bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pathologically induced alterations in the dimensions of the hepatic portal vasculature of mice infected with Schistosoma mansoni
Authors: McHugh S. M. , Coulson Patricia S. , Wilson R. A. 
Published: June 2009

SUMMARYAlterations in the hepatic portal vasculature of NMRI mice infected with Schistosoma mansoni were assessed using a microsphere injection technique. The accumulation of eggs in the livers of infected mice and the development of portal hypertension were closely related to the worm pair burden during the first 15 weeks of infection. Individual variation between mice harbouring identical patent worm pair burdens was partially explained by the reduced fecundity of females from sexually biased infections. As eggs accumulated in the liver and portal hypertension increased, the number of injected microspheres escaping from the hepatic portal system rose in rank order of diameter from 9 μm through 15 μm and 25 μm to 50 μm. There was a strong correlation between the numbers of parasite eggs in the lungs and injected microspheres recovered from the lungs. The pattern of detection of microspheres in the lungs indicated a progressive increase in diameter of intra-hepatic porta-systemic connexions, followed by development of large-bore extra-hepatic collateral vessels. An accurate temporal profile of the pathological state of the host and the extent of collateral vessel formation was obtained. Injection of 141Ce-labelled microspheres demonstrated that the arterial supply to all organs of the body was affected by alterations in the micro-vasculature of the liver and lungs.
Theoretical basis for the use of pathogens as biological control agents of pest species
Authors: Anderson R. M. 
Published: June 2009

SUMMARYThe population dynamics of insect–pathogen interactions are examined with the aid of simple mathematical models. Three concepts of central importance to the interpretation of population behaviour are discussed, namely the ability of the pathogen to persist within its host population, the ability to regulate and depress host population abundance, and the ability to induce non-seasonal cyclic changes in host density. The selection of pathogen species or strains to depress pest population growth is discussed and the optimal characteristics are shown to be intermediate pathogencity combined with an ability to reduce infected host reproduction, high transmission efficiency, including elements of vertical as well as horizontal transmission stages. When the pathogen plays a significant role in the regulation of host population growth, it is argued that many insect–pathogen interactions will exhibit non-seasonal oscilations in host and pathogen abundance. Mathematical models are used to explore the patterns of population behaviour that result from the continual introduction of a pathogen into a target pest population. It is shown that there exists a critical introdution rate, above which the eradication of the pest is theoretically possible. Significant reductions in pest population abundance will not occur until the introduction rate approaches this critical value, whereupon the oscillatory behaviour of the interaction between host and pathogen population will be suppressed.A general dicussion is given of the problems arising from the combined use of chemical agents and pathogens for the control of pest species, and the evolutionary pressures acting on host and pathogen populations.
Trematodes: antagonism between species and sterilizing effects on snails in biological control
Authors: Combes Claude 
Published: June 2009

SUMMARYThere are two ways in which trematodes can be used in the control of other trematodes which transmit diseases of medical or veterinary importance. Either they can interfere with the reproductive capacity of the host species of snails, or they can exert an antagonistic effect against the larval stages of the target trematode species inside the snail. Often the two effects act together.There are six essential criteria for the selection of a suitable species of snail for control: (1) complete and permanent sterilizing effect; (2) clear dominance over target trematodes; (3) strong infectivity to molluscs of all ages; (4) high egg productivity in the definitive host; (5) lack of pathogenicity towards man and domestic animals; (6) ease and low cost of maintenance of the life-cycle.Various field trials are discussed and it is considered that trematode species producing rediae are usually dominant over those producing only sporocysts (such as the schistosomes). Most species used in control trials to date have belonged to the family Echinostomatidae as they have rediae, and eggs that can be produced in large numbers in a laboratory host such as the rat.The mathematical basis and feasibility of control schemes are discussed and it is concluded that much more information is necessary before their potential can be evaluated.
Pathophysiological changes in urine and blood from calves experimentally infected withSarcocystis cruzi
Authors: Fayer R. , Lynch G.P. 
Published: June 2009

SUMMARYTwo 8-week experiments were conducted to determine the relationships between nutritional stress and pathophysiological changes in male Holstein calves infected withSarcocystis cruzi. Calves were infected by oral inoculation with 200000S. cruzisporocysts. In the first experiment weight gain reduction was greatest in inoculated calves during weeks 4 and 5 after inoculation. Feed intake was reduced during the 5th week. Erythrocyte count was reduced during week 5 and haemoglobin was reduced during week 6. The 24-h excretion of urinary and urea nitrogen from the inoculated calves was increased by treatment. In the 2nd experiment, both the feed-restricted and inoculated calves lost weight during weeks 4 and 5; feed intake was lower from week 5 to 8 inclusive. Urine volume from inoculated calves was lower during week 8. Lower urine excretions of sodium and potassium resulted fromS. cruziinoculation. There was a non-significant trend for higher urinary zinc excretion in the inoculated group during week 4. Urine nitrogen excretion from inoculated calves was higher during weeks 4 and 6; nitrogen excretion from the feed-restricted group was higher during week 6. The urinary excretion of 3-methylhistidine from the inoculated calves was higher during week 4 and excretion of guanine was higher during weeks 4, 5 and 8.S. cruzihas several specific pathophysiological effects on calves beyond those induced by nutritional stress.
Phagocytosis and killing ofTrypanosoma dionisiiby human neutrophils, eosinophils and monocytes
Authors: Thorne Kareen J. I. , Glauert Audrey M. , Svvennsen Rosamund J. , Franks David 
Published: June 2009

