Utilization of a single-species molluscan community of Lymnaea peregra by metacercariae of Echinoparyphium recurvatum over a summer (July–September) period in south-east England showed an increase in the mean number of cysts per host with host size and time of exposure. Aggregation resulting from host and habitat-related factors increased with host size and time of exposure. Encystment within the host was restricted to the peripheral organs in smaller juvenile snails but as snails increased in size, metacercariae were distributed throughout the tissues.

The prevalence of helminths recovered from 108 birds representing eight species of Ciconiiformes from the Brazilian west-central region are presented. The digeneans Ascocotyle (Phagicola) longa, Clinostomum marginatum, Cotylotretus grandis, Ithyoclinostomum dimorphum, the nematodes Contracaecum multipapillatum, Desmidocercella ardeae, Eustrongylides ignotus, and the cestode Valipora mutabilis were identified. Contracaecum multipapillatum was the most prevalent species and E. ignotus the most pathogenic. Gross lesions due to infections with C. multipapillatum were characterized by ulcerative processes and hyperemia of the mucosa whereas those caused by E. ignotus consisted of perforations of the gastric mucosa and fibrotic tubular lesions in the gastric serosa. Histopathological examinations revealed necrosis and mixed leucocyte infiltrations and discrete compression of the mucosa in C. multipapillatum infections. Destruction of the mucosa and submucosa with the presence of fibrous capsules were observed in E. ignotus infections. Reports of accidental human infections, with severe clinical signs induced by these parasites, indicate the necessity of a proper evaluation of the pathogenicity of helminths of aquatic birds.

Thirty-six helminth species were found in 324 gulls examined during June 1994 to February 1996 from different localities of Galicia: 25 trematodes (Brachylaima sp., Brachylecithum microtesticulatum, Cardiocephaloides longicollis, Cryptocotyle lingua, Cryptocotyle concavum, Diplostomum spathaceum, Echinostephilla virgula, Galactosomum phalacrocoracis, Gigantobilharzia acotylea, Gymnophallus deliciosus, Gynaecotyla longiintestinata, Himasthla elongata, Himasthla quissetensis, Knipowitschiatrema nicolai, Levinseniella (Levinseniella) propinqua, Maritrema gratiosum, Maritrema linguilla, Microphallus primas, Microphallus similis, Ornithobilharzia canaliculata, Parorchis acanthus, Phagicola minuta, Psilostomum brevicolle, Renicola sp. and Stephanoprora denticulata), four cestodes (Alcataenia micracantha, Microsomacanthus ductilis, Tetrabothrius (Oriana) erostris and Wardium cirrosa), six nematodes (Anisakis simplex, Contracaecum rudolphii, Cosmocephalus obvelatus), Eucoleus contortus, Paracuaria adunca and Tetrameres (Tetrameres) skrjabini) and one acanthocephalan (Arhythmorhynchus longicollis). Tetrabothrius erostris was the most prevalent species (79.6%), followed by C. obvelatus (47.8%), C. lingua (37.4%), G deliciosus (30.9%), G. longiintestinata (22.8%), P. adunca (21.9%), B. microtesticulatum (17.6%), E. contortus (14.5%) and M. similis (9.3%). Microphallus similis was the dominant species, with a Berger-Parker index (BP) of 0.32, followed by T. erostris (BP=0.10). All species presented an aggregated dispersion except G. acotylea and G. phalacrocoracis, which showed a random dispersion. Species that seem to have the greatest predilection for specific sites along the intestine are: C. longicollis and A. micracantha (first third), Brachylaima sp., M. similis and G. longiintestinata (last third) and A. longicollis (second half). Eight species are known to be pathogenic to commercially important fish or molluscan species and several are pathogenic to humans.

The monoclonal antibody IACR-CCNj.3d has previously been used to isolate a gene (gp-col-8) with strong similarity to cuticular collagen from a mixed stage Globodera pallida cDNA expression library. The antibody has also been shown to label specifically the amphidial canal of pre-parasitic second stage juveniles (J2) of several plant nematode species without any reactivity on the cuticular surface, indicating that this protein is either not present or is inaccessible on the cuticular surface. This paper investigates the cross-reactivity of Mab IACR-CCNj.3d with Meloidogyne arenaria and the localization of the putative collagen protein on the cuticular surface of parasitic stages in planta and on the cuticular surface of juveniles inside eggs. The antigen was shown to be present in all developmental stages of the two species of potato cyst nematodes and M. arenaria. The antibody bound strongly to the amphidial canal and hypodermis of pre-parasitic J2 and adult females. The antigen was present on the cuticular surface of the sausage-shaped J2 in planta and of first stage juveniles (J1) inside the eggs. The presence of collagen on the surface of the cuticle of moulting stages of plant parasitic nematodes has been observed for the first time. It is clear that this protein has a role in the construction of the cuticle of the first stage juveniles and parasitic second stage juveniles, during moulting inside the eggs and in the root tissue, respectively.

