bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic control of susceptibility toTaenia crassicepscysticercosis
Authors: Fragoso G. , Lamoyi E. , Mellor A. , Lomeli C. , Govezensky T. , Sciutto E. 
Published: June 2009

SUMMARYWe previously reported that genes within the major histocompatibility complex influence the intensity ofTaenia crassicepsmurine cysticercosis. This genetic control, readily apparent in mice of BALB background, was further studied inH-2congenic and recombinant B10 mice as well as in BALB/c substrains differing in expression of Qa-2 antigens. Similarly low parasite numbers were found in all B10-derived strains infected, regardless ofH-2haplotype, indicating that the effect ofH-2genes in controlling susceptibility is overridden in mice of B10 background. BALB/c substrains differed significantly in susceptibility. BALB/cAnN was highly susceptible, whereas BALB/cJ, in contrast, was highly resistant and BALB/cByJ showed intermediate susceptibility. Susceptibility or resistance in BALB/c substrains may be associated to differences known to distinguish them, such as serum testosterone levels and Qa-2 protein expression. In bidirectional F1 hybrids of C57BL/6J and BALB/cAnN resistance to cysticercosis was inherited as a dominant autosomal trait. In F1 hybrids of BALB/cJ with BALB/cAnN, BALB/cByJ and BALB.K resistance was also inherited as a dominant trait. However, in (BALB/cAnN × BALB/cByJ)F1 and (BALB/cAnN × BALE.K)F1 hybrids, dominant susceptibility to cysticercosis was observed.
The distribution of faecal nematode egg counts in Scottish Blackface lambs following natural, predominantly Ostertagia circumcincta infection
Authors: Stear M. J. , Bairden K. , Duncan J. L. , Gettinby G. , McKellar Q. A. , Murray M. , Wallace D. S. 
Published: June 2009

SUMMARYFaecal samples were taken in 2 consecutive years from Scottish Blackface lambs on a commercial farm in central Scotland to examine variation among lambs in the number of nematode eggs in their faeces. Samples were taken at intervals of 4 weeks from 1 to 5 months of age. Lambs were treated with a broad-spectrum anthelmintic at each sample date. Ewes and lambs were naturally infected by grazing pasture contaminated with mixed, predominantly Ostertagia circumcincta, nematode species. The ewes were removed from the lambs when the lambs were three months old. Only 3 of the 6 sets of samples taken prior to removal of the ewes fitted a negative binomial distribution but all sets of samples taken after this did so. The mean and the variance differed with the month and year of sampling. The amount of variation among lambs increased as the lambs grew from 3 to 5 months of age, possibly because of heterogeneity in the rate of development of protective responses. Counts taken in August and September, when the lambs were 4 and 5 months of age, were positively correlated with each other. In contrast, counts taken at 1 or 2 months of age were negatively correlated with counts taken when the lambs were 3–5 months old. Sex, date of birth, sire and dam were all associated with variation in faecal egg counts but the size and significance of their influence was dependent upon the date when faecal samples were taken. Four factors: sire, dam, sex and year accounted for over two-thirds of the variation among older lambs in faecal egg counts.
Immunity to tapeworms: intraspecific cross-protective interactions betweenHymenolepis citelli, H. diminutaandH. microstomain mice
Authors: Alghali Sidi T. O. , Grencis R. K. 
Published: June 2009

SUMMARYInteractions between tapeworm species in a single host offer intriguing opportunities for immunological studies that attempt to identify the mechanism(s) underlying protection against cestode infections. Mice that are immunized againstHymenolepis citelliinfections were shown to be refractory to subsequentH. diminutachallenge infections. The reciprocity of the response was also demonstrated, although the protection recorded forH. diminutawhen mice are sensitized withH. citelliis weaker than that observed when mice are primed withH. diminutaagainstH. citellichallenge.H. citelliwas also shown to be expelled simultaneously during the rejection phase ofH. diminutain concurrent infections, indicating the susceptibility of the former tapeworm to the rejection mechanism initiated by the latter.H. microstomaimmunized mice were shown to be strongly protected against heterologousH. citellichallenge. However, mice primed againstH. citelliwere not as strongly protected againstH. microstomachallenge infections: a statistically significant protection was obtained only after a 12-cysticercoidH. citelliprimary infection, although a 6-cyst infection did stunt the growth ofH. microstomachallenge worms. It is presently suggested that the cross-protective responses observed in the study betweenH. citelli, H. diminutaandH. microstomamay have emanated from a specific immunological cross-reactivity due to the sharing of similar immunogens.
Patterns of haemozoin accumulation in tissue
Authors: Sullivan A. D. , Ittarat I. , Meshnick S. R. 
Published: June 2009

