bluuebunny/crossref_metadata_2025_split huggingface dataset:
Faecal egg counts and nematode fecundity: Heligmosomoides polygyrus and laboratory mice
Authors: Keymer A. E. , Hiorns R. W. 
Published: June 2009

SUMMARYThe results are presented of an experimental investigation of the relationship between faecal egg counts and worm burden in outbred MF1 mice infected with Heligmosomoides polygyrus (Nematoda). The sex-ratio of the adult parasites was found to be significantly female biased, but independent of parasite burden. Evidence was also found to suggest a significant association between parasite density and mating success. The linear logarithmic relationship (gradient of approximately 2) between the variance and mean of repeated egg counts from individual mice could not be disrupted by controlled experimental conditions, and is therefore concluded to be an inherent feature of the biology of helminth-host interactions. A significant positive association was detected between host faecal output and parasite fecundity; further investigation of the cause of this association is now required. Average faecal production was found to be inversely related to worm burden. In combination, the above two factors account partly, but not completely, for the observed density dependence in the absolute rate of parasite egg production. Two epidemiological consequences of the relationship between faecal production and parasite fecundity are discussed. First, absolute rates of egg production can only be estimated by temporal egg counts (epd). Secondly, measurements of egg production/g of faecal material (epg) are more reliable indicators of worm burden than measurements of epd. Both faecal output and worm fecundity respond as might be predicted to a period of host food deprivation; faecal egestion and measurements of epd are signifcantly depressed, and measurements of epg are significantly increased. The data are consistent with the hypothesis that egg production and faecal output are causally associated, but that other factors relating to parasite density also influence egg production. Of the possible causes for the high variability in parasite egg production between mice harbouring low number of worms, the most likely explanation seems to be host heterogeneity (possible genetic in origin). This is discussed in relation to similar patterns observed in data collected from human populations in areas of endemic helminth infection.
Parasite utilization of a host community: the distribution and occurrence of metacercarial cysts of Echinoparyphium recurvatum (Digenea: Echinostomatidae) in seven species of mollusc at Harting Pond, Sussex
Authors: Evans N. A. , Whitfield P. J. , Dobson A. P. 
Published: June 2009

SUMMARYThe occurrence, in September 1979, of Echinoparyphium recurvatum metacercarial cysts in a community of molluscan hosts at Harting Pond, West Sussex, was investigated. The parasite exhibited broad host specificity with all 7 species comprising the molluscan community being infected. There were marked differences, however, in the extent to which each host species was utilized and using the mean number of parasites/ individual mollusc as a parameter of infection the mollusc species may be ranked in descending order of utilization as follows: Sphaerium corneum, Lymnaea peregra, Valvata piscinalis, planorbids, Pisidium subtruncatum and Potamopyrgus jenkinsi. Combination of basic infection data with population estimates for each mollusc species in the study area showed that the bivalve P. subtruncatum and the prosobranch V. piscinalis were the most important hosts because they contained approximately 90% of the total number of cysts. In both of these hosts the cyst population was over-dispersed and the degree of over-dispersion increased with host size. The pattern of second intermediate host utilization is discussed in relation to the likely flow of E. recurvatum between the first intermediate host (L. peregra) and wildfowl definitive hosts at Harting.
Establishment and maintenance of behavioural dominance in male mice infected withTrichinella spiralis
Authors: Rau M. E. 
Published: June 2009

SUMMARYTrichinella spiralis infections influenced the establishment and maintenance of behavioural dominance among outbred male mice. Infected animals assumed a subordinate status when challenged by normal or more lightly infected conspecifics both in an unfamiliar test arena and in their established home cages. These effects were demonstrable during the acute and the chronic phases of infection. The significance of this phenomenon to the survival of the mouse host and the transmission of the parasite is discussed.
Parthenogenesis and asexual multiplication among parasitic platyhelminths
Authors: Whitfield P. J. , Evans N. A. 
Published: June 2009

