bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population dynamics in echinococcosis and cysticercosis: evaluation of the biological parameters of Taenia hydatigena and T. ovis and comparison with those of Echinococcus granulosus
Authors: Gemmell M. A. , Lawson J. R. , Roberts M. G. 
Published: June 2009

SUMMARYAn evaluation has been made of the biological and epidemiological parameters that determine the basic reproductive rates of Taenia hydatigena and T. ovis. These host-parasite systems are characterized by (i) no overcrowding in either host; (ii) no parasite-induced mortality of either host; (iii) no density-dependent constraint in the definitive host, but a strong, rapidly mobilized, short-acting immunity in the intermediate host and (iv) egg production which, in the natural environment, is high enough to prevent superinfection. It is considered that tapeworms with these characteristics are more stable to fluctuations in environmental conditions and to control measures such as dog dosing, than species which have a low egg production and infectivity such as Echinococcus granulosus. Reciprocal immunity exists between T. hydatigena and T. ovis in sheep. Exposure to T. hydatigena suppresses infection by T. ovis, but not by E. granulosus. This has important epidemiological consequences where these parasites co-exist.
Population dynamics in echinococcosis and cysticercosis: mathematical model of the life-cycles of Taenia hydatigena and T. ovis
Authors: Roberts M. G. , Lawson J. R. , Gemmell M. A. 
Published: June 2009

SUMMARYIt is shown that under the conditions that prevailed in New Zealand in the late 1950s, Taenia hydatigena was hyperendemic, the life-cycle being regulated by a density-dependent constraint in the form of acquired immunity, and T. ovis was rare. The control measures that caused Echinococcus granulosus, which was endemic at the time, to decline towards extinction reduced T. hydatigena and T. ovis to endemic status only. A non-linear integrodifferential equation model, which was previously linearized to describe the life-cycle of E. granulosus in dogs and sheep in New Zealand, is used to describe the life-cycles of T. hydatigena and T. ovis. The model is then used to compare and contrast the population dynamics of these three species. The model is used to demonstrate that the endemic steady state is structurally unstable, and may be asymptotically unstable to small perturbations. It is also shown that despite the lower infection pressure experienced by the intermediate host in the endemic state, the numbers of larvae in sheep may be higher than in the hyperendemic state. Finally it is shown that the partial success of the control measures against T. hydatigena may have caused an increase in the numbers and prevalence of T. ovis larvae in sheep due to the reciprocal immunity between the two species.
Hymenolepis diminuta: the role of the tail in determining the position of the worm in the intestine of the rat
Authors: Hopkins C. A. , Allen L. M. 
Published: June 2009

SUMMARYOne-worm infections ofHymenolepis diminutain rats had their strobila severed surgically, in the neck region, on day 14 of an infection. The scolex and remaining strobila survived but were recovered from a more posterior region of the intestine where small worms are attached during development. The movement to the new region was usually not complete in 24 h, but was complete by 72 h, and probably by 48 h. The operation, involving laparotomy and an incision in the duodenal wall which avoided severing the strobila, had no effect on the position of the worm but did depress the growth of the worm during the ensuing 24 h. It is suggested that (1) the preferred site forH. diminutais 30–50 % down the small intestine, (2) the worm monitors information about its position from all over its strobila and (3) as the worm grows, its position is determined by balancing the input of adverse information from its tail and head ends. The slowness with which surgically shortened worms return to the preferred site may be due either to delay in the worm ‘realising’ it has no tail, or to the location stimuli in the intestine being disturbed for 24 h by the operation.
Pseudechetus fimbriatus gen. et sp.nov., a caligid copepod from Kerala coastal waters
Authors: Prabha C. , Krishna Pillai N. 
Published: June 2009

SUMMARYPseudechetus fimbriatus gen. et sp.nov. from the throat of a carangid is described. The new genus has the closest resemblance to Parechetus Pillai from which it differs in the presence of 4 processes instead of 2 on the genital segment and a pair of processes on the abdomen instead of wings. The sternal fork carries accessory tines anteriorly making it a double structure.
An enzyme-linked immunosorbent assay (ELISA) for detection of antibodies toEncephalitozoon cuniculiand its use in determination of infections in man
Authors: Hollister Wafaa S. , Canning Elizabeth U. 
Published: June 2009

