A partial immunocharacterization of oncosphere and metacestode antigens of Taenia solium was carried out and compared to antigens from other taeniid species. The results indicated that T. solium metacestode antigen contained epitopes cross reactive with rabbit anti-sera to adult and oncospheral stages of the parasite. Oncospheres, however, consisted largely of stage specific antigens. Western blot analysis indicated that T. solium and T. pisiformis shared several oncospheral antigens; however, this was not the case with T. solium and T. hydatigena. Western blot analysis showed a time-related increase in the number of molecules recognized by antibodies to T. solium oncosphere and metacestode antigens in pigs experimentally infected with T. solium eggs. Oncosphere specific antibodies were detected in pig sera one month after experimental infection whereas antibodies to cystic stage antigens were not present until the 3rd to 5th month post infection. Sera from neurocysticercotic patients as well as naturally infected cysticercotic pigs recognized high molecular weight antigens in the oncospheres.

The results obtained in a study of seroprevalence by means of ELISA and immunoblot with crude larval extracts of Anisakis simplex using 1008 human sera from Spanish people showing no clinical suspicion of anisakidosis are given. For the evaluation of the results obtained by ELISA the Diagnostic Index (DI) was used, as the ratio between the optical density resulting from the test serum and the optical density of the negative control. Forty-seven sera showed DIs between 1.5 and 2, and 14 sera were greater than 2. After comparison of the immunoblot analysis with the immunorecognition pattern of a human anisakidosis reference serum, a diagnostic criterion could be established for those sera that, at a 1/100 dilution, showed a DI by ELISA greater than 1.5. Seven of 14 selected sera with DIs in ELISA higher than 1.3 showed anti-Anisakis specific IgE antibodies by RAST fluoroimmunoassay.

Biological control of parasitic nematodes of domestic animals can be achieved by feeding host animals chlamydospores of the nematode-trapping fungus Duddingtonia flagrans. In the host faeces, D. flagrans develop traps that may catch nematode larvae. In experiments on agar, D. flagrans had a growth rate between 15 and 60 mm/week at temperatures between 20 and 30°C. The presence of nematodes induces the fungus to produce traps. The rate of trap formation in D. flagrans has an optimum at 30°C, producing 700–800 traps/cm2/2 days, when induced by 20 nematodes/cm2 on agar. Approaching 10 and 35°C the ability to produce traps is gradually reduced. The response of chlamydospore production on agar to changes in temperature is the same as that for trap formation. On agar, at 10, 20 and 30°C D. flagrans loses its trap inducibility after 2–3 weeks. During the ageing process, increasing numbers of chlamydospores are produced up to a certain limit. The time for reaching maximum chlamydospore concentration coincided with the time for loss of induction potential. The implications of these results in relation to biological control in faeces are discussed.

Histological and histochemical studies were made on the excysted metacercariae and cercariae of Echinostoma revolutum and E. trivolvis. The paraoesophageal glands of the cercariae of both echinostome species stained positively with the intravital dyes, neutral red and nile blue sulphate. The paraoesophageal glands of excysted metacercariae of E. revolutum did not display positive staining with the intravital dyes. Some excysted metacercariae of E. trivolvis displayed positive staining of the paraoesophageal glands, while others displayed either a negative reaction or reduced staining. The lack of staining with intravital dyes, of paraoesophageal glands of excysted metacercariae of E. revolutum, suggests that the glands play a role in either the final stages of encystment, or in excystation in E. revolutum.

Soil sampling was conducted within Peninsular Malaysia with the aim of recovering entomopathogenic nematodes (Steinernematidae and Heterorhabditidae). Extensive sampling was performed in the Cameron Highlands, which are climatically distinct from the lowlands, and characterized by lower temperature and humidity. The major areas sampled in the lowlands were at the campus of Universiti Pertanian Malaysia (orchards and plantations), Puchong (secondary rainforest) and along the east coast of the country. Entomopathogenic nematodes were recovered using the Galleria mellonella baiting method. Nematodes were recovered from 10% of the 425 samples assayed. Identifications, using a PCR method, revealed that the 21 identified steinernematids belonged to two different genetic types and that four out of the five heterorhabditids were Heterorhabditis indicus, the remaining heterorhabditid being a new species. The nematodes are currently being screened to evaluate their biocontrol potential for use in Malaysia against foliage-feeding lepidopteran pests of crucifers.

