Clinical characteristics and epidemiology of intestinal tapeworm infections over the last decade in Tokyo, Japan: A retrospective review.

BACKGROUND: Tapeworm (cestode) infections occur worldwide even in developed countries and globalization has further complicated the epidemiology of such infections. Nonetheless, recent epidemiological data on cestode infections are limited. Our objectives were to elucidate the clinical characteristics and epidemiology of diphyllobothriosis and taeniosis in Tokyo, Japan. METHODOLOGY/PRINCIPAL FINDINGS: We retrospectively reviewed 24 cases of human intestinal cestode infection from January 2006 to December 2015 at a tertiary referral hospital in Tokyo, Japan. The patients included were diagnosed with cestode infection based on morphological and/or molecular identification of expelled proglottids and/or eggs and treated in our hospital. Fifteen and 9 patients were diagnosed with diphyllobothriosis and taeniosis, respectively. The median patient age was 31 years (interquartile range [IQR]: 26-42 years), and 13 (54%) were male. Most of the patients (91.7%) were Japanese. All patients were successfully treated with praziquantel without recurrence. Diphyllobothriosis was caused by Diphyllobothrium nihonkaiense in all patients. Taeniosis was due to infection of Taenia saginata in 8 [88.9%] patients and T. asiatica in 1 [11.1%] patient. All patients with taeniosis were infected outside Japan, as opposed to those with diphyllobothriosis, which were domestic. The source locations of taeniosis were mostly in developing regions. The median duration of the stay of the patients with taeniosis at the respective source location was 1 month (IQR: 1-8). CONCLUSIONS/SIGNIFICANCE: The cestode infection, especially with D. nihonkaiense, has frequently occurred, even in Japanese cities, thereby implicating the probable increase in the prevalence of diphyllobothriosis among travelers, as the number of travelers is expected to increase owing to the Tokyo Olympics/Paralympics in 2020. In addition, medical practitioners should be aware of the importance of providing advice to travelers to endemic countries of taeniosis, including the potential risks of infection and preventive methods for these infections.

Extracorporeal worm extraction of Diphyllobothrium nihonkaiense with amidotrizoic acid in a child.

Infection cases of diphyllobothriid tapeworms are not much in the below teen-age group. We report a case of Diphyllobothrium nihonkaiense infection in a 13-year-old boy. He presented with severe fatigue, occasional abdominal pain at night time. He also had several episodes of tapeworm segment discharge in his stools. By his past history, he had frequently eaten raw fish including salmon and trout with his families. Numerous eggs of diphyllobothriid tapeworm were detected in the fecal examination. We introduced amidotrizoic acid as a cathartic agent through nasogastroduodenal tube and let nearly whole length (4.75 m) of D. nihonkaiense be excreted through his anus. After a single dose of praziquantel, the child's stool showed no further eggs, and his symptoms disappeared. The evacuated worm was identified as D. nihonkaiense by mitochondrial cox1 gene analysis. Here we report a successful extracorporeal worm extraction from an infection case of D. nihonkaiense by the injection of amidotrizoic acid.

Growth, nutritional composition, and hematology of Arctic charr (Salvelinus alpinus) exposed to toxaphene and tapeworm (Diphyllobothrium dendriticum) larvae.

Toxaphene, an organochlorine pesticide, is the major contaminant of Arctic charr (Salvelinus alpinus) in the Canadian Arctic. The objective of this study was to investigate the combined effects of toxaphene exposure and infection by the larval stage of the cestode Diphyllobothrium dendriticum on fish growth, nutritional composition, and hematology. Hatchery-reared Arctic charr were subjected to one of four treatments: (1) oral administration of corn oil (control); (2) single oral dose of 10 microg/g wet wt toxaphene dissolved in corn oil; (3) exposure to 15 larval D. dendriticum; and (4) exposure to toxaphene and D. dendriticum in combination. The experiment was run for 104 days. Mean final toxaphene concentrations in charr muscle were 0.121, 0.336, 0.131 and 0.458 microg/g wet wt in each treatment group, respectively. Exposure to toxaphene and D. dendriticum decreased fish growth and condition as well muscle lipid and protein content. However, toxaphene did not increase the susceptibility of Arctic charr to parasite infection. Overall, 25 of 40 fish (62.5%) exposed to larval D. dendriticum became infected. Parasitized charr had decreased hematocrits and increased lymphocyte:erythrocyte ratios. Although total blood cell counts were decreased in all treatments compared with controls, differential leucocyte counts were unaffected. Our results suggest that toxaphene does not moderate Arctic charr resistance to D. dendriticum and there is no contaminant-parasite interaction at environmental levels.

