In the serodiagnosis of alveolar echinococcosis, the detection of specific reactions against not only protein but also carbohydrate antigen is useful and both antigens supplement each other. Though recombinant protein antigens have recently advanced, the preparation of carbohydrate antigen still depends on extraction from crude antigens. In the latter case, it is not conventional to obtain carbohydrate antigen as a single component for examination and research. Therefore, chemically synthesized carbohydrate antigens were prepared for serodiagnosis by the enzyme-linked immunosorbent assay (ELISA). Four antigens with the structure of glycosphingolipids from Echinococcus multilocularis were examined and one antigen, Galβ1-6(Fucα1-3)Galβ1-6Galβ1-ceramide, was found to show significant serodiagnostic potential in differentiating alveolar from cystic echinococcosis.

Wild Lymnaea tomentosa snails, recovered from Lake Wanaka, New Zealand, were established in the laboratory. Wild snails, naturally infected with echinostomes, provided metacercariae for infection of laboratory maintained snails. Metacercarial cysts from wild and laboratory snails were then used to attempt infection of definitive host candidates. Laboratory snails provided convenient packaging of known numbers of cysts. Metacercariae excysted in the small intestines of ducklings to mature in 6 days. Worms were expelled as they became gravid. Attempts to establish infections in experimental hosts other than ducklings were not successful. No worms were recovered from mice, white rats, guinea pigs, hamsters or immunosuppressed white rats.

Relationships between the species diversity of different taxa, the mean number of articles published per year on each taxon, and the mean impact factor of the journals in which they appear, were examined across six taxa of helminths: Nematomorpha, Acanthocephala, Monogenea, Trematoda, Cestoda and Nematoda, the latter including only animal parasitic nematodes. The mean annual output of scientific articles per taxon was not related to the species diversity of these taxa or, at least, not significantly. Thus, the large volume of publications on nematodes is not merely a reflection of their estimated diversity. There were significant differences among taxa in the mean impact factor of the journals in which papers on each taxon appeared, with nematodes having the highest mean score, followed by trematodes and cestodes. In addition, across the six taxa, the mean journal impact factor correlated positively and significantly with the mean annual number of papers published: not only are there more papers published on nematodes and trematodes than on nematomorphs or acanthocephalans, but they are also generally published in higher-ranking journals. These results suggest that there is an increasing gap in the quantity and general importance of the research carried out on different helminth taxa.

In recent years there have been major socio-economic changes within Afghanistan such that the present public health burden of soil-transmitted helminths (STH), especially that within school-aged children, remains to be determined. A baseline parasitological survey was therefore carried out in four defined areas of Afghanistan to better assess the distribution, prevalence and intensity of STH infections prior to a nationwide de-worming campaign beginning within World Food Programme assisted schools. A cross-sectional examination of 1001 children aged between 8 and 15 years old revealed that approximately half (47.2%) were infected with at least one STH. Infections with Ascaris lumbricoides were most widespread (40.9%) and elevated prevalences were detected in urban environments; for example, schoolchildren in Kabul were more likely to be infected (OR=2.2, 95% CI 1.6–3.0) than elsewhere and these infections were often of higher intensity (OR=7.6, 95% CI 4.9–11.8). Trichuris trichiura (9.9%) and hookworms (0.7%), previously unknown from Afghanistan, were encountered. The blood haemoglobin concentration of surveyed children was also assessed: 4% resulted to be anaemic (Hb<11 g dl−1), and 0.4% to be severely anaemic (Hb<7 g dl−1).

Fascioliasis is an important trematode infection of herbivores worldwide with increasing evidence of prevalence as a disease of humans. Vaccination studies with purified native and recombinant Fasciola antigens suggest that this approach to diminished morbidity and mortality and reduced transmission is a realistic goal. Among the major potential vaccine candidates are fatty acid binding protein (FABP), cysteine (cathepsin) proteases, haemoglobulin, leucine aminopeptidase, and a saposin-like protein. In the case of Fasciola hepatica FABP, cross-reaction and cross-protection against Schistosoma mansoni is an important feature. In addition to protective effects with significant worm burden reductions, some vaccine candidates also have anti-fecundity (smaller flukes), anti-pathology (less liver lesions), and anti-embryonation effects. Optimism is tempered by the fact that fascioliasis in humans is an orphan disease and in need of governmental and foundation support.

