Factors regulating gastrointestinal nematode infrapopulations are to a great extent density-dependent. Here, 23 natural infrapopulations (41–281 individuals) of the viviparous nematode Procamallanus elatensis (Camallanidae) from the fish Siganus rivulatus were found distributed in a well-defined fundamental niche (posterior 55% of the intestine). Immature worms were mostly found in the anterior third of this niche, while mature worms were found in aggregations posterior to them and followed by gravid females in the posterior 20% of the intestine. This distribution strongly suggests that worms migrate towards the posterior intestine while they mature, copulate and reproduce. In small infrapopulations, the sex ratios were distinctly female-biased and the number of gravid females was low. In large infrapopulations, the sex ratios were distinctly male-biased and the number of gravid females was high. However, the mean lengths of both immature males and females and mature females decreased dramatically as the infrapopulation size increased, while those of mature males increased significantly. These results strongly suggest intraspecific competition and density-dependent regulation of mean worm length, and the increase in the mean length of mature males strongly suggests intense sexual selection and competition between mature males. Production of larvae by female worms decreased significantly as the infrapopulation size increased, suggesting a density-dependent reduction in female worm fertility. The results are statistically significant and strongly suggest that infrapopulation self-regulation is through density-dependent mechanisms, in which development of immature worms, infrapopulation size, sex ratio, sexual selection and carrying capacity of the fundamental niche play essential roles in shaping and regulating the infrapopulations.

Faecal surveys are commonly used as non-invasive means to evaluate population abundance of animals as well as comparable indexes of prevalence and intensity of diseases between populations, especially macroparasites. While faecal surveys are among one of the simplest means to perform these evaluations, they are time consuming and labour intensive. The present study evaluated 80 red deer (Cervus elaphus) faecal samples collected in two study sites for the presence and abundance of first-stage larvae of the nematode Elaphostrongylus cervi and established pools of samples for epidemiological analysis. The analysis of 20–30 individual samples would produce a reliable estimate of the ‘true’ prevalence, and the error of the smaller sample size only doubled that of the 80 reference samples. The analysis of 5 pools of 5 pellet groups each, or of 4 pools of 10 pellet groups each, provided a reliable estimation of the ‘true’ excretion abundance estimated by the analysis of all 80 samples. These pools comprise a cost-effective and dependable alternative for measuring and obtaining comparable abundances of parasitic faecal excretion stages in red deer populations, which is very valuable for epidemiological and ecological research as well as for management purposes.

Methods of treatment of trichinosis have been reviewed by van Someren (1938), and it was stated that no experimentally confirmed therapeutic measure had yet been found for the treatment of this disease by destruction of the nematodes in the body. In an attempt to discover a satisfactory chemotherapeutic measure, an experimental trial was made of an anthelminthic “Butolan” (Bayer), which has been shown to give very satisfactory results in cases of oxyuriasis, and in some ascariasis infections.

Amongst cestodes collected from birds in the Lake Kariba district, Southern Rhodesia, was a dioecious species of the genus Gyrocoelia Fuhrmann, 1800, obtained from a darter, Anhinga rufa.

Ortlepp (1037) described, from a single poor specimen, a new species in this genus, which he termed G. kiewietti. Ortlepp thought that his specimen was functionally monoecious, the ovary and vitellaria appearing after the testes had disappeared. Although the present material is definitely functionally dioecious, it is thought that it is the same species as Ortlepp found as the number, size and arrangement of the rostellar hooks are very similar.

A method is described by means of which trichostrongylid spicules are separated from the surrounding soft tissues and their examination made easier. NaOH and KOH are the most satisfactory substances for this purpose, though both substances eventually act on the chitin of the spicules themselves, causing distortion. The reaction takes place at a temperature of 37°C. with reasonable speed. Spicules of Ostertagia can also be freed satisfactorily by this method but those of Nematodirus are quickly affected by the alkali, with consequent distortion.

Neodiplostomum (Conodiplostomum) ramachandrani Betterton, 1976 has been reported from four species of rodent hosts: Echinosorex gymnurus (Raffles): Rattus whiteheadi (Thos); R. muelleri (Jentink) and Callosciurus notatus (Boddaert). A comparison of trematodes recovered from these hosts revealed patterns of host-induced morphological variation taking place. Because N. (Conodiplostomum) ramachandrani shows little generic difference from Fibricola intermedius (Pearson, 1959) Sudarikov, 1960 it is transferred to the genus Fibricola and is now designated Fibricola ramachadrani (Betterton, 1976) Palmieri, Krishnasamy and Sullivan.