SUMMARYA sensitive fluorometric method for assaying malarial pigment, haemozoin, has been developed and used to determine the haemozoin content of blood and tissue samples.Plasmodium falciparumrings and trophozoites were found to contain 23 and 339 ng haemozoin/106parasitized red blood cells (PRBCs), respectively. UnsynchronizedPlasmodium bergheiNK65 or ANKA parasites from infected mice contained 27 and 61 ng haemozoin/106PRBCs, respectively. An exponential accumulation of haemozoin within 18 days after infection was demonstrated in liver and spleen tissue, representing up to 0·2% of the tissue by wet weight by day 18. Histology indicated that the accumulation occurred predominantly in the tissue monocytes. In the brain, the levels of haemozoin after 8 days of infection were considerably lower than they were in the liver or spleen, and most of the pigment appeared to be that present inside parasitized red blood cells. CBA/Ca mice infected withP. bergheiANKA (a cerebral malaria model) had significantly higher amounts of haemozoin in the brain than did ICR mice infected withP. bergheiNK65. Thus, haemozoin levels in tissue increase with the duration of infection, and its presence may be associated with cerebral pathology.
Susceptibility ofBrugia malayiandOnchocerca lienalismicrofilariae to nitric oxide and hydrogen peroxide in cell-free culture and from IFNγ-activated macrophages
Authors: Taylor M. J. , Cross H. F. , Mohammed A. A. , Trees A. J. , Bianco A. E. 
Published: June 2009

SUMMARYThe susceptibility ofBrugia malayiandOnchocerca lienalismicrofilariae to H2O2and NO either in cell-free culture or from IFNγ-activated macrophages was examined. In cell-free culture,O. lienalismicrofilariae were highly susceptible to H2O2induced toxicity, exhibiting rapid reductions in motility and viability. The addition of exogenous catalase abrogated H2O2-induced killing. In contrast,B. malayimicrofilariae were relatively resistant to H2O2, with concentrations as high as 50 μM having no effect on motility or viability. On exposure to NO, both species showed reductions in motility within 5–30 min, but longer was required to see effects on the viability of microfilariae. Parasites incubated with IFNγ-activated macrophages also exhibited marked reductions in motility and viability. In cultures withB. malayiand activated macrophages, inhibition of these effects was achieved by the addition of eitherL-NMMA, to abolish NO production, or neutralizing anti-TNFα antibodies. Attempts to inhibit parasite killing by the addition of catalase to macrophage cultures were ineffective. The results of this study show thatB. malayiandO. lienalismicrofilariae have different susceptibility to H2O2, but are equally affected by exposure to NO. Moreover both species are killed by IFNγ-activated macrophages and in the case ofB. malayi, killing is dependent on the generation of NO via TNFα.
Eosinophils are the major effector cells of immunity to microfilariae in a mouse model of onchocerciasis
Authors: Folkard S. G. , Hogarth P. J. , Taylor M. J. , Bianco A. E. 
Published: June 2009

SUMMARYMice inoculated with microfilariae of the filarial nematodeOnchocerca lienalisclear their parasites over a period of 3–4 months and are highly resistant to re-infection. We have investigated the comparative roles of the eosinophil, macrophage and neutrophil in effecting this parasite clearance, employing agents specifically to perturb cell functionin vivo. Using the anti-IL-5 monoclonal antibody TRFK-5, we show that eosinophils are of primary importance in effecting resistance to re-infection. Ablation of macrophages (with carbon) and neutrophils (with the monoclonal antibody NIMP-R14) had no effect on parasite clearance following re-infection. Neutralization of these 3 cell types during a primary infection showed that while the removal of both eosinophils and macrophages caused a small but significant delay in parasite clearance, the depletion of neutrophils had no effect. This report describes the first direct evidence for eosinophil-mediated killing of microfilariaein vivo, and is consistent with Th-2 cell responses previously described in this model.
Establishment, survival and site selection of the cestode Eubothrium crassum in brown trout, Salmo trutta
Authors: Kennedy C. R. 
Published: June 2009