Difilobotriasis humana por diphyllobothrium pacificum: un nuevo caso en Antofagasta, norte de Chile / Diphyllobothrium pacificum human infection: report of one case

We report a 26 years old asymptomatic female that expelled spontaneously a 39 proglottid strobila. The taxonomic study of proglottids and eggs found in the stool examination concluded that the patient was infected by Diphyllobothrium pacificum. This infection was probably acquired by the ingestion of raw fish (Sciaena deliciosa) with lemon in a traditional plate called "cebiche". She was treated with a single dose of praziquantel in a dose of 10 mg/kg body weight. After 24 h of treatment there were no scolices on feces. The patient did not have anemia. All eight family members studied, did no have the infection. A follow up stool examination three months later remained negative

[The action of fenasal on the cestode Diphyllobothrium latum]. / Vozdeistvie fenasala na tsetodu Diphyllobothrium latum.

The present study used an experimental invasion model to examine the invasion and behaviour of D.latum cestoda and its tissue structural disorders after in vivo phenasal administration. Phenasal caused an increased development of the granular endoplasmic reticulum in the cells of the tegument and yolk glands, their local spread, and a formation of vacuoles in the tegumental cells and an appearance of myelins which were rather great in size. There were no changes in tegumental microtrichia.

[The action of albendazole on the broad tapeworm]. / Deistvie al'bendazola na lentesa shirokogo.

Studies of the effects of the anthelminthic agent albendazole on the tissues of D. latum in vivo showed large shapeless protrusions of the outer tegumental cytoplasm on the surface of strobila, the mitochondrial degeneration in the tegumental cells and their nucleolar material segregation. After in vitro treatment cavitary formations in the outer tegumental syncytium, muscular fascicle loosening, decreased glycogen levels, and altered secret granules in the vitellaria were found. Thus, albendazole might affect the biochemical system of the parasite, since there is a relationship between some biochemical processes and morphological changes.

The effect of praziquantel, an antihelminthicum, on the peptidergic nervous system of the tapeworm Diphyllobothrium dendriticum.

The effect of the antihelminthic substance Praziquantel on the peptidergic nervous system in the adult gull-tapeworm Diphyllobothrium dendriticum was tested. As well as increasing muscle contraction the drug provoked a fall in the amount and size of the peptidergic nerve terminals in the subtegumental region. The number of small clear vesicles in the terminals also fell.

A comparison of the effects of flubendazole and thiabendazole on the larvae of Angiostrongylus cantonensis, Trichinella spiralis, Diphyllobothrium erinacei and Hymenolepis nana in mice.

Flubendazole or thiabendazole were administered orally to mice harbouring larvae of Angiostrongylus cantonensis, Trichinella spiralis, Diphyllobothrium erinacei or Hymenolepis nana 5-10, 28-33, 21-26 and 1-6 days post-infection respectively. All the mice infected with A. cantonensis were completely cured after treatment with flubendazole at 5 mg/kg/day for 6 days. No noticeable damage was found in the cerebral hemispheres of the mice treated with flubendazole and examined under a dissecting microscope. On the other hand, larvae were found in or on the cerebral hemispheres showing obvious haemorrhage in the control mice. The mice treated with flubendazole gained weight while the control mice lost weight. No larvicidal effect of thiabendazole on A. cantonensis was found at a dose of 10 mg/kg/day for 6 days. The mean reduction of larval T. spiralis in mice treated with flubendazole at 5, 50 and 100 mg/kg/day for 6 days was 64, 100 and 99% respectively. In comparison, thiabendazole showed no efficacy against T. spiralis larvae at 50 or 100 mg/kg/day. Mice harbouring plerocercoids of D. erinacei or H. nana larvae were not cured with either flubendazole or thiabendazole at 50 or 100 mg/kg/day for 6 days.

[Ultrastructural changes of the tegument on Diphyllobothrium erinacei and Hymenolepis nana treated with paromomycin sulfate in vitro].

