bluuebunny/crossref_metadata_2025_split huggingface dataset:
The dynamics of intestinal helminth communities in eels Anguilla anguilla in a small stream: long-term changes in richness and structure
Authors: Kennedy C. R. 
Published: June 2009

SummaryThe prediction that species richness and diversity of intestinal helminth communities in eels would change over time in response to habitat changes was tested over a period of 13 years in a small stream subjected to extensive human management. Nearly all measures of helminth community structure adopted indicated a decline in richness and diversity over the first 6 years followed by a recovery over the last few years to levels unexpectedly close to those at the start of the investigation. Changes in total number of species suggested that the component community was far richer (from 3–9 species) at the end of the period. By contrast, changes in diversity and dominance measures revealed less variation than expected and suggested that there was an underlying stability of community structure characterized by high dominance by a single species, although the identity of this changed, low diversity and a large proportion of the eel population harbouring 0 or only 1 species. A similar pattern of changes was recorded in the infra-communities, where values of species richness and diversity were very similar at the commencement and termination of the study. It appeared that those helminths that colonized in the recovery period contributed to community richness but had little impact on community structure. The helminth communities clearly did change in response to habitat changes, and the evidence for a fixed number of niches and an underlying constancy in helminth community structure in eels is evaluated.
Rapid changes in the surface of parasitic nematodes during transition from pre- to post-parasitic forms
Authors: Proudfoot L. , Kusel J. R. , Smith H. V. , Harnett W. , Worms M. J. , Kennedy M. W. 
Published: June 2009

SummaryAll mammalian-parasitic stages of a range of nematode species investigated (Brugia pahangi, Acanthocheilonema viteae, Strongyloides ratti, Nippostrongylus brasiliensis, Trichinella spiralisandOstertagia ostertagi) labelled in a surface-restricted manner with the fluorescent lipid analogues 5-N-(octadecanoyl)aminofluorescein (AF18) or nitrobenzoxadiazole-cholesterol (NBD-chol), but failed to bind other similar probes. In contrast, the surfaces of the ‘pre-parasitic’ infective stages of these species had affinity for neither AF18 nor NBD-chol. This exclusion of lipid analogues changed rapidly upon exposure of the larvae to tissue culture conditions which mimic the mammalian tissue environment (e.g. RPMI 1640/37°C) such that the above probes could then insert into the surface layer of the larvae. The dauer larva ofCaenorhabditis elegansalso excluded the probes, but became permissive to labelling upon stimulation to emerge from the dauer state. The time taken for the surface transformation to occur ranged from less than 10 min in the vector-borne parasites to approximately 5 h in those which enter by the oral route, with direct skin-penetrators occupying an intermediate position. In all cases, the alteration proceeded too rapidly for it to have been associated with a moult. Fluorescence Recovery After Photobleaching (FRAP) studies ofA. viteaelarvae showed that approximately 50% of the AF18 probe was free to diffuse within the plane of the surface immediately after transformation. This is only a transitory state because AF18 was found to be highly restricted in its lateral diffusion on the surface of adult parasites. In the larvae ofS. ratti, the change in affinity for AF18 was accompanied by the rapid shedding of an otherwise stable surface coat of polyanionic material, here visualized by labelling with fluorescein-conjugated cationized ferritin. Incubation of larvae in lipid-rich host serum during the induction of transformation inhibited subsequent labelling with AF 18. This possibly reflects competition for insertion sites and anin vivopropensity towards the acquisition of host lipid by invading parasites.
Eperythrozoon mariboi sp.nov., (Protophyta: Order Rickettsiales) a parasite of red blood cells of the flying fox Pteropus macrotis epularius in New Guinea
Authors: Ewers W. H. 
Published: June 2009