SUMMARYAn enzyme-linked immunosorbent assay (ELISA) was used to detect antibodies toEncephalitozoon cuniculiin man, using spores derived from tissue culture as antigen. Negligible cross-reactions were found with other microsporidia of vertebrate or of invertebrate origin and there was no cross-reaction withToxoplasma gondii, using ELISA, immunoperoxidase or immunofluorescence staining. A high prevalence of antibodies toE. cuniculiwas found in patients suffering from schistosomiasis, malaria and neurological and psychiatric disorders, but not in healthy individuals.
L-Glutamine: an amino acid required for maintenance of the tegumental membrane potential of Schistosoma mansoni
Authors: Lane Carolyn A. , Pax R. A. , Bennett J. L. 
Published: June 2009

SUMMARYThe tegumental membrane potential (–63±2·9 mV) of adult male Schistosoma mansoni in RPMI-1640 is significantly depolarized (–26±7·3 mV) when the parasite is incubated in inorganic media (Hank's Balanced Saline or RPMI-1640 without organic constituents). Of 9 amino acids (L-glutamine, D-glutamine, L-arginine, L-proline, L-aspartate, L-glutamate, L-asparagine, L-isoleucine and L-methionine) L-glutamine alone is sufficient to repolarize the membrane potential to a value (–56±4·5 mV) not significantly different from that found in RPMI-1640. Repolarization by glutamine is dose-dependent, with significant effects obtained as low as 0·10 mM. The concentration of phosphate in the medium also significantly alters the membrane potential. Physiological levels of phosphate (5·6 mM) are necessary in conjunction with L-glutamine to obtain the full repolarization of the membrane potential. In the absence of organic constituents, the membrane potential is strongly dependent on the external medium pH. When L-glutamine is present in the medium, the membrane potential becomes virtually independent of the external pH.
Schistosoma mansoni: structural damage and tegumental repair after in vivo treatment with praziquantel
Authors: Shaw M. K. , Erasmus D. A. 
Published: June 2009

SUMMARYThe long-term, in vivo effects of a single, subcurative dose (200 mg/kg body weight of mouse) of praziquantel on the structure of adult Schistosoma mansoni and on the process and speed of tegumental repair are described. In both male and female worms praziquantel caused often extensive damage to the tegument, in the form of surface blebbings, swellings and lesions, and vacuolization and disruption of the subtegumental tissues. Repair of the drug-induced tegumental damage occurred slowly with partial and, more rarely, complete repair only being seen after 65 days post-treatment (p.t.), although signs of damage were still observed, particularly in male worms, at 100 days p.t. In contrast, repair of damage to the subtegumental/parenchymal tissues including the tegumental perikarya occurred relatively quickly, with the majority of worms examined appearing normal by 8–12 days p.t. The possible role(s) of the host immune response in relation to the speed of tegumental repair in vivo is discussed.
Identification and characterization of a polysaccharide-containing antigen fromSchistosoma mansonieggs which cross-reacts with the surface of schistosomula
Authors: Dunne D. W. , Bickle Q. D. 
Published: June 2009

SUMMARYAntisera were produced by immunizing rabbits with either a trichloroacetic acid-soluble fraction, or a high molecular weight (Mr) fraction ofSchistosoma mansoniSEA (a salinesoluble fraction of homogenized egg). Both of these sera reacted monospecifically in immunoelectrophoresis against unfractionated SEA, recognizing a cathodally migrating antigen. This antigen had been identified previously as being responded to byS. mansoni-infected mouse sera, and has been designated K3(Kappa 3). The rabbit antisera were used to partially characterize antigen K3as havingMrin the range > 750 – 70 K, and being resistant to boiling, resistant to the action of proteases, but sensitive to periodate. It partially binds to Concanavalin A. In addition to SEA, the antigen was present in homogenized cercariae and schistosomula, but not adult worms, and it was also present in detergent extracts of intact cercariae and schistosomula. Using an antibody-dependent cell adherence assay, anti-K3serum was found to react with the surface of live cercariae and with the surface of schistosomula recovered from the skin of mice infected up to 48 h previously. Anti-K3serum also reacted with the surface ofS. bovis, S. haematobiumand to a lesser extentS. japonicumschistosomula.
Vaccination of young lambs by means of a protein fraction extracted from adultHaemonchus contortus
Authors: Munn E. A. , Greenwood C. A. , Coadwell W. J. 
Published: June 2009

