Molecular detection of Diphyllobothrium nihonkaiense in humans, China

The cause of diphyllobothriosis in 5 persons in Harbin and Shanghai, China, during 2008–2011, initially attributed to the tapeworm Diphyllobothrium latum, was confirmed as D. nihonkaiense by using molecular analysis of expelled proglottids. The use of morphologic characteristics alone to identify this organism was inadequate and led to misidentification of the species.

[Morpho-functional changes of cloacal bursa of the herring gull in experimental infection with gull tapeworm]

Using the methods of light microscopy, the quantitative changes in the cells of the cloacal bursa of herring gull (Larus argentatus mongolicus) chicks were studied during experimental infection with gull-tapeworm Diphyllobothrium dendriticum. The area of the follicles within the bursa and the number of eosinophils in the infected chicks were found to increase. In the follicles the number of blast cells and large lymphocytes was elevated. The reduction of small lymphocytes and plasma cells numbers in the infected gulls may be due to a slower cell cycle or cell migration into the inflammatory focus. Overall, the changes in the bursa indicate the suppression of the B-link of the host immune system in tapeworm invasion.

[The reaction of the bursa and thymus eosinophils in the herring gull after the experimental infection with gull-tapeworm]

Using the methods of light microscopy, eosinophil topography, quantitative and qualitative changes (degranulation level of and a cationic protein content) were studied in the thymus and bursa of 36 herring gull nestlings Larus argentatus mongolicus (Suskin, 1925) 2 weeks after experimental infestation with gull-tapeworm Diphyllobothrium dendriticum (Nitsch, 1824). Eosinophils in the thymus were located in trabecules, mainly close to the blood vessels, thymic (Hassall's) corpuscles and also directly inside them, while in the bursa they were found within the internodular space. As compared with the control bird counts, relative eosinophil count in the birds with an average invasion intensity was increased 3.8 times in the thymus and 2.5 times in the bursa. In birds with high invasion intensity, these counts were increased 4 times in the thymus and 1.2 times in the bursa.

[Changes in mast cell composition in the hamster duodenum in experimental diphyllobothriosis]

The morphometric investigation was performed to study the reaction of mast cells (MC) in mucosal lamina propria of hamster duodenum to experimental infection with tapeworm Diphyllobothrium dendriticum. The invasion was found to result in a significant increase of MC cells absolute content, changes in the proportions of their functional groups, increased anaphylactic MC degranulation, enhanced MC precursor migration and their accelerated differentiation.

A rare case of diphyllobothriasis from Pondicherry, South India

Diphyllobothriasis is an intestinal parasitic infection caused by the ingestion of raw fresh-water fish containing the infectious larvae of Diphyllobothrium spp. This infection is uncommon in India. We report a case of diphyllobothriasis that occurred in Pondicherry, India, in a 5-year-old boy hailing from a fishing community. He attended the Pediatric OPD with spontaneous discharge of segments of the adult parasite. The segments (macroscopically and microscopically) were identified as those of Diphyllobothrium latum. The stool examination also revealed characteristic oval eggs.

Selected pathological, immunohistochemical and ultrastructural changes associated with an infection by Diphyllobothrium dendriticum (Nitzsch, 1824) (Cestoda) plerocercoids in Coregonus lavaretus (L.) (Coregonidae)

The pathological changes induced by an infection of Diphyllobothrium dendriticum (Nitzsch, 1824) plerocercoids in powan, Coregonus lavaretus (L.), from Loch Lomond, Scotland, were assessed using immunohistochemical and ultrastructural techniques. In a sample of 26 powan, the occurrence of encysted plerocercoids of D. dendriticum on the outer surface of the stomach was 38.5% (n = 10) with the number of cysts ranging from 4 to 15 and measuring 4.2 +/- 1.0 mm x 3.4 +/- 0.9 mm (mean +/- SD). Histological examination of intestinal samples also revealed plerocercoids (2-21) encapsulated within a proliferation of mesenteric fibrous tissues of the gastric wall and, occasionally, by the gut lamina propria-submucosa and lamina muscularis. In section, cysts were tri-layered and were formed from a series of concentric whorls of fibroblast and collagen fibre-based connective elements. The extent of necrosis within each muscle layer and the serosa of the stomach differed, notably within the latter that was marked by a chronic inflammatory reaction and fibrosis. Within the cyst and around it, a large number of degranulating mast cell/eosinophilic granule cells were seen, in addition to melano-macrophage centres. Immunohistochemical staining of sections of infected stomach revealed a high density of elements, in close proximity to plerocercoids, staining positive for serotonin, bombesin, substance P and galanin. Uninfected material did not present the same levels of activity. Sections through both infected and uninfected tissue were also tested for elements containing vasoactive intestinal peptide, met-enkephalin, calcitonin gene-related peptide, neuropeptide Y and nitric oxide synthase, but these were absent.

