The congeners Gyrodactylus salaris and G. derjavini are specific ectoparasites of Atlantic salmon Salmo salar and brown trout S. trutta, respectively. To elucidate the involvement of lectin–carbohydrate interactions in this host specificity, carbohydrates on the tegument of the two species and the corresponding lectin activity of their hosts have been studied. Carbohydrate composition on the tegument differed significantly between the two gyrodactylids. Three of four commercially available peroxidase-labelled lectins with primary affinity towards D-mannoside, D-GalNAc and L-fucose bound more strongly to G. derjavini than to G. salaris. Lectins with an affinity towards D-mannoside and D-GalNAc bound significantly stronger to the cephalic lobes on G. derjavini compared to the tegument and sheaths of the hamuli. One brown trout strain and three different salmon strains were tested for lectin activity in skin and plasma. Two Baltic salmon strains and one strain from the Atlantic region were included. Brown trout differed significantly from the salmon strains when skin samples were tested for D-GalNAc activity. Lectins binding to other carbohydrates showed trends for similar host differences. The implications of carbohydrate–lectin interactions for host specificity in gyrodactylids are discussed.

The genus Onchocerca (Nematoda: Filarioidea) consists of parasites of ungulate mammals with the exception of O. volvulus, which is a human parasite. The relationship between O. volvulus, O. ochengi and O. gibsoni remains unresolved. Based on morphology of the microfilariae and infective larvae, vector transmission and geographical distribution, O. ochengi and O. volvulus have been placed as sister species. Nevertheless, the cuticle morphology and chromosomal data (O. volvulus and O. gibsoni have n=4 while O. ochengi is n=5) suggest that O. gibsoni could be more closely related to O. volvulus than O. ochengi. Sequences from the 12S rRNA, 16S rRNA and ND5 mitochondrial genes have been used to reconstruct the phylogeny of five Onchocerca species including O. volvulus. Analyses with maximum likelihood and maximum parsimony showed that O. ochengi is the sister species of O. volvulus, in accordance with the classification based on morphology and geographical location. The separate specific status of the species O. gutturosa and O. lienalis was supported, although their phylogenetic relationship was not well resolved. The analyses indicated that the basal species was O. gibsoni, a South-East Asian and Australasian species, but this result was not statistically significant. The possible involvement of sympatric speciation in the evolution of this group of parasites is discussed.

Interactions between schistosomes are complex with some different species being able to mate and hybridize. The epidemiology of schistosomiasis in specific areas of South West Cameroon has evolved remarkably over 30 years as a result of hybridization between Schistosoma guineensis and S. haematobium. Morphological and biological data suggest that S. haematobium replaced S. guineensis in areas of Cameroon through introgressive hybridization. Data are reported on the use of single stranded conformational polymorphism (SSCP) analysis of the nuclear ribosomal second internal transcribed spacer (ITS2) of individual schistosomes from hybrid zones of Cameroon. The data show that since 1990 S. haematobium has completely replaced S. guineensis in Loum, with S. haematobium and the recombinants still present in 2000. This study illustrates the complexities of the dynamics between S. haematobium and S. guineensis in South West Cameroon.

Skin responses of fish to various parasites have been shown to involve various immunologically competent cells producing factors which guide the reactions of epithelial cells. However, the present study has demonstrated that a monoculture of epithelial cells has the ability to encapsulate and partially degrade ectoparasites without involvement of leukocytes. The ectoparasitic monogeneanGyrodactylus derjavini was kept on a monolayer of Epithelioma Papulosum Cyprini (EPC) cells in 24-well multidishes supplied with tissue culture medium. Gyrodactylus derjavini did not reproduce but survived an incubation period of up to139 h in the system. Due to sterile conditions, dead gyrodactylids were not subjected to microbial degradation and remained intact for several weeks. However, at 40 days G. derjavini was overgrown by EPC-cells and became partly degraded during the following 15 days. Analysis of enzyme reactivity in EPC-cells showed reactions for ten enzymes including esterases, amidases, phosphatases and phosphohydrolases. No marked differences for the ten enzymes between cell cultures with and without the ectoparasites were found but it cannot be excluded that some of these enzymes took part in parasite degradation. The study showed the in vitro capability of epithelial cells to interact, encapsulate and degrade G. derjavini without the involvement of leukocytes. This response probably is non-specific and will not exclude that various immunocompetent cells and their products normally optimize and accelerate elimination of invading parasites in vivo.

