bluuebunny/crossref_metadata_2025_split huggingface dataset:
An investigation of the prevalence of intestinal parasites in pre-school children in Ghana
Authors: Annan Akweley , Crompton D. W. T. , Walters D. E. , Arnold S. E. 
Published: June 2009

SUMMARYEvidence for the presence of 11 intestinal parasites in pre-school children from 4 rural villages in Ghana was obtained from an examination of stool samples. Striking differences were detected between the prevalence of some of the 6 common infections in the 4 villages. The prevalance of Ascaris lumbricoides varied from about 76% in one village (Oshiyie, coastal savanna) to apparently 0% in another (Akuma, forest zone). No differences in prevalence for any infection were observed to be sex dependent. Investigation of the relationship between age of the children and prevalance showed that the degree of prevalence of both A. lumbricoides and Trichuris trichiura had essentially levelled off by the time the children were 4 years old. There was no evidence to suggest that the prevalence of either Entamoeba sp. or spp. or hookworm was approaching a maximum value, even in the oldest children. These trends applied across the villages regardless of the differences in prevalence values for the infections. On average, the children of Oshiyie were found to harbour twice as many infections as the children of the other villages. The investigation of the prevalence data revealed evidence of associations between pairs of infections, particularly those involving hookworm and T. trichiura.
Properties and localization of chitin synthase inAscaris suumeggs
Authors: Dubinský P. , Ryboš M. , Turčeková Ľ. 
Published: June 2009

SUMMARYInvestigations were carried out into the properties and localization of chitin synthase (EC 2.4.1.16) in connection with the formation ofAscaris suumegg-shells. The chitin synthase of eggs exhibited properties very similar to those found in other chitin-synthesizing organisms. It was stimulated by the presence of ATP, GlcNAc and Mg2+with maximal activity at pH 7·0. In the phase of active chitin synthesis, during formation of the primary shell layers, chitin synthase was bound to the structures of the eggs. On completion of chitin synthesis in the eggs, the amount of the enzyme increased in the soluble fraction. Two forms of chitin synthase have been found in the eggs, namely an inactive (zymogenic) and an active form. Transformation of these two enzyme forms represents a key mechanism in the regulation of chitin synthesis inA. suumeggs.
A method for estimating possible parasite-related host mortality, illustrated using data from Callitetrarhynchus gracilis (Cestoda: Trypanorhyncha) in lizardfish (Saurida spp.)
Authors: Adjei E. L. , Barnes A. , Lester R. J. G. 
Published: June 2009

SUMMARYThe frequency distribution of parasites in hosts commonly follows a negative binomial or similar distribution. Under certain conditions the magnitude of parasite-associated host mortality can be estimated by comparing the tail of the observed distribution to that of the distribution predicted from the first few points of the data. For the technique to work the following assumptions need to be met: mortality in lightly infected fish must be rare; infection and consequent mortality occur only in fish younger than those sampled; and the frequency distribution of the parasite at the time of infection should conform to a known probability distribution. The method was applied to frequency distributions of blastocysts of Callitetra rhynchus gracilis in 898 Saurida tumbil (Bloch) and 5013 S. undosquamis (Richardson). Parasite-associated mortality in S. tumbil was calculated to be at least 11 % in males and 2% in females. For S. undosquamis, estimated mortality was about 5% in males and 3% in females. The numbers of parasites estimated to produce a 0·5 probability of death, the parasitological equivalent of an LD50 were 3·4 and 5·7 for S. tumbil males and females, and 18 and 3 for S. undosquamis males and females respectively.
Observations on chromosomes and gametogenesis ofTransversotrema patialense(Trematoda)
Authors: Havi R. Mad , Ramanjaneyulu J. V. 
Published: June 2009

SUMMARYThe karyotype ofTransversotrema patia1enconsists of 10 pairs of chromosomes (2n= 20) of which 5 pairs are metacentrics and 5 pairs are submetacentrics. The chromosomes are large and range in size from 5 to 12 μm. The total chromosome length of the diploid complement is 16783 μm. Stages of spermatogenesis including the two gonial divisions and two reduction divisions leading to production of spermatozoa occur in cercarial embryos inside snail tissue, while the maturation divisions of the ovum occur in eggs freshly liberated by the fluke. The chiasma frequency is high, being 3888/cell and 388/bivalent. Cytological data indicate an independent phylogenetic status for the family Transversotrematidae.
Ascaris infections in humans from North America: molecular evidence for cross-infection
Authors: Anderson T. J. C. 
Published: June 2009

