters, types, amount and localization of their nutritive reserves.

• Klíčová slova
• Cytochemistry, Diphyllobothriosis, Diphyllobothrium latum, Ultrastructure, Vitellogenesis,
• MeSH
• difylobotriáza parazitologie   veterinární   MeSH
• Diphyllobothrium růst a vývoj   fyziologie   ultrastruktura   MeSH
• fertilita MeSH
• lidé MeSH
• vitelogeneze * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: In Europe, the tapeworm Dibothriocephalus latus (syn. Diphyllobothrium latum) is a well-known etiological agent of human diphyllobothriosis, which spreads by the consumption of raw fish flesh infected by plerocercoids (tapeworm's larval stage). However, the process of parasite establishment in both intermediate and definitive hosts is poorly understood. This study was targeted mainly on the scolex (anterior part) of the plerocercoid of this species, which facilitates penetration of the parasite in intermediate paratenic fish hosts, and subsequently its attachment to the intestine of the definitive host. METHODS: Plerocercoids were isolated from the musculature of European perch (Perca fluviatilis) caught in Italian alpine lakes. Parasites were examined using confocal microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Immunofluorescence tagging was held on whole mount larvae. RESULTS: The organisation of the central and peripheral nervous system was captured in D. latus plerocercoids, including the ultrastructure of the nerve cells possessing large dense neurosecretory granules. Two types of nerve fibres run from the body surface toward the nerve plexus located in the parenchyma on each side of bothria. One type of these fibres was found to be serotoninergic and possessed large subtegumental nerve cell bodies. A well-developed gland apparatus, found throughout the plerocercoid parenchyma, produced heterogeneous granules with lucent core packed in a dense layer. Three different types of microtriches occurred on the scolex and body surface of plerocercoids of D. latus: (i) uncinate spinitriches; (ii) coniform spinitriches; and (iii) capilliform filitriches. Non-ciliated sensory receptors were observed between the distal cytoplasm of the tegument and the underlying musculature. CONCLUSIONS: Confocal laser scanning microscopy and electron microscopy (SEM and TEM) showed the detailed microanatomy of the nervous system in the scolex of plerocercoids, and also several differences in the larval stages compared with adult D. latus. These features, i.e. well-developed glandular system and massive hook-shaped uncinate spinitriches, are thus probably required for plerocercoids inhabiting fish hosts and also for their post-infection attachment in the human intestine.

• Klíčová slova
• Cestoda, Glands, Immunofluorescence, Microtriches, Plerocercoids, Protonephridia, Receptors, Ultrastructure,
• MeSH
• Diphyllobothrium anatomie a histologie   ultrastruktura   MeSH
• larva anatomie a histologie   ultrastruktura   MeSH
• mikroskopie elektronová rastrovací MeSH
• nemoci ryb parazitologie   MeSH
• nervový systém ultrastruktura   MeSH
• potrava z moře (živočišná) parazitologie   MeSH
• transmisní elektronová mikroskopie MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Tapeworms (Cestoda) continue to be an important cause of morbidity in humans worldwide. Diphyllobothriosis, a human disease caused by tapeworms of the genus Diphyllobothrium, is the most important fish-borne zoonosis caused by a cestode parasite. Up to 20 million humans are estimated to be infected worldwide. Besides humans, definitive hosts of Diphyllobothrium include piscivorous birds and mammals, which represent a significant zoonotic reservoir. The second intermediate hosts include both freshwater and marine fish, especially anadromous species such as salmonids. The zoonosis occurs most commonly in countries where the consumption of raw or marinated fish is a frequent practice. Due to the increasing popularity of dishes utilizing uncooked fish, numerous cases of human infections have appeared recently, even in the most developed countries. As many as 14 valid species of Diphyllobothrium can cause human diphyllobothriosis, with D. latum and D. nihonkaiense being the most important pathogens. In this paper, all taxa from humans reported are reviewed, with brief information on their life history and their current distribution. Data on diagnostics, epidemiology, clinical relevance, and control of the disease are also summarized. The importance of reliable identification of human-infecting species with molecular tools (sequences of mitochondrial genes) as well as the necessity of epidemiological studies aimed at determining the sources of infections are pointed out.

• MeSH
• difylobotriáza epidemiologie   přenos   MeSH
• Diphyllobothrium klasifikace   fyziologie   MeSH
• lidé MeSH
• ptáci parazitologie   MeSH
• ryby parazitologie   MeSH
• savci parazitologie   MeSH
• zoonózy epidemiologie   přenos   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

The broad fish tapeworm Dibothriocephalus latus is a causative agent of human food-borne disease called diphyllobothriosis. Medical importance, scattered geographical distribution and unknown origin of D. latus in Europe and North America make this species to be an interesting model for population genetics. Microsatellite markers were originally designed by library screening using NGS approach and validated as tools for future studies on population genetics of D. latus. Out of 122 candidates selected after NGS analysis, 110 yielded PCR products of the expected size, and in 78 of them, a declared repetitive motif was confirmed by Sanger sequencing. After the fragment analysis, six loci were proved to be polymorphic and tested for observed (Ho) and expected (He) heterozygosity, and deviations from Hardy-Weinberg equilibrium (HWE). They promise future application in studies on genetic interrelationships, origin and migratory routes of this medically important emerging tapeworm.

• Klíčová slova
• Broad Fish tapeworm, Diphyllobothriidea, Microsatellites, Population genetics, Short tandem repeats,
• MeSH
• Diphyllobothrium klasifikace   genetika   MeSH
• genetická variace * MeSH
• genotypizační techniky metody   MeSH
• mikrosatelitní repetice * MeSH
• populační genetika metody   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH
• Severní Amerika MeSH