SUMMARYPopulation dynamics, site selection, growth and maturation of the cestode Eubothrium crassum in a natural population of Salmo trutta in a small lake were studied over a period of 1 year, the life-span of a cohort in fish. Infection of fish commenced in spring but peaked in July. Small, plerocerciform parasites initially located in the intestine, but then some moved into the pyloric caecae whilst others, the majority in heavy infections, were lost from the fish causing a fall in abundance from 460 to 10 over 2 months. This mortality was density dependent. Initially, parasites were distributed more evenly throughout the caecae but as time increased larger parasites were found preferentially in the anterior caecae before moving back into the intestine when gravid, preparatory to being lost in the following summer. Only a small proportion of the infrapopulation became gravid. Although the proportion of caecae occupied was initially density dependent, by the time of maturation several preferred anterior caecae remained unoccupied and mean intensity always exceeded unity. Neither growth nor maturation was affected by intraspecific competition. It was concluded that caecal availability did not set a limit or threshold of infrapopulation density, and in this respect E. crassum–S. trutta differed from some acanthocephalan-fish systems but was similar to others. Heavy infection followed by heavy mortality appeared to be typical of this parasite-host system in other localities, and of several other cestode-fish systems. The implications of this for population regulation are discussed.
Identification and characterization of threeEncephalitozoon cuniculistrains
Authors: Didier E. S. , Vossbrinck C. R. , Baker M. D. , Rogers L. B. , Bertucci D. C. , Shadduck J. A. 
Published: June 2009

SUMMARYMicrosporidia are increasingly recognized as causing opportunistic infections in immunocompromised individuals.Encephalitozoon cuniculiis probably the most studied mammalian microsporidian that infects insects and mammals, including man. In this study, 8E. cuniculiisolates were compared and were found to fall into 3 strains. Strain type I includes the rabbit type isolate, as well as isolates from an additional rabbit, a dwarf rabbit, and a mouse. Strain type II includes 2 murine isolates and strain type III includes 2 isolates obtained from domestic dogs. By SDS-PAGE, the 3 strains differ primarily in the molecular weight range of 54–59 kDa where strain type I displays an apparent broad singlet at 57 kDa, strain type II displays an apparent doublet at 54 and 58 kDa, and strain type III displays an apparent broad band at 59 kDa. Antigenic differences were detected in the molecular weight regions of 54–58 kDa as well as 28–40 kDa by Western blot immunodetection using murine antisera raised againstE. cuniculi, Encephalitozoon hellem,and theEncephalitozoon-like Septata intestinalis.Polymerase chain reaction (PCR) products containing only small subunit rDNA sequences from the differentE. cuniculiisolates formed homoduplexes whereas PCR products containing intergenic rRNA gene sequences formed heteroduplexes in mobility shift analyses.FokI digestion of the PCR products containing the intergenic rRNA gene region resulted in unique restriction fragment length polymorphism patterns, and DNA sequencing demonstrated that in the intergenic spacer region, the sequence 5'-GTTT-3' was repeated 3 times in strain type I, twice in strain type II, and 4 times in strain type III. This study indicates that there exist at least 3E. cuniculistrains which may become important in the epidemiology of humanE. cuniculiinfections. Furthermore, as additionalE. cuniculiisolates are characterized, these strains will be named or reclassified once the criteria for taxonomy and phylogenetic tree construction for microsporidia become better defined.
Gene flow and cross-mating in Plasmodium falciparum in households in a Tanzanian village
Authors: Babiker H. A. , Charlwood J. D. , Smith T. , Walliker D. 
Published: June 2009

