A dot-blot enzyme-linked immunosorbent assay (dot-blot ELISA) using an electroeluted 31-kDa glycoprotein from adult worms of Parastrongylus cantonensis as the specific antigen was evaluated for the immunological diagnosis of patients infected with P. cantonensis. The sensitivity and specificity for the detection of serum antibody to P. cantonensis in dot-blot ELISA were both 100%, as determined with serum samples of ten P. cantonensis-infected patients, 60 patients with other related parasitic infections, and 20 uninfected controls. The test was as sensitive and specific as the immunoblot test which revealed a reactive band of 31 kDa. Both the dot-blot ELISA and immunoblot detected all sera from ten P. cantonensis-infected individuals, but not with those of other heterologous parasitoses (gnathostomiasis, toxocariasis, filariasis, paragonimiasis, cysticercosis and malaria) or sera from healthy controls. The dot-blot ELISA is much simpler to perform than the immunoblot technique, and the test can be applied under field conditions where sophisticated facilities are lacking.

1. P.silusiae is shown to be unable to resist desiccation on a microscope slide for periods above half an hour, although larvae within the uterus of the mother can survive for somewhat longer periods.

2. When “protected” by a colloidal gel, the worms are shown to resist desiccation for several months. Such “protected” worms are more resistant to temperature extremes than “non-protected” ones.

8. P. silusiae is immobilized in glucose solutions above 1M strength, although it can resume mobility on dilution of the solution, even after fourteen days in 4 M glucose solution.

4. P. silusiae is shown to be positively chemotactic towards oxygen, in addition the gravid females are negatively geotactic.

5. Drosophila fimcbr is is shown to act as a dispersal agent for P. silusiae.

We describe Monorchis lewisi n. sp. (Monorchiidae) from the surf bream, Acanthopagrus australis (Günther, 1859) (Sparidae), in Moreton Bay, eastern Australia. The new species differs from most existing species of Monorchis Monticelli, 1893 in its possession of an elongate I-shaped excretory vesicle, and from other congeners in the relative configuration of the gut and suckers. Ovipusillus mayu Dove & Cribb, 1998 is re-reported from Gnathanodon speciosus (Forsskål, 1775) (Carangidae) from Moreton Bay. We report new second internal transcribed spacer (ITS2) and 28S rDNA sequence data for both species. Bayesian inference and Maximum Likelihood analyses of the 28S rDNA dataset suggest that existing subfamily and genus concepts within the family require substantial revision.

The immunology of Ascaris suum was studied in vitro using the fluorescent antibody technique. Fluorescein isothiocyanate labelling of globulin was used in the direct and indirect method and by a combination of both methods.

Fluorescein labelled antibody was incorporated into precipitates at the mouth, excretory pore, anus and on the cuticle of third stage larvae.

The possible intercuticular localization of fluorescent antibody in moulting larvae and fluorescence of the ends of broken larvae were further observed.

Circumlarval precipitates did not form nor did the larvae fluoresce in normal serum.

The results indicate (1) that antigenic sites are located at the natural orifices and cuticle and (2) that the dead internal tissues and possibly the moulting substance are also antigenic.

The effect of existing Brugia pahangi infections on the establishment of a subsequent population was studied using jirds which had pre-challenge infections of 4 and 8 months duration. Necropsies were performed 28 days post-challenge inoculation in order to separate challenge and initial worm populations. The results indicate that existing infections of 4 or 8 months duration increase the susceptibility to subsequent homologous infections. The location of challenge population worms in tissue sites examined did not differ significantly between previously infected and uninfected groups. Previous infections did not affect the early growth of challenge population worms as indicated by their length.