SUMMARYEperythrozoon mariboi sp.nov. is described from the red blood cells of splenectomized flying foxes (Pteropus macrotis epularius), from New Guinea. The parasite is polymorphic. The most common form is a fine line 5–8 μ long extending across the red blood cell. Marginal forms are also found. Multiple infections of the host cell also occur. In the initial infection ring forms were common, as well as other forms.Parasitaemia was followed by anaemia, and the infections were characterised by repeated relapses at irregular intervals.This work was supported by Grant No A1–08449 from the National Institutes of Health, United States Department of Health, Education and Welfare. I would like to thank Mr T. Ikupu and Mr T. Engendi, both of the University of Papua and New Guinea, for technical assistance; Mrs M. Cahill, also of the University of Papua and New Guinea for attempting to culture the organisms; Dr D. Weinman of Yale University, for confirming the identity of the parasites; Dr T. J. Dondero of the Hooper Foundation for translating some of the references into English; and Dr F. Colley also of the Hooper Foundation, for comments on the manuscript.The analysis of some of the data in this paper was done while I was on study leave at the Institute for Medical Research, Kuala Lumpur, and I would like to thank its Director for the hospitality provided.I would especially like to thank Mr Yap Loy Fong, Institute for Medical Research, Kuala Lumpur, for preparing Fig. 1.
Studies on the sex ratio of worms in schistosome infections
Authors: Mitchell G. F. , Garcia E. G. , Wood S. M. , Diasanta R. , Almonte R. , Calica E. , Davern K. M. , Tiu W. U. 
Published: June 2009

SUMMARYSex ratios of adult schistosomes in mice are almost invariably different from 1·0 and are biased towards males. The bias applies to wild rats infected withSchistosoma japonicumand trapped in an endemic area of the Philippines (male: female ratio = 1·7). It also applies to cercariae of snails collected in such areas and assessed by infection of laboratory mice using cercariae from individual snails (male: female ratio may approach 6·0). Experiments were designed to determine if duration of infection in the mammalian host was a factor that influenced the sex ratio of miracidia used for infecting snails and subsequently mice. BALB/c and C57BL/6 mice were infected with 100 cercariae ofS. mansoni, and liver eggs harvested at early and late time points for infection of snails and production of cercariae. Two phenomena were demonstrated: firstly, a more pronounced male bias when eggs were harvested late compared with early in infection; secondly, a reduced apparent hatchability of eggs in BALB/c compared with C57BL/6 livers. The possibility is raised by the data that female miracidia within eggs of chronically infected individuals may be more prone to immune damage than male miracidia with important epidemiological consequences.
Proteolytic activity inTritrichomonas mobilensis
Authors: Bózner P. , Demeš P. , Štefanovič J. 
Published: June 2009

SUMMARYCell extracts of an entero-invasive protozoon of squirrel monkeys,Tritrichomonas mobilensis, contained relatively high proteolytic activity, measured on hide powder azure (HPA). Multiple proteinase forms, optimally active at pH 5–7, were detected by electrophoretic analysis in gelatin-containing polyacrylamide gels. Three major proteinase bands of apparent low molecular weights,Mr18, 23 and 30 kDa, were seen on gels. Inhibition-activation studies suggest that only cysteine proteinases were involved in HPAase and gelatinolytic activities ofT. mobilensiscell extracts.
Trichobilharzia ocellata: chemical stimuli of duck skin for cercarial attachment
Authors: Feiler W. , Haas W. 
Published: June 2009

SUMMARYTrichobilharzia ocellatacercariae attach readily to the foot skin of their duck host, but poorly to preen-gland contents. The attachment to duck foot disappears when the skin surface lipids are extracted, and can be restored by reapplication of the lipids to the skin. Hydrophilic skin extracts are without any effect. Thin-layer chromatographic fractionation of duck-foot skin surface lipids reveals cholesterol and ceramides as attachment stimuli. A stimulation of cercarial attachment by these hydrophobic host signals is supported by the host identification pattern of the cercariae, which secures a close contact with encountered substrates.
Breakdown of the blood-brain barrier in murine cerebral malaria
Authors: Thumwood C. M. , Hunt N. H. , Clark I. A. , Cowden W. B. 
Published: June 2009

SUMMARYCerebral malaria in A/J and CBA/H mice infected withPlasmodium bergheiANKA is accompanied by mononuclear cell infiltration, haemorrhage and cerebral endothelial cell damage. This damage is presumably one of the causes of the breakdown of the blood—brain barrier which was detected by measuring the movement of the dye Evans blue and radioisotope labelled albumin and erythrocytes. The density of brain tissue, measured by a Percoll gradient technique, was significantly reduced in mice exhibiting cerebral symptoms, suggesting the occurrence of cerebral oedema.
Random mating in a natural population of the malaria parasitePlasmodium falciparum
Authors: Babiker H. A. , Ranford-Cartwright L. C. , Currie D. , Charlwood J. D. , Billingsley P. , Teuscher T. , Walliker D. 
Published: June 2009