SUMMARYThe cell-mediated resistance of human leucocytes toTrypanosoma dionisii, a bat parasite related toT. cruzi, was investigated. Human peripheral blood neutrophils and monocytes were cytotoxic toT. dionisiias assessed by electron microscopy and by induction of99mTc release from trypanosomes pre-labelled with [99mTc]pertechnetate. The enhancement of cytotoxicity by specific antiserum varied considerably from one individual to another. Neither blood lymphocytes nor blood eosinophils induced99mTc release fromT. dionisii. The trypanosomes were readily phagocytosed by neutrophils and monocytes even in the absence of added antiserum but the rate was enhanced when antiserum was present. Eosinophils also phagocytosedT. dionisiibut only in the presence of antiserum. Investigation by electron microscopy revealed thatT. dionisiiis rapidly destroyed in the phagocytic vacuole of neutrophils and monocytes and by eosinophils. Phagocytosis, ultrastructural damage and induction of99mTc release occurred more rapidly in neutrophils than in monocytes.
Immunity in human schistosomiasis mansoni: prevention by blocking antibodies of the expression of immunity in young children
Authors: Butterworth A. E. , Bensted-Smith R. , Capron A. , Capron M. , Dalton P. R. , Dunne D. W. , Grzych J. M. , Kariuki H. C. , Khalife J. , Koech D. , Mugambi M. , Ouma J. H. , Siongok T. K. Arap , Sturrock R. F. 
Published: June 2009

SUMMARYA total of 129 children were treated forSchistosoma mansoniinfections, and followed for intensity of reinfection at3-monthly intervals over a 21-month period. Blood samples were taken before treatment and at 5 weeks and 6, 12 and 18 months after treatment. This paper presents a statistical analysis of the relationship between various immune responses and subsequent reinfection. Responses analysed were: blood eosinophil levels; IgE antibodies against schistosomulum antigens; IgG antibodies mediating eosinophil-dependent killing of schistosomula; antibodies inhibiting the binding to schistosomulum antigens of two rat monoclonal antibodies that also recognize egg antigens; the levels of anti-adult worm and of anti-egg (total, IgM and IgG) antibodies; and IgM anti-schistosomulum antibodies. Results for each assay were well correlated for each of the five separate blood samples. None of the assays were predictive of resistance to reinfection, butsusceptibilityto reinfection was strongly correlated with results in the preceding blood samples for total anti-egg antibodies and the inhibition of binding of one of the two monoclonal antibodies. Further analysis also revealed a correlation between reinfection intensities and both IgM anti-schistosomulum antibodies and IgM and IgG anti-egg antibodies. These results are consistent with the hypothesis that early infections elicit the development, in response to egg antigens, of antibodies that block immune mechanisms directed against schistosomula. Blocking antibodies may be IgM, but might also be of an ineffective IgG isotype. The existence of such antibodies in young children would explain the slow development of immunity in the face of a range of detectable, potentially protective immune responses.
The functional morphology of the copulatory apparatus of Ergenstrema labrosi and Ligophorus angustus, monogenean gill parasites of Chelon Labrosus
Authors: Llewellyn J. , Anderson Maria 
Published: June 2009

SUMMARYThe male intromittent apparatus of Ergenstrema labrosi and Ligophorus angustus, monogenean parasites of the thick-lipped grey mullet Chelon labrosus, consists of a slender flexible penis tube with an expanded proximal region and whose distal end passes freely through a canal in an accessory sclerite; the tube is surrounded by a sleeve of longitudinal muscle and the apparatus works in a manner generally similar to an engineer's Bowden cable. There is a substantial difference in the form of the accessory sclerite in the two species. In both parasites there is a slender sclerotized vagina which, in L. angustus, is short and straight or curved but in E. labrosi is about 7 times longer and forms a spiral. The special role of the sclerotization of the distal part of the vagina may be to resist perforation of the wall by the exceedingly fine penis tube and the consequent discharge of sperms into the parenchyma.
Endodyogeny in Isospora rastegaievae from the Eurasian hedgehog (Erinaceus europaeus L.)
Authors: Matuschka F.-R. 
Published: June 2009

SUMMARYIsospora rastegaievae undergoes its asexual development in the intestinal tract of hedgehogs by endodyogeny. Using light- and electron-microscopy it was demonstrated that daughter organisms were formed by typical endodyogeny as described for different coccidia.
Susceptibility to coccidiosis: effect of strain of mouse on reproduction ofEimeria vermiformis
Authors: Rose M. Elaine , Owen Dawn G. , Hesketh Patricia 
Published: June 2009