SUMMARYAmong flatworms with parasitic and commensal modes of existence, parthenogenesis and asexual multiplication appear to be largely confined to the Digenea and Cestoda, the only parasitic platyhelminths that routinely utilize indirect life-cycles. Parthenogenesis is apparently restricted to a minority of adult digeneans and cestodes inhabiting their final hosts, and a survey is made of the particular modes of parthenogenesis (i.e. apomictic, automictic and generative) which are employed by such adults. Asexual (amictic) multiplication, in the form of fissioning, is demonstrated by young adults of the cyclophyllidean cestode, Mesoces-toides corti, but is otherwise not exhibited by adult cestodes or digeneans, other than in the perplexing phenomenon of proglottid formation in polyzoic tapeworms. Secondary multiplication is of ubiquitous occurrence in digenean life-cycles in the form of the proliferation which takes place within sporocysts and rediae (germinal sacs) located in the first intermediate host. The controversy concerning the nature of this multiplication is reconsidered in the context of recent findings which have centred on cellular aspects. On the basis of present evidence germinal sac multiplication should be regarded as an asexual rather than a parthen-ogenetic process. The cestode asexual multiplication which occurs in intermediate hosts is a function of the metacestode stage of development. Metacestode proliferation is only known from about 20 species and 6 families of polyzoic cestodes with approximately half the described instances occurring in the family Taeniidae. The organization of these proliferative metacestodes, findings concerning their totipotent stem cells and the ontogeny of buds and new scolices are all reviewed. Finally, the capacity for population expansion of multiplicative larval digeneans and metacestodes are compared, while the ecological roles and the genetical consequences of both parthenogenesis and amictic multiplication in the two taxa are also examined.
The number and size of ovarian balls ofMoniliformis(Acanthocephala) from laboratory rats
Authors: Crompton D. W. T. , Arnold Susan , Walters D. E. 
Published: June 2009

SummaryBy means of conventional light microscopical and counting procedures, estimations have been made of the average number and size of ovarian balls from unfertilized and fertilized femaleMoniliformis dubius. The observations were made on worms recovered from experimental primary infections lasting 1, 2, 3, 4, 5, 8, 11, 14, 17 and 20 weeks in male rats. The number of ovarian balls rises to about 6300 per worm, with the maximum being attained more rapidly in unfertilized than in fertilized females. On average more ovarian balls were present in unfertilized than in fertilized females, but a marked decline in number occurred in both groups of worms towards the end of the experimental period. Similarly, on the basis of the area within the elliptical profiles of fixed ovarian balls, it appeared that those from unfertilized females were generally larger on average than those from fertilized worms.
Synchronization of Plasmodium falciparum gametocytes using an automated suspension culture system
Authors: Ponnudurai T. , Lensen A. H. W. , Meis J. F. G. M. , Meuwissen J. H. E. Th. 
Published: June 2009

SUMMARYAn automated suspension culture system for the cultivation of Plasmodium falciparum is described which retains a degree of flexibility which is absent in other automated culture apparatuses. Not only does this system of cultivation promote rapid multiplication of asexual parasites but also permits the development and maturation of gametocytes. Using a combination of gelatin flotation and N-acetyl glucosamine treatment synchronous development of gametocytes was achieved. The total time for gametocyte maturation in vitro under the conditions provided was 7 days. Stages II and V required 48 h for development whilst I, III and IV needed 24 h each. Mature microgametocytes were relatively long lived in comparison with macrogametocytes. Electron microscopic study of the synchronized stages confirmed the observations of Sinden (1982) but, in addition, we noted the presence of Garnham bodies, a cytostome in all stages and dense spherules in stages I–III similar to the fenestrated buttons in sporozoites and exoerythrocytic forms. The relationship between the number of osmiophilic bodies in the mature gametocytes and their ability to escape from the red cell is reaffirmed.
Quantitative and qualitative change in production of excretions/secretions byLitomosoides cariniiduring development in the jird (Meriones unguiculatus)
Authors: Harnett W. , Meghji M. , Worms M. J. , Parkhouse R. M. E. 
Published: June 2009

