bluuebunny/crossref_metadata_2025_split huggingface dataset:
Life-cycle of Isospora ohioensis in dogs
Authors: Dubey J. P. 
Published: June 2009

SummaryThe life-cycle of Isospora ohioensis in dogs is described. Eight dogs were killed 6, 16, 24, 48, 72, 96, 114 and 120 h after feeding 106I. ohioensis sporocysts to each. First divisional stages occurred in the jejunum at 48 h post-inoculation (p.i.). At 48 h, zoites occurred in pairs in parasitophorous vacuoles of surface epithelial cells of the jejunum. The parasitophorous vacuoles were 7–9 × 6 μm and the zoites were 7–9 × 2·5 μm in sections. At 72 h, uninucleated zoites, multinucleated zoites and meronts containing fully formed merozoites occurred in surface epithelial cells of the jejunum. At 96, 114 and 120 h asexual multiplication occurred throughout the small and large intestine, mostly in the ileum. The number of asexual generations was not determined. At least 2 structurally distinct meronts were identified at 96–120 h p.i. Type I meronts contained larger merozoites (11 × 3 μm) than those (7·5 × 1·5 μm) in Type II meronts. Meronts were merozoite-shaped and contained up to 8 nuclei. Uninucleated, binucleated and multinucleated zoites occurred within the same parasitophorous vacuole. Gamonts occurred in surface epithelial cells of the small intestine, caecum and colon, but predominantly in the ileum, 96–120 h p.i. Macrogamonts were 13–17 × 11–12 (14·5 × 12·8) μm in sections and 21–26 × 17–25 (21·7 × 17·6) μm in smears. Microgamonts were 13–17 × 8–15 (15·3 × 11·4) μm in sections and 24–30 × 15–24 (27 × 19) μm in smears and contained up to 50 microgametes. The cycle was also studied in 6 dogs killed 6, 12, 24, 48, 96 and 120 h after feeding tissues of laboratory mice that had been infected with I. ohioensis oocysts 17 days earlier. Stages were not seen in the dogs killed at 6 and 12 h p.i. Asexual and sexual stages were structurally similar in size and location to the oocyst-induced cycle but their development was faster by 24 h in the mouse-induced cycle. Extra-intestinal stages were not found in sections of mesenteric lymph nodes, spleen, lung, liver, heart, skeletal muscle and brain. However, biological evidence indicated that I. ohioensis invaded the spleens and mesenteric lymph nodes of dogs fed oocysts.
A suggested terminology for populations of coccidia (Eimeriorina), particularly of the genus Eimeria (Protozoa: Apicomplexa)
Authors: Joyner L. P. , Canning Elizabeth U. , Long P. L. , Rollinson D. , Williams R. B. 
Published: June 2009

SummaryA short list of terms has been compiled which provides for the discussion of variation of coccidia of the genus Eimeria at infrasubspecific levels. Based upon this list, guidelines are given for the designation of strains and lines.
The development of the tapeworm Diphyllobothrium latum (L. 1756)(Cestoda; Pseudophyllidea) in its definitive hosts, with special references to the growth patterns of D. dendriticum (Nitzsch, 1824) and D. ditremum (Creplin, 1827)
Authors: Andersen Karin 
Published: June 2009

SummaryWhen Diphyllobothrium latum develops from larva to adult in a definitive host, it first sheds the entire larval ‘body’ before growth of an adult strobila starts. This process of shedding off the entire larval abothrial extremity, piece by piece, takes about 48 h. By this time the larva has usually reached the anterior third of the small intestine of the host. D. dendriticum and D. ditremum develop quite differently, although exhibiting similar anterior migrations. In these two species the larvae develop directly into adults without the larval ‘bodyRsquo; first being shed. The implications of the observed differences in growth pattern between these three species of Diphyllobothrium to the classification of diphyllobothriid cestodes is discussed briefly.
Propagation ofNosema eurytremae(Microsporida: Nosematidae) from trematode larvae, in abnormal hosts and in tissue culture
Authors: Higby G. C. , Canning Elizabeth U. , Pilley Barbara M. , Bush P. J. 
Published: June 2009