Strong unique continuation properties and a classification of the asymptotic profiles are established for the fractional powers of a Schrödinger operator with a Hardy-type potential, by means of an Almgren monotonicity formula combined with a blow-up analysis.

The effect of cadmium exposure of the snail first intermediate host Lymnaea peregra on the incidence of encystment of Echinoparyphium recurvatum (Digenea: Echinostomatidae) cercariae without emergence from the snail was investigated. Exposure to 100 μg l−1 Cd for 72 h caused a significant increase in the incidence of first host encystment when compared to controls. In addition, autometallographic staining of E. recurvatum daughter rediae and developing cercariae showed that there was metal accumulation within their body tissues. The significance of these findings to parasite transmission in metal-polluted environments is discussed.

Populations of bank voles (Clethrionomys glareolus) in a fragmented forest habitat in north-east Poland showed local differences in helminth infection intensity, morphometric measures and organ weights that were consistent with differences at the same locations two years previously. Although overall intensities of infection were lower than previously, and there were some differences in the relative intensities of individual helminth species, site differences remained significant and were consistent across replicated subsites. In keeping with site differences in helminth infection and adrenal gland weight and asymmetry, voles at site 1 (high intensity infection) had higher circulating concentrations of corticosterone than those at site 2 (low intensity infection). Since males were sampled outside the breeding season, and thus non-scrotal, testosterone levels were low and did not differ between sites. As previously, voles at site 1 also showed greater hind foot asymmetry. Dyadic interactions between males from the same and different sites in the laboratory showed that males from site 1 were significantly less aggressive, especially when confronted with intruder males from site 2. There was no relationship between aggressiveness and intensity of infection overall or at site 1, but a significant negative relationship emerged at site 2. Aggression thus appeared to be downregulated at the higher intensity site independently of individual levels of infection. Terminal corticosterone concentrations were greater at site 1 and lower among residents that initiated more aggression. While corticosterone concentrations rose over the period of testing, they did not correlate with the amount of aggression initiated or received.

The life cycle of the heterophyid fluke, Haplorchis pumilio is elucidated for the first time from the Indian region. Various stages in the life cycle were established based on observations made on natural infections found in snails and fish in a freshwater stream at Visakhapatnam, India and experimental infections carried out in the laboratory. The thiarid snail, Thiara tuberculata served as the first intermediate host and a wide range of freshwater fish as second intermediate hosts. Natural infections with adult flukes were found in the piscivorous birds Ardeola grayii and Bubulcus ibis. Adults were raised experimentally in day-old chicks. Distinguishing features of the cercaria of H. pumilio are: a large body size (200–224×92–96 μm), body–tail ratio of 1:2.1 and densely distributed pigment granules in the parenchyma imparting a brownish tinge to the body. Natural infections with metacercariae were found in the freshwater fish Channa punctatus, C. orientalis, Puntius sophore, Gambusia affinis and fingerlings of Cyprinus carpio and Liza macrolepis. Additionally, experimental infections were established in Therapon jarbua, Esomus danricus and Oreochromis mossambica. Metacercariae were embedded in the caudal muscles of fish and heavy infections induced mortality. Metacercariae were infective at about 15 days of age.

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.

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.

The morphology of the different larval stages and life cycle of Hypoderaeum conoideum (Trematoda: Echinostomatidae) are described. The freshwater snail species Lymnaea peregra (Gastropoda: Lymnaeidae) serves as the natural first intermediate host and this and L. corvus serve as experimental first intermediate hosts. These and other freshwater snails, such as Physella acuta and Gyraulus chinensis, in turn serve as second intermediate hosts. Adult worms were obtained from chicks and ducks, but not from rats, mice and golden hamsters. The morphology of the larval stages is compared with previous work on H. conoideum. Several aspects of the biology of the life history stages are described with emphasis on the transmission dynamics of the free-living stages. Differential suitability of the snail species that may act as first and/or second intermediate hosts is studied and discussed.