The aim of this study was to evaluate the pattern of local immune cell infiltration in human cystic echinococcosis (CE) by identifying the subtypes of immune cells using immunohistochemistry (IHC). Fifty surgically removed hydatid cyst samples and surrounding tissues were collected from patients referred to Al-Zahra Hospital, Isfahan, Iran. IHC was performed on the surrounding host tissue of hydatid cysts using anti-human CD3, CD19, CD8, CD4, CD68, CD56, Ki-67 and Foxp3 (forkhead box P3) antibodies. The results were then compared to hepatocellular carcinoma and chronic hepatitis. In the host-tissue reaction site of liver hydatid cysts, a distinct pattern of local immune cell response, which outwardly consisted of a pack of the fibrous elements, a layer of palisading macrophages, an eosinophil-containing layer and a layer of accumulated lymphocytes, was observed. However, in some cases there were no positive cells for CD56+ natural killer cells and Foxp3+ regulatory T cells. The CD3+ T cells were the predominant inflammatory cells in all groups, followed by CD19+ B cells. It can be concluded that different immune cells are involved in the local response to human hydatid cysts.

1. Three exceedingly interesting parasites of the super-family Ascaridoidea have been discussed in this paper. A new genus Lappetascaris is described from two different kinds of fish and a new subfamily has been established to include this genus. The latter is based on its peculiar head structures and the cuticle.

2. Thynnascaris inquies (Linton, 1901) n.comb, is reported for the first time since its original description, from the type host of a new locality.

3. Goezia intermedia n.sp. is described and a comparative study of the related species has been carried out.

Inequality in body sizes is a common feature in populations of helminth parasites, with potential consequences for egg production and population genetics. Inequalities in body lengths and the effects of intraspecific competition on worm length were studied in a species of mermithid nematode parasitic in the crustacean Talorchestia quoyana (Amphipoda: Talitridae). The majority of the 753 worms recovered were relatively small, and an analysis using a Lorenz curve and Gini coefficient suggested that there were no marked inequalities in body lengths among the worms. Total worm length in the 356 infected amphipods (i.e. the sum of the lengths of all the worms in a host) increased steadily as a function of the number of worms per amphipod, whereas the length of the longest worm per amphipod peaked in amphipods harbouring intermediate numbers of worms. This last result was not significantly accounted for by the observed increase in host size with increasing intensity of infection, but resulted from a correlation between worm length and host size. As the number of worms per amphipod increased, the relative sizes of the second-, third-, and fourth-longest worms per host increased markedly. This means that relative inequalities in sizes become less pronounced, i.e. subordinate worms get closer in size to the longest worm, as the number of worms per host increases. The main consequence of this phenomenon is that worm sizes in the mermithid population are more homogeneous than they would be if intraspecific competition had stronger effects on worm growth.

A unique human case of alveolar echinococcosis was described in 1979 from the Klatovy district of the Czech Republic. However, there were no previous epidemiological studies in this area focusing on detection of the source of infection – Echinococcus multilocularis adults producing eggs. During the period June 1997 to April 1999, 29 out of a total of 46 (63.3%) red foxes (Vulpes vulpes) in the Klatovy district and one of four foxes (25.0%) in the Pilsen South district were found to be infected with adult worms of E. multilocularis. No E. multilocularis adults were found in other animals from the Klatovy district (i.e. three specimens of Martes martes, two Martes foina, one Mustela erminea, two Meles meles and one Felis catus f. domestica). An examination of faecal samples from 55 dogs (Canis familiaris) from the Klatovy district resulted in the detection of E. multilocularis DNA in one (1.8%) sample. The present results support the possibility that human alveolar echinococcosis previously described in the Czech Republic had the character of an autochthonous infection. There are also indications of a potential risk of infection to humans.

The viability rate of hydatid cysts was investigated in animals slaughtered in the abattoir of Thessaloniki, Macedonia, Greece. Two hundred sheep (100% infection rate), 106 cattle (56.6% infected), 203 pigs (9.3%) and 52 goats (15.4%) were examined. All fertile cysts contained viable protoscoleces. In sheep there was a mean of 1.1 (29.8% of total cysts) fertile cysts per animal containing 297.3 (81.3%) viable protoscoleces. The percentage of viable protoscoleces in the lungs was 82.3% and in the liver 71.2%. In cattle there was a mean of 0.1 (6.6% of total) fertile cysts per animal containing 46.4 (72.2%) viable protoscoleces. The percentage of viable protoscoleces in the lungs was 69.5 and in the liver 87. In swine there was a mean of 0.02 (9.5% of total) fertile cysts per animal containing 32.0 (76.8%) viable protoscoleces. The percentage of viable protoscoleces in the lungs was 97.1 and in the liver 68.9. In goats there was a mean of 0.1 (12.5% of total) fertile cysts per animal containing 12 (54.6%) viable protoscoleces. The percentage of viable protoscoleces in the lungs was 54.4% but no fertile cysts were found in the liver.

