bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parasite development and host responses during the establishment ofTrypanosoma bruceiinfection transmitted by tsetse fly
Authors: Barry J. D. , Emery D. L. 
Published: June 2009

SUMMARYFollowing inoculation ofTrypanosoma bruceiinto large mammals by the tsetse fly a local skin reaction, the ‘chancre’, develops due to trypanosome proliferation. We have cannulated the afferent and efferent lymphatics of the draining lymph node in goats and examined the onset of a cellular reaction, the emigration of the parasite from the chancre and the development of both antigenic variation and the specific immune response. The chancre first became detectable by day 3 post-infection, peaked by day 6 and then subsided. Lymphocyte output increased 6- to 8-fold by day 10 and the number of lymphoblasts increased 50-fold in this period. Both then declined. Trypanosomes were detected in lymph 1–2 days before the chancre, peaked by days 5–6, declined during development of the chancre and then peaked again. The bloodstream population appeared by days 4–5 and displayed different kinetics from that in lymph. Recirculation of parasites through the lymphatics ensued. Lymph-borne trypanosome populations were highly pleomorphic. Parasites in lymph expressed firstly a mixture of the Variable Antigen Types (VATs) which are found characteristically in the tsetse fly, this being followed by a mixture of other VATs. The two groups overlapped in appearance. In the bloodstream the same sequence of events occurred although 2 or 3 days later. The specific antibody response, as measured by radioimmunoassay and agglutination, arose within a few days of the first detection of each VAT. Activities appeared first in the lymph and then in plasma.
Chimaerocestos prudhoeigen. et sp. nov., representing a new family of tetraphyllideans and the first record of strobilate tapeworms from a holocephalan
Authors: Williams H. H. , Bray R. A. 
Published: June 2009

SUMMARYChimaerocestos prudhoeigen. et sp. nov. fromRhinochimaera atlanticain the North Atlantic off north-eastern Scotland represents a new family, the Chimaerocestidae, of tetraphyllideans and is the first record of a strobilate tapeworm from a holocephalan. The main taxonomic features are described and figured along with aspects of the ecology and mode of attachment to the gut mucosa. The lobed annular ovary and distribution of the vitellarium in two fields are characteristic features. About 15 eggs are deposited together in capsules.C. prudhoeiis discussed in relation to other unusual fish tapeworms and the evolutionary biology of tapeworms, and to our scant knowledge of the holocephalans.
Migrational responses of Hymenolepis diminuta to surgical alteration of gastro-intestinal secretions
Authors: Sukhdeo M. V. K. , Mettrick D. F. 
Published: June 2009

SUMMARYThe effects of the direction of gut flow, of injections of glucose and saline into different regions of the small intestine and of surgical re-routing or ligature of gastric, biliary and pancreatic secretions into the small intestine have been correlated with changes in the migratory response of the rat tapeworm Hymenolepis diminuta. Reversing the normal anterior to distal flow of luminal contents in the small intestine did not affect worm migration following feeding. Injections of a glucose-saline solution into the duodenum did not initiate a migratory response; similar injections into the mid- and posterior regions of the small intestine resulted in migrational responses similar to those following intragastric glucose feeding. Re-routing gastric secretions to the distal duodenum inhibited anterior migration of the worms beyond the new point of entry of gastric juices. Results following re-routing and ligation of the biliary and pancreatic secretions suggest that there is a potent cue to anteriad migration in the pancreatic secretions. Biliary secretions also appear to contain an additional migratory cue to worm migration. In order of importance the factors stimulating/inhibiting worm migration are pancreatic > gastric > biliary > glucose. The results support the hypothesis that the factors affecting worm distribution in the small intestine are interactive and synergistic, involve other luminal factors, such as 5- hydroxytryptamine and the physico-chemical gradients, and are of a regional nature such that the migratory response of a particular worm is directly related to its position in the small intestine when the cues to relocation are received.
The large-scale preparation of purified sporozoites of Eimeria spp. by metrizamide density-gradient centrifugation
Authors: Wisher M. H. , Rose M. E. 
Published: June 2009

