Diphyllobothrium Research Articles

Intestinal Parasitic Infection in Roman Britain: Integrating New Evidence from Roman London

ABSTRACT The aim of this study is to estimate the minimum prevalence of intestinal parasites in the population of Roman London through analysis of pelvic sediment from 29 third- to fourth-century burials from the 1989 excavations of the western cemetery at 24–30 West Smithfield, 18–20 Cock Lane and 1–4 Giltspur Street (WES89). Microscopy was used to identify roundworm eggs in 10.3 per cent of burials. We integrate these results with past palaeoparasitological work in the province of Britannia to explore disease, hygiene and diet. The most commonly found parasites (whipworm and roundworm) were spread by poor sanitation, but other species caught from animals were also present (fish tapeworm, beef/pork tapeworm and liver flukes). Parasite diversity was highest in urban sites. The health impacts of these infections range from asymptomatic to severe.

Risk factors associated with street food consumption in Dhaka city due to faeco-oral parasitic infection in food vendors

Ready to eat foods that are sold in streets and busy public places and popular for their affordability, accessibility and distinct flavour and taste are termed as street foods. Due to their low-income levels, the majority of people in developing countries rely on street food for their daily dietary needs. In Bangladesh, many street food vendors target young school-going children by selling attractive food items in front of schools. To understand the implications of street food consumption in Dhaka city, 200 school-based street food samples and 200 corresponding faecal samples from vendors around 50 schools were analyzed using the Formal-ether concentration method from September 2021 to June 2022. 10 parasite species (Entamoeba histolytica, Blastocystis hominis, Cystoisospora belli, Diphyllobothrium latum, Hymenolepis diminuta, Hymenolepis nana, Ascaris lumbricoides, Enterobius vermicularis, Trichuris trichiura, Ancylostoma duodenale) were identified by microscopic observation. From food and the corresponding stool samples, 7 parasite species were found. B. hominis caused the greatest proportion of infections (21.5%), followed by C. belli (20.5%), A. lumbricoides (17%), D. latum (4.5%), H. nana (3%), T. trichiura (2.5%) and E. histolytica (0.5%). Statistical analysis revealed that city corporation, age, smoking status and use of today’s materials next day (p < 0.05) were associated with parasites present in stool. In the food samples, city corporation, age, use of mask, currently having disease, using today’s materials next day were significantly associated with presence of parasites (p < 0.05). This study is one of the first to correlate the lack of hygienic practices of the food vendors with an increased risk of parasitic infection in the vendors and their street foods resulting the possibility of transmission to the consumers. The study findings indicate the urgent need to ensure food quality.

Therapeutic efficacy of a three-component anthelmintic drug against cestodosis and nematodosis of small domestic animals

The purpose of the study therapeutic efficacy of combined anthelmintic drug on dogs and cats of different age groups naturally infected with cestodes and nematodes.Materials and methods. The study drug in the suspension form contains oxantel pamoate, pyrantel pamoate, praziquantel, and additives as active ingredients. The therapeutic efficacy of the drug was evaluated on 228 animals naturally infected with nematodes or cestodes in the Podolsk Experimental Production Base of the VNIIP – FSC VIEV. The animals were divided into experimental and control groups of 6 animals each. The experimental dogs and cats were administered the study drug while the control animals were not given the drug. Clinical examinations and laboratory tests of fecal samples were performed on days 10, 20 and 30 after the start of the experiment. The method of helminthoscopy was used to detect segments and helminthoovoscopy as per Fülleborn to detect helminth eggs/cocoons in animal fecal samples with their subsequent differentiation. The results were statistically processed by the Student method using Microsoft Excel 2016.Results and discussion. It was found that anthelmintic drug based on oxantel pamoate, pyrantel pamoate and praziquantel had high therapeutic efficacy against parasitism in dogs and cats of nematodes Toxocara spp., Toxascaris leonina, Trichuris vulpis, Uncinaria stenocephala, Ancylostoma spp. and cestodes Echinococcus spp. (except for cats), Mesocestoides spp., Taenia spp., Dipylidium caninum, and Diphyllobothrium latum. When the drug was used in the animals of different age groups, no side effects or complications were recorded.