Owing to the failure of the potato crops in South Lincolnshire in areas where the eelworm Heterodera schachtii was known to occur, investigations were undertaken by this Institute to determine to what extent the nematode was responsible for the losses incurred, and to discover some method for its control. This work was begun by Dr. D. O. Morgan in the autumn of 1924. In order to gain a general knowledge of the natural conditions under which the nematode occured, and to obtain some indication of the most promising lines on which fundamental research might be carried out, extensive field observations were made. By this meand much data was accumulated which has been of great service in the carrying out of later laboratory adn field studies.

The ultrastructure of the cuticle of infective juveniles (IJs) of Steinernema carpocapsae (newly emerged and 80-day-old) and newly emerged IJs of S. riobravis, S. feltiae and S. glaseri was examined using transmission electron microscopy. The thickness of four distinctive layers of the cuticle was measured: epicuticle, cortical and median layer, striated layer and fibrous mat. The thickness of the cuticle was correlated with the size of the IJ. In the case of newly emerged IJs, the smallest species, S. carpocapsae, had a cuticle thickness of c. 270 nm compared with c. 460 nm for S. glaseri, the largest of the four species. The overall thickness of the cuticle or the thickness of the cuticle layers was not correlated with the ability of the IJs of the four species to survive desiccation per se. The major difference between newly emerged IJs of the four species was that S. carpocapsae had a proportionately thicker striated layer compared with the other three species. The significance of this is not known but it may be an adaptation involving the nictation behaviour of this species. A substantial change was observed in the cuticle of aged (80-day-old) IJs of S. carpocapsae, whereby the thickness of the cortical and median layer increased by more than 100% and the overall thickness of the cuticle increased by about 50%. Two possible explanations for this increase are: (i) new material was synthesized; or (ii) the fluid content of this layer increased due to an increase in the permeability of the outer layers of the cuticle. The ultrastructure of the sheaths of S. feltiae and S. glaseri was also examined and, apart from S. glaseri having a thicker sheath, the structure of the sheath in both species was similar, with the epicuticle and striated layer still visible.

The interaction between Bothriocephalus acheilognathi Yamaguti, 1934 (Cestoda)and pronephric lymphocytes of carp, Cyprinus carpio L. was studied by examining proliferation of lymphocytes isolated from both naïve fish and fish injected intraperitoneally with cestode extract. Lymphocytes from naïve hosts were stimulated to proliferate in the presence of the extract depending upon the extract protein concentrations; lower concentrations (0.01–0.05μg/ml) induced the greatest response, and immunosuppression occurred at higher concentrations. Significant differences were noted in fish that received intraperitoneal injections of parasite extracts. Five days post-injection, lymphocyte proliferation was significantly greater in these individuals compared with sham injected or untreated controls. This difference was reduced at 10 days post-injection, although the response was dependent on the concentration of the parasite extract. The possible significance of the observed stimulation/suppression of lymphocyte activity to establishment of the parasite in the wild is discussed.

This study aimed to evaluate the community composition and structure of the helminths found in 13 anuran species, and to evaluate whether this parasite community is determined by anuran characteristics. We found that the helminth fauna of the amphibians from five anuran families consisted of 13 taxa and that Cosmocercidae gen. sp. was the most prevalent taxon, followed by Oswaldocruzia subauricularis. Host body size was a determining factor of the composition and structure of the parasitic fauna. Helminth abundance and richness were positively correlated with host body size. The host Leptodactylus latrans had the highest helminth richness (n = 8). The frog Hypsiboas faber had the greatest helminth diversity (H′ = 0.711). The mean helminth species richness and diversity differed significantly between host species (P < 0.05). Taken together, our data indicate that, in sympatric species of amphibians, the morphological and behavioural characteristics of the hosts are important for structuring the helminth parasite communities.