SUMMARYA method is described for the reproducible purification of greater than 1·0 × 108 sporozoites of Eimeria spp. by centrifugation on metrizamide density-gradients. The mean contamination of the purified sporozoite fraction by sporocysts and sporocyst debris was less than 6% and the recovered sporozoites were fully viable, infective and ultrastructurally intact.
Effect of copper and zinc upon the survival and infectivity of Echinoparyphium recurvatum cercariae
Authors: Evans N. A. 
Published: June 2009

SUMMARYAt concentrations ranging from 0·1 to 10·0 mg/l, copper and zinc reduced both the longevity and infectivity of Echinoparyphium recurvatum cercariae. Concentrations of 10·0 mg/l copper and zinc in hard water reduced the time to 50% mortality of cercariae from 30·5 h to 8·5 h and 15·5 h respectively. Copper-induced effects upon cercarial infectivity were particularly severe and exposures of cercariae to 0·5 mg/l of this metal for as little as 15 min caused significant reductions in their ability to infect molluscan 2nd intermediate hosts. Water hardness had a marked influence on copper toxicity but had a much lower effect on the toxicity of zinc. Metal concentrations found to exert a profound influence on parasite transmission in the present laboratory-based study have been found to occur in natural, albeit polluted, freshwater habitats.
Localized skin changes at the site of immunization with highly irradiated cercariae of Schistosoma mansoni are associated with enhanced resistance to a challenge infection
Authors: Miller Kathleen L. , Smithers S. R. 
Published: June 2009

SUMMARYThe level of immunity to a percutaneous cercarial challenge with Schistosoma mansoni was assayed 4–6 weeks after immunization of mice with highly irradiated (20 krad.) cercariae or schistosomula. When immunization and challenge occurred through the same skin site, resistance, particularly that which occurred in the skin, was greater than that observed when immunization and challenge occurred in different sites. The enhanced resistance is believed to be due to localized changes in the skin; 4 weeks after exposure to irradiated cercariae, abdominal skin is characterized by a thickened epidermis, changes in the ground substance and a cellular infiltration of the dermis. A convenient mouse model is described in which one or both ear pinnae are exposed to irradiated cercariae and a percutaneous challenge is given via the abdomen, thus eliminating the effects of local skin changes. In this model, the majority of the challenge infection which succumbs to the immune response appears to be killed in the skin.
Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse. The effect of varying the route and the number of primary infections, and the correlation between the size of the primary infection and the degree of resistance that is acquired
Authors: Long E. , Harrison R. , Bickle Q. , Bain J. , Nelson G. , Doenhoff M. 
Published: June 2009

SUMMARYMice given primary infections of Schistosoma mansoni by percutaneous or subcutaneous routes were found to acquire a higher degree of resistance against homologous challenge after 7–8 weeks than mice infected intraperitoneally. Mice infected by the intraperitoneal route tended to have smaller worm burdens than those infected with the same number of cercariae by the other two routes and this may, in part, have contributed to the relative lack of efficacy of intraperitoneal infections in inducing resistance to re-infection. The same degree of resistance was acquired after primary percutaneous infection irrespective of whether it was administered in 3 equivalent weekly doses, or the same total number of cercariae was administered as a single infection. The same degree of resistance was also observed when a percutaneous challenge was administered on the same or a different skin site to that which received the percutaneous primary infection. The degree of resistance to re-infection acquired after a percutaneous primary infection correlated well with the size of the primary worm burden and the number of eggs in the intestine and liver, but did not correlate with the number of eggs in the lungs.
Morphology of the reproductive system of femaleMoniliformis dubius(Acanthocephala)
Authors: Asaolu S. O. 
Published: June 2009

SUMMARYBy means of light and electron microscopical techniques, the organization of the reproductive tract of femaleMoniliformis dubiusis described. The tract consists of an efferent duct system associated with 2 ligament sacs present in the body cavity. The efferent duct system consists of uterine bell, uterus and vagina. The uterine bell contains a complex system of routes and is associated with the ligament sacs in a way that facilitates egg sorting. The dorsal and ventral ligament sacs exist with separate cavities at the posterior end, where they are attached to the efferent duct, but merge into a single sac at the anterior of the trunk.
Elleipsisoma thomsoni Franca, 1912: an Apicomplexan parasite in the red blood cells of the mole (Talpa europaea)
Authors: Mohamed Hassan A. , Molyneux D. H. 
Published: June 2009

