The redia, cercaria and metacercaria of Opisthodiscus nigrivasis from Ancylastrum fluviatilis are described. Observations were made on the behaviour of the cercaria and experimental infections with metacercariae have been carried out in laboratory-raised frogs of the species Rana ridibunda. Some features of the morphology of these juvenile stages and aspects of the behaviour of the cercaria are compared with those of others related species.

The best known biological cycles in the Diplodiscinae are those of Diplodiscus subclavatus (Pallas, 1970) Diesing, 1836, and Megalodiscus temperatus (Stafford, 1905) Hanvood, 1932. The first was described by Looss (1892), who showed that the molluscs Planorbis nitidus, Pl. vortex, Pl. rotundatus, Pl. spirorbis and Pl. contortus acted as intermediate hosts. More recently Milka (1970) found young forms of D. subclavatus in Pl. planorbis and gave a brief description of the redia and cercaria of this species.

In view of Morgan's (1943) contribution “The Physalopterinae (Nematode) of Aves”, it is unnecessary here to review the literature in this group; but it should be noted that Morgan regards Physaloptera alata as having four pairs of pedunculated papillae on the male tail, whereas Cram (1927), reproducing Rudolphi's (1819) and Seurat's (1914) descriptions, states the number to be five. Ortlepp (1922), Li (1934) and Singh (1949) also described the number as five.

TPase and SDII activities were studied in various tissues of Ceylonocotyle scoliocoelium maintained in vitro in medium A for 15 days, using standard histochemical techniques. Results were compared with the normal activities of these enzymes in the tissues of worms freshly collected. Low ATPase and SDH enzyme activities in the tissues of cultured flukes indicated their low metabolic rate. Intensity of enzymatic reactions was also found to be tissue specific. The suitability of culture medium ‘A’ for the in vitro cultivation of amphistomes is discussed.

The young of all nest dwelling birds are fed continuously by their parents. It is the latter therefore who choose the food which is mostly composed of that which the adult birds feed on. Under these circumstances it is therefore not surprising that fledglings when still in the nest are found to harbour helminths of which the larval forms were contained in the food.

An account is given of the general morphology of Echinopardalis lerouxi n.sp., from the intestine of Canis adustus, in Northern Rhodesia. This new acanthocephalan agrees with the characters of the genus Echinopardalis, and differs from all the other known species included in this genus. The characteristic features of the species are enumerated.

13 species of ccstodcs from 13 species of Philippine birds are reported from Palawan Island. Raillietina (R.) palawanensis n. sp., from Chalcophaps i. indica, has three or four testes, and a cirrus pouch 93 to 108 µm long, 28 to 45 µm wide, and its egg capsules are 10 to 12 µm long, seven to nine µm wide, each containing four to six eggs. Raillietina (R.) passeriformicola n. sp., from Gracula religiosa palawanensis, has seven to nine testes, and a cirrus pouch 134 to 170 µm long, 47 to 68 µm wide. Its egg capsules are 79 to 115 µm wide, containing 7 to 12 eggs each. Raillietina (R.) fischthali n. sp., from Ducula aenea palawanensis, has 12 to 15 testes, and a cirrus pouch 130 to 150 µm long, 52 to 72 µm wide. Its egg capsules are 130 to 200 µmi wide each containing 50 to 70 eggs. Raillietina (R.) johri Ortlepp, 1938, is redescribed. Anonchotaenia chauhani Mukherjee, 1965 is shown to be a junior synonym of A. gaugl Singh, 1952.

Ring-necked pheasants were exposed to artificially limited 10-day infections with heterakids either from 0-10 or 10–20 days old. The number and length of worms developing from a subsequent challenge dose were compared with those in nonimmunized control birds and with those in birds that had been exposed to a continuous immunizing infection for a total of 49 days: 28 days before challenge and 21 days during the challenge infection.

The ultrastructure of the dorsal oesophageal gland ampulla and its relationship with the oesophagus, oesophageal ultrastructure, and control mechanisms in oesophageal activity were studied. Terminal ducts of the sub-ventral glands open through the oesophageal crown at the base of the buccal cavity. The terminal duct of the dorsal oesophageal gland running through the dorsal gutter opens to the exterior at the rim ‘groove’ of the buccal capsule. The posterior oesophageal region is clavate and the cuticle of the lumen folds to form outlet valves, ‘valvulae’. An inconspicuous oesophago-intestinal valve (three lobes) connects oesophagus and intestine and is visualized in the open and shut position. In the female reproductive tract, with the exception of the uterus, the cells lie on a thick, irregular (convoluted) basal lamina. The apical plasma membrane of the uterus, and seminal receptacle, extend into the lumen by microvilli-like projections with which spermatozoa make intimate contact. The lumen of the uterus is filled with oocytes, fertilized and unfertilized. Testicular cells have two parts linked by a rachis. Spermatocytes are elongated with a large nucleus, distinct nuclear membrane, and many granules. The apical membrane of the rachis forms long microvilli-like projections with balloon-like tips. The amoeboid spermatozoa contain membrane specializations, a nucleus devoid of a membrane, and are enclosed by a pseudopodial-like extension.

