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PubMed1979

The morphology and ultrastructure of the female reproductive ducts in the metacercaria and adult of Cryptocotyle lingua (Creplin) (Digenea:Heterophyida).

Encysted metacercariae of C. lingua require 38 days in the fish second intermediate host before they are infective to the bird definitive host. Morphogenesis of the metacercaria is arrested shortly after 38 days. The ovary and testes are recognizable at 10 days. By 38 days the lumen of the oviduct is apparent and cilia form on the epithelial lining. The receptaculum seminis remains rudimentary. The cells of the uterine primordium are vacuolated but no lumen is present. Laurer's canal, vitelline glands, and Mehlis's glands are not recognizable. Morphogenesis is resumed in the bird intestine. During day 1 the oviduct and receptaculum seminis complete their development; Laurer's canal and the uterine lumen are formed. During day 2 the cilia in the female ducts become motile and the vitelline and Mehlis's glands are present. Fertilization occurs on day 2 to day 3 and eggs arrive in the uterus on day 3.

Animals↗
PubMed2006

The life cycle of Haplorchis pumilio (Trematoda: Heterophyidae) from the Indian region.

The life cycle of the heterophyid fluke, Haplorchis pumilio is elucidated for the first time from the Indian region. Various stages in the life cycle were established based on observations made on natural infections found in snails and fish in a freshwater stream at Visakhapatnam, India and experimental infections carried out in the laboratory. The thiarid snail, Thiara tuberculata served as the first intermediate host and a wide range of freshwater fish as second intermediate hosts. Natural infections with adult flukes were found in the piscivorous birds Ardeola grayii and Bubulcus ibis. Adults were raised experimentally in day-old chicks. Distinguishing features of the cercaria of H. pumilio are: a large body size (200-224 x 92-96 micro m), body-tail ratio of 1:2.1 and densely distributed pigment granules in the parenchyma imparting a brownish tinge to the body. Natural infections with metacercariae were found in the freshwater fish Channa punctatus, C. orientalis, Puntius sophore, Gambusia affinis and fingerlings of Cyprinus carpio and Liza macrolepis. Additionally, experimental infections were established in Therapon jarbua, Esomus danricus and Oreochromis mossambica. Metacercariae were embedded in the caudal muscles of fish and heavy infections induced mortality. Metacercariae were infective at about 15 days of age.

Animals↗
PubMed1976

Haplorchoides Chen, 1949 (Haplorchinae: Heterophyidae) in freshwater fishes.

Two metacercariae of Haplorchoides, recorded in the fingerlings of over a dozen species of freshwater fishes, are described and illustrated. Ovigerous flukes were recovered from older specimens of two species of fishes procured from the same locality. Comparison of taxonomic characters of the juveniles and adults suggests that they are conspecific. The metacercariae and adults are assigned to two new species, Haplorchoides pearsoni and H. Mehrai. The observations, presented herein, necessitated a review of the species named under this genus and a revision of the generic diagnosis. The reports on fish intermediaries of H. attenatus have been enlarged.

Animals↗
PubMed2001

Effects of heavy metal pollution on swimming and longevity in cercariae of Cryptocotyle lingua (Digenea: Heterophyidae).

Effects of heavy metal pollution on the cercariae of the marine trematode Cryptocotyle lingua (Creplin) were studied by measuring horizontal swimming rate (HSR) and longevity. These factors are important for transmission to the next host, a fish. Cercariae released by Littorina littorea (L.) collected from polluted and unpolluted sites were compared. Both HSR and longevity were significantly reduced in cercariae from the polluted environment. Cercarial quality was therefore reduced, directly or indirectly, by development within a metal-accumulating host. Cercariae released by hosts from a clean environment were subjected to nominal concentrations of 2 and 3 mg/l copper, 1 and 2 mg/l zinc, 2 and 5 mg/l iron and 2 and 4 mg/l manganese in artificial seawater. In all cases the HSRs and longevity were reduced. The effect was more pronounced in the higher concentrations. The significant HSR tests indicate that the absorption and effect of metals occurred within 1 min. The cercarial tegument, specialized for absorption in endoparasitic environments, is possibly responsible. Cercariae may therefore be excellent indicator organisms for pollution. The pollution-induced reductions in cercarial quality seem capable of producing transmission failure. Heavy metal pollution could therefore alter parasite populations and communities.