SUMMARYLambs aged 48–150 days which had been injected with extracts enriched in a functional antigen (contortin) obtained from adultHaemonchus contortusdeveloped specific circulating antibodies and were less susceptible to haemonchosis when challenged 1 month later with a single dose of 20000–25000 infective 3rd-stage larvae. Sera from 18 out of a total of 19 lambs injected with the extract contained precipitating antibodies to 2–5 components of the extract. None of these lambs died. The one extract-injected lamb which did not develop antibodies and 9 of the 13 lambs used as controls died of haemonchosis. The average weight of worms recovered was 1·45 g from the immune lambs and 5·72 g from the non-immune lambs.
The effect of Trichostrongylus tenuis on the caecal mucosa of young, old and anthelmintic-treated wild red grouse, Lagopus lagopus scoticus
Authors: Watson H. , Lee D. L. , Hudson P. J. 
Published: June 2009

SUMMARYThe caecal mucosa of wild young and adult grouse infected naturally with Trichostrongylus tenuis was examined by means of scanning electron microscopy and compared with adult grouse which had been treated with an anthelmintic. The caecal mucosa of young red grouse with low worm burdens possessed longitudinal plicae and exhibited little damage. The caeca from adult grouse, most of which carried high worm burdens, showed a localized depression of plicae and atrophy and cell disruption in areas of nematode aggregation. Caeca from adult birds treated with an anthelmintic showed a similar caecal structure to lightly infected caeca from young birds. It is concluded that the normal functioning of the caeca is probably affected by heavy infections of T. tenuis.
Cultivation of Trypanosoma cruzi in irradiated muscle cells: improved synchronization and enhanced trypomastigote production
Authors: Schmatz D. M. , Murray P. K. 
Published: June 2009

SUMMARYSince the in vitro production of trypomastigote stages of Trypanosoma cruzi in cell culture is frequently limited by (1) host cell overgrowth and (2) by the unequal redistribution of parasites after cell division resulting in asynchronous release of trypomastigotes, a culture system was devised in which host cell mitosis was inhibited by irradiation prior to parasite infection. L-6 rat myoblast cells when exposed to 3000 rad. of gamma radiation lost their ability to divide but remained susceptible to infection with, and capable of supporting the intracellular growth of, T. cruzi. Using this approach it proved possible to have virtually 100% of cells infected and achieve much better synchronization of trypomastigote release than with conventional culture systems. Additionally, the total number of parasites provided approached 1 × 109 trypomastigotes/ 150 cm2 flask, a significant increase over other culture systems. Preliminary studies with Plasmodium fallax and Eimeria tenella indicate that irradiated host cells may be utilized to advantage for the cultivation of other intracellular protozoa.
Characterization of excretory-secretory antigens ofFasciola hepatica
Authors: Irving D. O. , Howell M. J. 
Published: June 2009

SUMMARYTwenty-one day oldFasciola hepaticawere recovered from the livers of infected mice and cultured for 5–7 days in a serum-free medium containing either [C]leucine, [C]isoleucine or [S]methionine, or in a medium containing [C]leucine and serum from a sheep vaccinated with excretory– secretory (ES) antigens of juvenileF. hepatica. All three labelled amino acids were incorporated into fluke proteins. Labelled proteins also appeared in the culture medium. Three major polypeptides detected in the culture media had apparent molecular weights of 26000, 24000 and 23000. All were immunoprecipitated from [C]leucine-labelled culture medium using antisera against fluke somatic antigens raised in rabbits or from sheep vaccinated with ES antigens of juvenileF. hepatica. A polypeptide of molecular weight 27 000 was also prominent in the culture medium when [C]isoleucine was used. This polypeptide was present as a minor component when [C]leucine and [S]methionine were included in the culture media; it did not appear to be immunoprecipitated by the above antisera from [C]leucine-labelled culture medium. In the presence of serum from vaccinated sheep, the ES antigens formed immune complexes which contained the polypeptides mentioned above, together with several higher molecular weight polypeptides. Additionally, a number of minor bands of varying molecular weight were present. After micro-Ouchterlony gel immunodiffusion, 2 precipitin lines formed between the labelled ES antigens and antisera. Electrophoresis of these indicated that the 23000, 24000 and 26000 Dalton labelled polypeptides were present in each. The higher molecular weight and the 27000 Dalton labelled polypeptides were also present in one of the lines.
Eimeria mitis: a comparison of the endogenous developmental stages of a line selected for early maturation and the parent strain
Authors: McDonald V. , Shirley M. W. 
Published: June 2009

