Two new species of Paramphtstomum from cattle are described, namely, P. hiberniae n.sp. and P. scotiae n.sp., first collected from Irish and Scottish cattle respectively.

A brief account of gametogenesis and early cleavage division is given.

The chromosome number for P. scotiae is n=8, 2n=16, for P. hiberniae no definite number is given but it is believed to be n = 8 (6–8), 2n=16 (12–16). Notes are made on some specimens received from the Netherlands and France.

P. hiberniae and P. scotiae are compared with P. cervi and P. leydeni.

The water rat Nectomys squamipes is endemic in Brazil and found naturally infected with Schistosoma mansoni. Helminth communities, their prevalences, intensity of infection and abundance in N. squamipes in an endemic area of schistosomiasis in the state of Rio de Janeiro, Brazil were studied. Four species of nematodes (Physaloptera bispiculata, Syphacia venteli, Hassalstrongylus epsilon and Litomosoides chagasfilhoi) were recovered in 85.3%, two trematodes (Schistosoma mansoni and Echinostoma paraensei) in 38.8% and one cestode species (Raillietina sp.) in 1.7% of rats examined. Rats were infected with up to five helminth species each, and these were highly aggregated in distribution. For H. epsilon and S. venteli, intensities and abundances were higher in adult male and subadult female hosts, respectively. Hassaltrongylus epsilon, P. bispiculata, S. venteli and S. mansoni were classified as dominant species, L. chagasfilhoi and E. paraensei as co-dominant and Raillietina sp. as subordinated. No significant correlation was found in the intensity of infecton between each pair of helminth species. Schistosoma mansoni was not related to any other helminth species according to their infection rates, althougth S. mansoni was well established in the natural helminth comunity of the water rat.

The possibility was examined of using a haemoglobinase released during in vitro incubation of adult Fasciola hepatica for immunodiagnosis of fascioliasis. By SDS gel electrophoresis the enzyme appeared as two closely migrating bands with a molecular weight of approximately 27 000 daltons. After Western blotting the bands reacted with serum from rats infected with F. hepatica and mice infected with Schistosoma mansoni. The enzyme was therefore not a good antigen for immunodiagnosis.

The pink shrimp Farfantepenaeus duorarum may acquire pollutants, helminths and symbionts from their environment. Statistical associations were studied between the symbionts and helminths of F. duorarum and pollutants in sediments, water and shrimps in Campeche Sound, Mexico. The study area spatially overlapped between offshore oil platforms and natural shrimp mating grounds. Spatial autocorrelation of data was controlled with spatial analysis using distance indices (SADIE) which identifies parasite or pollutant patches (high levels) and gaps (low levels), expressing them as clustering indices compared at each point to produce a measure of spatial association. Symbionts included the peritrich ciliates Epistylis sp. and Zoothamnium penaei and all symbionts were pooled. Helminths included Hysterothylacium sp., Opecoeloides fimbriatus, Prochristianella penaei and an unidentified cestode. Thirty-five pollutants were identified, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides and heavy metals. The PAHs (2–3 ring) in water, unresolved complex mixture (UCM), Ni and V in sediments, and Zn, Cr and heptachlor in shrimps were significantly clustered. The remaining pollutants were randomly distributed in the study area. Juvenile shrimps acquired pesticides, PAHs (2–3 rings) and Zn, while adults acquired PAHs (4–5 rings), Cu and V. Results suggest natural PAH spillovers, and continental runoff of dichlorodiphenyltrichloroethane (DDT), PCBs and PAHs (2–3 ring). There were no significant associations between pollutants and helminths. However, there were significant negative associations of pesticides, UCM and PCBs with symbiont numbers after controlling shrimp size and spatial autocorrelation. Shrimps and their symbionts appear to be promising bioindicators of organic chemical pollution in Campeche Sound.

Studies on the population dynamics and natural infection of Lymnaea columella by Fasciola hepatica were carried out from September 1999 to December 2000 in a low-lying area near Itajubá in the Brazilian State of Minas Gerais. A total of 626 snails were collected monthly at nine different sites, counted, and dissected to search for larvae of F. hepatica. The highest populations of L. columella were reached in October of 1999 and August of 2000, and the highest natural infection rates of snails by F. hepatica were reached in September 1999 (5.2%) and July 2000 (3.9%). The removal by farmers of aquatic plants from the drainage furrows caused a drastic reduction in this snail population.