SUMMARYCases of human Ascaris infection occur sporadically in areas such as N. America and Western Europe, where this parasite is thought to be non-endemic. Clinical case histories suggest that many of these cases may be cross-infections from pigs. I describe patterns of variation in the ribosomal DNA of Ascaris from 9 such cases. For comparative purposes, I also describe patterns of variation in parasites obtained from pigs and humans from worldwide locations. A Hae III restriction site distinguishes two classes of rDNA repeats; repeats bearing this restriction site were found in > 96% of parasites from pig populations worldwide and in all 9 worms from humans in N. America. In contrast, repeats bearing this restriction site were detected in < 2% of parasites from humans in endemic areas. The molecular data clearly incriminate pigs as the source of infection in the N. American cases. I discuss evolutionary and public health implications of incomplete host fidelity in Ascaris.
Antibodies to the glutamate dehydrogenase ofPlasmodium falciparum
Authors: Ling I. T. , Cooksley S. , Bates P. A. , Hempelmann E. , Wilson R. J. M. 
Published: June 2009

SUMMARYPolyclonal antisera raised againstPlasmodium knowlesireacted with (1) NADP-specific glutamate dehydrogenase (GLDH) ofP. knowlesi, (2) GLDH ofP. falciparumand (3) GLDH ofProteus spp. The antisera did not react with NAD(P) GLDH from bovine liver. Polyclonal antisera raised against the GLDH ofProteus spp. cross-reacted with GLDH fromP. falciparum. Monoclonal antibodies (McAbs) obtained from mice immunized with Proteus GLDH were either specific for the bacterial enzyme or cross-reacted withP. falciparumGLDH. The selected McAbs did not react with GLDI-1 fromP. knowlesi,P. chabaudiorP. berghei. The GLDH ofP. falciparumwas shown to be a cytosolic protein (by FAT) with a subunit molecular weight of approximately 49000 Da (by immunoprecipitation) having a pre dominantly hexameric form (by sucrose density gradient). Implications of the conserved sequences of GLDHs and other enzymes are discussed.
Experimental infection ofTribolium confusum(Coleoptera) byHymenolepis diminuta(Cestoda): host fecundity during infection
Authors: Maema Malefane 
Published: June 2009

SUMMARYSome effects ofHymenolepis diminutaon the fecundity ofTribolium confusumare described. Host fecundity is observed to be reduced exponentially with increasing parasite burden/host, although there are differences in the ability of individual hosts to respond to parasitism. Of particular interest is the finding that host fecundity is greatly reduced in young beetles on or by day 14 post-infection (p.i.). This age-related reduction in host fecundity is discussed in relation to the population dynamics of this hostr-parasite relationship.
Efficacy of treatment of murineSchistosoma mansoniinfections with praziquantel and oxamniquine correlates with infection intensity: role of host antibody
Authors: Fallon P. G. , Hamilton J. V. , Doenhoff M. J. 
Published: June 2009

SUMMARYThe reduction in worm burden obtained by treatment ofSchistosoma mansoniwith praziquantel and oxamniquine was greater in mice with heavy infections than in relatively lightly infected animals. The reduction in worm burden achieved by each drug correlated with the size of the pre-treatment worm burden (r2= 0·82 and 0·81 for praziquantel and oxamniquine, respectively). Intensity of infection did not affect the degree of tegumental damage and drug-induced antigen exposure on worms recovered soon after treatment with praziquantel. However, praziquantel-treated worms from mice with heavy infections had significantly more murine antibody attached to the treated-worm surface than worms from praziquantel-treated lightly infected mice. Heavily infected mice had greater levels of circulating anti-worm antibodies than lighter infected mice. The correlation between infection intensity and cure rates achieved by praziquantel and oxamniquine may thus be a reflection of the higher litres of relevant antibody in heavily infected mice mediating death of drug-treated worms.
Proteinases releasedin vitroby the parasitic stages ofTeladorsagia circumcincta, an ovine abomasal nematode
Authors: Young C. J. , McKeand J. B. , Knox D. P. 
Published: June 2009