The serotoninergic and peptidergic components of the nervous system of the cercaria of Sanguinicola inermis (Digenea: Sanguinicolidae) were examined using whole-mount immunocytochemistry and a plan of the nervous system has been described. Antibodies to serotonin (5-hydroxytryptamine, 5-HT) and the neuropeptides, FMRFamide, GFNSALMFamide (S1) and SGPYSFNSGLTFamide (S2) were used in the study. Immunoreactivity (IR) was demonstrated to all but the S2 antisera and showed a similar fundamental distribution. IR was found in paired cerebral ganglia located anteriorly within the body and connected by a cerebral commissure. From the ganglia paired ventral and dorsal longitudinal nerve cords extend anteriorly into the cephalic organ and into the body. There is no apparent connection with the tail. Several transverse commissures connect the longitudinal nerve cords throughout the body and several associated cell bodies have been located. A double-stranded dorsal and ventral longitudinal nerve cord extends the length of the tail and six cell bodies are associated with these cords, uniquely demonstrating either FMRFamide and S1, or 5-HT-like IR. Only 5-HT-like IR was found to extend into the posterior tail furcae and there appears to be a lack of any peripheral tegumental innervation. Double-labelling experiments suggest that the serotoninergic and peptidergic components of the cercarial nervous system are distinct.

The presence of naturally occurring entomopathogenic nematodes (epns) was surveyed in the West-Flanders province in the north-west of Belgium. In 21 sites of different agronomical situations, 130 soil samples were taken. Using the Galleria larva bait technique, 16 soil samples were found positive for epns. Fifteen samples were found to contain Steinernema spp. (nine S.feltiae, five S. affinis, one Steinemema species B3). The remaining positive sample contained Heterorhabditis sp. (North West European strain). The morphometric characters of the isolates were highly variable and did not correspond precisely to the original descriptions; however, biochemical characterization confirmed their identity. The epns were isolated from 50%, 18.8% or 12.3% of the samples taken in sand dunes, grassland or woodlands, respectively. S. feltiae and S. affinis were isolated in these three habitats; Heterorhabditis sp. was found in a grassland habitat. Steinernema feltiae was prevalent in loamy sand soils with a wide range of organic matter content; S. affinis, Heterorhabditis sp. and Steinernema species B3 were isolated in sandy loam soils. All the positive sample sites were in the pH range of 4.0–8.1. This is the first report of naturally occurring entomopathogenic nematodes in Belgium.

A total of 120 gastro-intestinal tracts and 960 faecal samples were examined to assess the prevalence and seasonal changes in the gastro-intestinal helminth parasites of Red Sokoto (maradi) goats slaughtered at Ibadan between May 1991 and April 1992. Egg types of strongyles, Strongyloides, Trichuris, Skrjabinema, Dicrocoelium and Moniezia were encountered in 93%, 83%, 44%, 0.9%, 2.3% and 31% of the faecal samples respectively. However, only strongyle, Strongyloides and Trichuris eggs occurred in large numbers and were more common during the rainy season than in the dry season. The parasites recorded and their prevalences were Haemonchus contortus (90.0%), H. ovis (5.0%), Strongyloides papillosus (80.8%), Trichostrongylus colubriformis (78.3%), T. axei (69.2%), Trichuris ovis (72.5%), T. globulosa (38.3%), Oesophagostomum columbianum (67.5%), Cooperia curticei (58.3%) Gaigeria pachyscelis (40.8%), Skrjabinema ovis (5.0%), Nematodirus battus (5.8%), Moniezia expansa (29.2%), M. benedeni (10.0%), Paramphistomum spp. (5.0%) and Cysticercus tenuicollis (33.3%). Haemonchus ovis is reported for the first time in Nigeria. Mixed infections were most prevalent. Young goats were more commonly infected and had higher worm counts than adult goats. Only Haemonchus, Trichostrongylus, Strongyloides and Cooperia spp. occurred in large numbers. Irrespective of the age of the goats, higher worm counts were generally encountered during the rainy season than in the dry season. The results are discussed in relation to the control of helminthiasis in grazing animals in Nigeria.