SUMMARYThe endogenous development of the Houghton (H) strain of Eimeria mitis (= mivati) was compared with the life-cycle of a precocious (HP) line derived from the H strain. In both parasites 4 generations of schizonts which developed in epithelial cells were observed: the 1st and 2nd were found in the crypts and the 3rd and 4th in the villi. Gametocytes and zygotes occupied epithelial cells at the tips of the villi. The onset of gametogony normally coincided with the maturation of 4th-generation schizonts. The infection was confined initially to an area of the gut extending from the jejunum to the ileo-caecal junction but 3rd-generation merozoites and subsequent stages were also found in the caeca and rectum. The life-cycle of the precocious line was shorter than that of the parent strain. Gametocytes appeared to develop from 3rd-generation as well as from 4th-generation merozoites. Also, sporozoites of the precocious line transformed to trophozoites before those of the parent strain. First-generation schizonts of the HP line tended to be smaller and to contain fewer merozoites than those of the H strain. The differences between the life-cycles of the two parasites account for the lower reproductive potential of the precocious line.
Isoelectric focusing of general protein and specific enzymes from pathotypes of Globodera rostochiensis and G. pallida
Authors: Fox P. C. , Atkinson H. J. 
Published: June 2009

SUMMARYVariations in the general protein and 40 enzymes of the 8 European pathotypes of the potato cyst nematode Globodera rostochiensis and G. pallida have been examined by isoelectric focusing (IEF) and cluster analysis. Differences in the protein patterns were observed and the presence of a major band at pH 8·0 allowed the two species to be discriminated. Extra isozymed of peptidase (EC 3.4. 11.*) and esterase (EC 3. 1. 1. 1) were also found in G. rostochiensis. Intra-species variation was seen within G. rostochiensis for superoxide dismutase (EC 1. 15. 1. 1) and within G. pallida for phosphoglucomutase (EC 2. 7. 5. 1) and glucose phosphate isomerase (EC 5. 3. 1. 9). The results suggest that the two species are very similar and the prospect for recognizing their pathotypes by IEF is discussed.
Determination of nuclear DNA of five Eucoccidian parasites, Isospora (Toxoplasma) gondii, Sarcocystis cruzi, Eimeria tenella, E. acervulina and Plasmodium berghei, with special reference to gamontogenesis and meiosis in I. (T.) gondii
Authors: Cornelissen A. W. C. A. , Overdulve J. P. , Van Der Ploeg M. 
Published: June 2009

SUMMARYDNA contents of individual stages of Isospora (Toxoplasma) gondii and other Eucoccida were measured after Feulgen-pararosaniline (SO2) staining either by direct microfluorometry or by scanning of microphotographic negatives. Frequency distributions were analysed using a computer program based on a mathematical model describing cell division. All stages of I. (T.) gondii, except fertilized macrogametes (2c), contained a haploid amount of DNA (1c), indicating that meiosis in I. (T.) gondii occurs during sporogony. Microgametes possessed 3·3% DNA in excess, presumably mitochondrial DNA. Nuclei of M2-and M3-merozoites differed in two characteristics: a small but distinct nucleolus was observed in almost 50% of the M2-merozoites but in none of the M3-merozoites; all M2 merozoites were strictly haploid, while all M3-merozoites were synthesizing DNA (17% above the haploid value). It may be concluded that all M2- and M3-merozoites are already sexually differentiated, i.e. are macro- and microgamontoblasts, respectively. DNA synthesis necessary for the development of the microgamont starts already in the microgamontoblast stage (M3-merozoite). M2-merozoites macrogametes, synthesize 11% extra DNA before fertilization, (after fertilization an extra amount of 12% of the diploid value was found), probably by amplification of genes for proteins which are needed for rapid maturation and later sporogony. Essentially parallel results have been found in Eimeria tenella and in crescent cystozoites of Sarcocystis cruzi. Absolute DNA values in representatives of the Eucoccida have been estimated as follows (10−15 g): I. (T.) gondii, 96; E. tenella and E. acervulina, both 75; S. cruzi, 216; Plasmodium berghei, 27. The value of the estimation of total haploid amounts as a tool in taxonomy of Eucoccida is discussed.
Characterization of the exposed carbohydrates on the surface membrane of adultSchistosoma mansoniby analysis of lectin binding
Authors: Simpson A. J. G. , Smithers S. R. 
Published: June 2009