Anisakis simplex crude extracts (CE) (IPI, ASAC and ALK-ABELLÓ), A. simplex larval antigens purified using a column of IgG anti-A. simplex (PAK) or a column of IgG anti-Ascaris suum (PAS), antigen eluted from columns of IgG anti-A. suum (EAS) and an A. suum adult CE were assayed by the skin prick test. Thirty percent of assayed patients showed a negative reaction in the Anisakis skin prick test. Of 70% positives, two patients had a weal greater than that produced by histamine with the A. simplex extract from ABELLÓ and IPI. The A. suum skin prick test was positive in 35% of patients, with a lower reaction than that observed with the A. simplex extract from IPI in 57% of the sera and a higher reaction in 28% of the sera. All patients with positive reactions with the crude extract also showed positive weals with the two purified antigens, PAK and PAS. All patients, except three, with a reaction to A. suum antigen, were positive to the EAS antigen. In five patients the weal size produced by PAS was greater than that observed with PAK, whereas in another six patients the contrary was observed. Only one of these six patients did not react to EAS antigen, coincident with the patient showing only a slight increase (7%) in the weal size induced by PAK vs. PAS. When the EAS antigen was tested on patients positive to both PAK and PAS, six patients presented a weal size of >30% and only three patients who were positive to PAS did not react to the EAS antigen. These three patients were also negative against the A. suum CE. Purification by affinity chromatography eliminates from the PAS antigen the proteins responsible for producing cross-reactions with Ascaris (present in the EAS antigen).

Little is known about immune responses in teleosts as linked to the aetiology of pollutants and parasitic diseases and in particular their combined effects on the host. Cadmium(Cd)-mediated immunological responses in the thymus and pronephros of juvenile carp (Cyprinus carpio), experimentally infected with the blood parasite, Sanguinicola inermis (Trematoda: Sanguinicolidae) for 30 days followed by an exposure to 0.1mg Cd2+ l−1 for 48 or 168h were investigated. Differential organ-specific changes occurred in both organs examined. In carp exposed to Cd, intracelluar spaces, vacuolation in the eosinophils, dissociation of cell membranes together with the formation of concentric whorls occurred. The thymus of infected carp exposed to Cd had a granular cytosol which contained vesicles with electron-dense inclusions, swollen mitochondria with distended cristae and condensed nuclei in the erythrocytes. Cell counts on the two organs revealed a differential response to cadmium exposure in S. inermis infected carp compared to control infected fish. A significant increase in the neutrophil, eosinophil and thrombocyte components occurred in the thymus in contrast to a significant decrease in pronephric neutrophils. In addition, there was a differential blastogenesis response in infected and Cd-exposed infected carp fry exposed to cercarial antigens and the mitogens, concanavalin A and pokeweed mitogen.

The development of the monogenean Diplozoon (Nordmann, 1832) (Diplozoidae) necessitates fusion of two larval stages (diporpae) into one double organism. How diporpae find, distinguish and contact each other is unclear, nor is the nature of the stimuli responsible for the dedifferentiation of cells and the formation of new tissues at the site of somatic fusion. Previous studies have implied a role for carbohydrates and glycoproteins in the interactions between helminth parasites and their hosts. Hypothetically, glycoconjugates may also be involved in the establishment of parasite–parasite associations. Changes in the surface saccharide residues during the development of Eudiplozoon nipponicum, a gill ectoparasite of carp (Cyprinus carpio) are described. Flat-fixed specimens and sections of diporpae, juveniles (just-fused) and adult worms were examined following exposure to a panel of 12 FITC-conjugated lectins. All developmental stages exhibited a specific surface binding pattern with ten lectins, indicating that Man/Glc, GlcNAc, Gal and GalNAc are probably present on their surfaces. No reaction was observed with Fuc-specific lectins (UEA-I and LTA). There is evidence that parasite development is accompanied by both qualitative and quantitative changes in the saccharide pattern distribution. The diporpa sucker reacted with nine lectins, excluding BS-II. A very strong binding of PNA, LCA and ConA (Gal and Man/Glc-specific lectins) was observed with the papilla glands of juvenile worms. The role of glandular secretions in this unique fusion process is discussed.

Eleven male two-month-old Holstein calves were used to determine the pathological changes induced by a Cooperia punctata infection. After weaning, ten calves received a single oral dose of 45,000 C. punctata infective larvae. One calf remained as a non-infected control. Groups of two calves were killed on days 7, 14, 21, 28 and 35 post-infection (p.i.) for determination of worm burdens and histopathological evaluation. The small intestine was sub-divided into three sections of approximately equal length, and representative samples of mucosa were fixed in 10% formalin, cut, and stained with haematoxylin-eosin. Samples of intestinal contents and mucosal digests were taken and fixed in 10% formalin for an estimation of total worm burdens. An increase in the number of adult parasites and a decrease in the number of larvae were observed with time (P<0.001). A higher concentration of worms was found in the first segment of the small intestine during the five weeks of observation. Histology showed larvae in the intestinal mucosa on day 7 p.i., with a discrete increase in the cellular response. Adult worms and a marked cellular infiltrate with eosinophils and neutrophils were present on day 21 p.i., and these persisted until day 35 p.i. Microcysts resulting from worm destruction were observed from day 21 p.i.