Stress response and phosphorylation of heat shock proteins (HSPs) 60, 70 and 90 were studied in Trichinella nativa, T. nelsoni, T. pseudospiralis and T. spiralis larvae at 30-min intervals following exposure to 20, 100 and 200 mM H2O2. There was a time- and dose-dependent differential survival for the infective stage larvae (L1) of these four Trichinella species. Immunoblotting analysis revealed that constitutive Hsp60 and Hsp70, but not Hsp90, from test Trichinella species are constitutively phosphorylated on serine/threonine residues as they converted to forms with increased sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) mobility by treatment with alkaline phosphatase. After exposure to H2O2, while there was a time-related occurrence of the three HSPs with decreased SDS–PAGE mobility, these HSPs were insensitive to alkaline phosphatase except in the case of exposure to 20 mM H2O2 for Hsp60 from all Trichinella species and Hsp70 from T. spiralis and T. nelsoni. The synthesis of HSPs forms with decreased SDS–PAGE mobility is a susceptibility signal because the lower concentration of peroxide (20 mM) did not cause a decrease on HSPs SDS–PAGE mobility in T. spiralis and T. nelsoni, the two more resistant selected Trichinella species.

Transmission of the fox tapeworm Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, is known to depend on various environmental factors which are subject to human influence. Epidemiological data suggest that in most endemic regions anthropogenic landscape changes (e.g. deforestation and agricultural practices) have led to more favourable conditions for the parasite's animal hosts, especially arvicolid rodents, thereby increasing the risk for parasite transmission and human disease. Examples are the conversion of forests or crop fields into meadows and pastures in Europe, China and North America, and overgrazing of natural grassland in central Asia. Other anthropogenic factors include interference with host population densities by wildlife disease control, changing hunting pressure and provision of new habitats, e.g. in urban areas. Domestic dogs may, under certain conditions, get involved in the otherwise largely wildlife-based transmission, and thereby greatly increase the infection pressure to humans. The introduction of neozootic host species may increase transmission, or even initiate the parasite's life-cycle in previously non-endemic regions. Lastly, the parasite itself may be accidentally introduced into non-endemic areas, if suitable host populations are present (e.g. in northern Japan).

The effect of oral administration of three different nematode-trapping fungi, in aqueous suspension containing either Dactylaria sp. or Arthrobotrys oligospora conidia or Duddingtonia flagrans chlamydospores, on the number of Haemonchus contortus infective larvae in sheep faeces, was evaluated. The three selected species of fungi produce three-dimensional adhesive nets in the presence of nematodes. Sixteen Creole sheep were divided into four groups of four animals each. Groups 1 and 2 were orally drenched with a suspension containing 2×107 conidia of either A. oligospora or Dactylaria sp. Group 3, received a similar treatment, with D. flagrans chlamydospores, instead of conidia, being administered, at the same dose. Group 4 acted as control, without any fungi. Faecal samples were collected directly from the rectum of each sheep and faecal cultures were prepared and incubated at 15 and 21 days. Larvae were recovered from faecal cultures and counted. The highest reduction of the nematode population occurred in the D. flagrans group, reaching reductions of 96.3% and 91.4% in individual samplings in plates incubated for 15 and 21 days, respectively. Arthrobotrys oligospora showed moderate reductions in the faecal larval population, ranging between 25–64% at 15 days incubation. In general, Dactylaria sp., was less efficient in its trapping ability. Despite the inconsistent results with Dactylaria sp., reduction percentages of 73.4% and 80.7% were recorded in individual samplings during the first and second days, in plates incubated for 15 days. Duddingtonia flagrans, was shown to be a potential biological control agent of H. contortus infective larvae.

The success of ring-necked pheasant (Phasianus colchicus) restocking in Asturias, northern Spain was assessed, and the role of parasites and predators in the mortality of released birds was studied. The experimental release of 56 radio-tagged pheasants showed that 98% of birds died within 12 days. As soon as 72 h after release, 67.5% of males and 55.0% of females were found dead. Foxes (Vulpes vulpes) killed 63% of the birds. The survival of those birds killed by foxes was lower than for birds which died due to other causes, and pheasants depositing eggs of the nematode Eucoleus contortus (Creplin, 1839) survived less than those apparently non-parasitized. No impact of the parasite on the pheasants' condition was found, but foxes preyed upon parasitized birds more than expected by random. The results suggest that: (i) the current pheasant releases in this area are unsuccessful and need to be improved; (ii) this is mainly due to intense predation by red foxes; and (iii) parasites could have some influence on the predation of released birds by foxes. However, the way parasites affect pheasant vulnerability remains unclear.