SUMMARYThe diversity of the genes encoding 2 merozoite surface proteins (MSP-1 and MSP-2) of Plasmodium falciparum has been examined in parasites infecting members of 4 households in a village in Tanzania. The polymerase chain reaction (PCR) was used to characterize allelic variants of these genes by the sizes and sequences of regions of tandemly repeated bases in each gene. In each household extensive polymorphism was detected among parasites in the inhabitants and in infected mosquitoes caught in their houses. Similar frequencies of the alleles of these genes were observed in all households. Capture-recapture data indicated that both Anopheles gambiae and A.funestus freely dispersed among households in the hamlet. The results confirm that cross-mating and gene flow occur extensively among the parasites, and are discussed within the context of spatial clustering of natural populations of P. falciparum.
Effects of phenothiazine neuroleptic drugs on the microtubular–membrane complex in bloodstream forms ofTrypanosoma brucei
Authors: Page A. M. , Lagnado J. R. 
Published: June 2009

SUMMARYAfrican trypanosomes are parasitic protozoa causing sleeping sickness in humans and related diseases in domestic animals against which no entirely satisfactory forms of chemotherapy are yet available. It was previously shown that related species of trypanosomes, as well as procyclic (insect) forms ofTrypanosoma bruceiare extremely sensitive to the action of phenothiazine neuroleptic drugsin vitro. In this work, we have carried out a more detailed investigation of the effects of thioridazine, one of the most potent neuroleptic phenothiazine drugs known, on the morphology of the infective bloodstream forms ofT. brucei, with particular reference to the parasite's prominent pellicular membrane complex. Our data show that this drug induces rapid changes in cell shape that appear to involve some reorganization of the microtubular membrane skeleton, but does not affect the structural integrity of the microtubular complex. Another early consequence of drug action involved damage to nuclear and cytoplasmic membranes and the appearance of tubular arrays of coated membrane within the flagellar pocket. It was also revealed that the drug induces a rapid release of the variant-specific glycoprotein (VSG) which makes up the surface coat protecting bloodstream forms of the parasite against the host immune system. Our evidence suggests that this release of VSG involves cleavage of the protein's glycosyl-phosphatidylinositol (GPI) membrane anchor by endogenous GPI-specific phospholipase C, probably as a consequence of minor damage to the parasite plasma membrane induced by the drug.
Eimeria tenella: infection with a single sporocyst gives a clonal population
Authors: Shirley M. W. , Harvey D. A. 
Published: June 2009

SUMMARYTwo genetically defined parents of Eimeria tenella, each characterized by a selectable phenotype, were mated to provide ‘recombinant’ oocysts for an analysis of the inheritance of DNA markers into the sporocyst stage of the life-cycle. A total of 23 populations was established from infection with a putative single sporocyst and their inheritance of DNA markers provided compelling evidence that the 2 sporozoites within each sporocyst are genetically identical. Each of the 5 polymorphic DNA markers used segregated independently within the ‘recombinant’ parasites and only 1 of the parental forms was inherited in 22 of the populations aimed to have been established from a single sporocyst.
Induction of changes in human behaviour by the parasitic protozoanToxoplasma gondii
Authors: Flegr J. , Zitková Š. , Kodym P. , Frynta D. 
Published: June 2009

SUMMARYToxoplasma gondii, the coccidian parasite, is known to induce changes in the behaviour of its intermediate hosts. The high prevalence of this parasite in the human population (20–80%) offers the opportunity of studying the influence of the parasite on human behaviour by screening of a normal population. A total of 224 men and 170 women were tested for toxoplasmosis and their personality profiles were measured by Cattell's questionnaire. Highly significant differences betweenToxoplasma-infected and uninfected subjects were observed (P< 0·01). For men the factorsG(low superego strength),L(protension),O(guilt proneness), andQ2(group dependency) were positively influenced in infected subjects. For women the prevailing factors wereA(affectothymia,P< 0·01),L(alaxia),O(untroubled adequacy) andQ2(self-sufficiency). To reveal whether toxoplasmosis induces personality factor-shifts or whether certain combinations of personality factors influence the probability of acquiringToxoplasmainfection, we examined the personality profiles of 164 male patients diagnosed with acute toxoplasmosis during the past 13 years. The existence of a positive correlation between the duration of latent toxoplasmosis and the intensity of superego strength decrease (P< 0·02) suggested that the decrease of superego strength (the willingness to accept group moral standards) was induced byT. gondiiinfection.
Pharmacology and efficacy of liposome-entrapped albendazole in experimental secondary alveolar echinococcosis and effect of co-administratration with cimetidine
Authors: Wen H. , New R. R. C. , Muhmut M. , Wang J. H. , Wang Y. H. , Zhang J. H. , Shao Y. M. , Craig P. S. 
Published: June 2009