On the basis of the morphological characterization of Chelatrema neilgherriensis Manjula & Janardanan, 2006 recovered from the freshwater fish Barilius gatensis (Valenciennes, 1844) in the Wayanad region of the Western Ghats, the diagnostic features of the genus Chelatrema Gupta & Kumari, 1973 have been modified. Based on the phylogenetic analysis of C. neilgherriensis and comparative morphology studies relative to members of other families of Gorgoderoidea Looss, 1901, this genus is placed in a new family Chelatrematidae n. fam. The studies revealed the molecular and morphological closeness of Chelatrema with Paracreptatrematina limi Amin & Myer, 1982, and the latter is transferred to this new family. Hence the new family Chelatrematidae n. fam. comprises the genera Chelatrema and Paracreptatrematina.

Pseudoacanthocephalus goodmani n. sp. is described from faecal pellets collected from Sclerophrys gutturalis (Power, 1927), the guttural toad. The species is characterized by a suite of characters, including a proboscis armature of 14–18 longitudinal rows of 4–6 hooks with simple roots, lemnisci longer than the proboscis receptacle, equatorial testes, a cluster of elongated cement glands and eggs without polar prolongations of the middle membrane 72.6–85.8 long. The toad had been accidentally translocated from Mauritius to the UK in a tourist's luggage and survived a washing machine cycle. The guttural toad was introduced into Mauritius from South Africa in 1922 and the cane toad, Rhinella marina (Linneaus, 1758), from South America, between 1936 and 1938. It seems most likely, therefore, that P. goodmani was introduced, with the guttural toad, from South Africa. The cane toad is host to the similar species, Pseudoacanthocephalus lutzi, from the Americas, but P. lutzi has not been recorded from places where the cane toad has been introduced elsewhere. Clearly, the guttural toad is a hardy and adaptable species, although it seems unlikely that it could become established in Northern Europe. Nevertheless, any accidental translocation of hosts poses the potential risk of introducing unwanted pathogens into the environment and should be guarded against.

New Zealand’s kākāpō parrot, once widespread, is now critically endangered due to habitat loss and introduced mammalian predators. Prior to major population decline, a unique kākāpō cestode, Stringopotaenia psittacea, was found in the 1880s and first described in 1904. Here we report the discovery of eggs of this cestode in kākāpō coprolites of pre-human settlement age from the Honeycomb Hill cave system, north-west Nelson. Analysis of 52 samples, including coprolites of post-human settlement age, from nine sites within six South Island locations across a wide geographic range, yielded only eight infected samples in this single cave system. Results suggest that prior to human settlement, S. psittacea was not widespread within and between kākāpō populations, in marked contrast to other parasite types of the extinct moa spp. Intense management of the last remaining kākāpō has endangered or possibly caused the extinction of this cestode. This is the first confirmed record of S. psittacea since its discovery in 1884.

An in vitro assay was used to examine the effect of Bothriocephalus acheilognathi Yamaguti, 1934 (Cestoda: Pseudophyllidea) on the polarization response of pronephric leucocytes of carp, Cyprinus carpio. Leucocytes, isolated from naive, naturally-infected fish and carp injected intraperitoneally with cestode extracts, were exposed to parasite extracts (protein concentrations 0–10.0 μg ml-1), for up to 24 h in the presence or absence of carp serum. In general, polarization responses of the pronephric leucocytes, primarily neutrophils and eosinophils, increased with incubation time although there was no significant difference in the response induced by the different protein concentrations. Differences in the polarization response were, however, observed in naive, naturally infected and injected fish and the cells responded differently in the presence and absence of carp serum. In the absence of carp serum the polarization response of pronephric leucocytes in vitro was significantly reduced with cells obtained from injected and naturally infected fish compared with those obtained from naive carp. This suppression of leucocyte migration was however reduced by the addition of carp serum to the in vitro system. The role of this interaction between the possible suppression of polarization induced by the parasite and stimulation by serum is discussed.