SUMMARYPropagation ofNosema eurytremae, a microsporidian pathogen of trematode larvae, was investigated by inoculation of spores into the haemocoele of insects and by growth in tissue cultures. Locusts and the larvae of three lepidopteran species were good hosts but cockroaches were not. Low replication was obtained in one lepidopteran species afterperos infection. Antibiotics controlled bacterial growth in suspensions of microsporidian spores but fungi were unaffected by all antibiotics tested, except at concentrations detrimental to the microsporidia. All stages of the microsporidium developed in cell lines ofXenopus laevisandAedes pseudoscutellariswhen spores were induced to hatch in contact with cell monolayers: theAedesculture was contaminated by yeasts. Repeated washing of theXenopuscells with fresh medium, after the sporoplasms ofN. eurytremaehad penetrated the cells, removed yeast contaminants and sterile cultures were obtained. Replication during 4 passages over 53 days was only 100 to 200-fold compared with the original inoculum but spores harvested from the cultures were infective to a fresh culture and toPieris brassicaeby inoculation into the haemocoele.
Genetic resistance to helminths. The influence of breed and haemoglobin type on the response of sheep to primary infections withHaemonchus contortus
Authors: Altaif K. I. , Dargie J. D. 
Published: June 2009

SummaryThe possible existence of strain and breed differences in the response of sheep to primary infections withHaemonchus contortuswas examined by comparing the establishment and pathogenic effects of the parasite in Scottish Blackface and Finn Dorset sheep grouped according to haemoglobin type and infected with 7–10000 3rd-stage larvae. Homozygous haemoglobin A-type sheep of both breeds had lower worm burdens and faecal egg outputs, and suffered less severe clinical and pathophysiological disturbances than animals homozygous for haemoglobin B. In addition, Scottish Blackface sheep displayed similar advantages over Finn Dorsets with the same haemoglobin type and variations in the severity of the disease as judged by a variety of pathophysiological indices correlated closely with parasite numbers. It was therefore concluded that genetic resistance operated primarily against worm establishment and that, barring the unlikely involvement of non-specific physiological factors, this was controlled by the immune response elicited. The nature of this response is unknown, but appeared to operate only against the larval stages, since the size and metabolic activities of the surviving worms were similar in all animals. In a subsequent experiment, designed to examine the response of Scottish Blackface sheep to heavy infection (45000 larvae), there was no correlation between worm establishment and haemoglobin type. This was possibly due to a delayed immune response arising from exposure to excessive amounts of antigen.
The stimulation of daughter redia production during the larval development of Fasciola hepatica
Authors: Wilson R. A. , Draskau Tove 
Published: June 2009

SummaryIn snails maintained at 20 °C rediae of Fasciola hepatica emerge from sporocysts from 11 days after infection onwards. The number of mother rediae rises steadily thereafter until at least 40 days after infection. Daughter rediae are seldom observed in mother rediae dissected from snails maintained at 20 °C. Their production can, however, be stimulated by subjecting the snail host to starvation, to low, and to high temperature shocks. The parasite is susceptible to stress from immediately after infection for about 16 days, when maintained at 20 °C. In general, the more extreme the shock, the greater is daughter redial production. Increasing the length of the period of stress from 12 h up to 9 days does not increase the production of daughter rediae, nor does repeated on/off cold shocks or continuous maintenance at 10 °C. Daughter rediae develop more rapidly than cercariae and leave the mother rediae several days earlier. There is no evidence that presence of daughter rediae coincides with the suppression of cercarial production. The findings are discussed with reference to possible mechanisms by which parasite development might be controlled.
Patterns in helminth communities: why are birds and fish different?
Authors: Kennedy C. R. , Bush A. O. , Aho J. M. 
Published: June 2009

SUMMARYRecently, some authors (Kennedy, 1981; Price & Clancy, 1983) have argued that there are fundamental differences between the communities of helminths in fish and bird hosts. Such differences are foreshadowed by the work of Dogiel (1964) and are apparent from survey data (e.g. Threlfall, 1967; Bakke, 1972; Hair & Holmes, 1975 on birds, and compare Chubb, 1963; Mishra & Chubb, 1969; Wootten, 1973; Ingham & Dronen, 1980 on fish). Questions still remain, however, as to whether the distinctions are truly justified and whether the differences are really fundamental. In this paper, we address these questions by examining helminth diversity in a series of hosts. We then discuss and provide explanations for the observed differences.
Energy metabolism and its regulation in the adult liver flukeFasciola hepatica
Authors: Lloyd G. M. 
Published: June 2009