SUMMARYThe rediscovery of Elleipsisoma thomsoni Franca 1912 from Talpa europaea is reported. This organism, whose identity as a parasite was initially doubted, is shown to be an intra-erythrocytic protozoan parasite. Light microscope observation confirmed the original description and 22/53 (42·5%) moles examined from a locality near Blackpool were positive. Organ impression smears demonstrated that E. thomsoni was concentrated in the heart and lungs, occasionally in the kidneys, liver and spleen. Electron microscope studies conclusively showed that the parasite was a member of the phylum Apicomplexa. A typical apical complex was present with rhoptries, micronemes, polar ring and microtubules but, in contrast to the genera Plasmodium, Babesia and Theileria, a conoid was also present. The parasitized red cells were larger than normal mature erythrocytes and the remaining cytoplasm of the erythrocyte was less dense than that of non-infected red cells. The problem of studying this enigmatic parasite and its life-cycle are described.
Thymidine uptake by chicken kidney cells parasitized by Eimeria tenella: evidence for a diffusable mediating substance
Authors: Urquhart Catriona 
Published: June 2009

SUMMARYThe pattern of DNA synthesis in chicken kidney (CK) cells parasitized by Eimeria tenella was altered; a 2-fold increase in the uptake of [3H]-thymidine occurred in these cells compared with that shown by the controls. This difference was significantly different at 16 h post-inoculation (p.i.) and reached a peak at 20 h p.i. Non-parasitized cells in co-culture with parasitized cells showed a level of incorporation intermediate between that of the parasitized and non-parasitized mono- cultures. It was shown that this stimulation was due to a factor released into the medium by the parasite or the parasitized cell. A possible course of events leading to induced and prolonged DNA synthesis by the host cell and the significance of this change in the life-cycle of the parasite is discussed.
Babesia divergens infections in the Mongolian gerbil: characteristics of a human strain
Authors: Liddell K. G. , Lucas S. B. , Williams H. 
Published: June 2009

SUMMARYA strain of the cattle piroplasm Babesia divergens isolated from a fatal human infection was propagated in the Mongolian gerbil through 150 semi-continuous intraperitoneal passages. The infection was normally fatal; death, accompanied by profuse haemoglobinuria and debilitation, occurred as early as 44 h after intraperitoneal inoculation of heavily parasitized blood with precipitous drops in red blood cell and platelet counts. The average maximum parasitaemia achieved increased on continuous passage reaching 80% by the 150th stage. Twenty-four hours after infection erythrophagocytosis and splenic congestion were apparent by light and electron-microscopical examination and by 48 h hepatic necrosis, renal tubular damage with haemoglobin cast accumulation and ischaemic necrosis of ileal mucosa had developed. Gerbils were highly susceptible to small numbers of parasites when the inoculum was either fresh parasitized blood in high dilution or erythrocytes concentrated from animals showing minimal parasitaemia. Animals inoculated with parasites preserved in dimethyl sulphoxide at low temperatures usually developed fatal infections. However, occasionally animals suffered at most a low grade parasitaemia subsequent to recovery with parasite elimination. These animals were immune to further challenge, and no chronic infections developed. A. field strain of B. divergens isolated locally from a case of bovine redwater behaved similarly to the human strain on continuous passage in gerbils.
Morphology of the reproductive system of maleMoniliformis dubius(Acanthocephala)
Authors: Asaolu S. O. 
Published: June 2009

SUMMARYThe histology of the reproductive system of maleMoniliformis dubiushas been studied by a variety of microscopical techniques. The system includes 2 testes from each of which arises a vas efferens. Products from the testis enter the vas efferens through openings present in the wall of the vas efferens. The testes are contained in a ligament sac and each testis is enveloped separately by an outgrowth of the ligament sac wall. There are 8 unicellular cement glands. The cement substance contains spherical electron-dense droplets presumed to be lipids. Saefftigen's pouch appears to be a hydraulic mechanism to regulate the turgidity of the wall of the bursal cap to effect successful copulation with female worms. The muscles attaching the genital sheath and bursa to the body wall are likely to be concerned with bursal eversion and inversion. Stimuli receptors connected to the genital nervous system are located in the penis and bursa.
Schistosoma mansoni: temporal distribution of radioselenium-labelled schistosomula in lungs of mice during the first two weeks of infection
Authors: Georgi Jay R. , Dean D. A. , Mangold Beverly L. 
Published: June 2009

