The metacercaria of the heterophyid digenean Cryptocotyle concavum (Creplin, 1825) Lühe 1899, as seen by light and transmission electron microscopy, from the common goby (Pomatoschistus microps) is enclosed within a rigid cyst wall composed of four layers of parasite origin surrounded by a host-derived capsule. The encysted parasite contains anterior glands with secretion-filled ducts opening at the anterior extremity of the ‘head’. Excystment in vitro occurred most readily at 40–42°C on treatment with alkaline bile salts following pretreatment with acid pepsin. After 1 min in pepsin, the metacercaria became intermittently active, periods of rotation lasting 1–3 sec alternating with quiescent periods of 20–40 sec. Metacercariae excysted, some in less than 1 min, after transfer to bile salts. The metacercaria emerged through a hole, which appeared in the cyst wall at the site of application of the ‘head’ of the parasite. Some of the anterior gland ducts of excysted metacercariae were empty, indicating that their secretions are involved in penetrating the cyst wall. Following pretreatment in acid pepsin, no excystment occurred in EBSS (Earle's balanced salt solution) ranging in pH from 2.0 to 4.0, but above pH 4.0, excystment increased, reaching a maximum between pH 7.5 and 8.5. Pepsin and bile salts were not essential for excystment and metacercariae emerged, although less readily, in alkaline EBSS with or without acid EBSS pretreatment. Some emerged in distilled water with no pretreatment. Although no excystment occurred in acid pepsin or in EBSS at pH 2.0 and already-excysted metacercariae were rapidly killed by acid (pH 2.0), acid pepsin pretreatment enhanced excystment in alkaline bile salts.

The egg shell of Dipetalonema viteae separated from the oolemma and became highly convoluted at an early stage of development. No second oolemma or trilaminate membrane was seen. Channels containing electron dense material (thought to be nutrient material from the uterine wall) were formed between adjacent embryos. Many developing embryos died.

Microvilli were formed by the uterine wall and developing embryos were closely apposed to these (again presumably to obtain nutrient).

Embryos emerged from the egg in the uterus and were born as unsheathed microfilariae.

The tegument of Postorchigenes gymnesicus has been studied by scanning and transmission electron microscopy. The general body tegument is spinous and contains mitochondria, biconcave disc-shaped vesicles bounded by an unitary membrane and displaying a protein content, and scarce spherical bodies. The tegument covering specialized body regions is aspinous. Few vesicles were evident in the tegument covering the suckers and oesophagus, being more abundant in the metraterm and cirrus where the tegument is thicker. Laurer's canal has a thick tegument with sparse vesicles, mostly arranged close to the apical membrane. A direct association was evident between the basal lamina underlying the spines and the muscular subtegumental fibres, suggesting a motile character for the spine.

Female ICR mice, 5 to 6 weeks old, were exposed by stomach tube to 25 metacercarial cysts of Echinostoma caproni per mouse. At 14 days post-exposure, mice were fed by stomach tube clorsulon (1000 mg/kg, 500 mg/kg and 100 mg/kg) or rafoxanide (50 mg/kg, 25 mg/kg and 5 mg/kg) dissolved in dimethylsulphoxide (DMSO) carrier and mebendazole (1000 mg/kg and 500 mg/kg) or arprinocid (100 mg/kg and 50 mg/kg) suspended in a 2:1 polyethylene glycol (PEG)/DMSO carrier. All drugs were obtained from Merck Inc. (Rahway, New Jersey, USA) and only single dose regimes were used. Experimentally infected mice that served as controls received either DMSO or 2:1 PEG/DMSO carriers or were not given the carrier. Mice were necropsied 15, 16, 18 and 20 days post-exposure to worms. Doses of 100 mg/kg of clorsulon and 50 mg/kg of rafoxanide were 100% effective in eliminating the echinostomes on day 1 post-administration of the anthelmintics. Mebendazole and arprinocid were ineffective in eliminating worms at 1 or 2 days post drug administration.

The species of Onchocerca described in this paper was received some months ago from Mr. J. L. Stewart, M.C., M.R.C.V.S., from Tamale, Gold Coast Colony. The cysts containing the parasites are found most commonly in the subcuticular connective tissue of the inter-costal muscles; but they are also found elsewhere, usually in a superficial position. Mr. Stewart in a letter accompanying the material, draws attention to their superficial resemblance to Cysticercus bovis.