SUMMARYExcretions and secretions (E–S) were collected from a series of developmental stages ofLitomosoides cariniimaintainedin vitro. Measurement of the protein content of E–S obtained from each stage indicates that the rate of production of E–S varies enormously during development of the worm. E–S was iodinated using both Iodogen and the Bolton and Hunter Reagent and was also biosynthetically labelled by incubating worms in the presence of [35S]methionine and [3H]leucine. Attempts to biosynthetically label E–S of mature worms and microfilariae with [3H]glucose were unsuccessful. Examination of radio-isotope labelled E–S by SDS–PAGE revealed that some components were sex specific and that the differences in total E–S production during development were due to the existence of both stage-specific components and components whose rate of release varied during parasite maturation. Antigenic characterization of E–S, carried out by immunoprecipitation in combination with SDS–PAGE, indicated that E–S consists of immunogenic components, a molecule which is probably a non-immunogenic parasite product, and host albumin. The implications of these findings for the construction of diagnostic tests to detect products of human filarial parasites are discussed.
Population regulation in ticks: the role of acquired resistance in natural and unnatural hosts
Authors: Randolph Sarah E. 
Published: June 2009

SUMMARYAttachment, engorgement and subsequent development of successive infestations ofIxodes triangulicepslarvae and nymphs on natural hosts,Apodemus sylvaticus, and unnatural hosts, laboratory mice, are compared. In laboratory mice, primary infestations above a threshold level of about 10 ticks elicit an immunological response which reduces, in a density-dependent manner, the rate of successful tick engorgement during subsequent infestations. In contrast, inA. sylvaticussuccessive infestations of larvae result in unchanged or slightly improved survival through to nymphs. The relevance of these results to the concept of host-parasite co-evolution and to tick population regulation is discussed.
Immune expulsion of Trichuris muris from mice during a primary infection: analysis of the components involved
Authors: Wakelin D. 
Published: June 2009

Immune serum accelerated the expulsion of Trichuris muris when transferred into normal mice on days 0 and 3 after infection, but had no effect when the recipient mice had been immunosuppressed by sublethal irradiation or by cortisone treatment. Delaying serum transfer until days 7 and 8 in normal mice failed to accelerate expulsion, although immune mesenteric lymph node cells (MLNC) accelerated expulsion whether transferred early or late in infection.Expulsion from NIH mice, normally complete by 12 days, was prevented by sublethal irradiation given as late as 9 days after infection, but could be restored by subsequent transfer of immune MLNC or, to a lesser degree, non-immune MLNC. Immune MLNC were unable to restore worm expulsion in mice irradiated before infection.These results are interpreted as showing that the immune expulsion of T. muris from mice during a primary infection requires the sequential activities of antibody-mediated and lymphoid cell-mediated components.
The pathology induced in laboratory rats by metacestodes ofTaenia crassicepsandMesocestoides corti(Cestoda)
Authors: Chernin J. , McLaren Diane J. 
Published: June 2009

SUMMARYSprague–Dawley rats were infected by intraperitoneal injection with either the cysticerci ofTaenia crassicepsor the tetrathyridia ofMesocestoides corti. Both species of metacestodes reproduce asexually in the peritoneal cavity. The effect ofT. crassicepsupon the rats was to cause chronic inflammation of the peritoneum, fibrous adhesions between the visceral organs and hyperplasia of the gut mesenteries which became extended into a large sac-like structure. Dead parasites surrounded by white calcareous material were found free in the peritoneum and attached to the inner body wall and viscera. The histopathology of the hyperplastic mesenteries and fibrous membrane is described. The tetrathyridia ofM. cortiwere found free in the peritoneal cavity as well as in the liver (mainly the left liver-lobe), gut mesenteries and in an outgrowth of the connective tissue associated with the pancreas. The connective tissue outgrowth comprised 2 layers; an inner reticular layer and a thickened marginal layer. Metacestodes were found in collagen—fibrin capsules within the connective tissue. A layer of mucopolysaccharide material was interposed between the parasite and the capsule wall. A possible method by which the parasites gain entry into the connective tissue is described. The connective tissues of rats harbouring eitherM. cortiorT. crassicepshad increased numbers of mast cells compared to connective tissues from control rats. Younger mast cells containing biogenic amines predominated in infected tissues whereas older heparin-containing cells dominated control tissues.
The host-parasite relationship of Schistosoma japonicum in CBA mice
Authors: Moloney N. A. , Webbe G. 
Published: June 2009