Snails of the family Lymnaeidae are of great parasitological importance due to the numerous helminth species they transmit, mainly trematodiases (such as fascioliasis) of considerable medical and veterinary impact. The present knowledge of the genetics and host–parasite relationships of this gastropod group is far from adequate. Fascioliasis is caused by two species, Fasciola hepatica and F. gigantica, which, as in the case of other trematodes, show a marked snail host specificity. Many lymnaeid species involved in fascioliasis transmission still show a confused systematic-taxonomic status. The need for tools to distinguish and characterize species and populations of lymnaeids is evident and the present review concerns new molecular tools developed in recent years using nuclear ribosomal DNA sequences. The small subunit or 18S gene and the internal transcribed spacers ITS-2 and ITS-1 are analysed and evaluated as markers for taxon differentiation and relationships within the Lymnaeidae from genus and species levels to subspecies and population levels. rDNA sequence differences and genetic distances, and their value for reconstructing phylogenetic trees using different methods are considered. Nuclear rDNA sequences are appropriate tools on which to base a review of the systematics and taxonomy of the family Lymnaeidae, without excluding other valuable snail characteristics already available. A reconstruction of the lymnaeid system towards a more natural classification will undoubtedly be helpful in understanding parasite transmission and epidemiological features as well the dispersion of an emerging-reemerging disease such as fascioliasis. Nomenclature for nuclear rDNA genotyping in lymnaeids includes the main rDNA sequence regions able to furnish important information on interspecific differentiation and grouping as well as intraspecific variability of lymnaeid species. The composite haplotype code includes the rDNA markers arranged in order according to their well-known usefulness, in its turn related to their respective, more or less rapid evolutionary ratios, to distinguish between different taxonomic levels, from supraspecific taxa to the species level and up to the population level.

The aim of this study was to verify whether cross-reactivity appeared between Toxocara canis and Anisakis simplex in an experimental rodent model. No cross-reactions were detected using sera from mice infected with T. canis eggs. When responses obtained against T. canis ES antigen using sera from BALB/c and C57BL/10 mice infected with T. canis eggs were compared with those obtained by testing sera from mice infected with one A. simplex L3, an increase in cross-reactions was observed using the C57BL/10 strain.

Two studies were conducted to investigate the growth and activity of the fungus, Duddingtonia flagrans, within cattle faecal pats. Artificial faecal pats were constructed with the centre separated from the outer layer by a nylon mesh. Eight treatments were tested, by varying the presence/absence of Cooperia oncophora eggs and fungal spores within each layer. With parasite eggs in the centre layer, a statistically lower recovery of larvae was observed compared to both pats with parasite eggs in the periphery and pats with parasite eggs throughout both layers. Regardless of location within the pat, if co-located with the parasite egg, D. flagrans was found to be effective in trapping developing larvae. The reduction in recovery of larvae from pats with parasite eggs and fungal spores in the centre was found to be significantly higher than when parasite eggs were in the centre and fungal spores in the periphery. In the second study, pats were made up in two treatments: pats containing fungal spores and C. oncophora eggs (fungus) and pats containing C. oncophora eggs (control). The pats were incubated at low or high humidity. Ten pats were used in a cross over where five pats incubated at low humidity for 7 weeks were removed, water added and then incubated at a high humidity for 1 week. Another five pats were incubated at a high humidity for 7 weeks, aerated and incubated at a low humidity for 1 week. There was no apparent growth of fungus in faecal pats incubated at a high humidity and less than 20% of larvae were recovered. The growth of D. flagrans was observed in faecal pats incubated at a low humidity, but a corresponding reduction in the percentage recovery of larvae did not occur, except in week 4. No statistical difference between fungal and control pats was seen in the change over pats. Nematophagous activity was assessed throughout the study and observed in the first 4 weeks within the pats containing fungus.