Diphyllobothrium latum: A case of an incidental finding

Colorectal cancer screening can be performed by fecal occult blood testing, sigmoidoscopy, double contrast barium enema or colonoscopy. Colonoscopy has the significant advantage that polyps can be removed during the same procedure. Occasionally, colonoscopy can also reveal unexpected findings, including parasitic infections, even in asymptomatic patients. Tapeworms or cestodes are hermaphroditic parasites, which can live for considerable periods of time in the human gastrointestinal tract. Fish tapeworm (Diphyllobothrium species) are endemic in various parts of the world, the commonest species being Diphyllobothrium latum. Humans are the main definitive host for D. Latum and the majority of individuals harbouring the parasite are asymptomatic, while 40% of infected individuals may have low vitamin B12 levels. We describe a case of D. latum infection found on routine colonoscopic screening for colorectal cancer in an asymptomatic patient, which was successfully treated with praziquantel. The infection likely arose following raw fish (sushi) consumption.

A surgically confirmed case of breast sparganosis showing characteristic mammography and ultrasonography findings

A case of breast sparganosis was confirmed by surgical excision of a worm (fragmented into 5 pieces) in a 59-year-old Korean woman suffering from a palpable mass in the left breast. Mammography and ultrasonography characteristically revealed the presence of several well-defined, isodense and hypoechoic tubular masses, in the upper quadrant of the left breast, each mass consisting of a continuous cord- or worm-like structure. During surgery, a long segment of an actively moving sparganum of Spirometra sp. and 4 small fragments of the same worm, giving a total length of 20.3 cm, were extracted from the upper outer quadrant of the left breast and the axillary region. The infection source remains unclear, because the patient denied ingesting any snake or frog meat or drinking untreated water.

Annoying vacation souvenir: Fish tapeworm (Diphyllobothrium sp.) infestation in an Austrian fisherman

Diphyllobothriosis is infestation with the fish tapeworm. Although the worldwide incidence has decreased in recent decades, increased travel and the new popularity of dishes involving raw fish (e.g. sushi) may provide a higher risk of infestation in formerly low-risk areas. We report an Austrian fisherman who passed a 75 cm tapeworm segment in his stool. Infestation presumably occurred 14 months earlier during a fishing tour in Alaska. At presentation, the patient was asymptomatic, reported no weight loss and showed neither anaemia nor eosinophilia. He was cured with a single dose of 10 mg/kg body weight praziquantel.

Reappearance of human diphyllobothriasis in a limited area of Lake Como, Italy

BACKGROUND

Very few sporadic cases of autochthonous diphyllobothriasis have been reported in Italy during the past 20 years, probably due to the drastic decrease or disappearance of some fish species, mainly Perca fluviatilis L., known as the intermediate host of the infective larval stage of this tapeworm. However, increasing consumption of raw or undercooked fish during the last years as influenced by Oriental cuisine, played an important role in a number of new single cases of the infection or microepidemics.

PATIENTS

We describe six cases which were diagnosed within a period of 4 months, which all originated from the area of Lake Como (Lombardy region). All subjects had previously eaten raw perch fillets. Four individuals complained of gastrointestinal signs and symptoms, whereas two were asymptomatic.

DISCUSSION

Parasitological diagnosis was achieved in four cases by recovery of typical operculated eggs in stool specimens; in two others by morphological features of proglottids recovered from feces. Treatment with niclosamide, as a single oral dose, cured the infection in all subjects. This is the first report of this infection in Italy in the last 10 years.

Tapeworms (cestodiasis)

Nearly all of the cestodes, or tapeworms (class Cestoda in the phylum Platyhelminthes, the flatworms), are parasitic as adults in the intestinal tract of vertebrates. This article discusses the epidemiology, diagnosis, and treatment of taeniasis, diphyllobothriasis, hymenolepiasis, dipylidiasis, and other tapeworm infections.

[Morphohistochemical studies of the carp intestines in bothriocephaliasis]

Morphohistochemical study of host-parasite relationships after the infection of carp with Bothriocephalus opsariichthydis was conducted. It has been found out that the whole parasite's strobile comes into close contact with tissues of the mucous membrane of the carp's gut. The destruction of the gut's wall results from its digestion or lysis that is confirmed by high activity of acid phosphatase. Together with epithelium of the mucous membrane of the gut exodermis of the helminth takes an active part in the digestion that is proved by similar histochemical processes.

[Changes in the argyrophil stroma of the liver of fishes infested with the pleurocercoids, Triaenophorus nodulosus and Diphyllobothrium dendriticum (Cestoidea, Pseudophyllidae)]

The argentaffine stroma of the liver of some fishes (Perca fluviatilis, Exos lucius, Paracottus kessleri, Coregonus autumnalis migratorius, Thymallus arcticus) is described. The nature and depth of pathological changes in the argentaffine stroma of the liver at its infection with pleurocercoids of pseudophyllids depend on the infection intensity, host's specificity and on the biocoenotic relationships of hydrobionts in a waterbody.