The successful use of helminths as therapeutic agents to resolve inflammatory disease was first recorded 40 years ago. Subsequent work in animal models and in humans has demonstrated that the organisms might effectively treat a wide range of inflammatory diseases, including allergies, autoimmune disorders and inflammation-associated neuropsychiatric disorders. However, available information regarding the therapeutic uses and effects of helminths in humans is limited. This study probes the practices and experiences of individuals ‘self-treating’ with helminths through the eyes of their physicians. Five physicians monitoring more than 700 self-treating patients were interviewed. The results strongly support previous indications that helminth therapy can effectively treat a wide range of allergies, autoimmune conditions and neuropsychiatric disorders, such as major depression and anxiety disorders. Approximately 57% of the self-treating patients observed by physicians in the study had autism. Physicians reported that the majority of patients with autism and inflammation-associated co-morbidities responded favourably to therapy with either of the two most popular organisms currently used by self-treaters, Hymenolepis diminuta and Trichuris suis. However, approximately 1% of paediatric patients experienced severe gastrointestinal pains with the use of H. diminuta, although the symptoms were resolved with an anti-helminthic drug. Further, exposure to helminths apparently did not affect the impaired comprehension of social situations that is the hallmark of autism. These observations point toward potential starting points for clinical trials, and provide further support for the importance of such trials and for concerted efforts aimed at probing the potential of helminths, and perhaps other biologicals, for therapeutic use.

Inflammatory bowel disease (IBD) is a chronic relapsing inflammation afflicting any part of the bowel wall as a result of a deregulated and inappropriate immune response. In recent years, experimental and clinical evidence has demonstrated that infection with parasitic worms could protect hosts from IBD. The aims of this study were to determine if the underlying mechanism of the host immune regulation inherent to Trichinella spiralis infection involves Foxp3-expressing regulatory T cells, and to gain insight about time-related interactions between intestinal nematode infection and induced colitis using an experimental model for ulcerative colitis. Mice were experimentally subjected to acetic acid-induced colitis, which was either preceded or followed by T. spiralis infection. Assessment of colitis was done by histopathological examination of the colon and determination of pentraxin 3 levels. Immunohistochemistry was done for demonstration of Foxp3-expressing regulatory T cells in colonic tissues. It was evident that T. spiralis infection ameliorated the severe inflammation induced by acetic acid, evidenced by amelioration of histopathological changes and diminution of pentraxin 3 levels. The amelioration was more pronounced when T. spiralis infection preceded the induction of colitis. Regarding the immunohistochemical staining of regulatory T cells, T. spiralis infection induced recruitment of Foxp3-expressing regulatory T cells to areas of inflammation. In conclusion, T. spiralis regulatory mechanism can improve inflammation of the colon through the ‘inflammatory–regulatory’ axis. Finally, it would be of great importance to apply these results to the development of new therapeutic approaches for the treatment of ulcerative colitis.

Anisakis sp. larvae when incubated in vitro produced secretions/excretions which released the dye from an azocoll substrate, indicating protease activity. The optimal conditions for enzyme release and activity were a temperature of 37°C and a pH of 7·5. In addition the larvae showed peak behavioural activity at 37°C, the body temperature of the final, marine mammalian host. The results are discussed in relation to their possible significance to the invasion of the various hosts in the life-cycle.

The classification of the nematodes occurring in the lungs (and related forms) of land mammals has always been one of considerable difficulty, in large part because of the existing very inadequate descriptions of many of the commoner forms. Most systematic helminthologists have followed and amplified the classification adopted by Railliet and Henry in 1907, a system which divided these nematodes into three main groups — those found in the blood-stream (Hæmostrongylus); those found in the larger bronchi (Dictyocaulus, Metastrongylus and Crenosoma); and those found in the minute bronchi and alveoli (Synthetocaulus). While the first two groups contain four well-defined zoological species, an examination of the forms included in the genus Synthetocaulus shews that it consists of a heterogeneous collection of species, which, although possessing a common habitat, are by no means so closely related as has been supposed, and, indeed, belong to several different genera.