SUMMARYProteinases released duringin vitromaintenance of third (L3) and fourth larval stage (L4) and adultTeladorsagia circumcincta(formerlyOstertagia circumcincta), an ovine abomasal nematode parasite, were characterized on the basis of pH optima, molecular size and specific proteinase inhibitor sensitivity. Enzyme activity was maximal at alkaline pH and stage-specific release was demonstrated. Proteinases released by the adult parasite degraded a variety of protein substrates including plasminogen, albumin and haemoglobin, in a pH-dependent manner. At alkaline pH fibrinogen degradation was restricted to the α and β peptide chains although the γ peptide chain was also degraded at acidic pH. Inhibitor sensitivity studies indicated that degradation was predominantly due to metalloproteinases although aspartyl proteinase activity was indicated at acidic pH.
The distribution and pathobiology ofNeoechinorhynchus cylindratusin the intestine of green sunfish,Lepomis cyanellus
Authors: Adel-Meguid M. , Esch G. W. , Eure H. E. 
Published: June 2009

SUMMARYThe status of bluegill (Lepomis macrochirus) and green sunfish (Lepomis cyanellus) as homologous hosts for the acanthocephalanNeoechinorhynchus cylindratuswas experimentally determined. It was found that the adult parasite did not establish in bluegills, but that these fish could serve as paratenic host. In contrast, complete growth and development to the adult stage occurred in the green sunfish. When green sunfish were intubated with 10 cystacanths/fish, the parasite exhibited a clear preference for the anterior half of the intestine; when 50 cystacanths/fish were intubated, the parasites showed a preference for the posterior half of the intestine. With repeated exposure of cystacanths, the parasites were distributed throughout the intestine. The extent of histopathology induced byN. cylindratuswas related to the numbers of parasites present. In light infections (10 cystacanths), the parasite penetrated deeply into the intestinal wall and connective tissue developed around the proboscis. In infections with 50 cystacanths, the proboscis penetration was shallow and little if any connective tissue accumulated. There was also an indication that in crowded areas, the parasites appeared to change their sites of attachment frequently. In both heavy and repeated infections, the parasites evoked significant goblet cell hyperplasia and substantial quantities of mucus covered the intestinal wall. It is suggested that the sticky covering and the presumed presence of antibodies in the mucus combined to create a protective barrier thereby reducing the numbers of parasites that could attach and become established.
Development and ultrastructure ofTrachipleistophora hominisn.g., n.sp. afterin vitroisolation from an AIDS patient and inoculation into athymic mice
Authors: Hollister W. S. , Canning E. U. , Weidner E. , Field A. S. , Kench J. , Marriott D. J. 
Published: June 2009

SUMMARYContinuous culture was achieved in several cell lines of a microsporidium obtained from the skeletal muscle of an AIDS patient. Development in COS-1 and RK13 cells was prolific. Spores from the original biopsy were also inoculated into athymic mice by i.m. and i.p. routes. Infection was found in several organs as well as in skeletal muscle after a few weeks. All stages were surrounded by an electron-dense surface coat. Meronts had 2–4 nuclei and divided by binary fission. In sporogony the surface coat became separated from the plasma membrane to form a sporophorous vesicle, within which division into sporoblasts was effected by repeated binary fissions. The number of sporoblasts (and later spores) within the sporophorous vesicles varied from 2 to > 32 and the sizes of the vesicles varied, according to the number of spores contained therein, from 5 μm diameter to 14·0 × 11·0 μm. Spores measured 4·0 × 2·4 μm and had a prominent posterior vacuole. The parasite differs from the genusPleistophorain that it does not form multinucleate sporogonial plasmodia and that the sporophorous vesicle enlarges during sporogony and its wall is not a multilayered structure. It is proposed to place it in a new genus and speciesTrachipleistophora hominisn.g., n.sp.
Changes in foraging behaviour during the infective stage of entomopathogenic nematodes
Authors: Lewis E. E. , Selvan S. , Campbell J. F. , Gaugler R. 
Published: June 2009