SUMMARYThe host–parasite relationship of the Chinese mainland strain of Schistosoma japonicum in CBA mice is described and compared to previous reports on this parasite in mice. S. japonicum took under 2 weeks to complete its migration to the portal system of mice, and peak passage of schistosomula through the lungs occurred 5–6 days after infection. The mean percentage establishment of worms, which was independent of the infecting inoculum, was 46%. The adult worm burdens remained constant over a 28-week period of infection. Male and female worms reached maximum mean lengths of 13 and 19 mm, respectively. Egg laying commenced 30 days after infection. The number of ova deposited in the liver stabilized at some 55000 by 12 weeks of infection with 30 cercariae, but the intestinal egg burden rose from 132000 at 12 weeks to 430000 at 28 weeks. Faecal eggs were first observed 6 weeks after mice were exposed to 100 cercariae and 7 weeks after lighter exposures. Faecal egg output also stabilized 12 weeks after infection. The formation of granulomas in the liver occurred within 2 weeks of egg deposition and encompassed a maximum area 14 weeks after infection. Fifty per cent mortality occurred 15 weeks after exposure, but only in hosts infected with 100 cercariae.
Strongyloides ratti: studies of 75Se-labelled larvae of the homogonic strain in female hosts
Authors: Wilson P. A. G. , Simpson Norma E. 
Published: June 2009

SummaryA prediction of the hypothesis of Wilson (1977, 1980a, b) to account for larval migration of homogonic Strongyloides ratti in the host is that the pattern of invasion of the mammary gland of a lactating rat will be quantitatively similar on both sides and independent of the point of entry into the body. Twenty-one suckled mother rats in 6 experiments in which live 75Se-labelled 3rd-stage homogonic larvae were injected under the skin of the upper flank had an overall distribution of label 30 h post-injection, as a percentage of the initial dose, in the quadrants, I (rear, injection side), II (rear, opposite injection side), III (front, injection side) and IV (front, opposite injection side) of the mammary gland as follows: 27·4%, 1·27%, 1·89% and 1·24%. Quantitative changes in mammary label between 30 and 48 h post-injection using live larvae, differences between mothers and virgins, and results after injection of heat-killed labelled larvae, confirm that the pattern is representative of the behaviour of normal (unlabelled) worms when injected. The theory is therefore disproved. The findings are put forward as the first quantitative evidence for major lymphatic involvement in migration of a skin-penetrating round worm. They need confirmation in similar experiments in which worms are allowed to penetrate the skin naturally. The role of isotope-labelled larvae versus traditional methods of estimating parasite content of host tissue is discussed.
Quantitative methods in the study of the pathogenesis of haemoprotozoal diseases
Authors: Losos G. J. , McMillan I. , Minder Ch. E. , Soulsby K. 
Published: June 2009

SummaryThe study of pathogenicity of haemoprotozoa and the pathogenesis of the diseases they cause requires quantitative descriptions. Statistical and mathematical methods are introduced to describe infectivity, parasitaemia, total body parasitosis and the severity of diseases.
Factors affecting surface changes in intact cercariae and cercarial bodies of Schistosoma mansoni
Authors: Pinto-Ramalho F. J. , Gazzinelli G. , Howells R. E. , Pellegrino J. 
Published: June 2009

The effect of different incubation media and of temperature on the induction of water sensitivity has been investigated in intact and tailless Schistosoma mansoni cercariae. Removal of the cercarial tail by vortex stirring and elevation of the temperature of the medium from 27 to 37°C resulted in the rapid onset of permeability changes in the larvae. The rate of change was greater in water than in TC-199 or Hanks' BSS media. Lowering the pH of the medium or increasing the concentration of Ca2+ ions decreased the rate of permeability change: raising the pH of the medium or the addition of 10−5 M EDTA enhanced the rate.Raising the temperature of the medium also increased the rate of permeability change in intact cercariae although the rates obtained varied with the different media tested, being greatest in TC-199.It is concluded that both temperature elevation and loss of the cercarial tail influence the onset and rate of permeability changes in cercarial bodies during the transformation to schistosomula.
The duration of passive protection against Taenia ovis larvae in lambs
Authors: Heath D. D. , Yong W. K. , Osborn P. J. , Parmeter S. N. , Lawrence S. B. , Twaalfhoven H. 
Published: June 2009