Anthropozoonotic parasitoses of dogs and cats in the urban ecosystem of Vladivostok, Russia

To investigate the role of domestic dogs and cats in the spread of parasitoses in the Vladivostok urban ecosystem. Biological materials from 782 dogs and 189 cats were used in the research, which were examined by methods of complete parasitological autopsy, microscopy and flotation of faecal samples using saturated solutions of zinc sulfate and sodium nitrate.Fourteen parasite taxa have been identified: nematodes (Nematoda) Ancylostoma caninum, Dirofilaria immitis, Toxascaris leonina, Toxocara canis, T. mystax, Uncinaria stenocephala, Taenia sp., T. hydatigena; tapeworms (Cestoda) Diphyllobothrium latum, Dipylidium caninum, Hydatigera taeniaeformis; flukes (Trematoda) Metagonimus sp.; and parasitic alveolates (Conoidasida) Cystoisospora sp., C. felis. The paper presents the values of the prevalence of infection and statistical reliability of their differences for different groups of animals, depending on gender and age. Nematodes were the core taxa of the parasitofauna identified. Explanations for the results obtained are offered and possible sources of human infection are described. Despite the fact that parasitic‐faunal complexes in the ecosystem of a modern city are much less branched and represented by fewer species than in the wild, there remains a high risk of human infection with zoonotic parasites in urban biocenoses due to the high level of intensive population interactions. Therefore, there is a requirement of high alertness of supervisory authorities in relation to anthropozoonotic parasitoses in an urban environment.

PREVALENCE OF ECTO AND ENDO PARASITES OF WHITE CATFISH (AMEIURUS CATUS) IN UKE RIVER, KARU LOCAL GOVERNMENT AREA OF NASARAWA STATE, NIGERIA

In Uke River, Karu Local Government Area, Nasarawa State, Nigeria, a six-month research was carried out between January and June 2023 to examine the gills and intestinal helminth and protozoan parasites of White Catfish (Ameiurus catus). A total of 100 fresh Ameiurus catus fish samples of both sexes, were obtained from the fishermen and conveyed to the Zoology laboratory of Nasarawa State University for examination. The fishes were processed and examined using gills, oesophagus, intestine and rectum. Twenty-two (22) out of 100 fishes were found to be infected with helminth and protozoan parasites and a total of 31 parasites were isolated belonging to protozoa (Eimeria spp, Hexamita spp, Protoopalina spp), nematode (Procamallanus spp), trematode (Dactylogyrus spp), Cestode (Diphyllobothrium latum, Bothriocephalus claviceps) taxonomic groups. The findings indicated that Ameiurus catus intestine contained a greater quantity of fish parasites (96%). A nematode (Procamallanus spp.) was found to have the highest prevalence of 45.16%. Although the Chi square results showed no significant difference (p&gt;0.05), the prevalence in Ameiurus catus was greater in female samples (63.64%) compared to male samples (36.36%). Fish weighing between 151-200 g (46.14%) and measuring between 21-30 cm (28.57%) had the highest percentage of parasite infection. Going forward, it is imperative to properly cook Ameiurus catus from the Uke River to prevent the spread of parasites to consumers. Additionally, it is advisable to steer clear of any potential actions that could contribute to the parasite predominance near the water body.