This paper forms a preliminary account of the occurrence of some helminths parasitic in sheep and pigs in South-Eastern England. The rocks of the Wye district are mainly Cretaceous, while Romney Marsh, with its extensive sheep population, is alluvial. Earlier workers have already considered certain helminthic parasites of this region. The present writer uses Morgan's technique. Thirteen helminths parasitic in the gut of sheep and lambs are listed with notes, and a record is made of some other observations, including the identification of Ascaris lumbricoides and Œsophagostomum dentatum from swine.

The present paper describes a new species of Dermadena (Digenea) parasitizing Pseudobalistes naufragium in Puerto Pizarro, northern Peru, using light and scanning electronic microscopy (SEM). Additionally, molecular analysis was also performed to determine the phylogenetic affinities of Dermadena within the Lepocreadiidae. The new species is differentiated from Dermadena spatiosa, Dermadena stirlingi and Dermadena lactophrysi by presenting a curved and well-developed external seminal vesicle. Also, SEM revealed numerous dome-shaped tegument protuberances forming glandular papillae with transversal wrinkles arranged roughly in concentric rows around the acetabular region, varying in size from large at the middle of the body to small at the margin. In the molecular phylogeny, the new species formed a well-supported clade with sequences of species from the Lepocreadiidae, confirming that it belongs to this family.

The present study pertains to two nematode genera, Pungentus Thome & Swanger, 1936 and Discolaimoides Heyns, 1963 which were collected from around the roots of Juglens regia, the common walnut tree in Kashmir. They are described herein as new species. Discolaimoides is recorded here for the first time from India.

The writer in 1934 briefly described this nematode which was collected from the common musk-shrew at Hyderabad Deccan, creating for its reception the new genus and species Gastronodus strasseni. The following account deals with the anatomy of the worm and the close relationship which exists between the genera Gastronodus Singh and Spirocerca Railliet and Henry, 1911.

This worm is of common oċcurrence in the musk-shrew, Crocidura caerulea, at Hyderabad and it forms largo nodules on the stomach walls of the host. In certain cases smaller nodules were also found in the mesentery. These are medium sized worms and when freshly extracted appear blood red in colour. The body is coiled and generally flexed at the extremities. In males and young adult females the body is of almost uniform diameter with blunt anterior and posterior ends, whereas in fully grown and gravid females the posterior 2/3 of the body is distinctly thicker than the anterior portion. The males are slender and smaller than the females. The cuticle is thick and bears fine transverse striations which are set quite close together. Irregular transverse wrinkles are also present on the body wall. The cervical papillae are located at the level of the nerve-ring and have the appearance of fine bristles.

The extent of New Zealand's freshwater fish-parasite diversity has yet to be fully revealed, with host–parasite relationships still to be described from nearly half the known fish community. While advances in the number of fish species examined and parasite taxa described are being made, some parasite groups, such as nematodes, remain poorly understood. In the present study we combined morphological and molecular analyses to characterize a capillariid nematode found infecting the swim bladder of the brown mudfish Neochanna apoda, an endemic New Zealand fish from peat-swamp-forests. Morphologically, the studied nematodes are distinct from other Capillariinae taxa by the features of the male posterior end, namely the shape of the bursa lobes, and shape of spicule distal end. Male specimens were classified into three different types according to differences in the shape of the bursa lobes at the posterior end, but only one was successfully characterized molecularly. Molecular analysis indicated that the studied capillariid is distinct from other genera. However, inferences about the phylogenetic position of the capillariid reported here will remain uncertain, due to the limited number of Capillariinae taxa characterized molecularly. The discovery of this new capillariid, which atypically infects the swim bladder of its host, which itself inhabits a very unique ecosystem, underlines the very interesting evolutionary history of this parasite, which for now will remain unresolved.

Specific and non-specific esterases have been localized in sections and whole mounts of Avitellina lahorea, an intestinal parasite of sheep and goats. Non-specific esterases (NSE) were found in the sucker muscles, post-acetabular ganglia, nerve trunks, tegument, excretory canals, cirrus sac, vagina, uterus and the inner membrane of the embryophore. Acetylcholinesterase (AChE) was observed in all the above organs, including vas deferens and sperm ducts, but was absent from excretory canals and eggs. Tests with acetylthiocholine iodide (AThChI) revealed the nervous system, vas deferens, sperm ducts, uterus, cirrus sac and the vagina. The intensity of activity of AChE and AThChI was weak compared to NSE.