Dexamethasone, a known immunosuppressant, was administered by bath or injection to Atlantic salmon Salmo salar (Conon stock) to study if this treatment could affect the susceptibility of fish to infections with a Danish strain of Gyrodactylus derjavini (Monogenea). Three groups of S. salar (Conon stock) were immersion treated either with 10, 60 or 240 μg dexamethasone l-1 water, respectively. In addition, one group (positive control) was treated intraperitoneally with 200 μg dexamethasone per fish and one negative control group was kept untreated. A single G. derjavini parasite was placed on the anal fin of each fish and the infection was subsequently monitored weekly for 6 weeks. An increase in parasite populations on the salmon was positively correlated with the amount of immunosuppressant used. Infection levels in the group immersion treated with dexamethasone (240 μg l-1 water) and in the i.p. treated positive control group were significantly higher compared to the untreated control group.

This study tested the hypotheses that ants (Formicidae) function as a first intermediate host of Mesocestoides (Cestoda: Mesocestoididae) and that deer mice (Peromyscus maniculatus) develop metacestode infections after ingesting cysticercoid or procercoid-infected ants. Field studies were conducted at an island fox (Urocyon littoralis littoralis) breeding facility located on San Miguel Island, California Channel Islands National Park, USA, where >40% of captive foxes were infected with adult Mesocestoides. Eight percent (8%) of deer mice at the fox pen site were infected with Mesocestoides metacestodes while none were infected at a distant site where foxes were absent (campground), thereby indicating the potential localized presence of a first intermediate host. To test whether ants from San Miguel Island contained Mesocestoides DNA, a polymerase chain reaction (PCR)-based diagnostic assay was developed using nested primers that could detect a single hexacanth larva within pooled samples of ten ants. Ants (Lasius niger and Tapinoma sessile) collected near the fox breeding facility were tested using the nested-PCR assay. Seven of 223 pooled samples of L. niger (3.1%) and 2 of 84 pooled samples of T. sessile (2.4%) tested positive for Mesocestoides DNA, while none of the ants were positive at the campground site. Positive samples were sequenced and found to match DNA sequences from Mesocestoides obtained from island fox and deer mice. Finally, to determine whether ants function as a first intermediate host for Mesocestoides, colony-raised deer mice (n=47) were fed L. niger (n=3860) or T. sessile (n=339) collected from the San Miguel Island fox breeding facility. No mouse became infected with Mesocestoides metacestodes after ingesting ants. While both L. niger and T. sessile from SMI were positive for Mesocestoides DNA, they were not infective to deer mice in the laboratory.

Knowledge of the morphological phenotypes of the liver fluke Fasciola hepatica (Trematoda: Digenea) is analysed. The influence of parasite age on its dimensions, the adult fluke growth model, variation in a biometric variable versus time, and variation in a biometric variable versus another biometric variable (allometric model) are revised. The most useful allometric model appears to be (y2m]#x2212;y2)/y2=c [(y1m−y1)/y1]b, where y1=body area or body length, y2=one of the measurements analysed, y1m, y2m=maximum values towards which y1 and y2, respectively, tend, and c, b=constants. A method based on material standardization, the measurement proposal and allometric analysis is detailed. A computer image analysis system (CIAS), which includes a colour video-camera connected to a stereomicroscope (for adult studies) and a microscope (for egg studies), facilitates the processing of digital imaging. Examples of its application for the analysis of the influence of different factors on the liver fluke phenotype are shown using material from the Northern Bolivian Altiplano, where human and domestic animal fascioliasis is caused by F. hepatica only. Comparisons between the development of livestock fluke populations from highlands and lowlands are discussed and the relationships between host species and liver fluke morphometric patterns is analysed.