SUMMARYThe surface architecture of adult maleSchistosoma mansoniwas explored using a range of lectins with differing carbohydrate specificities. Highest specific binding was achieved with concanavalin A and the agglutinin of molecular weight 60000 fromRicinus communis; the binding of wheat germ agglutinin was mostly non-specific. Small amounts of peanut agglutinin and soybean agglutinin binding were observed and the binding of these lectins was increased by pre-treating the parasite with neuraminidase. The fucose binding protein ofLotus tetragonolobusfailed to bind. These results indicate that mannose and/or glucose, galactose,N-acetyl-glucosamine,N-acetyl-galactosamine and sialic acid are exposed on the surface of the adult male schistosome.
Growth, development and pairing of Leucochloridiomorpha constantiae (Trematoda) metacercariae on the chorio-allantois of chick embryos cultivated in vitro
Authors: Fried B. , Fine R. H. , Felter Barbara L. 
Published: June 2009

SUMMARYA simple in vitro technique was devised to culture chick embryos in Petri dishes from the 4th to the 21st day of incubation. Leucochloridiomorpha constantiae (Trematoda) metacercariae were placed either singly or multiply (5/embryo) on the chorio-allantois of in vitro grown embryos on day 7 and were removed on day 14. Growth and development studies were also made on worms grown singly or multiply (5/chick) in the bursa of Fabricius of the domestic chick. Worms grown singly or multiply in embryos were sexually mature, although eggs from these worms were abnormal when compared with eggs from worms recovered from chicks. The mean body area of worms from chicks was 2–3 times greater than that of worms from embryos. The mean body area of single worms from embryos was significantly larger than that of worms grown multiply in this site. However, the mean body area of multiple worms from the chick was significantly larger than that of single worms from this site. Worm pairs or clusters were seen in all embryos with the multiple infections.
Transmission ofSchistosoma mansonifrom man to snail: experimental studies of miracidial survival and infectivity in relation to larval age, water temperature, host size and host age
Authors: Anderson R. M. , Mercer J. G. , Wilson R. A. , Carter N. P. 
Published: June 2009

SUMMARYWe report the results of experimental work on (a) the influence of temperature on the age-dependent survival and infectivity of the mira-cidia ofSchistosoma mansoniand (b) the relationship between snail age, snail size and susceptibility to infection. The death rate of miracidia declined exponentially with age where life-expectancy was maximal (approximately 16 h) at 15 °C. Infectivity also declined rapidly with larval age but, in contrast to larval survival, the rate of infection was at a maximum at 25 °C. Snail susceptibility was shown to be more closely correlated with host size rather than host age. Susceptibility declined exponentially with increased host size. Size-dependent susceptibility was shown to generate concave age-prevalence curves for infection within snail populations, where the maximum prevalence is generated in snails of intermediary age. Simple mathematical models are developed to aid estimation of larval survival and infection rates and experimental results are discussed in relation to the overall transmission success of the parasite from man to snail.
The pattern of infestation of the beach-hopper amphipod Orchestoidea corniculata, by a parasitic mite
Authors: Kitron Uriel D. 
Published: June 2009

SUMMARYThe frequency distribution of an ectoparasitic mite, Gammaridacarus orchestoideae, on its amphipod host, Orchestoidea corniculata, was found to differ significantly from random for all monthly samples taken between October 1977 and October 1978. The negative binomial distribution provided a good fit to these aggregated distributions. The degree of aggregation was negatively correlated with the prevalence of infestation. Prevalence and intensity were highest in the winter, when the degree of aggregation was lowest, and vice-versa in the late summer. This seasonal pattern can be explained through changes in size and density of the host population, which are associated with changes in the size of the habitat of the hosts. Within each sample the host population was highly heterogeneous with regard to infestation by mites. Females carried heavier loads of mites than did males. Both prevalence and intensity were low in the post-moult stages of the moult cycle. Reproductive females showed lower prevalence and intensity of infestation than did either non-reproductive females or males. Analysis of the regression analysis of ‘mean crowding’ on mean density also indicated that aggregation stemmed from a non-random distribution of individual parasites, rather than from clumping of the infective stages of the parasite. Heterogeneity of the host population is suggested as an important cause of the aggregated distribution of the parasite population.