Development of Neostrongylus linearis larvae was studied in the snail intermediate hosts Oestophora (Oestophora) barbula, Oestophorella buvinieri, Cepaea nemoralis and Helix (Cryptomphalus) aspersa. The molluscs of each species, all adults, were divided into groups of 40 for infection purposes. The infection doses for the first two snail species were 90 and 50 first stage larvae (L1) of N. linearis, respectively. For C. nemoralis two batches were tested: one with 200 L1 kept at 19°C and the other with 250 L1 at a temperature of 21°C. The same was done with Helix (C.) aspersa with 200 L1 at a temperature of 21°C, on the one hand and 300 L1 at 24°C on the other. One or two molluscs of each species were killed in series from the 6th day post-infection (p.i.) until the 44th. Percentage values for total larvae (1, 2 and 3) and L3 were higher with the lower dose for C. nemoralis, whilst the same was true with the higher dose in Helix (C.) aspersa. In both cases, the higher temperature appeared to contribute to cycle acceleration. Using one way analysis of variance, statistically significant differences were detected between the species of molluscs tested concerning percentages of L1 which penetrated, total larvae and L3. According to our results, the decreasing order of susceptibility of these species of molluscs as experimental intermediate hosts of N. linearis is: O. buvinieri, Oestophora (O.) barbula, C. nemoralis and Helix (C.) aspersa. It is the first time that Oestophora (O.) barbula and Oestophorella buvinieri have been named as experimental intermediate hosts of N. linearis.

During the period 1990–1998, 99 cases of human cystic hydatidosis (12.4 cases per year) were surgically treated at the two main hospitals in Arbil province, northern Iraq, and from this the human occurence for the province was estimated to be 2 per 100,000 inhabitants. In the same area, 1270 sheep, 550 goats and 320 cattle were examined at slaughter for hydatid cysts and prevalence rates were found to be 15.0%, 6.2% and 10.9%, respectively. A decreasing tendency in livestock prevalences was found towards the end of the study period. As in humans, most of the hydatid cysts in livestock were located in the liver. Fertility of sheep cysts, i.e. those containing protoscoleces, was found to be significantly higher (64%) than that of goats (35.7%) and cattle (29.8%). The percentage of fertile cysts containing viable protoscoleces varied between 63 and 82% in the livers and between 72 and 79% in the lungs of the different animal species. A total of 97 stray dogs were examined post-mortem in the years 1991, 1992 and 1998, and Echinococcus granulosus worms were found in the intestines of 48 dogs (49.5%). High worm burdens (> 1000) were observed in 37% of the dogs, medium worm burdens (200–1000) in 41%, and low worm burdens (< 200) in 22%. In 1998, the prevalence of canine echinococcosis (24.3%) was found to be significantly lower than in 1991 (70.4%) and 1992 (60.6%). The prevalence of human hydatidosis did not differ significantly over the years, but the study confirmed that hydatidosis is endemic in northern Iraq, and that housewives, labourers and farmers appear to be at the greatest risk of infection.

The nematode genus Acrobeles is composed of two morphological groups distinguished by the presence (‘double’ cuticle) or absence (‘single’ cuticle) of the refringent inner layer of the cuticle. In the present study, four species of this genus, two with ‘single’ cuticle (Acrobeles ciliatus and Acrobeles cylindricus) and two with ‘double’ (Acrobeles aenigmaticus and Acrobeles complexus) are studied from coastal dunes in Spain. This study provides detailed morphological and morphometrical analyses for the four species, while molecular analysis, based on 18S and 28S ribosomal DNA, is provided for A. complexus. The four species are studied with scanning electron microscopy, which is obtained for the first time for A. cylindricus. These analyses revealed morphological and molecular differentiations between both groups, appearing as two related monophyletic entities. The subgenera Acrobeles and Seleborca, formerly considered as separate genera, are proposed to accommodate both groups.