Between November 1998 and October 2000, freshwater snails were collected monthly from the highveld and lowveld areas of Zimbabwe to determine the occurrence of larval trematodes. A total of 13,789 snails, representing ten species, were collected from 21 sites and 916 (6.6%) harboured patent trematode infections. Eight morphologically distinguishable types of cercariae were identified. Bulinus tropicus had the highest overall prevalence of infection (13.1%). The echinostome was the most common type of cercaria recovered, contributing 38.2% of all infections. Schistosoma cercariae were recovered mainly from the highveld and comprised 8.0% of all infections. Amphistome cercariae contributed 37.6% of all infections and were recorded from both the highveld and lowveld areas with a peak prevalence occurring during the post-rainy period (March–May). The main intermediate host for amphistomes was B. tropicus. Infections in B. globosus, B. forskalii and Biomphalaria pfeifferi with amphistome cercariae are new records for Zimbabwe.

Abbreviations of the complex life cycle of trematodes, from three to two hosts, have occurred repeatedly and independently among trematode lineages. This is usually facultative and achieved via progenesis: following encystment in the second intermediate host, the metacercaria develops precociously into an egg-producing adult, bypassing the need to reach a definitive host. Given that it provides relatively cheap insurance against a shortage of definitive hosts, it is not clear why facultative progenesis has only evolved in a few taxa. Here a comparative approach is used to test whether progenetic trematodes are characterized by larger body size and egg volumes, two traits that correlate with other key life history features, than other trematodes. These traits may constrain the evolution of progenesis, because precocious maturation might be impossible when the size difference between the metacercaria and a reproductive adult is too large. First, trematode species belonging to genera in which progenesis has been documented were found not to differ significantly from other trematode species. Second, using within-genus paired comparisons across 19 genera in which progenesis has been reported, progenetic species did not differ, with respect to body size or egg size, from their non-progenetic congeners. Third, using intraspecific paired comparisons in species where progenesis is facultative, no difference was observed in the sizes of eggs produced by worms in both the intermediate and definitive host, suggesting that opting for progenesis does not influence the size of a worm's eggs. Overall, the lack of obvious differences in body or egg size between trematodes with truncated life cycles and those with the normal three-host cycle indicates that basic life history characteristics are not acting as constraints on the evolution of progenesis; trematodes of all sizes can do it. Why facultative progenesis is not more widespread remains a mystery.

The bioactivity of an ethyl acetate extract of ginger (Zingiber officinale) towards Schistosoma mansoni adult pairs, both cultured in vitro and in vivo in laboratory mice, was investigated by monitoring worm mortality and fecundity. In vitro, a concentration of 200 mg l-1 of extract killed almost all worms within 24 h. Male worms seemed more susceptible than female under these conditions. Cumulative egg output of surviving worm pairs in vitro was considerably reduced when exposed to the extract. For example, after 4 days of exposure to 50 mg l-1, cumulative egg output was only 0.38 eggs per worm pair compared with 36.35 for untreated worms. In vivo efficacy of the extract was tested by oral and subcutaneous delivery of 150 mg kg-1 followed by assessment of worm survival and fecundity. Neither delivery route produced any significant reduction in worm numbers compared with untreated controls. Worm fecundity was assessed in vivo by cumulative egg counts per liver at 55 days post infection with mice treated subcutaneously. Such infections showed egg levels in the liver of about 2000 eggs per worm pair in 55 days, in both treated and control mice, with no significant difference between the two groups. To ensure that density-dependent effects did not confound this analysis, a separate experiment demonstrated no such influence on egg output per worm pair, at intensities between 1 and 23 worms per mouse.

Evidence is accumulating rapidly showing that temperature and other climatic variables are driving many ecological processes. At the same time, recent research has highlighted the role of parasitism in the dynamics of animal populations and the structure of animal communities. Here, the likely interactions between climate change and parasitism are discussed in the context of intertidal ecosystems. Firstly, using the soft-sediment intertidal communities of Otago Harbour, New Zealand, as a case study, parasites are shown to be ubiquitous components of intertidal communities, found in practically all major animal species in the system. With the help of specific examples from Otago Harbour, it is demonstrated that parasites can regulate host population density, influence the diversity of the entire benthic community, and affect the structure of the intertidal food web. Secondly, we document the extreme sensitivity of cercarial production in parasitic trematodes to increases in temperature, and discuss how global warming could lead to enhanced trematode infections. Thirdly, the results of a simulation model are used to argue that parasite-mediated local extinctions of intertidal animals are a likely outcome of global warming. Specifically, the model predicts that following a temperature increase of less than 4°C, populations of the amphipod Corophium volutator, a hugely abundant tube-building amphipod on the mudflats of the Danish Wadden Sea, are likely to crash repeatedly due to mortality induced by microphallid trematodes. The available evidence indicates that climate-mediated changes in local parasite abundance will have significant repercussions for intertidal ecosystems. On the bright side, the marked effects of even slight increases in temperature on cercarial production in trematodes could form the basis for monitoring programmes, with these sensitive parasites providing early warning signals of the environmental impacts of global warming.