The random amplified polymorphic DNA (RAPD) assay was used to find molecular markers able to distinguish Trichinella spiralis from T. britovi, the two recognized Spanish Trichinella species. Fourteen Spanish Trichinella isolates, as well as reference Trichinella isolates representing the five species T. spiralis (T1), T. nativa (T2), T. britovi (T3), T. pseudospiralis (T4) and T. nelsoni (T7) and the three other taxa Trichinella T5, Trichinella T6 and Trichinella T8 of the genus, were characterized by RAPD using both purified and crude DNAs from infective muscle larvae (ML) and seven arbitrary primers. Three primers yielded diagnostic RAPD markers for the Spanish T. spiralis and T. britovi isolates as well as for the Trichinella reference isolates analysed, and in the case of crude DNAs the results were obtained in few hours. In addition, the species-specificity of the diagnostic RAPD markers from Spanish Trichinella isolates was studied by cross-hybridization assays. These assays confirmed that the selected diagnostic DNA fragments were not species-specific, but showed potential differences in the copy number among the examined Trichinella genetic clusters.

Enzyme electrophoresis has been used to examine genetic diversity in a population of Proteocephalus exiguus La Rue, 1911 (Cestoda: Proteocephalidae), parasitizing salmonid and coregonid fishes. Among 16 loci tested, three polymorphic loci (Ada, Got, Pgm-2) were found. Six different genotypes at the Got locus distributed in Hardy-Weinberg equilibrium suggest remarkable genetic flexibility of P. exiguus. Balancing selection is proposed as the mechanism maintaining genetic variation within the species. Data of genetic variability parameters (Ho = 0.064; He = 0.07; P = 0.19) and outcrossing rate (t = 0.842) of P. exiguus population have been provided. Possible factors affecting these data are discussed.

The effects of high fat diets (HFDs) on the host–parasite relationship of Echinostoma caproni in ICR mice were studied. Two HFDs were used, one consisting of a customized high fat diet (CHFD) with 45% lipid in the form of cottonseed oil, and the second consisting of an egg yolk diet (EYD) from domestic hens' eggs, with 31% lipid. Controls for both diets consisted of mice fed a standard laboratory diet with 5% lipid. Mice were each fed 25 cysts of E. caproni by stomach tube and necropsied 2, 3 and 4 weeks postinfection (PI). The weight of mice on the CHFD declined significantly compared to mice on the control diet, but there was no significant decline in weight of mice fed EYD compared to the controls. Worm recoveries from mice on both HFDs were significantly less than those from control hosts. There was a significant decline in worm dry weight, body area and uterine egg counts in worms on HFD compared to those on the control diet. Worms from hosts on HFD were located more anteriad in the gut than those recovered from mice on the control diet.

Two Norway rats, Rattus norvegicus, were found to be naturally infected with Echinococcus multilocularis in Japan. One of them was simultaneously infected with at least three different sized metacestodes of Taenia taeniaeformis. These two R. norvegicus rats and another R. norvegicus naturally infected with T. taeniaeformis and Capillaria hepatica were examined to see if they showed any antibody responses against these two cestode parasites with the view to obtaining more information on the importance of rats as the intermediate host for E. multilocularis. These R. norvegicus showed very poor antibody responses against the two cestode species, although the Wistar rats, R. rattus, experimentally infected with a single smaller sized metacestode of T. taeniaeformis showed stronger responses not only against T. taeniaeformis but also against E. multilocularis. Therefore the three R. norvegicus naturally infected with E. multilocularis and/or T. taeniaeformis demonstrated virtually no immune response, at least against these cestodes.