The effects of temperature on survival, infectivity and in vitro encystment of Echinostoma caproni cercariae in artificial spring water (ASW) were studied. Effects of aging cercariae in ASW at various temperatures showed that at 23°C cercariae achieved 50% survival in 24 h, compared to 92 h at 12°C. Cercariae aged in ASW at 28 and 37.5°C showed 50% survival at 16 and 10 h, respectively. Cercariae aged at different temperatures for various times were used to infect juvenile Helisoma trivolvis (Colorado strain) snails maintained in ASW at 23°C. Index of infectivity was based on counting encysted metacercariae in the snails at 8 to 12 h post-infection. Cercariae aged at 23, 28 and 37.5°C showed 50% encystment at 6, 8 and 4 h, respectively. Cercariae aged at 4°C showed 50% encystment in 10 h and cercariae aged at 12°C showed 50% encystment beyond 16 h. Cercariae showed maximal longevity and infectivity in snails when aged at 12°C in ASW. For E. caproni, as in other digeneans, the infective period of cercariae is markedly shorter than the maximal life-span at any given temperature. Studies on in vitro encystment of E. caproni cercariae in Locke's solution:ASW (1:1) showed that encystment was optimal at 23°C (78% encystment) and that it declined to 44% at 28°C and became almost nil (0.02%) at 12 or 37.5°C.

Twelve extracts of 11 Guatemalan medicinal plants were initially screened in vitro for potential macrofilaricidal activity against Brugia pahangi, a lymphatic dwelling filarial worm, using concentrations from 125 to 1000 μg ml−1 of each extract that could be dissolved in the culture medium. Of 12 extracts used, the ethanol extract of leaves of Neurolaena lobata showed the strongest activity against the motility of adult worms. Subsequently, the extract of N. lobata was extensively examined in vitro for macro- and micro-filaricidal effects using a series of concentrations of 500, 250, 100, 50 and 10 μg ml−1. The effects were assessed by worm motility, microfilarial release by female worms and a MTT assay. The effect on the motility of adult worms was observed in a concentration- and time-dependent manner. The time required to stop motility of both sexes of adult worms was 6 h at 500 μg ml−1, 24 h at 250 μg ml−1, and 3 days for females and 4 days for males at 100 μg ml−1. The movement of females ceased at 4 days at a concentration of 50 μg ml−1 whereas the motility of males was only reduced. The loss of worm's viability was confirmed by the MTT assay and was similar to the motility results. These concentrations, including 10 μg ml−1, prevented microfilarial release by females in a concentration- and time-dependent manner. Concentrations higher than 100 μg ml−1 even induced mortality of the microfilariae. The present study suggested that the ethanol extract of Neurolaena lobata has potential macro- and micro-filaricidal activities.

Variability in Echinococcus granulosus is very important epidemiologically since strain characteristics may influence local patterns of transmission of hydatid disease. To classify the genotype presented in pig protoscoleces of the Slovak territory, a DNA-based approach has been used. Nucleotide sequences for a 471 bp region of the mitochondrial NADH dehydrogenase 1 (ND1) gene revealed a substantial affinity of isolates examined to the G7 genotype. Only a 0.9–3.4% sequence variation was recorded for E. granulosus samples compared with the reference G7 variant. To distinguish between G7 and G9 genotypes not differing in ND1 sequences, isolates were additionally examined by PCR-RFLP analysis of the nuclear ITS1 region. The resulting two-banded pattern is characteristic for the G7 strain. The data presented thus provides the first explicit evidence of the G7 genotype in the Slovak region.

Contamination of soil with feline and canine ascarid eggs in eight playgrounds in Kırıkkale, Turkey was investigated monthly from February 2003 to January 2004. Dog faeces were also collected and all samples were examined using the zinc sulphate centrifugal flotation method. Eggs of Toxocara were observed in 5 of 8 (62.5%) of playgrounds examined and in 15.6% of 480 soil samples. The number of eggs varied from 1 to 11. Eggs were observed in soil samples collected in February, March to June, August and November, with embryonated eggs appearing in June and August. Eggs of Toxascaris leonina and Taenia spp. and oocysts of Isospora spp. were also found in 1.5%, 1.0% and 0.2% of soil samples, respectively. Of 26 samples of dog faeces collected, 7.7% were contaminated with Toxocara spp. and 11.5% with Taenia spp. The presence of Toxocara eggs in the city playgrounds and dog populations suggests a potential human health hazard due to toxocariasis.