SUMMARYThe number of schistosomula in lungs was determined by compressed organ autoradiography at intervals up to 14 days after exposure of mice to 75Se-labelled cercariae by tail immersion. Probit analysis of compressed lung autoradiogram focus counts, expressed as percentages of initial infection level, yielded estimates of the average time of arrival, peak accumulation in the lungs and average time of departure of schistosomula: 4·5±0·87, 6·3 ± 0·45 and 11±0·58 days, respectively. At peak accumulation 92±3·5 % of the initial number of schistosomula were found in the lungs. It thus appears that little or no significant attrition of schistosomula occurred in the skin and, instead, that most of the 50–70% of penetrant cercariae that fail to reach adulthood are lost somewhere between the pulmonary and hepatic phases of development. Loss of 75Se label from schistosomula during the first 14 days was exponential, with an average half-life of 4·5±0·81 days. However, the high sensitivity of autoradiography tended to compensate for this rather rapid rate of label loss. It was pointed out that autoradiographic detection of schistosomula as discrete loci of radioactivity can also be expected to overcome the problem posed by the accumulation in such tissues as liver and kidney of 75Se label that has become separated from larvae.
Evidence against the hypothesis that metacestodes of Hymenolepis diminuta inhibit corpora allata functioning in the intermediate host, Tenebrio molitor
Authors: Hurd Hilary , Weaver R. J. 
Published: June 2009

SUMMARYSeveral of the pathophysiological responses made by the beetle Tenebrio molitor, when infected with metacestodes of Hymenolepis diminuta, may be attributed to a parasite-induced reduction in host juvenile hormone titre. It has been suggested that production of this hormone by the corpora allata may be inhibited in parasitized insects. This hypothesis was tested using an in vitro radiochemical assay to compare the biosynthesis of juvenile hormone by single pairs of corpora allata taken from mated 12- and 15-day-old infected and control female insects. The results demonstrate, however, that there was no difference in hormone production associated with metacestode infection. Other possible mechanisms for parasite interference in this host endocrine system are discussed.
Parasitological observations ofSchistosoma bovisin normal and T-cell deprived mice
Authors: Murare H. M. , Doenhoff M. J. 
Published: June 2009

SUMMARYA laboratory life-cycle ofSchistosoma boviswas established in order to study the host-parasite relationship in immunologically intact and T-cell deprived mice. Normal mice were found to have ‘self-cured’ theirS. bovisinfections almost completely by 10 weeks after cercarial administration, and there was no evidence of self-cure by day 79 in T-cell deprived animals, Thus, groups of deprived mice autopsied between 9 and 11 weeks after infection were invariably found to have greater worm burdens and a greater total number of eggs in the liver than comparably-infected normal mice. However, liver egg counts/worm pair were similar in the two types of host, and differences between normal and deprived mice with respect to totalS. bovisegg counts in the intestine were also not consistently in the same direction in all experiments. Faecal egg counts were always less in deprived mice than in normal mice, even in an experiment in which the deprived mice had a significantly higher intestinal tissue egg count than the normal control group. The results are discussed in relation to the better knownS. mansoni/mouse host-parasite relationship.
Trypanosoma musculi:influence of uric acid onin vitroformation of metacyclic trypomastigotes
Authors: Roger M. , Viens P. 
Published: June 2009

SUMMARYUric acid is the most important constituent in the urine of insects. Infective metacyclic forms of the stercorarian trypanosomes are produced in the rectum of their insect vector and are thus in contact with uric acid. Using a culture system which permitted the growth of the insect stages ofTrypanosoma musculi, we studied the influence of uric acid on the metacyclogenesis of this parasite. When added to the culture, uric acid enhanced the production of metacyclic forms. Furthermore, it rendered these trypanosomes highly infective by the oral route. It is suggested that uric acid may play an important role on the metacyclogenesis ofT. musculi.
Microfilaria density distribution in the human population and its infectivity index for the mosquito population
Authors: Park Chai Bin 
Published: June 2009