Clinical case of funicular myelosis in combination with a concomitant genetic predisposition to folate cycle disorder

Funicular myelosis (sub­acute combined degeneration) is a disease characterized by the development of degeneration of the posterior and lateral cords of the spinal cord. Funicular myelosis is a neurological complication of vitamin B12 deficiency, which occurs as a result of reduced intake of vitamin B12 with food, malabsorption, in connection with taking some drugs (metformin, proton pump inhibitors, and nitrous oxide), with invasion by Diphyllobothrium latum. The disease is usually characterized by the presence of paresthesias, the development of sensitive ataxia, and impaired gait. The aim of the work was to demon­strate a clinical case of funicular myelosis in a young patient in order to improve the diagnostic process, paying attention to the genetic profile and identifying a concomitant predisposition to folate cycle disorder. A clinical case of funicular myelosis in a 39-year-old woman is described. The patient came to the neurology department with complaints of numbness in the upper and lower limbs, periodic shooting pains along the spine when the head is tilted forward. During the neurological examination, the following was observed: a decrease in vibrational, muscle-joint, discrimination sensitivity in the upper limbs, paresthesias in the distal parts of the limbs, and sensitive ataxia. According to the results of the magnetic resonance imaging (MRI) of the spinal cord, a lesion of the posterior cords on the long segment (C2-Th1) was found, which corresponds to the subacute degeneration of the spinal cord, which arose due to the deficiency of holotranscobalamin (active B12). The patient received appropriate treatment and was discharged home. Subsequently, the patient was found to have a concomitant genetic predisposition to folate cycle disorder and the development of thrombophilia. A year later, the woman again came to the neurological department. We carried out a repeated examination, evaluation of the results of the MRI of the cervical spine and other examinations in dynamics. According to the results of the literature analysis, additional markers for the diagnosis of funicular myelosis (in particular, homocysteine), the causes of hyper­homocysteinemia and its effects on the body were described. Timely detection and treatment of vitamin B12 deficiency is quite important, since in severe cases the development of spastic paraplegia is possible. Recovery of lost functions depends on the extent of spinal cord damage and the duration of the disease. If anemia is observed together with neurological symptoms, it is necessary to be especially attentive to possible funicular myelosis and to carry out appropriate diagnostic searches. And when detecting hyperhomocysteinemia, it is advisable to take into account other factors that can cause an increase in the level of homocysteine, in addition to a deficiency of vitamins B6, B12 and folic acid.

Molecular identification and prevalence of plerocercoid larvae (Cestoda: Diphyllobothriidae) in some commercial fish species from Peru.

Diphyllobothriosis, a fish-borne zoonosis in South America, is mainly caused by the Pacific broad tapeworm Adenocephalus pacificus Nybelin, 1931, a parasite of considerable concern in fishery resources due to its impact on public health. A new diphyllobothrid, Diphyllobothrium sprakeri Hernández-Orts et al. Parasites Vectors 14:219, 2021, was recently described from sea lions from the Pacific Coast, but marine fish acting as intermediate hosts are unknown. The objective of this study was to confirm the presence of plerocercoid larvae of Diphyllobothriidae Lühe, 1910 (Cestoda: Diphyllobothriidea) in nine fish species of commercial importance in Peru. Of a total of 6999 fish (5861 Engraulis ringens, 853 Sciaena deliciosa, 6 Sciaena callaensis, 171 Scomber japonicus, 40 Trachurus murphyi, 40 Ariopsis seemanni, 18 Merluccius peruanus, 5 Sarda chiliensis, and 5 Coryphaena hippurus), 183 were infected with plerocercoid larvae, representing a total prevalence of 2.61% and a mean intensity of 3.2. Based on mtDNA cox1 sequences of 43 plerocercoids, a phylogenetic analysis revealed that 41 belong to A. pacificus and two to D. sprakeri. These findings are first molecular data for D. sprakeri larvae, and the infections of E. ringens and T. murphyi by plerocercoid larvae represent the first records of intermediate/paratenic hosts for this species. Hence, the findings of the current study enhance our understanding of the presence of diphyllobothriid species in commercial fish from the Southeastern Pacific Ocean and their potential impact on seafood safety for local human populations.