SUMMARYEncapsulation of the benzimidazole albendazole in multilamellar liposomes results in a preparation in which this normally insoluble anti-hydatid drug is well solublilized in aqueous media. The high entrapment efficiency observed (75–87%) and the stability of the formulation make this a promising delivery vehicle for improved chemotherapy with albendazole. In particular, the high degree of association with phospholipid may give rise to increased oral bioavailability. Oral adminisration of albendazole in liposomes led to increased concentration and/or altered metabolism of albendazole sulphoxide (ABZSX) in liver and/or plasma in non-infected Wistar rats. Results from experiments using cotton rats (Sigmodon hispidus) infected with metacestodes of Echinococcus multilocularis show that entrapment within liposomes clearly increases the uptake of albendazole via the oral route. This was reflected by increased levels of albendazole and the two major metabolites in plasma, liver and cyst homogenate when a dose of liposomal albendazole (35 mg/kg) was given orally compared to free albendazole at 50 mg/kg. There was a 75–94% reduction in biomass of the metacestode and a significant increase in survival time for the animals treated with liposome entrapped albendazole. A clear difference in distribution of albendazole and its metabolites in the liver and the metacestode tissues in the presence of cimetidine indicated that the latter has a profound effect on the metabolism of albendazole. There appeared to be a synergistic interaction between albendazole and cimetidine, since the metabolism of albendazole was markedly altered in the combined cimetidine/liposome–albendazole group, and higher therapeutic effect was observed. These findings indicate potential both for improvement of treatment of larval E. multilocularis infection and for reduction of albendazole dose levels.
Competitive exclusion in human schistosomes: the restricted distribution ofSchistosoma intercalatum
Authors: Tchuenté L. A. Tchuem , Morand S. , Imbert-Establet D. , Delay B. , Jourdane J. 
Published: June 2009

SUMMARYA study on the immune and mating interactions betweenSchistosoma intercalatumandS. mansonihas been carried out. The immunologically mediated interactions and mating patterns observed between the two species demonstrate thatS. mansoniis competitively dominant overS. intercalatum. WhenS. mansonifemales are absent,S. mansonimales are more competitive thanS. intercalatummales at pairing withS. intercalatumfemales. The use of a mathematical model shows how the abundance ofS. mansoniworms per host could dramatically affect the mating probability ofS. intercalatumfemales with their homologous males. It appears that the competitive exclusion between these two species of schistosomes may probably be an important factor restricting the distribution ofS. intercalatumin Africa.
Re-assessing the global prevalence and distribution of lymphatic filariasis
Authors: Michael E. , Bundy D. A. P. , Grenfell B. T. 
Published: June 2009

SUMMARYThis paper estimates the global burden of lymphatic filariasis based on a review of the published literature on infection and disease surveys. A method for aggregating and projecting prevalence data from individual studies to national, regional and global levels, which also facilitates the estimation of gender and age-specific burdens, is presented. The method weights in favour of the larger, and hence presumbably more reliable, studies and relies on estimated empirical relationships between gender, age, infection and disease in order to correct studies with incomplete data. The results presented here suggest that although the overall prevalence of filariasis cases is 2·0% globally (approximately totalling 119 million cases), the disease continues to be of considerable local importance, particularly in India and Sub-Saharan Africa. Estimates by age and gender clearly show that, unlike other helminth infections, filariasis is mainly a disease of the adult and older age-classes and appears to be more prevalent in males. This work suggests that the derivation of more accurate estimates of the burden of filariasis will require a better understanding of both the epidemiology and the spatial aspects of infection and disease. It also suggests that filariasis is preventable based on a geographically targeted strategy for control.