We have previously described the characteristics of a relatively non-pathogenic laboratory strain of S. mattheei, attenuation of which was apparently caused by passage in hamsters. We now show that chronic infection with this avirulent strain largely protects sheep from the manifestations of acute schistosomiasis when challenged with a virulent strain of S. mattheei.

Four sheep were each infected with 10 000 cercariae of the avirulent strain and, together with four worm-free sheep, challenged 63 weeks later with 10 000 S. mattheei cercariae of a pathogenic strain. Four more sheep acted as uninfected controls. Following challenge, the animals were weighed and bled weekly for PCV and serum protein determinations, and egg counts were carried out fortnightly on faeces taken from the rectum. Red cell and albumin turnover were monitored for two weeks immediately before challenge and for a similar period before necropsy, when the adult worms were recovered by perfusion and tissues sampled for histopathology and egg counting.

The unvaccinated sheep developed severe disease 6—12 weeks after exposure characterised by marked anaemia, hypoalbuminaemia and hyper-gamma globulinaemia coinciding with the passage of blood-stained faeces and progressive inappetence. In the vaccinated sheep, there was and even earlier rise in gamma globulins, but the other clinico-pathological changes were generally slower to develop and much milder in severity. The parasitological data showed that although this was partly due to a reduction in the establishment of the challenge worm population the main factor was probably a reduction in the fecundity of these worms.

Data on the interposition of the immunoreactive nerve cords in Cercaria parvicaudata Stunkard & Shaw, 1931 (Trematoda: Renicolidae) and its chaetotaxy were obtained. The nervous system of C. parvicaudata was described using immunostaining of 5-hydroxytryptamine and FMRFamide immunoreactive nerve elements. The morphology and distribution of sensory receptors were analysed using scanning electron microscopy and the silver nitrate impregnation technique. Our integrated approach to the study of the nervous system revealed a clear colocalization of surface papillae with nerve cords and commissures in C. parvicaudata. The structure of the nervous system in C. parvicaudata differs partly from the classical model that defines the entire nomenclature of chaetotaxy.

Despite many recent advances in the study of nematicides and in the breeding of resistant strains of plants, control of cyst forming nematodes is still best accomplished by crop rotation; to be fully effective, it is also desirable that a field in which it is proposed to grow a susceptible crop should be sampled and an estimate made of the population of nematodes present: such an estimate is susceptible to different sources of error and although it is possible to decrease the magnitude of these errors a compromise has to be reached between the conflicting claims of precision on the one hand and the expenditure of man-power on the other; it is desirable that this compromise be based on factual data rather than guesswork; good estimates of the order of magnitude of the different types of error are therefore desirable.

Trehalose 6-phosphate (T6P) synthase (TPS; EC 2.4.1.15) was isolated from muscles of Ascaris suum by ammonium sulphate fractionation, ion-exchange DEAE SEPHACELTM anion exchanger column chromatography and Sepharose 6B gel filtration. On sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE), 265-fold purified TPS exhibited a molecular weight of 66 kDa. The optimum pH and temperature of the purified enzyme were 3.8–4.2 and 35°C, respectively. The isoelectric point (pI) of TPS was pH 5.4. The studied TPS was not absolutely substrate specific. Besides glucose 6-phosphate, the enzyme was able to use fructose 6-phosphate as an acceptor of glucose. TPS was activated by 10 mM MgCl2, 10 mM CaCl2 and 10 mM NaCl. In addition, it was inhibited by ethylenediaminetetra-acetic acid (EDTA), KCl, FeCl3 and ZnCl2. Two genes encoding TPS were isolated and sequenced from muscles of the parasite. Complete coding sequences for tps1 (JF412033.2) and tps2 (JF412034.2) were 3917 bp and 3976 bp, respectively. Translation products (AEX60788.1 and AEX60787.1) showed expression to the glucosyltransferase-GTB-type superfamily.