Albino mice were infected per os with 1000 infective larvae of Ancylostoma caninum and pulmonary superoxide dismutase activity was studied after completion of lung migration. The total superoxide dismutase activity per mg of lung protein was elevated by 15% in infected mice. Of the two forms of superoxide dismutases studied, that containing Cu-Zn was elevated by 44%. this suggests that A. caninum in mice may result in histopathological changes leading to transient pulmonary oxygen toxicity.

The different stages of the life cycle of parasites are important components of ecosystems. Changes in environmental conditions may affect free-living stages, host–parasite interactions and ecosystem functioning. The larvae of Chordodes nobilii, which belongs to the parasitic phylum Nematomorpha, are susceptible to extreme temperatures and different pollutants, but the effects of pH and moderate temperature variations have not been evaluated yet. Our objective was to assess the effect of temperature, pH and their interaction on the infectivity of C. nobilii larvae to Aedes aegypti larvae over time. Larvae were treated with factorial combinations of temperature (18, 23 and 28°C), pH (7, 8 and 9) and time periods (24 and 48 h). Results show a highly significant interaction among all variables. The highest infectivity was recorded at 18°C and pH 7 at 24 and 48 h, and the lowest one at 28°C and pH 8 at 24 and 48 h. Infectivity differed significantly among the three temperatures only at pH 8 and 48 h, decreasing with increasing temperature. Our study is the first report of the effect of pH on a Nematomorpha species and suggests that the infectivity of C. nobilii larvae may be affected negatively by an increase in temperature and its interaction with pH and time. Since parasites must be considered for a better understanding of the effects of stressors on freshwater ecosystems, our results may help in the design and analysis of studies of anthropogenic impact.

Temnocephalids are ectosymbionts of various freshwater animals. A species tentatively identified as Temnosewellia aff. vietnamensis (Platyhelminthes: Rhabdocoela: Temnocephalidae) is reported based on materials collected from the body surface of the freshwater crabs Eriocheir japonica (Brachyura: Varunidae) and Geothelphusa exigua (Potamidae) in Kagoshima, southern Japan. The temnocephalid is characterized as follows: the cirrus composed of a cone-shaped shaft and a cylindrical introvert 42–77 μm long; the introvert covered with approximately 30 vertical rows of fine sharp spines; the four seminal receptacles; and a long, curved oviduct with vaginal gland; a pair of gland cells (Haswell's cells) present anterior to the excretory ampullae. Bayesian inference trees using partial nuclear 28S rDNA (28S) and mitochondrial cytochrome c oxidase subunit I (COI) genes supported that the specimens collected from both crab species are conspecific but these also showed the geographical variations among them on both 28S and COI. The previous records of the genus Temnosewellia in East to South Asian countries are assembled and shown on the map (fig.7, this paper).

Strongyloidiasis and leptospirosis are neglected tropical diseases that have affected many countries across the world. In this study, we evaluated the seroprevalence of Strongyloides stercoralis among patients with leptospirosis in northern Iran. We evaluated 156 laboratory- or clinically confirmed leptospirosis cases. The overall seroprevalence of S. stercoralis was 32.0% (95% confidence interval (CI): 27.4–36.5%, 50/156). Seropositivity was significantly associated with agricultural activities (odds ratio (OR): 2.84, 95% CI: 1.0–8.77) and gastrointestinal disorders (OR: 2.4, 95% CI: 1.1–4.9). Laboratory findings indicated that seropositivity of S. stercoralis was significantly associated with decreased levels of platelet and elevated levels of creatinine, alanine aminotransferase and aspartate aminotransferase (P < 0.05). Our findings suggested a higher exposure to S. stercoralis larvae among patients with leptospirosis. The public health and medical communities may benefit from this research through preventive measures to improve farmers’ knowledge and awareness regarding strongyloidiasis and leptospirosis and the associated risk factors.

Urocystis prolifer Villot, 1880 is an intestinal parasite of Sorex spp. In the Palaearctic. There are significant differences in the descriptions of both adults and stages of ontogenesis of U. prolifer as described by various authors. The experimental infection of intermediate hosts with cestodes has been conducted. An overview of the geographical distribution, infestation of the definitive hosts and the development of the metacestode stages of U. prolifer are presented. The cestode is characterized by an extensive geographic area in the Palaearctic, wide host specificity and very high rates of infection of its definitive host. Urocystis prolifer has been recorded mostly in the taiga and forest zones of Palaearctic. Fourteen species of Sorex were registered as the definitive host. Redescription of U. prolifer and an amended generic diagnosis are provided. A complete description of the ontogeny from oncosphere to fully developed metacestode is given. Features of development of the metacestode are an asexual larval reproduction, the absence of the anterior and posterior obturator valve in the cyst of the fully developed urocyst, as well as excretory bodies.