Clinical and serological investigations on 175 cattle were carried out in 1999 at the slaughterhouse of Jijel, northeastern Algeria, to verify if partial ablation of a liver infected with Fasciola hepatica represents a good epidemiological indicator in the case of fasciolosis, as partial excision of the liver is widespread throughout North African countries. This study was also performed to determine if there is a direct relationship between the quantity of liver confiscated for fasciolosis and the serological response of slaughtered animals. A significant relationship between highly infected livers and positive serological titres was noted. However, two groups of results were conflicting: the presence of macroscopically healthy, undamaged livers with a positive serology (8.3% of 120 cattle), or the existence of highly damaged livers with a negative serology (13.0% of 31 cattle). These results indicate that partial removal of the liver in the case of fasciolosis is unreliable, so this method does not represent a good tool to establish epidemiological data on this disease.

Parasite heterogeneity is thought to be an important factor influencing the likelihood and the dynamics of infection. Previous studies have demonstrated that simultaneous exposure of hosts to a heterogeneous mixture of parasites might increase infection success. Here this view is extended towards the effect of parasite heterogeneity on subsequent infections. Using a system of the tapeworm Schistocephalus solidus and its copepod intermediate host, heterogeneity of the tapeworm surface carbohydrates is investigated, i.e. structures that are potentially recognized by the invertebrate host's immune system. With lectin labelling, a significant proportion of variation in surface carbohydrates is related to differences in worm sibships (i.e. families). Tapeworm sibships were used for experimental exposure of copepods to either homogeneous combinations of tapeworm larvae, i.e. worms derived from the same sibship or heterogeneous mixtures of larvae, and copepods were subsequently challenged with an unrelated larva to study re-infection. Contrary to expectation, neither an effect of parasite heterogeneity on the current infection, nor on re-infection were found. The effect of parasitic heterogeneity on host immunity is therefore complex, potentially involving increased cross-protection on the one hand, with higher costs of raising a more heterogeneous immune response on the other.

Laboratory investigations on three aquatic populations of Galba truncatula, originating from the Peruvian Altiplano and French Massif Central, were carried out during three successive snail generations to determine if these populations might be successfully used for the metacercarial production of Fasciola hepatica under experimental conditions. High numbers of surviving snails at day 30 post-exposure (>70%), high prevalences of F. hepatica infections (>60%), and prolonged productions of cercariae for a mean period of 35 to 47 days were observed in the three populations, whatever the snail generation. In the Peruvian population, metacercariae of F. hepatica significantly decreased in numbers from a mean of 251 in the parent snails to 124 per snail in the F2 generation, whereas no significant variation was observed in the two French populations. As these aquatic snails rarely emerged out of water, the use of these populations for the commercial production of F. hepatica metacercariae was of great interest, because the daily time spent watching the breeding boxes of snails was clearly shorter, thereby reducing the cost of producing metacercariae compared with using amphibious snails reared with romaine lettuce.

A total of 301 blue whiting, Micromesistius poutassou Risso, 1826, ranging in length from 17 to 28 cm, from Motril Bay (Mediterranean coast, south Spain) were examined for anisakid nematodes, as these fish are common items in the Spanish Mediterranean diet. Three anisakid species were morphologically identified with a total prevalence of 10.63%. Anisakis simplex s.l. Rudolphi, 1809 had a prevalence value of 6.65%, compared with 2.66% for A. physeteris Baylis, 1923 and 2.33% for Hysterothylacium aduncum Rudolphi, 1802. Variations in prevalence values with season and host size are discussed. Allozyme markers (leucine aminopeptidase-1) were used to identify anisakid nematodes assigned to the A. simplex complex and all examined larvae were found to correspond genetically to A. pegreffii Nascetti et al., 1986.