First report on fish-borne Zoonotic cestode larvae of Dibothriocephalus lühe, 1899 in freshwater fish, Oreochromis niloticus (Linnaeus, 1758), from the Hemavati river, Karnataka (India)

The Broad Tapeworm, Dibothriocephalus Lühe, 1899 is a widespread cestode parasite infecting freshwater fishes worldwide and is the causative agent of zoonotic disease Diphyllobothriasis. Freshwater food fish, Oreochromis niloticus (Linnaeus, 1758), is of immense commercial importance and consumed all over the world due to its affordability and palatable nature. The present study records the occurrence of Dibothriocephalus larvae in the intestine of Oreochromis niloticus, collected from the Hemavati River, Hassan district, Karnataka and forms the first report of Dibothriocephalus larvae in Oreochromis niloticus and also forms the first report from Karnataka, India.

Outcome of parasitological examinations in dogs in Germany: a retrospective survey

Dog faecal samples examined from January 2019 to December 2019 were retrospectively analysed for frequency of endoparasites. The examinations were performed with several different methods: 29,219 samples were examined by flotation method and sodium acetate-acetic acid-formalin concentration (SAFC) technique, 1,330 samples by Baermann-Wetzel migration technique, 12,221 samples using a Giardia coproantigen enzyme-linked-immunosorbent assay (ELISA), 1,180 samples using a Cryptosporidium coproantigen ELISA, 1,671 samples by polymerase chain reaction (PCR) testing for Giardia duodenalis and 447 samples by PCR testing for Cryptosporidium spp.. A total of 7.1% of the samples were positive for parasites in the microscopical examination using the flotation method and SAFC technique. The parasites found included Cystoisospora spp. (2.8%), Giardia duodenalis (2.3%), Ancylostomatidae (1.8%), Toxocara canis (1.6%), Trichuris vulpis (0.7%), Toxascaris leonina (0.5%), Capillaria spp. (0.2%), Angiostrongylus vasorum (0.2%), Crenosoma vulpis (0.1%), Taeniidae (0.1%), Sarcocystis spp. (0.03%), Dipylidium caninum (0.01%), Diphyllobothrium latum (< 0.01%), Spirurida (< 0.01%) and Opisthorchiidae (< 0.01%). Using the Baermann-Wetzel migration technique, Angiostrongylus vasorum was found in 0.75% and Crenosoma vulpis in 0.3% of the samples. ELISAs for Giardia duodenalis and Cryptosporidium spp. revealed 13.9% and 1.0% positive faecal samples, and Giardia duodenalis and Cryptosporidium spp. PCRs 19.4% and 2.0%, respectively. Dogs in the first year of life were more frequently infected with parasites than older animals. In the microscopic examination using flotation method and SAFC technique, the significantly highest detection rates were found in dogs up to six months of age (p < 0.001).

Casual finding in colonoscopy: Diphyllobothrium latum.

Diphyllobothrium spp., also known as fish tapeworms, is the largest human tapeworm, reaching up to 25 meters of length. Human are considered the definitive host in the Diphyllobothrium lifecycle. Adult tapeworms attach to human intestinal mucosa with to bilateral grooves. There are at least 14 different species of Diphyllobothrium spp. Capable of causing Dyphyllobothriosis, being D. latum and D. nihonkaiense the most frequent etiologic agents in humans. We present the clinical picture and endoscopic images on a patient with incidental finding of Dyphyllobothriosis in a colonoscopy.

Infection of guppies (Poecilia reticulata) with the Asian fish tapeworm Schyzocotyle acheilognathi in an urban stream in Brazil.

Schyzocotyle acheilognathi is a fish tapeworm native to Asia but has been reported as an alien species on practically all other continents. Its invasive potential is due to its low host specificity and high adaptability to different environments, and its spread to new areas can result in economic and ecological impacts. Studies reporting this species in South America are still scarce, indicating the need to monitor its dispersion to new areas. Herein, tapeworms found in guppies, Poecilia reticulata, from an urban stream located in Belo Horizonte, Minas Gerais, Brazil, in April 2021 were subjected to morphological and molecular characterization. As a result, 5/13 (38.5%) of the P. reticulata specimens evaluated were infected with intestinal tapeworms. It was verified a mean intensity of infection of 7.8 (1-25) and a mean abundance of infection of 3 (0-25). The morphology of the cestodes obtained was compatible with that of S. acheilognathi. Moreover, genetic analysis based on cytochrome c oxidase subunit 1 gene (Cox-1) revealed 97.89-99.77% similarity to isolates of this species from different localities. The possibility that S. acheilognathi is expanding to new regions of South America is discussed.