The excretion of bronchopulmonary nematode infective larvae was evaluated in 160 faecal samples of Spanish ibex (Capra pyrenaica hispanica) collected from 13 populations in Castilla-La Mancha, south-central Spain in September 2003. Intensities and prevalences were compared with pasture availability, abundances of wild and domestic ungulates at both levels, i.e. for populations and for faeces in a two-step procedure. Protostrongylid larvae showed similar infection rates (mean intensity: 1.56±0.12, n=94; mean prevalence: 25.62±6.86%, n=160) to Dictyocaulus spp. (mean intensity: 1.03±0.11, n=48; mean prevalence: 30.00±7.11%, n=160). At the population level, positive correlations were found between the prevalences of both bronchopulmonary taxa. The prevalence in both groups, but not intensity, also correlated positively with Spanish ibex abundance indexes both for the populations and individual faeces. These findings suggest that: (i) parasite spreading across Spanish ibex populations in Castilla-La Mancha could respond to host density-dependent processes; and (ii) these populations may have similar exposition and/or susceptibility to both bronchopulmonary taxa resulting in similar host–parasite patterns, despite their different life cycles. Bronchopulmonary outputs in the Spanish ibex from Castilla-La Mancha seems not to represent a health risk for this endemic wild ungulate but may be useful in any health surveillance scheme for the increasing populations of Spanish ibex.

Hard structures of helminths have often been used for taxonomic identification but are usually not clearly defined when treated with conventional methods such as ammonium picrate-glycerin for monogeneans and glycerin for nematodes. The present study reports a rapid and simple technique to better resolve the hard parts of selected monogeneans and nematodes using 5–10% alkaline sodium dodecyl sulphate (SDS). In comparison with established methods, SDS-treated worms become more transparent. In monogeneans treated with SDS, clear details of the hooks, hook filaments, anchors, bars and the sclerotized copulatory organs could be observed. In SDS-treated nematodes, spicules and ornamentations of the buccal capsules could be clearly seen.

Despite the commercial and zoonotic importance of larval anisakid infestations of teleosts, their distribution among Australia's diverse marine fish fauna is poorly understood. A preliminary survey of Australia's tropical north-west revealed a generally high prevalence of larval anisakids representing four genera (Anisakis, Terranova, Thynnascaris and Raphidascaris) among only seven fish species. The potential impact of high larval anisakid infections on both the health of recreational fishermen and aquaculture environments is discussed.

Experiments on larval emergence in a series of constant temperatures showed that, of those temperatures tested, 25°C. was the optimum. Results suggest that constant temperatures do not provide optimum conditions for larval emergence and that a higher rate of emergence may occur under fluctuating temperatures. The rate of larval emergence in beet diffusate increased as the initial oxygen concentration increased. Pre-treatment of cysts at low oxygen concentrations reduced the subsequent emergence in diffusate.

1. The results of a survey of 194 Peruvian and Colombian primates for filarial infections are presented. Nine genera and 14 species of marmosets and monkeys are represented in the survey. A blood film survey revealed microfilariae in 82, of 42% of the animals. Adult worms were recovered from 21 of 61 dissected animals. The 209 adult worms belong to four species: Dipetalonema gracile, Dipetalonema caudispina, Tetrapetalonema marmosetae, and Tetrapetalonema tamarinae, a new species.

2. New host records for Dipetalonema gracile are: Tamarinus nigricollis, Cebus albifrons, and Saimiri boliviensis. Saimiri boliviensis is a new host for Dipetalonema caudispina. New hosts for Tetrapetalonema marmosetae are: Oedipomidas oedipus, Saimiri sciurea, S. boliviensis, and Ateles paniscus.

3. The adult worms and microfilaria of a new species of filarial worm, Teirapetalonema tamarinae, are described from a Peruvian tamarin marmoset, Tamarinus nigricollis.

(1) The structure of the microfilaria of Brugia (B. patei and B. pahangi) is redescribed and the development of B. patei is followed in the mosquito Aedes togoi for the first 4 days, up to the moult to the second larval stage.

(2) The buccal cavity, the pharynx (or oesophagus), and the pharyngo-intestinal valve of the second stage larva are formed around the pharyngeal thread of the microfilaria. Part of this thread is moulted with the microfilarial cuticle at the moult to the second larval stage.

(3) The intestine of the second stage larva is built up around the Innenkörper of the microfilaria from cells of the nuclear column.

(4) The R cells (G 2—G 4 cells) of the microfilaria and the anal vesicle of the microfilaria continue into the second stage larva and eventually the rectum is formed between them.

(5) The G cell (G 1 cell) does not form part of the gut of the second stage larva but becomes incorporated into the body wall with other cells from the nuclear column.

(6) The subcuticular cells of the microfilaria continue as elongate spindle shaped cells in the cords of the second stage larva.

(7) The significance of these results, which are at variance with earlier descriptions, are discussed and it is concluded that the microfilaria of Brugia is a very much modified first stage nematode larva, adapted to life in the capillaries of the vertebrate host. The microfilaria begins the metamorphosis to the structure of the second larval stage soon after entry into the insect vector.