SUMMARYThe adult liver fluke,Fasciola hepatica, inhabits the bile duct of its final host, usually cattle or sheep. The veterinary aspects of infection withF. hepaticacan represent a major problem and consequently fascioliasis can have serious economic effects. As recently as 1972 the loss in revenue due to liver fluke infestations in the UK was estimated at an incredible £50 million per annum (Coles, 1975). Not only canF. hepaticainfect cattle and sheep, but also outbreaks of human disease have been reported. The last serious outbreak in Britain was in 1968 when at least 49 cases were identified (Ashton, Boardman, D'Sa, Everall & Houghton, 1970; Hardman, Jones & Davies, 1970).
Membrane potentials in an acanthocephalan worm (Macracanthorhynchus hirudinaceus)
Authors: Miller D. M. , Wong B. S. , Dunagan T. T. 
Published: June 2009

SUMMARYThe resting membrane potential of the acanthocephalan rete system in Macracanthorhynchus hirudinaceus was −35±1·5 mV (n = 20) and was dependent upon the external potassium concentration. The membrane potential reached 0 mV when the external potassium concentration was 160 mM. Spontaneous spike potentials of 45 mV ± 10 were dependent on calcium flux. The membrane potential was depolarized by acetylcholine, potassium-free medium, calcium ions and chloride-free medium but not by changes in the external sodium concentration. Spontaneous potentials were increased in number by acetylcholine and calcium at concentrations above 3 mM, but were decreased in number by chloride- and calcium-free medium. Hence the rete system potentials are very similar to smooth muscle potentials in many respects.
Evolutionary implications ofTribolium confusum–Hymenolepis citelliinteractions
Authors: Schom C. , Novak M. , Evans W. S. 
Published: June 2009

SUMMARYHymenolepis citellicaused a marked mortality inTribolium confusumduring the first 14 days of infection. The mortality was higher when the beetles were starved for 6 days immediately prior to infection (73–93%) than when they were starved for 1 day (51%). Regardless of the starvation time, the majority of beetle deaths occurred between days 8 and 11 post-infection (p.i.) and the precise survival time for individuals tended to vary inversely with the number of parasites they contained. With few exceptions beetles that survived until day 15 p.i., when the experiments were terminated, contained 14 or fewer cysticercoids, whereas those that died on or before day 14 p.i. contained 20 or more parasites. Mortality was equally high in both sexes but the mean survival time was significantly shorter for female beetles (8·8 days) than for males (9·6 days). Also, parasite development rate varied with the sex of the host. When parasite populations recovered from beetles that died on the same day were compared, the degree of development attained by those from males was significantly higher than in the populations grown in female hosts. The line ofH. citelliused in these experiments has been maintained in the laboratory for the past 5 years. The results obtained with the current generation of this line were compared with those obtained with it 2 years earlier (approximately 16 generations ago). Mortality was lower with the current generation (67%) than with the earlier generation (93%). However, with the latter generation, the mean parasite population size in beetles that survived to day 15 p.i. was significantly higher (14·1 cysticercoids/beetle) than in those infected with the recent generation (7·3–7·9) cysticercoids/beetle). These findings suggest that relatively high selection pressures have been applied byT. confusumtoH. citelli, thereby reducing the number of parasite lines with high infectivity and consequently improving host survivorship. The host also responded to artificial, directed selection for reduced cysticercoid number (heritability estimates of 0·30 ± 0·12 and 0·26 ± 0·12) and increased survival (heritability estimates of 0·28 ± 0·12 and 0·15 ± 0·083). The realized heritability was 0·37 for cysticercoid number and 0·17 for increased survival.
The appearance of bisporocystic oocysts of Eimeria maxima in drug-treated chicks
Authors: Norton C. C. , Joyner L. P. 
Published: June 2009