Diversity of aquatic parasites in pristine spring waters in Tehsil Babuzai, Swat, Pakistan.

Global access to clean and safe drinking water remains a formidable challenge, contributing to a myriad of health issues. This research exposes the existence of waterborne parasites in seemingly pristine spring waters, indicating potential contamination. Daily extensive sampling of Seventeen water sources was conducted in the untarnished freshwater streams of Tehsil Babuzai, District Swat, Khyber Pakhtunkhwa, Pakistan, from February to September 2021. Employing a stringent filtration process, the collected samples were effectively concentrated to detect any waterborne parasites. Subsequent application of the wet mount technique, combined with the capabilities of a compound microscope, revealed a disconcerting reality: all examined samples tested positive for various parasites. Identified parasites included Schistosoma species, Ascaris lumbricoides, Trichiuria trichiuria, Taenia saginata, Entamoeba histolytica, Amoeba, Lacrymana olor, Tintinnids, Paramecium, Dileptus, Euglena, Loxodes striatus, Acanthocyclops lynceus, Spondylosium, Oscillatoria, Cyanobacteria, Cilindros, Cilindros cerro, Commensal amoeba mature cysts,, Filliform larva of Strongyloides, Cercaria larva, Larva of Taenia solium, Egg of Enterobius vermiculais, Egg of Isospora belli, Egg of Tapeworm, Egg of Schistosoma species, Egg of Toxocara, and Egg of Diphyllobothrium latum. These findings clearly demonstrate the presence of a diverse array of parasites in the freshwater springs of Tehsil Babuzai, Swat, Pakistan. Implementing robust water treatment protocols, conducting regular monitoring and testing, and raising awareness about the risks of waterborne parasites are crucial steps to safeguard public health in the region.

Parasitic Contamination of Street Food Samples From School-Based Food Vendors of Dhaka City, Bangladesh

Street food is an old notion that arose from the need of quick access of light food to satisfy hunger. With the mention of street food in Bangladesh, a picture is visualized which includes open stalls with uncovered food, unawareness of vendors about hygienic practices, lack of safe source of water for cleaning and preparing food, increasing pollution in surrounding environment leading to infestation with various parasites and causing diarrhoeal diseases in people. The aim of the present study was to determine the prevalence of parasites in school-based street foods in Dhaka city. A total of 200 food samples were examined containing three representative types of street foods: tamarind water of snacks (79 samples), sliced fruits (71 samples) and fruit juices (50 samples) using Formal-ether concentration technique. Among them, 164 (82%) samples were contaminated with Entamoeba histolytica, Blastocystis hominis, Cystoisospora belli, Diphyllobothrium latum, Hymenolepis diminuta, Hymenolepis nana, Ascaris lumbricoides, Enterobius vermicularis, Trichuris trichiura and Ancylostoma duodenale. C. belli was the most prevalent (38%), followed by A. lumbricoides (33%) and B. hominis (33%). While comparing the parasite prevalence in three types of street foods, the highest prevalence was observed for C. belli (21.5% in tamarind water of snacks, 6.5% in sliced fruits and 10% in fruit juices) followed by A. lumbricoides, B. hominis and D. latum. There were significant associations (p&lt;0.05) among the different food types with B. hominis, C. belli, D. latum and A. lumbricoides positive samples. The study implicates that parasitic contamination of school-based street foods is alarming and it is urgent to take necessary steps to ensure the food safety. Bangladesh J. Zool. 51(2): 217-229, 2023