Animals↗
PubMed2005

Redescription and surface ultrastructure of Pygidiopsis macrostomum (Digenea: Heterophyidae).

Pygidiopsis macrostomum Travassos, 1928, a poorly known species originally described from a single specimen from Rattus norvegicus (Erxleben, 1777) in Brazil, is redescribed on the basis of metacercariae from the mesenteries of naturally infected guppies Poecilia vivipara Bloch and Schneider, 1801 (Poeciliidae), and adults obtained from an experimental infection of hamsters. Pygidiopsis macrostomum is characterized by the absence of oral spines, vitellaria extending forward to ventral sucker, uterus reaching pharyngeal level, X-shaped excretory vesicle, and an oral sucker/acetabulum ratio of 1:0.8. The surface ultrastructure shows that the tegument of the metacercaria does not strongly differ from that of adults. The brush-shaped spines of P. macrostomum are similar to those reported for Pygidiopsis summa and Pygidiopsis ardeae, but no differences in spine shape were observed throughout the body.

Animals↗
PubMed2006

Taxonomic status, redescription, and surface ultrastructure of Ascocotyle (Phagicola) pindoramensis n. comb. (Digenea: Heterophyidae).

Pygidiopsis pindoramensis Travassos, 1928, is redescribed from the holotype and specimens obtained from experimental infections of hamsters with metacercariae of the naturally infected poeciliids Poecilia vivipara and Phalloptychus januarius from Rio de Janeiro, Brazil. Ascocotyle (Phagicola) pindoramensis (Travassos, 1928) n. comb. is proposed, based on the presence of a solid, tapering muscular posterior prolongation of the oral sucker and Ascocotyle (Phagicola) mollienisicola (Sogandares-Bernal and Bridgman, 1960) is synonymized with A. (P.) pindoramensis because of the identical morphology and measurements of adults and metacercariae, similar spectrum of fish intermediate hosts (poeciliids), and the same site of infection of the metacercariae. Trematodes designated as Pygidiopsis pindoramensis, previously reported from Argentina and Mexico, represent another species of Pygidiopsis Looss, 1907, because they possess circumoral spines and their oral sucker is devoid of the posterior muscular prolongation. Data on the surface morphology of metacercariae and adults of A. (P.) pindoramensis are inferred from scanning electron microscopy observations.

Animals↗
PubMed1988

Stictodora sp. (Trematoda: Heterophyidae) recovered from a man in Korea.

Two adult specimens of heterophyid fluke, which belong to the genus Stictodora, were collected from the stool of a 24-year old man after chemotherapy. The flukes were morphologically characterized by their small body size (0.90~0.98 mm long and 0.38 mm wide) and peculiar structure of ventrogenital sac with armed gonotyl (with about 12~15 spines) not enveloping genital pore. Species identification is deferred until more worms are obtained, although they closely resemble Stictodora fuscatum (Onji and Nishio, 1916). The patient used to eat raw flesh of mullets and gobies, which are regarded as the infection source of Stictodora sp., together with 3 other kinds of heterophyids described elsewhere. This is the first record of human Stictodora infection in the literature.

Journal Article↗
PubMed2000

Surface ultrastructure of excysted metacercariae of Haplorchis taichui (Trematoda: Heterophyidae).

The morphology of newly excysted juvenile Haplorchis taichui was studied using a light and a scanning electron microscope (SEM). The reproductive organs were well developed. The whole body surface was covered with numerous transverse rows of scale-like spines, which had 3-11 points at the tip. The spines on the dorsal were similar with those on the ventral surfaces in shape, size and number of points. The spines in anterior were digitated into 10-11 points, then 8-9 points and 7 points. The presence of 3 points in each spine was observed in the area adjacent to the excretory pore. Two types of sensory papillae existed throughout the body: type I, ciliated knob-like swellings and type II, round swellings of the tegument. The rapid maturation of H. taichui results from the development of both internal and external organs during the newly excysted stage.

Animals↗