SummaryA line of Eimeria maxima acquired resistance to Lerbek (a mixture of clopidol and methyl benzoquate) after serial passage against rising drug levels. Abnormal bisporocystic oocysts which appeared throughout this series were picked out individually and these produced infections in further groups of chicks. Serial passages of selected bisporocystic forms raised their proportion in oocyst yields to about 80% after 10–14 passages, but a few normal oocysts were still present.
Migration of the schistosomula of Schistosoma mansoni from skin to lungs
Authors: Miller Patricia , Wilson R. A. 
Published: June 2009

SummaryThe number of schistosomula recovered from abdominal skin declined exponentially with time after infection. However, this decline was shown to be an untrue reflection of the numbers present because of changes in recoverability on days subsequent to infection. Digestion of skin by the enzymes collagenase and hyaluronidase produced a small increase in the number of schistosomula recovered. The number of schistosomula present in abdominal skin and capable of reaching maturity was estimated by exciting the area to which cercariae had been applied, from groups of hosts at daily intervals after exposure. The number of worms maturing in each group of hosts was then determined. The mean duration of stay of schistosomula in mouse, hamster and rat abdominal skin was estimated at 88, 64·5 and 70 h, respectively. The fluid content of abdominal skin to which cercariae had been applied, increased following infection but it was concluded that this alone was not the predominant factor controlling exit of worms. The stimulation of a delayed hypersensitivity response not directed against schistosomes (in mice previously sensitized with 1-chloro,2–4-dinitrobenzene (DNB)) 1 day after exposure to cercariae, produced a significant increase in the number of schistosomula leaving the skin and reaching maturity. Schistosomula can be recovered from the axial lymph nodes of mice, hamsters and rats. If the schistosomula from mice are injected into the tail vein of uninfected mouse hosts, they have the same chance of maturing as comparable skin schistosomula. They are therefore apparently unharmed by their passage through the nodes. Interference with lymphatic drainage by surgical removal of lymph nodes has no effect on the number of schistosomula recovered from the lungs, but the peak recovery is delayed by 24 h. The hamster cheek-pouch, a site with no afferent lymphatic drainage, was also used to investigate the importance of the lymphatic exit route. There was no reduction in the number of adult worms recovered following infection at this site compared with the normal abdominal skin site. The migration of schistosomula to deeper tissues and their entry into blood vessels was followed using the cheek-pouch preparation. It was concluded that the major route of exit from the skin is the blood vascular system.
The oocyst sporulation time ofEimeriaspecies from the fowl
Authors: Norton C. C. , Chard M. J. 
Published: June 2009

SUMMARYFreshly isolated oocysts were sporulated at 29°C with constant aeration. Minimum sporulation time was determined by dosing the developing oocysts at intervals of 1 h to successive groups of chickens to assess the first occurrence of infective forms. Microscopic analysis of the sporulating oocysts allowed calculation of the time required for 50% of the oocysts to complete the process. This was considered to be the most accurate determination and the most useful for comparative purposes. For 7 species of coccidia in the fowl, the 50% sporulation times were as follows:Eimeria acervulina11·4 h;E. brunetti38·3 h;E. maxima38·1 h;E. mivati19·0 h;E. necatrix19·7 h;E. praecox24·8 h;E. tenella21·2 h.
Stage-specific proteins of the avian malariaPlasmodium lophurae
Authors: Sherman I. W. , Tanigoshi Linda 
Published: June 2009

SUMMARYThe proteins in the soluble and membrane fractions ofPlasmodium lophurae, separated by SDS-PAGE and stained with Coomassie blue, were distinct from one another and different from the soluble and membrane proteins of the host cell, the duckling erythrocyte. Pulse-labelling of malaria-infected red cells containing schizonts or trophozoites with [14C]isoleucine, followed by parasite isolation, SDS-PAGE and autoradiography, showed a pattern of incorporation into soluble proteins identical to the banding pattern of gels stained with Coomassie blue. On autoradiograms, the banding patterns of the membrane proteins of trophozoites and schizonts labelled with [14C]isoleucine were similar. No qualitative differences in the soluble proteins of trophozoites and schizonts were apparent when isoleucine was used as the radiotracer; however, the banding pattern of membrane and soluble proteins labelled with [14C]isoleucine were distinct from each other. The banding pattern of soluble proteins, after staining with Coomassie blue, was distinctly different from the array of bands seen after autoradiography of parasites derived from infected cells pulse-labelled with [14C]histidine. Only small amounts of contaminating haemoglobin in the soluble protein fraction of parasites were labelled with histidine; the membrane fraction, on the other hand, had high incorporation into a single 43 kDalton band, the histidine-rich protein. No band differences, either in the membrane or soluble fractions, were observed in autoradiograms after pulse-labelling trophozoites and schizonts with [14C]histidine. The most consistent and distinct differences in protein synthesis were seen inP. lophuraepulse-labelled with [14C]proline. Autoradiograms of both soluble and membrane fractions showed the presence of bands unique to the trophozoite and schizont–stage-specific proteins.
The open-field behaviour of mice infected with Trichinella spiralis
Authors: Rau M. E. 
Published: June 2009