SUMMARYThe genetic structure of a population of the malaria parasitePlasmodium falciparumhas been examined in a village in Tanzania. Seventeen alleles of the merozoite surface protein MSP-1 and 23 of MSP-2 were detected by the polymerase chain reaction (PCR) among the blood parasites of the inhabitants. Most infections contained mixtures of genetically distinct parasite clones. PCR was then used to examine individualP. falciparumoocysts, the products of fertilization events, in wild-caught mosquitoes. Forty-five out of 71 oocysts were heterozygous for one or both genes, showing that crossing between clones was taking place frequently, following uptake of mixtures of gametocytes by the mosquitoes. The frequency of heterozygous forms showed that random mating events probably occurred within mosquito bloodmeals between gametes belonging to different parasite clones.
Trypanosoma (Nannomonas) godfreyi sp. nov. from tsetse flies in The Gambia: biological and biochemical characterization
Authors: McNamara J. J. , Mohammed G. , Gibson W. C. 
Published: June 2009

SUMMARYWe provide evidence from isoenzyme analysis, hybridization with repetitive DNA probes, behavioural studies and morphometrics that 4 trypanosome isolates from Glossina morsitans submorsitans in The Gambia constitute a new species now named Trypanosoma (Nannomonas) godfreyi. The bloodstream trypomastigotes of T. (N.) godfreyi are relatively small with a mean length of 13·7 μm (range: 9·1–21·8 μm) and a mean width of 1·65 μm (range: 0·65–2·69 μm). There is no free flagellum and the marginal kinetoplast is subterminal to a rounded posterior end; the undulating membrane is usually conspicuous. As with other Nannomonas, T. godfreyi developed in the midgut and proboscis of Glossina and infections matured in 21–28 days in laboratory G. m. morsitans. In The Gambia the normal vertebrate host appears to be the warthog, Phacochoerus aethiopicus, although elsewhere other wild and domestic suids may also be implicated in the life-cycle. T. godfreyi was identified unequivocally using a 380 bp DNA probe specific for a major genomic repeat sequence; its isoenzyme profile distinguished it clearly from T. simiae and three strain groups of T. congolense: savannah, riverine-forest and kilifi.
Polymerase chain reaction detection ofTrypanosoma cruziin human blood samples as a tool for diagnosis and treatment evaluation
Authors: Britto C. , Cardoso M. A. , Vanni C. M. Monteiro , Hasslocher-Moreno A. , Xavier S. S. , Oelemann W. , Santoro A. , Pirmez C. , Morel C. M. , Wincker P. 
Published: June 2009

SUMMARYTrypanosoma cruzispecific sequences were amplified by the polymerase chain reaction from total blood of human chagasic patients and normal individuals. A 330 bp fragment originating from kinetoplast DNA was specifically detected in most chagasic individuals. We tested the sensitivity and specificity of this method in normal and affected individuals attending the Evandro Chagas Hospital, Rio de Janeiro. The results of these tests were compared with serological diagnosis performed using standard techniques, and in some cases with xenodiagnosis. We found that none of the serologically negative individuals gave any specific amplification product, whereas 55 out of 61 patients previously serodiagnosed as chagasic were positive using the PCR method (sensitivity: 90%). Xenodiagnosis, which is currently considered to be the most sensitive parasitological technique for Chagas' disease diagnosis, detected only 12 out of 28 serologically positive patients (sensitivity: 43%). The usefulness of the PCR method was further investigated with chagasic patients who had received anti-parasite treatment with benznidazole. It has always been difficult to evaluate the incidence of cure in such cases by serology, since a humoral response againstT. cruziantigens may remain for years even in the absence of the parasite. We observed a positive amplification result in only 9 out of 32 treated patients who remained reactive when tested using classical serology. These observations suggest that PCR is the most sensitive technique available for direct detection ofT. cruziin chagasic patients and that it can be a very useful instrument for the follow-up of patients after specific treatment.
Inhibition of malarial invasion by intracellular antibodies against intrinsic membrane proteins in the red cell
Authors: Dluzewski A. R. , Rangachari K. , Tanner M. J. A. , Anstee D. J. , Wilson R. J. M. , Gratzer W. B. 
Published: June 2009