The microhabitat distribution of two congeneric species Dactylogyrus carpathicus and D. malleus (Monogenea) parasitizing the gills of the barbel (Barbus barbus L.) was investigated. We tested whether congeneric species exhibited microhabitat preference and whether interspecific interactions could be attributed to the microhabitat segregation of congeners. The outlying mean index method was used to evaluate species microhabitats. Gill variables (different microhabitats within gills) were used as environmental factors characterizing the gills. When abundances of both species were highest, and no significant difference was found between the abundance of the two species, the gill segments and gill areas were the most important factors segregating the Dactylogyrus species on the gills. Niche overlap was low within each of the four gill arches, and parasites were segregated in the same microhabitats within each gill arch. When abundances of both species were low, each monogenean species was segregated at the level of the gill arches. When abundances of both species increased, the niche and overlap between species increased. The distribution of both congeneric species confirmed microhabitat preference within the gills. The results suggest that microhabitat preference is dependent on species abundances, species being segregated in the case of low abundance, possibly to increasing mating opportunities. Both niche and overlap between species increased with species abundance. In the case of the high abundance of both species, microhabitat preference seems to be related to interspecific interactions between monogenean species, as previously found for endoparasitic species.

An understanding of the mechanisms that determine host and parasite relationships is a central aim in parasitology. Association of a parasite species with a host species may be influenced primarily by phylogenetic constraints that cause parasite species to co-speciate with their host species, or predominantly by ecological parameters that influence all other co-evolutionary scenarios. This study aimed to investigate the role of co-speciation as well as other co-evolutionary scenarios in influencing the assemblages of tapeworm parasites (marine cestodes) in skate hosts (Rajiformes) using a modification of the PACo (Procrustean Approach to Cophylogeny) method. The study found that phylogeny and host ecology are both significant predictors of skate–tapeworm relationships, implying that co-speciation as well as other co-evolutionary scenarios are shaping these associations. The study also investigated the key ecological parameters influencing host-switching and found that host diet, distribution depth, average body size and geographical location have a combined effect. Given the importance of parasites in ensuring healthy and stable marine ecosystems, the findings of this study have implications for conservation management worldwide.

Trichinellosis is a serious food-borne zoonotic infection of cosmopolitan distribution. Currently, treatment for trichinellosis is far from ideal. Given the important role of oxidative stress and immune-mediated inflammation in the pathogenesis of trichinellosis, this study was designed to evaluate the possible protective effects of resveratrol (RSV) during the intestinal and muscular phases of Trichinella spiralis infection in mice. The oral administration of RSV at a dose of 20 mg/kg once daily for two weeks resulted in significant reductions in both adult and larval counts; significant improvements in the redox status of the small intestine and muscles; a significant reduction in interleukin 4, pentraxin 3 and vascular endothelial growth factor expression; and the mitigation of intestinal and muscular inflammation. In conclusion, this study identifies RSV as a promising agent for the treatment of experimental trichinellosis, and more studies in experimental animals and humans are worth consideration.

Preliminary electron microscope observations have shown that in the miracidium of Schistosoma mattheei the surface of the apical epidermal plate consists of branching and anastomosing microvilli. It is suggested that this arboreal arrangement serves to attach the miracidium to the body surface of snail hosts during attempts to penetrate; the apical papilla can therefore be regarded as an attachment organ, functionally analogous to the suckers of the adult schistosome. It is also suggested that the degree of ‘fit’ between the attachment organ and the snail body surface may be an important factor determining the success of attempts by the miracidium to penetrate.

Electron microscopy has also shown that the so-called penetration and apical glands are single flask-shaped cells. No endoplasmic reticulum and very few ribosomes were seen in these cells and it is therefore suggested that, in the mature (free-swimming) miracidium, the “glands” are not functional as such; they are simply sacs full of fluid. If they contain histolytic substances they must either have been synthesized at an earlier stage in the life history of the organism or they are synthesized elsewhere and passed into the “glands”.

Histochemical attempts to identify leucine aminopeptidase and mucin in the contents of the “glands” of S. mansoni miracidia were unsuccessful. It is concluded that these substances probably do not play any role in the penetration into or attachment on snail intermediate hosts by S. mansoni miracidia.

From original observations and from data in the literature, a key to cercariae of British strigeoids for which life-cycles are known has been compiled. The value of various characters of systematic importance is discussed.