Fasciola hepatica secretes proteolytic enzymes to aid it to penetrate and migrate through the host tissues. Two of these proteinases have been purified and shown to be cathepsin L-like, and are termed, CL1 (27.5 kD) and CL2 (29 kD). The immunogenicity of these proteinases was investigated over the course of an experimental infection and following drug treatment. Four groups of rabbits were studied: group 1: orally infected with 50 metacercariae; group 2: infected and treated 8 weeks after infection; group 3: infected, treated at week 8 and reinfected at week 13 and group 4: non-infected control group. Sera were collected weekly from each group until week 20 postinfection. CL1 and CL2 were incubated with the different sera and then analysed by gelatin substrate polyacrylamide gel electrophoresis (GS-PAGE). Analysis of groups 1, 2 and 3 showed that CL1 and CL2 neutralizing antibodies appear at week 5 post-infection. In group 1, these remained throughout the 20 weeks of infection. In group 2, neutralizing antibodies disappeared at week 13, that is, 5 weeks after anti-Fasciola treatment. In group 3, CL1 and CL2 neutralizing antibodies disappeared at week 13 but reappeared by week 15, that is 2 weeks after reinfection. Pooled sera from group 4, showed no inhibitory capacity. ELISA results using CL1 and CL2 as antigen, correlate very well with the inhibitiory time course observed by GS-PAGE. These results suggest that purified cathepsin Ls are antigenic molecules recognized early in the infective process and capable of inducing a specific humoral response, strong enough to neutralize, at least partially, their enzymatic activity.

A thermostable serum constituent is described which has a lethal effect on the miracidia of F. hepatica. This requires the thermolabile components of guineapig complement for its lethal action. It is apparently similar to substances present in other normal sera and which have an antagonistic action on a wide range of organisms. The mode of action is discussed.

The absorption spectra of haemoglobins from A. glabratus and P. corneus and from B. (P.) globosus and B. (B.) tropicus angolensis were established. There was no difference between the spectra of snails which transmit Schistosoma mansoni or S. haematobium and the spectra from related insusceptible species.

The snail haemoglobins produced absorption spectra which differed from mammalian pigments only in the position of a single peak.

Snail blood occasionally produced additional small peaks in the ultra-violet region, which may have been due to blood proteins other than the respiratory pigment.

High performance thin layer chromatography (HPTLC) was used to determine phospholipids and sphingolipids in the intestinal mucosa of ICR mice infected with Echinostoma caproni for two weeks. The major phospholipids detected in both infected and non-infected mucosa were phosphatidylcholine (PC) and phosphatidylethanolamine (PE). HPTLC-densitometric analysis showed that there was a significant decrease in the weight of both PC and PE in the intestinal mucosa of infected mice compared to that of the uninfected controls. Cerebrosides and sulphatides, but not sphingomyelin, were identified in the intestinal mucosa of both infected and uninfected hosts. There was an apparent increase in the cerebroside content of the mucosa of infected versus control mice. The pathobiochemical changes seen in the polar lipid content of infected hosts probably reflect the feeding and behavioural activities of E. caproni in the mouse intestine.

The nematode Angiostoma glandicola sp. n. found parasitizing Megaustenia sp. snails (Pulmonata: Helicarionidae) collected in Dong Nai Province, Vietnam, is described and illustrated. The new species is characterized by its unusual host location (the digestive gland) and in having: two circles of cephalic probolae, six lips each bearing two prominent papillae, amphids situated at posterior of lips, the presence of lateral alae, an enlarged stoma, a club-shaped pharynx with cuticularized valves in the bulb, the nerve ring situated on the junction of the corpus and isthmus and the excretory pore opposite the bulb. Oviparous females have a mid-body vulva position, long reflexed ovaries and short divergent uteri, and a conical tail with a slightly triangular tip. Males have long, curved, not distinctly cephalate spicules and a small gubernaculum, nine pairs of pedunculate genital papillae (GP) incorporated into the bursa (three precloacal, six postcloacal in two groups: GP 4–7 closely behind the cloaca and GP 8–9 distanced), of which GP 5 and 8 terminate on dorsal edge of the bursa and GP 8 and 9 are fused at the base, the bursa nearly reaches the tail tip, unpaired precloacal GP and a pair of ventral circumcloacal GP not incorporated into bursa. It clearly differs from other species of the genus by having cephalic probolae vs. no cephalic probolae and the specific number and disposition of male GP. A partial sequence of D2D3 large subunit (LSU) rDNA was obtained and subjected to phylogenetic analyses. Relationships within the Angiostoma genus are discussed.