SUMMARYStudies of foraging strategies are often complicated by competing goals of the forager. In contrast, non-feeding infective juvenile entomopathogenic nematodes forage exclusively for a single host. Two questions were posed: (1) what is the relationship between metabolic rate, energy reserves and foraging strategy and (2) when a foraging strategy fails, will an infective-stage parasite switch strategies? Three species of entomopathogenic nematodes were stored in water and changes in their behaviour, metabolic rate, energy reserves, and infectivity were measured throughout the storage period.Steinernema carpocapsaeambushes insect hosts, whereas S.glaseriandHeterorhabditis bacteriophoracruise forage.Steinernema carpocapsaewas least active and had the lowest metabolic rate.Heterorhabditis bacteriophorawas more active and had the highest metabolic rate.Steinernema glaseriwas most active and had an intermediate metabolic rate. Neither cruising species changed foraging strategy.Steinernema carpocapsaedecreased nictation (a behaviour associated with ambushing only) and increased their locomotory rate. Any change in searching strategy occurred without assessment of the profitability or distribution of potential hosts, but the advantage this confers is unknown.
Reduced spatial learning in mice infected with the nematode, Heligmosomoides polygyrus
Authors: Kavaliers M. , Colwell D. D. 
Published: June 2009

SUMMARYParasite modification of host behaviour influences a number of critical responses, but little is known about the effects on host spatial abilities. This study examined the effects of infection with the intestinal trichostrongylid nematode, Heligmosomoides polygyrus, on spatial water maze learning by male laboratory mice, Mus musculus. In this task individual mice had to learn the spatial location of a submerged hidden platform using extramaze visual cues. Determinations of spatial performance were made on day 19 post-infection with mice that had been administered either 50 or 200 infective larvae of H. polygyrus. The infected mice displayed over 1 day of testing (6 blocks of 4 trials) significantly poorer acquisition and retention of the water maze task than either sham-infected or control mice, with mice that had received 200 infective larvae displaying significantly poorer spatial performance than individuals receiving 50 larvae. The decrease in spatial learning occurred in the absence of either any symptoms of illness and malaise, or any evident motor, visual and motivational impairments. It is suggested that in this single host system the parasitic infection-induced decrease in spatial learning arises as a side-effect of the host's immunological and neuromodulatory responses and represents a fitness cost of response to infection.
Damage to malaria-infected erythrocytes following exposure to oxidant-generating systems
Authors: Wozencraft Anne O. 
Published: June 2009

SUMMARYA study has been made of the damage incurred by normal andPlasmodium falciparum-infected human erythrocytes following exposure to a variety of oxidant-generating systems. Hydrogen peroxide, produced by the glucose–glucose oxidase system, increased methaemoglobin formation within normal erythrocytes while normal levels of oxyhaemoglobin were maintained. Exposure to products of the xanthine–xanthine oxidase interaction did not have the same effect. Malondialdehyde measurements indicated that the host cell membranes of parasitized cells had undergone lipid peroxidation even before exposure to the oxidant-generating systems. Lipid peroxidation of normal and parasitized cell membranes was increased upon exposure to reagent-grade hydrogen peroxide and alloxan: this increase was not observed following exposure to the two enzyme–substrate systems that generated reactive oxygen intermediates. In addition, the effects of parasitism on intracellular levels of catalase and superoxide dismutase were assessed. Normal and parasitized erythrocytes were found to possess similar levels of these enzymes, which protect against oxidant-induced damage. It was therefore concluded that the increased susceptibility of infected cells to oxidant damage was probably not related to any decrease in the function of these enzymes.
A study on antigen recognition by onchocerciasis patients with different clinical forms of disease
Authors: Lucius R. , Büttner D. W. , Kirsten Christa , Diesfeld H. J. 
Published: June 2009