Clinical, parasitological and pathological responses of a tropical out-bred domestic rabbit to experimental Trichostrongylus colubriformis infection were used to evaluate its suitability as a laboratory host and model for studying the host–parasite relationships of T. colubriformis. In the first experiment, three groups each of 16, predominantly juvenile male, 8- to 10-week-old rabbits were given a single pulse infection with 500, 5000 or 25000 infective larvae (L3) of T. colubriformis, to represent low, medium and high levels of infection, respectively. A fourth group of 16 rabbits of similar age formed the uninfected controls. In the second experiment, two groups of 10 juvenile (8- to 10-week-old) and 10 adult (8- to 10-month-old) rabbits were similarly infected with 20000 L3, with appropriate naïve controls. Prepatency was 14 and 16 days and peak faecal egg counts occurred on days 24 and 20 after infection in young and adult rabbits respectively. Peak worm counts occurred on day 14 in both age groups and at all levels of infection. Subsequently, parasite burdens declined in a highly significantly dose- and age-dependent manner. At low and moderate levels of infection, approximately 83–98% of worms were recovered from the first 60 cm of the small intestine. Worm fecundity was also significantly influenced by host age and larval dose. Host age also had a significant effect on worm length. Infections with T. colubriformis were associated with a highly significant loss of body weight, accompanied by anorexia, diarrhoea and 25% mortality at high dose levels during the patent period of infection. There were no significant changes in packed cell volume and eosinophil counts at all ages and levels of infection but significant lymphocytosis occurred at the high dose level between days 7 and 21. Parasite-specific serum IgG responses were not related to worm burden. Overall, data showed that this miniature, docile and relatively inexpensive breed of rabbit is a potentially valuable laboratory host for studying T. colubriformis infections. The larval dose, duration of infection and host age were major determinants of host responsiveness to primary infections in this rabbit genotype.

The course of infection of 2-year-old ruffe (Gymnocephalus cernuus L.) from the Oder River (Germany/Poland) with third-stage larvae (L3) of Anguillicola crassus (Nematoda: Anguillicolidae) was investigated at monthly intervals between March 1994 and March 1995. Of 230 fish examined, 152 (66%) harboured viable L3. Monthly prevalences fluctuated between 12 and 96%; mean intensities ranged from 1.0 to 5.6 L3 per infected fish. Temperature-dependent differences in infection were noted with the prevalence and mean intensity of infection being significantly higher (Chi-Square test and Mann-Whitney-U-test, respectively; P<0.01) at water temperatures less than 10°C (cold period) than at those above (warm period). These differences remained significant even after the division of fish samples into two size classes (8.5–10.5 cm, 11–13 cm). Although the paratenic hosts may acquire infections year round, the results suggest that ruffe become infected mainly during the cold season and that the host's feeding ecology determines the final course of infection.

This communication reports incidental observations on Toxascaris leonina infections in a beagle breeding colony. Regular faecal monitoring demonstrated that T. leonina was endemic in the adult dam population within this colony. Small numbers of T. leonina eggs were also detected in the faeces of weaned pups from eight weeks of age possibly produced by a patent infection. This would mean a pre-patent period for T. leonina of 56 days or less. Worm counts on 10 pups showed that 60% of pups had acquired a T. leonina infection by 12 weeks of age. Since prenatal and lactogenic transmission do not occur and as the pups were kept in an environment which reduced chances of infection with T. leonina and there was no apparent source of paratenic hosts, the source of infection must have been embryonated T. leonina eggs from the whelping environment. These observations on T. leonina demonstrate that, if pups are exposed to an infected environment, patent infections may be seen in a younger age group than is normally associated with T. leonina infections.

The host specificity and distribution of Eubothrium crassum (Bloch, 1779) and Eubothrium salvelini (Schrank, 1790), morphologically fairly similar pseudophyllidean tapeworms parasitizing salmonid fish, were critically assessed on the basis of morphological and genetic evaluation of extensive material collected from different definitive hosts and geographical regions in Europe. Eubothrium crassum occurs in fish of the genera Salmo, i.e. salmon (S. salar – both freshwater and marine), sea trout (S. trutta trutta), brown trout (S. trutta fario), and lake trout (S. trutta lacustris), and also in Danubian salmon (Hucho hucho) and vendace (Coregonus albula). Eubothrium salvelini parasitizes Arctic char (Salvelinus alpinus) and brook trout (Salvelinus fontinalis) in Europe, and also whitefish (Coregonus wartmanni). Rainbow trout (Oncorhynchus mykiss), which is not a native European fish species, was found to be a suitable definitive host for both Eubothrium species, which may occur simultaneously in the same fish. Previous records of E. crassum in Arctic char and brook trout, and those of E. salvelini in fish of the genus Salmo were most probably misidentifications. Most studies of Eubothrium have involved salmonids from the northern part of Europe, with few records from southern and south-eastern Europe. This study also confirmed the reliability of the morphology of the apical disc for the discrimination of E. crassum and E. salvelini.