The importance of developing effective assays to diagnose, monitor and evaluate human lymphatic filariasis has been emphasized by the World Health Organization. Presently, few immunodiagnostics are available for filarial monitoring programmes. The Wuchereria bancrofti (Wb) SXP-1 parasite protein, with 84% homology to Brugia malayi (Bm) SXP-1, was found to be highly immunogenic. WbSXP-1 is one among the diagnostic candidate molecules that were used for developing a rapid-antibody-flow-through diagnostic kit for filariasis. Studies were initiated with the aim of developing monoclonal antibodies against recombinant WbSXP-1 and prospective applications for the detection of both circulating Wb and Bm antigens in serum samples from infected individuals. The monoclones 1A6C2 of subclass IgG1k, and 2A12F8 of class IgM, specifically detected Wb and Bm microfilaria isolated from patients and did not show cross-reactivity with other filarial recombinant antigens. We anticipate that this work will address the problems faced in the rapid diagnosis of human lymphatic filariasis in endemic areas in developing countries.

Adult Ascaris suum were dissected to obtain different worm components (body wall, body fluid, ovaries, uterus and oesophagus) which were used as antigens when testing 95 sera of naturally A. suum-infected Iberian pigs by enzyme-linked immunosorbent assay (ELISA) and Western blot (WB). Pigs with patent Ascaris infections had significantly lower ELISA optical density values than pigs without adult worms when using the body fluid and the body wall as antigens. A poor negative correlation was found between adult intestinal worm burden or eggs in faeces and specific antibody responses, measured by ELISA and WB using all antigens. By WB, the recognition of specific bands was variable, but three groups of bands with molecular weights of 97 kDa, 54–58 kDa and 42–44 kDa were generally recognized by sera from naturally infected pigs as well as from hyperimmunized pigs when using the five antigen extracts. The ELISA and WB techniques may be used for immunodiagnosis, using somatic adult worm antigens, to declare young pigs to be Ascaris-free but cannot be used for individual Ascaris-diagnosis in adult Iberian pigs.

The Chinese sleeper (Perccottus glenii), an invasive Asian fish, was first registered in Germany in 2009 (westernmost extent of its invasive range). We sampled Chinese sleepers from two localities on the Bücherlgraben creek (a tributary of the River Naab) in south-eastern Germany in November 2015 and examined them for parasite infection. Twelve taxa were registered, including ciliates (unidentified Trichodina), a monogenean, three cestode species, two digenean taxa, two acanthocephalan species, two nematode species and one mollusc glochidia. Infracommunities consisted of 1–5 species, with 10% of fish uninfected. Three parasite species (Acanthocephalus anguillae, Gyrodactylus luciopercae and Pseudocapillaria tomentosa) were recorded on Chinese sleepers for the first time. The results highlight the important role of the Chinese sleeper as a second intermediate host in the life cycle of heron and grebe parasites. The Chinese sleeper parasite community displayed low homogeneity at both localities sampled, with allogenic parasites (metacercariae and mesocercoids) mostly shared. Differences between localities were mainly caused by autogenic parasites. No invasive parasites associated with the Chinese sleeper were observed in the study area, all parasites being representatives of European fauna. This supports the hypothesis of introduction via the aquarium trade or through transport with commercial fish.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) regulates a wide range of biological processes, including pathogen evasion. In the present research, the GAPDH gene of Haemonchus contortus (HcGAPDH) was cloned and characterized. Specific primers for the rapid amplification of cDNA ends (RACE) were designed based on the expressed sequence tag (EST, AW670737) to amplify the 3′ and 5′ ends of HcGAPDH. The full length of cDNA from this gene was obtained by overlapping the sequences of 3′ and 5′ extremities and amplification by reverse transcription polymerase chain reaction (RT-PCR). The biochemical activities of the recombinant protein HcGAPDH, which was expressed in prokaryotic cells and purified by affinity chromatography, were analysed by assays of enzymatic activity, thermal stability and pH. The results showed that the cloned full-length cDNA comprised 1303 bp and encoded a peptide with 341 amino acid residues which showed sequence similarity to several known GAPDHs. The biochemical assay showed that the protein encoded by the HcGAPDH exhibited enzymatic activity with NAD+ as a cofactor. HcGAPDH was stable between pH 5 and 9 and maintained activity at high temperatures of up to 75°C. The natural GAPDH of Haemonchus contortus detected by immunoblot assay was approximately 38 kDa in size, and the recombinant HcGAPDH was recognized strongly by serum from naturally infected goats.

Galls, in the inflorescences of various species of grasses, caused by nematodes have been known since Steinbuch first described them, in 1799, in the flowers of Agrostis capillaris and Phalaris phleoides. Since that time they have been found in several other species of grasses and have been studied principally by entomologists interested in galls caused by insects. The causative organisms have received but little serious attention from helminthologists in recent years.