SUMMARYIt has previously been shown that antibodies against the transmembrane proteins, band 3 and glycophorin A, inhibit entry of the merozoite into the red cell and, in the case of band 3, it was established that attachment of the parasite to the cell is not prevented. We have found that antibodies against the cytoplasmic domains of band 3 and of glycophorin A, when present in the interior of resealed ghosts of human red cells, also inhibit invasion byP. falciparum. It is inferred that attachment of the merozoite to the red cell causes structural effects that are transduced to the membrane cytoskeleton and the antibodies against transmembrane proteins interfere with the invasion sequence at this level.
Increased oviposition and growth in immature Biomphalaria glabrata after exposure to Schistosoma mansoni
Authors: Thornhill Joyce A. , Jones Janet T. , Kusel J. R. 
Published: June 2009

SUMMARYBiomphalaria glabrata snails are known to be castrated by infection with the trematode parasite Schistosoma mansoni 4–6 weeks post-infection. The pattern of oviposition in the first 35 days post-exposure (p.e.) was investigated, in snails aged 14 weeks and measuring 7–10 mm diameter which had not commenced egg-laying, by counting the numbers of eggs laid in 7-day intervals. A group of exposed snails was compared with a control non-exposed group. The exposed group included both parasitized and non-parasitized snails, and showed a significant increase in the median number of eggs laid during the periods 14–21 and 22–28 days p.e. Throughout the entire 35-day period exposed non-parasitized snails laid significantly more eggs than control snails, while parasitized snails laid significantly more eggs than controls during days 22–28 p.e. and significantly fewer during days 29–35 p.e. Parasitized snails also laid significantly more eggs/egg mass in the period 16–28 days p.e. than did control snails. Growth of the snails was measured. By day 28 p.e. the mean diameter of the exposed group was significantly greater than that of the control group. The increase in oviposition by snails soon after exposure is discussed in terms of a compensatory response for expected future suppression of egg-laying. The fact that parasitized and non-parasitized snails both show increased oviposition indicates that normal development of the parasite is not necessary to trigger the response.
The aggregation response of Trichostrongylus colubriformis: a basis for the rapid interpretation of in vitro anthelmintic screens
Authors: Jenkins D. C. , Rapson E. B. , Topley P. 
Published: June 2009

SUMMARYAn in vitro anthelmintic primary screen in which the effects of compounds on the aggregation response of newly moulted adult worms of Trichostrongylus colubriformis was monitored is described. Representatives of all the major classes of the anti-trichostrongyle anthelmintics all inhibited worm aggregation completely when present in the culture medium either at or at less than micromolar concentrations. The screen proved highly selective for these broad-spectrum agents, much higher concentrations of the narrower spectrum anthelmintics, active only against blood-sucking nematodes, trematodes and/or cestodes, having little or no effect on this response. This in vitro assay, based solely on the occurrence or absence of worm aggregation following the final moult in culture, proved very easy to interpret rapidly and accurately. It can be recommended therefore for the primary mass screening of synthetic compounds or natural products for intrinsic activity against the trichostrongylid helminths of ruminants.
Entomopathogenic nematode (Heterorhabditidae and Steinernematidae) spatial distribution in turfgrass
Authors: Campbell J. F. , Lewis E. , Yoder F. , Gaugler R. 
Published: June 2009

SUMMARYUnderstanding the temporal and spatial distribution of entomopathogenic nematodes is essential for determining the role of these insect parasites in soil communities and ultimately for their use in suppression of pest insect populations. We measured the vertical and horizontal distribution of endemic populations of entomopathogenic nematodes (Steinernema carpocapsae and Heterorhabditis bacteriophord) in turfgrass. Vertical distribution was determined by taking soil cores every 3 h from 05.00 to 23.00 h, over 4 days, and dividing the cores into 8, 1 cm deep sections. Steinernema carpocapsae was recovered primarily near the soil surface: 50% of positive sections were recovered in the thatch or first 1 cm of soil. S. carpocapsae recovery was lower during the middle of the day and none were recovered in the upper section. H. bacteriophora was recovered uniformly throughout the top 8 cm of soil and its vertical distribution did not change over the course of the day. Horizontal distribution was measured as the number of nematodes recovered from cores taken from 12 randomly selected 0·3 × 0·8 m sections from within four 15·3 × 15·3 m plots. Samples were collected biweekly over a 9-month period. H. bacteriophora had a patchier distribution than S. carpocapsae and both nematode species had more patchy distributions then their potential hosts. Our results support the hypothesis that these two species of nematode utilize different foraging strategies; S. carpocapsae primarily a surface adapted ambusher and H. bacteriophora as a cruise forager.
Improvements in appetite and growth in helminth-infected schoolboys three and seven weeks after a single dose of pyrantel pamoate
Authors: Hadju V. , Stephenson L. S. , Abadi K. , Mohammed H. O. , Bowman D. D. , Parker R. S. 
Published: June 2009