New Gland Type Discovered in Cestodes: Neurosecretory Neurons Release a Secret into the Fish Host

Free endings of peripheral neurosecretory neurons (NNs) were found in the tegument of plerocercoids of five species of parasitic cestodes of fish in an ultrastructural study. The free terminals secreted vesicles on the tegument surface and into the host body. Secretion was experimentally shown to increase in response to the host fish blood serum. In the cestode body, NNs form paracrine-type contacts near the cell membranes of the frontal glands, the tegument, and muscles, functioning as endocrine glands. Simultaneously, NNs function as exocrine glands and secrete the so-called manipulative factors, which influence the physiology of the host.

Results of the archaeoparasitological analysis of soil samples from the necropolis of the 2nd c. AD settlement of Pantikapaion

In the paper, the results of an archaeoparasitological analysis of a population group from the ancient Greek city of Panti-kapaion, located in the historical centre of the modern city of Kerch (Republic of Crimea), are presented. The aim of the study is to obtain information about the parasitic diseases, state of health, nutrition, and hygiene in a part of the population of the city. The materials for the study were soil samples obtained during the treatment of the human sacra from 31 burials of the necropo-lis, dated to the 2nd century AD. In the result of the conducted investigation, the parasitic spectrum of the studied population group was determined. Eggs of three species of helminths were found. The discovery of eggs of broad tapeworm (Dibothrio-cephalus latum) in the soil samples indicates the presence in the diet of the studied population group freshwater fish that were not sufficiently thermally treated. The archaeoparasitological data from archaeological sites of a chronologically close period in the territory of the Northern Black Sea region suggests that diphyllobothriasis was a decease far from being rare in this area. The presence of eggs of human roundworm (Ascaris lumbricoides) and whipworm (Trichuris trichiura) in the samples likely indicates the challenging sanitary-hygienic environment in the city and insufficient hygienic skills in the studied group. The analysis of the archaeoparasitological data within the historical context and utilisation of the archaeopathological material from the archaeological sites in the Northern Black Sea region permitted to identify the factors that had an influence on the wide spread of geohelminths. The humid and warm climate facilitated maturation of geohelminth eggs in the soil, while the human activities concerned with the irrigation of the territory, building public water collection points, and waste buildup in the streets, in combination with the high population density, were causing the rise of the infectious hazard. The relatively high incidence rates of Trichuris trichiura and Ascaris lumbricoides may indicate a high prevalence of certain bacterial intestinal infections transmitted by the identical route. The occurrence of geohelminths, alongside the archaeological data, can indicate a low social status of the studied population group.

PALEOEPIDEMIOLOGY OF DIPHYLLOBOTHRIOSIS: CULTURAL AND ENVIRONMENTAL FACTORS AFFECTING ADENOCEPHALUS INTENSITY AND PREVALENCE.

Peruvian and Chilean mummies and coprolites provide a source of population-based parasitological information. This is especially true of the fish tapeworm, Adenocephalus pacificus. Our analysis of Chinchorro and Chiribaya mummies and diversified coprolite samples from Chile and Peru show variation in infection. There is a statistically significant difference in prevalence between Chinchorro hunter-gatherer and Chiribaya mixed-subsistence contexts. Furthermore, the most pronounced differences occur between populations within these groups. Chinchorro differences in cemeteries at the same location can be related to El Niño-Southern Oscillation variations. Pronounced prevalence variations between 3 Chiribaya villages within 7 km of each other relate to fish distribution and preparation variation. As with other recent archaeoparasitology studies, eggs-per-gram data exhibit overdispersion.