SUMMARYIn an attempt to induce passive protection in lambs against Taenia ovis larvae that would last for the 15–20 weeks from birth to slaughter as fat lambs, one group of ewes was immunized by a series of injections of 2000, 4000, 8000, 16000 and 32000 activated oncospheres of Taenia ovis prior to parturition. Another group of ewes was not immunized. All ewes had previously grazed pasture lightly infected with T. ovis eggs. Most lambs from non-immunized ewes developed cysts after oral infection with T. ovis eggs. However, no lambs from immunized ewes developed cysts up to and including 6 weeks after birth. Between 8 and 16 weeks after birth a proportion of lambs were found to be susceptible to infection. By 18 weeks after birth all lambs were apparently susceptible. The 99% confidence band for the mean duration of demonstrable complement-fixing antibody titres was 6·2–7·8 weeks for lambs from immunized ewes. The persistence of maternal protective antibody in some lambs could possibly preclude successful active immunization of all lambs against T. ovis larvae before 18 weeks of age.
The species of Eimeria in rabbits for meat production in Britain
Authors: Catchpole Janet , Norton C. C. 
Published: June 2009

SUMMARYEight species of coccidia were recognized in 596 faeces samples from 3 commercial rabbitries in South East England. The level of infection was related to management methods and at one site it was reduced by an outbreak of mucoid enteritis and/or its treatment with oxytetracycline. In samples from rabbits managed conventionally in wire cages over droppings-pits, 96% contained oocysts and of these, 60% had 1000–10000 oocysts/g. Mixed infections were common, 67% of the animals carrying 2–4 different species. Eimeria media, E. magna and E. perforans occurred most frequently; E. coecicola, E. irresidua and E. flavescens were less common and E. intestinalis and E. piriformis were relatively rare. E. stiedai was not recorded.
Brittlestar host specificity and apparent host discrimination by the parasitic copepod Ophiopsyllus reductus
Authors: Emson R. H. , Mladenov P. V. 
Published: June 2009

SUMMARYHost specificity of a siphonostome copepod Ophiopsyllus reductus was confirmed by the results of an extensive survey of co-existing possible alternate host brittlestars. The parasite was found only on Ophiocomella ophiactoides. The ability to discriminate between potential hosts was tested experimentally. O. ophiactoides was always preferred and, in experiments with unrelated alternative hosts, the discrimination was absolute. When closely related species were the alternate host, discrimination was less complete. It is suggested that the discrimination is due to recognition of either tactile or chemical characteristics of the preferred host.
Parasite-mediated reductions in the growth of nymphal backswimmers
Authors: Lanciani C. A. , May P. G. 
Published: June 2009

SUMMARYEngorged, parasitic water mites were observed to decrease the growth rate and to increase the stadium length of nymphal backswimmers. Unengorged mites were found to have no effect on the host. The extended stadium lengths of parasitized hosts should reduce the instantaneous rate of natural increase of populations of parasitized hosts because this rate is sensitive to any factor that delays the onset of reproduction.
Observations on tanning of the potato cyst-nematode,Globodera rostochiensis
Authors: Awan F. A. , Hominick W. M. 
Published: June 2009

SUMMARYColour changes that occur during tanning of intact and puncturedGlobodera rostochiensisfemales and of isolated cuticle are described. Experiments with catechol and enzyme inhibitors show that the tanning enzyme, a phenoloxidase, is located in the cuticle, soluble in aqueous media and relatively abundant. Substrate for the enzyme is limited in the cuticle. Pseudocoelomic fluid of yellow females promoted tanning and contains either phenolic substrate(s) for the enzyme or part of a biochemical system responsible for release of the substrate. The substrate or biochemical system is thermolabile. Apparently, the tanning enzyme and its substrate(s) are partitioned in living females but the partitioning breaks down after death and the cuticle tans to form the cyst.
Amplification of the cestode surface: a stereological analysis
Authors: Threadgold L. T. , Robinson A. 
Published: June 2009

SUMMARYA stereological study was undertaken on the length, diameter and numbers of microtriches and on the structural and functional amplification factors of the adult cestodes, Hymenolepis diminuta, Hymenolepis nana, Eubothrium crassium, Proteocephalus pollanicoli, the plerocercoid of Schistocephalus solidus and the cysticercus of Taenia crassiceps. The study showed wide variations in these stereological parameters between species, stages and regionally in the same species. A comparison of the present results with previous studies has shown a large measure of agreement but some differences are evident and possible explanations of these differences are proposed.