Clear spot lesions were formed on the liver surface in guinea-pigs repeatedly infected with swine lungworm, Metastrongylus apri. The largest lesion, measuring 0.25 cm in diameter, was hard and yellow and showed a large granuloma in the lobule. The nematode larva was located at the centre of the lesion. This finding is likely to be an example of erratic parasitism in guinea-pigs with metastrongylidiasis.

Cortisol production in fry of rainbow trout (367–456 mg body weight) infected with the ectoparasitic monogenean Gyrodactylus derjavini (mean intensities 4.7 and 4.9 parasites per fish) was studied at two temperature levels, 4–6°C and 11–12°C, respectively. Due to difficulties in obtaining an adequate amount of plasma from the small sized fish, the corticosteroid concentration was measured in the body fluid recovered (as supernatant) after sonication and centrifugation of whole fry. Infected fry at 11–12°C showed an elevated level of cortisol compared to uninfected fry. However, the cortisol concentration was lower than in fish exposed to handling stress. At 4°C, the cortisol level in infected fish compared to uninfected was insignificantly increased. The findings are discussed in relation to the role of monogeneans as inducers of secondary infections.

Outbred LACA mice and inbred NIH mice were administered low (100 ova), medium (1000 ova), high (3000 ova) and trickle (4×250 ova) doses of Toxocara canis ova and the effect of infection on activity was examined with respect to: (i) the dose of ova administered and (ii) the number of larvae recovered from the brain. Larval recovery from the brain was significantly reduced in NIH mice compared to LACA mice for the 1000, 3000 and trickle doses. Mice from each strain were divided into larval intensity groupings based upon the number of larvae recovered from their brain. Activity for each mouse was measured pre- and post-infection by observing its behaviour in the home cage. Activity was assessed by monitoring six different independent categories of murine behaviour – ambulation, grooming, rearing, digging, climbing and immobility. Within each behavioural category, the duration of time spent at each behaviour per mouse within one thousandth of a second, the number of short bouts performed and the number of long bouts of behaviour performed were recorded over a 20 min period. Activity of LACA and NIH mice differed prior to infection. LACA mice spent more time immobile compared to NIH mice, which ambulated and climbed more. Variations in activity were also observed between groups of mice prior to infection. The effect of infection differed by strain, by dose and by larval intensity. Post-infection LACA mice became more immobile and ambulated less. NIH mice showed reduced immobility, but while ambulation decreased digging and climbing increased post-infection. Short bouts of activity remained unchanged among LACA mice post-infection but showed an increase for some behaviours in NIH mice.

A multi-dot enzyme-linked immunosorbent assay (ELISA) was developed for the rapid and simple differential diagnosis of eosinophilic meningitis due to helminth infections. Ultrafiltered, purified antigens of Parastrongylus (=Angiostrongylus) cantonensis, Gnathostoma spinigerum and Taenia solium metacestodes, the most common parasites that invade the central nervous system and cause eosinophilic pleocytosis, were dotted onto a single nitrocellulose membrane strip. Antigen-coated strips, when blocked with 5% skimmed milk and dried, were stable for at least 6 months at 4°C. With peroxidase conjugated anti-human immunoglobulins and 4-chloro-1-naphthol as a substrate, antibodies in the corresponding patients' sera were clearly detected on the membrane strip as well-defined blue dots. Although cross-reactions between P. cantonensis and G. spinigerum antigens were observed with the use of partially purified antigens, the darkest dot correlated well with the infecting parasites in all cases. This fast, easy and economical multiple dot-blot ELISA method is useful for the differential diagnosis of eosinophilic meningitis caused by parasitic helminths, as semi-purified antigens can be easily obtained by ultrafiltration and used. Further improvements using highly specific parasite antigens may make this multi-immunodot test more suitable for wide-scale use in field studies and diagnostic laboratories.