SUMMARYSera from 40 onchocerciasis patients from the Yemen Arab Republic with either mild localized forms of onchocerciasis, intermediate or severe localized forms of the disease or generalized forms of infection were studies with rspect to their IgG and IgM response againstOnchocerca volvulusantigens. Immunoblotting, performed with SDS–PAGE-separated proteins of femaleO. volvulusand quantified by densitometric scanning, revealed IgG and IgM antibodies against worm components in sera of all patients. Persons with intermediate or severe localized forms of onchocerciasis had a stronger IgG response against more proteins than individuals of the other group. However, some antigens (Mr21, 23, 30, 33 kDa) induced comparable quantities of IgG in all groups. The IgM response of patients with mild localized forms of onchocerciasis was more intensive and directed against more antigensthan in the other groups. No antigens were detected that were recognized only by individuals with low levels of microfilaridermia. In all groups, varying concentrations of antibodies against cuticle, muscle/hypodermis layer and/or uterus of femaleO. volvuluswere detected by the indirect immunofluorescence test using frozen worm sections as antigen. The highest mean antibody titres were found in patients with intermediate and severe localized forms of disease.
Population dynamics in echinococcosis and cysticercosis: mathematical model of the life-cycle of Echinococcus granulosus
Authors: Roberts M. G. , Lawson J. R. , Gemmell M. A. 
Published: June 2009

SUMMARYA mathematical model of the life-cycle of Echinococcus granulosus in dogs and sheep in New Zealand is constructed and used to discuss previously published experimental and survey data. The model is then used to describe the dynamics of transmission of the parasite, and the means by which it may be destabilized. It is found that under the conditions that prevailed in New Zealand during the late 1950s, at the time of surveys of this parasite, the dog–sheep life-cycle was not regulated by any effective density-dependent constraint. In contrast there was evidence for an effective acquisition of immunity to reinfection by cattle. The long time to maturity of the cyst in sheep, together with the practice of feeding aged sheep to dogs, provides a time delay in the intermediate host. By comparison, the time to maturity of the adult stage in dogs is short, but it is of sufficient magnitude to be a key factor in the destabilization of the system by a regular dog-dosing programme. The model used to describe the life-cycle is a linear integrodifferential equation of the Volterra type. Such equations are intrinsically unstable in that a small perturbation in parameters can drive a previous equilibrium solution to zero. At the time of the surveys, the value of the basic reproductive rate, R0 was close to 1, and it has since been reduced below 1 by control measures.
Interactions between the plasma proteins ofBiomphalaria glabrata(Gastropoda) and the sporocyst tegument ofSchistosoma mansoni(Trematoda)
Authors: Bayne C. J. , Loker E. S. , Yui Mary A. 
Published: June 2009

SUMMARYThe tegumental surface ofSchistosoma mansonisporocysts is the site of both nutritive and immunological interactions with haemolymph cells and plasma ofBiomphalaria glabrata, the schistosome intermediate host. Within minutes of being placed in host plasma, sporocysts acquire plasma antigens, and within 3 h host plasma antigens are present on the surface at near steady state. Though a wide variety of peptides is acquired, there is selection. Furthermore, some differences occur in the peptides acquired from the plasma of susceptible and resistant strains of snail. Acquired antigens are rapidly processed, and are predominantly undetectable in tegumental extracts after a few hours. In contrast, rabbit antibody on sporocysts remainsin situfor at least 48 h, so under some conditions there is stable expression of certain tegumental antigenic determinants.These data, obtained using antibodies to snail plasma antigens and to sporocyst tegumental antigens, are discussed in the light of current ideas on the cellular and molecular basis of susceptibility and resistance in this host#parasite system.
Inequalities in the individual reproductive success of parasites
Authors: Dobson A. P. 
Published: June 2009

SUMMARYTwo simple methods of measuring the levels of inequality in reproductive success of different individuals in parasite populations are presented. These techniques are then applied to a number of sets of data for cestodes and acanthocephalans. The analysis suggests that both population density and host nutrition are important in determining the observed degree of inequality in reproductive success and body size. Cestodes, with a more flexible growth form, are shown to exhibit higher levels of inequality than acanthocephalans. The discussion outlines the evolutionary importance of considering variation in the reproductive success of different individuals.