The effects of paromomycin sulfate on Diphyllobothrium erinacei and Hymenolepis nana in vitro were examined morphologically with a scanning and a transmission electron microscope. D. erinacei was incubated for 3 and 6 hours at 37 degrees C in a culture medium, 0.85% physiological saline solution, containing 0.5% paromomycin sulfate. H. nana was incubated in the same medium for 3 hours only. The concentration of paromomycin sulfate was set basing on the results which Kitamoto (1968) reported as the concentration level in feces after administrations of this drug in a clinical survey. The effect of the drug on the surface structure in both worms appeared markedly in the neck region. Mechanisms of breakdown on the tegument were supposed as follows. First, microtriches were disconnected from the tegumental surface and many vesicles were formed in the cytoplasm of the tegument. Finally, the tegument layer was excoriated to exposed the basal lamina. In 6 hours incubation, this surface of the worm suffered more damage than that in 3 hours. The damage of the basal lamina as in the case of D. latum expelled from a man by paromomycin (Y. Tongu et al.), however, could not be observed in the present study in vitro. It suggests that the destruction of basal lamina usually observed with the expelled worms from clinically treated human might be due to the combined effect of digestive enzymes secreted from host and the mechanical impact of intestinal peristalsis. Some of the vesicles in the tegument may originate from mitochondria because the fine structure of cristae were occasionally observed remaining in the vesicles.

[In vitro and in vivo effects of paromomycin sulfate on tapeworm, especially Diphyllobothrium ditremum, and clinical effects on diphyllobothriasis in man].

Plerocercoids of D. ditremum were obtained from the Japanese surfsmelt (Hypomesus pretiosus) and administered to Golden hamsters. The animals were treated with paromomycin sulfate on the 16th day of infection. Anthelmintic effect was imperfection after administration of 530 mg/kg in 4 divided doses. Kamala and bithionol, however, successfully expelled the worm at the doses of 80 and 160 mg/kg and 12.5--70 mg/kg, respectively. The balloon-like structures and the other morphological changes of the tegument such as exfoliation of microtriches were remarkably observed on the worms immersed in 2% solution of paromomycin sulfate. Four human cases of diphyllobothriasis were treated with paromomycin sulfate at the doses of 46--56 mg/kg. No side effects were observed. Stool examination made 1 month after treatment were negative to the eggs. From these results, an anthelmintic effect of paromomycin sulfate was shown in the concentration of 2% on D. ditremum in vitro and in the dosage of 46--56 mg/kg in diphyllobothriasis lata patients.

[The effect of paromomycin sulfate on Diphyllobothrium latum].

Nine vital tapeworms were expelled from 7 patients with diphyllobothriasis latum by the modified Damaso De Rivas' method. Seven worms of them placed in 1% and 5% paromomycin solution (37 degrees C, pH 6.8--6.9) and 2 were in physiological saline at 37 degrees C as controls. In both 1% and 5% solution, the movement of worms stopped completely within 15 minutes. When they were taken out from the solution and washed thoroughly with physiological saline solution, they did not move any longer and died soon. As for the controls, they were moving with animation in physiological saline at 37 degrees C even after 60 minutes. Pathohistologically (H.E. stain), the scolex was seriously affected down to the immature proglottid; degeneration and desquamation of the villi and cuticle with somatic cells exposed and edematous swelling of the whole body. Somatic cells had degenerative necrosis, plasmatomy and disorder in the disposition of the circular muscle and longitudinal muscle were marked. Scanning electronmicroscopy revealed that the worms treated with paromomycin had the scolex remarkably impaired and destroyed the villous epithelial layer and cuticle of the immature proglottid adjacent to the scolex desquamated exposing somatic cells regardless of the duration of exposure to and the concentration of paromomycin, while in the controls, the scolex was normal and the worm surface was closely covered with normal villi. Aminoglycoside antibiotics are known to have neurotoxic effect in general. It seems to be related to this neurotoxicity that paromomycin solution stopped the movement of worms. The changes occurring in the tapeworms were irreversible and the worms died soon. It is suggested that when patients with diphyllobothriasis latum are administered with paromomycin, the alterations of the worms induced by paromomycin are accelerated by potent human digestive juice.

[Therapeutic effect of paromomycin sulfate in the treatment of Diphyllobothrium latum infections and an observation on the worm tissues affected by the drug].