Polymorphic molecular markers are being identified to characterize the genomes of parasitic nematodes. The aim is to construct a map with markers evenly spread over the six chromosomes. With such a map, regions can be identified that are under selection pressure when attempts are being made to eradicate worms, be it by drugs, vaccines or genetic resistance in the sheep. Several types of markers have been developed, microsatellites, transposon-associated markers, amplified fragment length polymorphism (AFLP) and expressed sequence tag (EST) markers. Linkage groups can be constructed using several generic crosses between inbred and drug resistant strains. EST markers will be especially important for comparative mapping with the genome of Caenorhabditis elegans, and therefore localization of the linkage group on a chromosome. It will then be possible to identify functional genes close to markers that have changed allele frequencies under selection pressure and identify the mechanisms of resistance to parasite control.

This paper describes a study carried out in a rural area of Ghana on the drinking water sources and other determinants of dracunculiasis (guinea worm disease). The results confirm the association between water source choice and the prevalence of the disease. A logistic regression model was used to show the combined effect of several behavioural, biological, and environmental risk factors. The important behavioural factors were related to the head of household, fetching of water, travelling, and farming. Age was found to be an important biological risk factor for dracunculiasis, but the greatest relative risk applied to those who had suffered from guinea worm disease in the previous year. Although males were significantly more infected than females when analysing the raw data, sex did not prove to be a significant risk factor in this model. Village of residence was an important environmental risk factor for dracunculiasis. Factors related to socio-economic status were not associated with the risk of infection. The paper concludes by presenting the policy implications of the study findings.

Experimental studies of mating behaviour of Schistosoma intercalatum and Schistosoma mansoni in mixed infections in mice showed that in simultaneous infections, without the possibility of choice of mate, heterologous pairing occurs readily. The paired females reach sexual maturity, are inseminated and lay parthenogenetic eggs. Miracidia originating from the S. mansoni male × S. intercalatum female are non infective to either Biomphalaria glabrata or Bulinus forskalii, whereas those from the reverse cross show a very low infectivity to only B. glabrata. The resulting haploid male cercariae also show a very low infectivity to mice (1.1%) and consequently only a very small number of adult worms develop. It appears from this study, on chromosomal and electrophoretic evidence, that generative (haploid) parthenogenesis occurs in S. mansoni females paired with S. intercalatum males.

During recent years the writer has had occasion to infest many rabbits with cercarial cysts of Fasciola hepatica. In all but three instances the infested rabbits have been killed within about ten weeks of the commencement of the experiment. These three rabbits remained infested over a long period and are the subjects of this note. They were kept under conditions which appeared to exclude all opportunity for further fluke infestation and no accidental infestation has been observed among the considerable number of similar rabbits used in other experiments during these years.

Bird schistosomes can cause a disease called cercarial dermatitis, or swimmer's itch, in humans. The disease occurs when people have direct contact with fresh water or sea water containing the free-swimming cercariae of the flukes. The symptoms are well known, and include intense itching, maculae, papulae, urticariae and, in some cases, local oedema with enlarged lymph nodes and fever. In this study, we present the geographical distribution of freshwater cercarial dermatitis in Norway. The study is based on random reports obtained from both individuals and physicians treating patients with itching skin rash after freshwater bathing. The first case of cercarial dermatitis in Norway was reported in 1980 and was traced to a lake near Trondheim in the central part of Norway. In the following years, an increasing number of cases were reported, especially in southern Norway. However, case reports are distributed almost all over the country, even from lakes in northern Norway. As far as we know, these are the northernmost case reports in Europe. So far, only one fluke species (Trichobilharzia franki) from a single infected snail (Radixauricularia) has been identified in Norway. However, unidentified schistosomatid ocellate cercariae have been found on several occasions in snails collected from six lakes where swimmer's itch is frequently reported. Future studies should be performed to identify the fluke species, as well as the most important snail and bird hosts, in Norwegian lakes.