Human diphyllobothriosis in Taiwan: A review of cases and molecular evidence of Dibothriocephalus nihonkaiensis

Diphyllobothriosis is an infectious disease caused by the consumption of raw freshwater or marine fish containing larvae of broad tapeworms (Diphyllobothriidae). In the present study, we critically reviewed all cases of human diphyllobothriosis reported from Taiwan, including unpublished reports from hospitals in Taipei. Genotyping based on mitochondrial DNA marker (cox1) confirmed that two of the recent cases were caused by Dibothriocephalus nihonkaiensis, which is not native to Taiwan and was probably imported with Pacific salmon infected with larvae of D. nihonkaiensis. The causative species previously reported in Taiwan could not be definitively confirmed. However, considering the distribution of Dibothriocephalus latus, which is not endemic in Taiwan, past cases diagnosed as D. latus are questionable.

Diphyllobothrium latum in a Russian Citizen Traveling in China.

Diphyllobothrium latum in a Russian Citizen Traveling in China.

Gastrointestinal Helminth Parasites of Pseudotolithus species from Lagos Lagoon, Lagos, Nigeria

The gastrointestinal helminth parasitic fauna of Pseudotolithus specimens, an economically important group of fishes fromLagos Lagoon, was examined to describe the effects of gastrointestinal helminth parasites on the state of health ofPseudotolithusspecies at Lagos Lagoon, Lagos, Nigeria. Fish specimens obtained from Makoko Fish Market were sacrificedfrom October 2019 to March 2020, and gastrointestinal helminth parasites were isolated. Pseudotolithus typhus (n = 76),Pseudotolithus elongatus(n = 104) and Pseudotolithus senegalensis(n = 120) were among the 300 fish specimens that wereanalysed. In total, 186 out of 300 fish specimens (62.0%) were found to have gastrointestinal helminth parasites after sixmonths of sample collection. Pseudotolithus senegalensis had the highest prevalence of infection, 76 (63.3%), followed by P.elongatus, 68 (65.4%) and P. typhus, 42 (55.3%), which had the lowest prevalence of infection. Five species of parasites,Capillaria sp., Echinocephalus sp., Orneoascaris sp., Diphyllobothrium latum, and Neochinorhyncus sp., were isolated.Neochinorhyncus and Orneoascarissp. had the highest prevalence among all Pseudotolithusspecies. The overall prevalenceof infection, 77 (41.4%), was recorded in Capillaria sp., while the least prevalence, 08 (4.3%), was from Echinocephalussp.The total prevalence for the present study is 62.0%. There was no significant difference in infection levels (P&gt;0.05) betweenthe two sexes, suggesting that neither sex was reliably affected by the parasite. Pseudotolithus species show a highprevalence of gastrointestinal helminths with a heavy parasitic burden, which may compromise the productivity,marketability, palatability, and or death of fish.

A possible circulation of a dominant Dibothriocephalus nihonkaiensis haplotype in Japan revealed by molecular analysis of clinical tapeworm samples.

Human diphyllobothriasis, caused by Dibothriocephalus nihonkaiensis, is prevalent globally, especially in regions where raw fish is consumed. Recent molecular diagnostic techniques have made species identification of tapeworm parasites and the determination of genetic variations among parasite populations possible. However, only a few studies done over a decade ago, have reported on the genetic variation among D. nihonkaiensis in Japan. The present study employed PCR-based mitochondrial DNA analysis to specifically detect D. nihonkaiensis from archived clinical samples, and to determine any genetic variation that may exist among the Japanese broad tapeworms from patients of Kanagawa Prefecture, Japan. Target genes were amplified from DNA extracted from the ethanol- or formaldehyde-fixed samples by PCR. Further sequencing and comparative phylogenetic analyses based on mitochondrial COI and ND1 sequences were also performed. In our results, all PCR-amplified and sequenced samples were identified as D. nihonkaiensis. Analysis of COI sequences revealed two haplotype lineages. However, clustering of almost all COI (and ND1) sample sequences into one of the two haplotype clades, together with reference sequences from different countries worldwide, revealed a common haplotype among D. nihonkaiensis samples in our study. Our results suggest a possible presence of a dominant D. nihonkaiensis haplotype, with a global distribution circulating in Japan. Results from this study have the potential to improve the management of clinical cases and establish robust control measures to reduce the burden of human diphyllobothriasis in Japan.