The negative binomial distribution model is reformulated and used to demarcate a host population at a specific level of infection by defining an attribute spanning a range of parasite aggregations. The upper limit of the range specifies the boundary for the classification of the host population and provides a technique to determine the cumulative probability at any level of parasite infection to a high degree of accuracy. This approach also leads to the evaluation of the k parameter, i.e. an inverse measure of dispersion of parasite aggregation, for each fraction of the host population with a discrete level of infection. The basic mathematical premise of the negative binomial function is unaltered in developing this reformulation which was applied to data on the distribution of the trichostrongylid nematode Heligmosomoides polygyrus in populations of the field mouse, Apodemus sylvaticus.

Nuclear magnetic resonance (NMR) spectroscopy was employed to investigate the effect of infection with Taenia crassiceps cysticerci on the lipid profile of mouse liver. Chloroform/methanol extracts of livers from infected mice showed lower concentrations of phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, total glycerophospholipid, triacylglycerol, total fatty acid (FA) and all measured FA components than those from controls. Furthermore, the ratios obtained on dividing concentrations of the FA components by that of total FA demonstrate that the concentration decreases caused by infection are less for polyunsaturated fatty acids (FAs) than for other FAs. Extracts of T. crassiceps displayed a similar lipid profile to that of host liver but contained a lower lipid content and a shorter average FA chain length.

Machine learning methods have been used in identifying omics markers for a variety of phenotypes. We aimed to examine whether a supervised machine learning algorithm can improve identification of alcohol-associated transcriptomic markers. In this study, we analysed array-based, whole-blood derived expression data for 17 873 gene transcripts in 5508 Framingham Heart Study participants. By using the Boruta algorithm, a supervised random forest (RF)-based feature selection method, we selected twenty-five alcohol-associated transcripts. In a testing set (30 % of entire study participants), AUC (area under the receiver operating characteristics curve) of these twenty-five transcripts were 0·73, 0·69 and 0·66 for non-drinkers v. moderate drinkers, non-drinkers v. heavy drinkers and moderate drinkers v. heavy drinkers, respectively. The AUC of the selected transcripts by the Boruta method were comparable to those identified using conventional linear regression models, for example, AUC of 1958 transcripts identified by conventional linear regression models (false discovery rate < 0·2) were 0·74, 0·66 and 0·65, respectively. With Bonferroni correction for the twenty-five Boruta method-selected transcripts and three CVD risk factors (i.e. at P < 6·7e-4), we observed thirteen transcripts were associated with obesity, three transcripts with type 2 diabetes and one transcript with hypertension. For example, we observed that alcohol consumption was inversely associated with the expression of DOCK4, IL4R, and SORT1, and DOCK4 and SORT1 were positively associated with obesity, and IL4R was inversely associated with hypertension. In conclusion, using a supervised machine learning method, the RF-based Boruta algorithm, we identified novel alcohol-associated gene transcripts.

Urine samples were assayed for urinary schistosomiasis in four local government areas (LGA) of Imo State, Nigeria between May 1998 and September 2000. A total of 3504 persons were sampled, with 880 (25.1%) being positive for urinary schistosomiasis, based on records of eggs of Schistosoma haematobium. The prevalence of S. haematobium infection differed in the various LGAs, with Oguta (38.9%) and Owerri-West (10.4%) showing the highest and the lowest values, respectively. Prevalence was higher in males (67.4%) than in females (32.6%) and in subjects 11–20 years of age (31.5%), while prevalence varied among different occupational groups, with farmers ranking the highest (41.6%). Visible haematuria was the predominant symptom (P<0.05). Of 880 persons positive for eggs of S. haematobium, 452 (51.4%) had visible haematuria, followed by suprapubic pains 214 (24.3%) and painful micturition 97 (11.0%). Although 367 (10. 5%) of the sampled subjects with eggs of S. haematobium showed no visible haematuria, 513 (14.6%) clearly demonstrated haematuria.