SummaryA new method of computing the infectivity index of microfilariae (mf) for the mosquito population is proposed using the estimated mf density distribution in the human population. The observed density distribution is considered a compound of the Poisson and the gamma distributions. The former distribution describes the probability of a specimen containing a specified number of mf and the latter describes the density distribution of mf in the host population. The mf infectivity index is the probability that a blood meal will include at least 1 mf, conditional on the population-density distribution of mf as specified by the gamma distribution. Actual data indicate that this population-density-based infectivity index can be considerably different from the conventional index based on the survey-density distribution. The level of the carrier rate of mf in a survey is greatly influenced, apart from the sample variation, by the average volume of blood taken from each person. The rate computed on the estimated population-density distribution of mf is convertible to any base amount of blood.
Use of two-colour flow cytometry to assess killing ofGiardia muristrophozoites by antibody and complement
Authors: Heyworth M. F. , Pappo J. 
Published: June 2009

SummaryA two-colour flow cytometry technique was used to assess killing ofGiardia muristrophozoites by rabbit anti-trophozoite antibodies and complement. Binding of rabbit antibody to trophozoites and killing of trophozoites were documented by flow cytometry, after incubating the organisms with fluorescein-conjugated anti-rabbit IgG and propidium iodide (PI). Percentages of PI+(dead) trophozoites ranged from >80%, after incubation with rabbit antiserum and complement, to <30%, after incubation with complement alone. The assay technique may be applicable to studies aimed at determining whether intestinal antibodies fromGiardia-infected mammals can killGiardiatrophozoites.
Effect of age and initial infection intensity on the rate of reinfection with Trichuris trichiura after treatment
Authors: Bundy D. A. P. , Cooper E. S. , Thompson D. E. , Didier J. M. , Simmons I. 
Published: June 2009

SummaryThe study examines the rate of re-acquisition of Trichuris trichiura infection after treatment in two populations, one of mixed age and the other of children with known preintervention infection intensity. A population living in a Caribbean village was treated with mebendazole and the rate of reacquisition of infection of four age classes (2–4, 5–10, 11–30, 30+ years) monitored over a 20-month period. The reinfection rate was higher in the child age-classes indicating either that children are more exposed to infection or that adults slowly develop a partially effective acquired immunity. A cohort of children (mean age 4·5 years) was separated into 3 intensity categories on the basis of expelled worm burdens and their rate of reacquisition of infection monitored over a 12-month period. The rate of reinfection was directly and positively associated with initial infection status. This may indicate that children with low intensity infections are consistently less exposed to infection or that they have effective immune responses. The latter conclusion, however, would imply that they had acquired this immunity early in life, and so appears to contradict the suggestion that resistance is only slowly acquired by adults. Reconciling these two conclusions may require more sophisticated immunological models than have been suggested previously for geohelminthiases.
An analysis of staining methods for the detection ofCryptosporidiumspp. oocysts in water-related samples
Authors: Smith H. V. , McDiarmid A. , Smith A. L. , Hinson A. R. , Gilmour R. A. 
Published: June 2009

SummaryThe ability of five staining techniques, originally developed for the rapid identification ofCryptosporidiumspp. oocysts in faecal samples, to detect oocysts in water and water-related samples was assessed. All the stains used (modified Ziehl Neelsen, auramine-phenol (Lempert), Wright-Giemsa, safranin-methylene blue and FITC-labelled monoclonal antibody) stained oocysts after storage in water for 2 months at 4 °C (71–89 % of control values). Storage of oocysts below 0 °C greatly reduced the staining ability of auramine-phenol. With the exception of oocysts stored in raw and final waters, the histochemical stains proved less useful in detecting oocysts than the monoclonal antibody. Organisms of similar size and shape took up these stains, causing confusion in interpretation. Cold Ziehl Neelsen and the FITC-labelled monoclonal antibody were best at identifying oocysts from a waterborne outbreak. Screening with a fluorescent antibody, followed by confirmation with cold Ziehl Neelsen, where possible, are the currently recommended procedures for the detection of oocysts in water-related samples.