SUMMARYAppetite and growth were studied in primary schoolboys (6–10 years) infected withAscaris lumbricoides(86%) andTrichuris trichiura(100%) who received a single dose of pyrantel pamoate (which has little or no effect onTrichuris trichiura) or a placebo. Boys were examined, allocated at random by descendingAscarisegg count to pyrantel (PR,n= 36) or placebo (PL,n= 36) groups, treated, and re-examined 3 and 7 weeks later. The 2 groups did not differ significantly before treatment in helminth infections, appetite, or growth. Three and 7 weeks after treatment, the PR group exhibited significantly greater increases than did the PL group in weight (0·2 kg and 0·4 kg more, respectively) and percentage weight-for-age (0·6% and 1·7% points more, respectively). Appetite increased significantly in the PR group at 3 and 7 weeks (P< 0·0005 andP< 0·01, respectively) but not in the PL group. The prevalence and intensity ofA. lumbricoidesinfection were greatly reduced in the PR group at 3 and 7 weeks (bothP< 0·0001) but not in the PL group. We conclude that treatment with pyrantel pamoate may improve appetite and growth in schoolchildren in areas whereA. lumbricoidesinfections and poor growth are highly prevalent.
The epidemiology of canine visceral leishmaniasis in southern France: classical theory offers another explanation of the data
Authors: Dye Christopher 
Published: June 2009

SUMMARYThis paper describes a compartmental model incorporating biological details of the transmission of canine visceral leishmaniasis in southern France. In contrast to earlier, empirical models (Jolivet, 1977; Rioux, Croset & Lanotte, 1977) the new model (1) predicts a threshold density of sandflies below which transmission cannot be sustained, (2) suggests that, until better data become available, the maximum prevalence of infection obtained at high sandfly density should be considered an unknown quantity.
Changes in the organization of the surface membrane upon transformation of cercariae to schistosomula of the helminth parasite Schistosoma mansoni
Authors: Foley M. , Kusel J. R. , Garland P. B. 
Published: June 2009

SUMMARYMerocyanin 540 (Mc540) is a fluorescent compound which is thought to bind to membranes in which there are substantial amounts of lipid in the lipid-crystalline phase. It is shown here to be of value in detecting the transformation by both mechanical and skin-penetration methods of the cercaria to the schistosomulum. The cercaria does not appear to bind Mc540, but the schistosomulum, binds Mc540 initially, in its anterior region, and at later times over the entire surface. The suggestion that transformation involves changes in the surface membrane lipid phase from gel to liquid-crystalline phase is supported by fluorescence recovery after photobleaching results with 5-N-(octadecanoyl)-amino fluorescein, a lipophilic dye which appears to be immobile in the cercaria, but fully mobile in the 40 min schistosomulum.
Effect of temperature on survival and infectivity of Echinostoma trivolvis cercariae: a test of the energy limitation hypothesis
Authors: Pechenik J. A. , Fried B. 
Published: June 2009

SUMMARYTrematode cercariae typically become unable to successfully infect a host many hours before they die. We examined the hypothesis that both time to 50% mortality and time to loss of infective capacity are controlled to the same degree by rates of energy expenditure, by determining the relative effects of temperature on both parameters. Infective capacity was assessed by exposing Echinostoma trivolvis cercariae of different ages to a suitable second intermediate host (the gastropod Biomphalaria glabrata) and counting 1–2 days later the number of metacercarial cysts formed. Temperature had a remarkably similar effect on time to 50% mortality and loss of infective capacity, supporting the hypothesis that both absolute and functional cercarial life-spans are limited by the rates at which energy stores are utilized.