In Brazil, acanthocephalans parasitise anurans in several biomes. In the present study, we performed an analysis of acanthocephalan infections across 175 anuran individuals from the Cerrado biome, belonging to ten species: Boana raniceps, Pithecopus hypochondrialis, Scinax fuscomarginatus, Scinax x-signatus, Leptodactylus pustulatus, Leptodactylus macrosternum, Leptodactylus vastus, Physalaemus cuvieri, Adenomera hylaedactyla, and Elachistocleis piauiensis. We also verified the specificity of the parasites using the STD* index. Additionally, we conducted a survey of acanthocephalan infection in anurans in South America. The studied assemblage in the Brazilian Cerrado presented 57 parasitised hosts of 175 specimens (overall prevalence: 32.6%). In total, 437 acanthocephalans cystacanths were recorded, among which 286 presented the same morphotype but could not be identified, 148 belonged to the genus Centrorhynchus, and three belonged to Oncicola. Unidentified acanthocephalans had a higher prevalence in L. vastus (53.85%) and the highest intensity was in L. pustulatus (17±16). The highest prevalence of Centrorhynchus sp. was in the species S. fuscomarginatus (28.57%), while the highest intensity was observed in L. vastus (111). The taxon Oncicola sp. it had a prevalence of 3.23% and an intensity of 3 only in S. x-signatus. The highest specificity was recorded for Oncicola sp. (STD*= 1), whereas the lowest was found in Centrorhynchus sp. (STD*= 2.21). Finally, according to the survey for South America, we found ten records of acanthocephalan taxa parasitizing 58 species of anurans distributed in seven countries (Brazil with the most records).

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.

S. fernandoi and S. pillaii are described as new species and are shown to differ specifically from each other and from S. japonensis, the only other species that has been reported as having spines on the spicules.

Sixteen specimens of a small trematode, belonging to the genus Leipertrema Sandosham, 1951, were collected from the intestine of a male Callosciurns notatus. This squirrel was caught at Subang, Selangor, Federation of Malaya,. on 17th December. 1960. The specimens differ from the only other member of the genus, Leipertrema rewelli Sandosham, 1951 from the pancreas of one Orang Utan, Pongo pygmaeus, (type specimens examined) and require description.

Mice presensitized with SEA and subsequently injected with S. japonicum eggs into their lungs or liver developed pathology similar to that found in infected mice and were consequently resistant to challenge (average 33% and 53%, respectively). However, soluble egg antigens were also capable of inducing low levels of resistance in mice (average 22·5%), but intact eggs alone injected into the lungs, liver or subcutance tissues were not. Thus, prior sensitization to ‘marginally’ protective soluble egg antigens is necessary for egg induced resistance.

Total RNA was extracted from packed infective larvae of Trichinella spiralis by centrifugation through a 5·7 M caesium chloride cushion. Polyadenylated messenger RNA was separated from total RNA in an oligothymidylic acid-cellulose gel column. The in vitro translation of the mRNA, isolated from infective larvae of T. spiralis, was carried out using the rabbit reticulocyte cell-free translation system. Incorporation of 35S-methionine into trichloracetic acid precipitates in the lysate containing mRNA was 5 times greater than that in control. The translation products were analysed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by autoradiography. Many polypeptides with molecular weights of less than 100 000 were synthesized in the lysate. A T. spiralis positive mouse serum was mixed with translation products to form antigen-antibody complexes, which were then absorbed by Staphylococcus aureus Cowan 1 strain and analysed by autoradiography of SDS-PAGE. An antigenic polypeptide with a molecular weight of 48 000 was demonstrated to react specifically with IgG antibody in T. spiralis positive mouse serum. T. spiralis larvae were cultured in methionine-free medium containing 35S-methionine, and antigenic polypeptides in somatic extracts and ES products were compared with those in translation products by autoradiography of SDS-PAGE. Several polypeptides in ES products and somatic extracts reacted specifically with IgG anitbodies in positive serum. Especially the polypeptide with a molecular weight of 48 000 in ES products strongly reacted with IgG antibody in positive serum.

In an experimental larval infection of Ancylostoma caninum in mice, the efficacy of various anthelmintics against the larvae migrated and established in the brain is reported for the first time. Albendazole and flubendazole were the most effective drugs. Thiabendazole, benacil, phenacizole, oxfendazole and mebendazole showed significant larvicidal activity. Tetramisole, levamisole, fenbendazole, Sch 18099, pyrantel pamoate, morantel tartrate and oxantel pamoate did not show any significant activity even at relatively high dose levels.