SUMMARYThe behaviour of mice exposed to graded doses of Trichinella spiralis larvae was monitored in an open-field situation. Ambulatory and exploratory activity declined significantly as the infections progressed, whereas the time spent inactive increased concomitantly. The advent of these behavioural changes coincided with the expected release of larvae by the adult worms and showed no clear signs of abating as late as 90 days post-inoculation. The levels of activity were negatively correlated with the inoculating dose. Such behavioural changes may render the host more vulnerable to predation and thus enhance parasite transmission.
Invasion of chicken caecal and intestinal lamina propria by crypt epithelial cells infected with coccidia
Authors: Fernando M. A. , Lawn A. M. , Rose M. Elaine , Al-Attar M. A. 
Published: June 2009

SUMMARYThe development of second generation schizonts ofEimeria necatrixandE. tenellawas studied with the electron microscope. Invasion of the crypt epithelial cells by merozoites of the first generation schizonts caused changes in the morphology of the infected cells and stimulated their migration into the lamina propria through breaks which appeared in the basement membrane of the crypts. Second generation schizonts developed in the lamina propria within these crypt cells whose epithelial origin was confirmed by their interconnection by desmosomes and tight junctions and by their possession of characteristic microvilli. A comparison is made between this invasion of the lamina propria by parasitized cells and invasion of connective tissue by malignant epithelial cells; the possible mechanisms involved are discussed.
Parasite-induced learned taste aversion involving Nippostrongylus in rats
Authors: Keymer Anne , Crompton D. W. T. , Sahakian B. J. 
Published: June 2009

SUMMARYAfter demonstrating that rats were capable of discriminating between the same diet treated with either flavour 1 or flavour 2 and that the 2 flavours of diet were equipreferred, an experiment was carried out to see whether learned taste aversion might play a role in the reduction of food intake that is commonly observed during the course of a parasitic infection. The results showed that rats, given a subcutaneous inoculation of approximately 6000 third-stage larvae of Nippostrongylus brasiliensis (Nematoda) while feeding on a diet containing flavour 2, strongly preferred to eat diet containing flavour 1 when given simultaneous choice conditions. Uninfected rats showed no preference and ate equal amounts of both flavoured diets. This effect is interpreted as the first experimental demonstration of learned taste aversion using a eukaryotic parasite as the inductive agent.
Identification ofTheileriainfections in living salivary glands of ticks
Authors: Young A. S. , Leitch B. L. , Leitch B. L. , Stagg D. A. , Dolan T. T. 
Published: June 2009

SUMMARYIt was found that interference contrast microscopy gave good morphological differentiation of the living and intact salivary glands from adult ixodid ticks,Rhipicephalus appendiculatusandAmblyomrna variegatum, removed by dissection. In many cases the individual cell types of the acini could be recognized. When the salivary glands of infected adult ticks were examinedTheileriaparasites were detected.Theileria parva, T. taurotragiandT. mutanscould be detected in the salivary glands after they reached the mature secondary sporoblast stage achieved even in unfed ticks. Parasites were detected only in type III acini. The morphology of tertiary sporoblasts and sporozoites of theseTheileriaspp. was clearly recognized in feeding ticks. Sporozoites ofT. parvaproved to be infective to cattle and to peripheral blood leucocytes of cattlein vitroafter interference contrast examination. Interference contrast examination of living salivary glands was used for selection of salivary glands with high infections ofT. parvasporozoites and the sporozoites could be separated in large numbers from these salivary glands. Using this technique it appeared possible to cloneTheileriaparasites from salivary glands with 1 infected acinus.