Paromomycin sulfate (aminosidine) at a single dose of 32 to 53 mg/kg was orally given to 24 cases with proven diphyllobothriasis. Evaluation of efficacy of the drug was based on stool examination for the eggs after 3--4 weeks of treatment. The cure rate was obtained as 96% (23/24), and 30 worms were expelled from 24 patients. Only 1 unsuccessfully treated case of 34-year-old man was retreated at the same dose of the drug 3 weeks later to obtain the cure. Thirty worms were composed of a single worm each from 21 patients, 2 worms from a patient, 3 from 1, and 4 from 1. Scolices of 7 (23.3%) out 30 worms were found. Vomiting as side effect of the drug was observed in only a case of 4-year-old girl at 40 minutes after administration of the drug but it was mild and transient. Clinical symptoms or complaints before treatment were as follows; abdominal discomfort in 12 cases, abdominal pain in 7, diarrhea in 4, fatigue in 2, tinnitus, vomiting and frequent stool in 1 each. Seven cases were almost asymptomatic. Morphological changes of the worms immersed in paromomycin solution (aminosidine) (1.66 mg/ml) for 1, 2 and 3 hours were observed in comparison with worms kept in physiological saline solution. The destructive effects were fragmentation, dissolution and desquamation of the outer cuticle and basement membrane with PAS stain at 3 hours of the experiment. The damages were also demonstrated in subcuticular tissues composing of muscle layer and parenchymal cells.

[Ultrastructural changes in Diphyllobothrium latum from a man treated with paromomycin sulfate].

The effect of paromomycin sulfate on Diphyllobothrium latum in vivo in man was examined morphologically with a scanning and a transmission electron microscope. The worm used for this study was expelled from a man by treatment with paromomycin sulfate at 1 dose of 50 mg/kg. The surface of the neck region suffered great damage. The effect of paromomycin sulfate resulted in the progressive breakup of the microtriches and the tegument. Even the basal lamina was lost in some parts. As a result, the muscle layers were exposed directly to the air. In the immature proglottid, the basal lamina remained as an outermost surface, although paromomycin sulfate caused a great loss of the tegument. The mature proglottid was lacking microtriches in some parts. However, most of the tegument was covered with microtriches. The gravid proglottid remained without any loss of microtriches.

Tratamiento de Teniasis y de Himenolepiasis con Praziquantel / Treatment of Teniasis and Hymenolepiasis using Praziquantel

Se hizo una evaluacion de praziquantel en el tratamiento de 60 casos de teniasis por TAENIA SOLIUM o T. SAGINATA, utilizando dosis unica de 10 mg/kg en la mitad de los pacientes y de 5 mg/kg en la otra mitad, con 100% de curacion. Se trataron con la misma droga 30 pacientes con himenolepiasis, 27 con HYMENOLEPIS NANA y 3 con H. DIMINUTA, en quienes se obtuvo curacion de 81.5% en el primer grupo y de los 3 casos del segundo grupo. La dosis utilizada fue unica, de 25 mg/kg en la mitad de los casos y de 15 mg/kg en la otra mitad. El medicamento se tolero bien y no demostro efectos toxicos. Se concluye que el praziquantel tiene ventajas sobre los tenicidas y tenifugos usados en la actualidad y anteriormente. Se realizo una evaluacion clinica de los pacientes parasitados por tenias y aunque se obtuvo una amplia variacion de sintomas, atribuidos por los pacientes a esta parasitosis, no se pudo concluir hasta que punto esa sintomatologia era realmente debida a la teniasis. El signo predominante, presente en 88.3% fue la eliminacion de proglotides, bien fuera espontaneamente o con las materias fecales. En los casos de himenolepiasis, principalmente en ninos, predomino la sintomatologia digestiva, dificil de decidir hasta que grado era producida por esta parasitosis o por causas asociadas

Tests with a new compound (Praziquantel) against Diphyllobothrium latum.

Praziquantel (Droncit) is a new anthelminthic agent with a strikingly wide therapeutic index. The efficiency of the drug against Diphyllobothrium latum was tested in vivo and in vitro. With a drug dose of 50 mg/kg, artificially infected hamsters were completely cured. The threshold value of the active dose was between 2-5 and 10-0 mg/kg. Clinical trials with Praziquantel against human diphyllobothriasis show great promise, all of ten patients treated with 25-0 mg/kg of the drug being cured. Praziquantel had little effect on larval or adult diphyllobothriids in vitro.