SUMMARYThe reproduction ofEimeria vermiformisin different strains of phenotypically normal mice and in mice with various immunological characteristics or defects was compared. In some strains of phenotypically normal mice there were marked differences in oocyst production, both in terms of numbers and in the duration of patency, allowing the strains to be classified as resistant or susceptible to infection withE. vermiformis. These differences were apparent only in primary infections; both types of strain were equally resistant to reinfection. Amongst the strains of mice with immunological deficiencies, reproduction of the parasite was greatest in the athymic (nu/nu) mutants and these mice were completely susceptible to reinfection. Strains of mice with lowered or defective antibody production, or with defective neutrophils and low NK cell activity (bg/bg) were more susceptible than the relevant controls to primary infection but all developed substantial immunity to reinfection. Asplenic (Dh/+) mutants were remarkably resistant to infection.
Changes in the somatic musculature of the 4th-stage larvae ofAscaris suumGoeze, 1782 (Nematoda: Ascaridoidea) developing in swine
Authors: O'Grady R. T. 
Published: June 2009

SUMMARYFourth-stage larvae ofAscaris suum, recovered from piglets at 11–22 days post-infection (p.i.), were examined by light microscopy for changes in the somatic musculature. During this time the estimated total number of muscle cells in the body increases from approximately 600 to 21 000 cells. This non-eutelic development appears to occur by division of platymyarian muscle cells into coelomyarian cells, thereby increasing the number of muscle cells/quadrant from 5 to 85. The incompleteness of these divisions results in sarcoplasmic connections among muscle cells, and between muscle cells and nerve chords. At 11 days p.i., immediately after the 3rd moult, the variation in muscle cell length in a quadrant, with the longest cells being at the lateral chords, has been established. The average muscle cell length at this point is 0·101 mm, the longest is 0·164 mm. These values have increased to 0·365 mm and 1·122 mm, respectively, by 22 days p.i. At 18 days p.i. those cells in the posterior section of the larva are still the shortest in the body.
Altered lysophospholipase B responsiveness in lactating mice infected with intestinal nematode parasites
Authors: Ngwenya B. Z. 
Published: June 2009

SUMMARYLactating and nulliparous outbred Swiss (CF-1 strain) mice were infected at 12–16 weeks of age withNippostrongylus brasiliensisorTrichinella spiralis. Lysophospholipase B levels in the intestinal tissue and faecal pellets were greatly depressed in infected lactating mice in contrast to infected nulliparous mice. Correlated with these depressions in lysophospholipase levels were markedly reduced numbers of bonemarrow eosinophils in infected lactating mice. Although the peak levels of lysophospholipase in the intestinal tissues occurred in both nulliparous and lactating mice by days 9 and 14 after infection withN. brasiliensisandT. spiralis, respectively, lactating mice had significantly lower lysophospholipase peak levels than nulliparous mice. The peak of luminal levels of the enzyme coincided with peak levels of the enzyme in the intestinal tissues and with theexpulsion of the majority of the worms from the small intestines of nulliparous mice. However, lactation delayed the temporal relation between the peak of lysophospholipase levels in the intestinal lumen and worm expulsion. These results suggest that lactation depressed the levels of the enzyme and interfered with its release into the intestinal lumen.
Cercaria vaullegeardi Pelseneer, 1906 (Digenea: Hemiuridae); the daughter sporocyst and emergence of the cercaria
Authors: Matthews B. F. 
Published: June 2009

SUMMARYThe daughter sporocyst of Cercaria vaullegeardi has hitherto been regarded as occurring within the haemocoel of the digestive gland of Gibbula umbilicalis. A re-examination has shown that an important part of the sporocyst, previously overlooked, extends from the digestive gland, through the afferent renal vein, the right kidney haemocoel and the transverse pallial vessel into the blood channel within a gill filament, thus providing a means of exit from the host directly into the mantle cavity. The sporocyst is described at light and electron microscope levels, and the emergence of the cystophorous cercariae is discussed.
Experimental infection of mice with the microfilariae ofOnchocerca lienalis
Authors: Townson S. , Bianco A. E. 
Published: June 2009

SUMMARYMicrofilariae ofOnchocerca lienaliswere obtained from the umbilical skin of naturally infected cattle and were injected into mice. Maximum numbers of microfilariae were recovered from the skin and ears of mice when using the subcutaneous route of inoculation. Microfilariae were distributed throughout the pinna of the ear but were concentrated towards the tip where histological sections showed them to be in the dermis and adipose tissue. Using the number of parasites recovered from the ears as an index of the intensity of infection it was found that inbred CBA/HT6T6mice were one of the most susceptible of 11 strains of mice examined. No difference in susceptibility was found between male and female CBA mice of the same age, but marked differences were demonstrated between male CBA mice of different ages. After infection with 5000 microfilariae the recovery of parasites from the ears increased rapidly to a peak at day 35 when 10% of the inoculum was recovered, and thereafter declined up to day 242. Over a range of inoculation doses examined it was found that there was a direct, linear relationship between the number of microfilariae recovered from the ears and the number in the inoculated dose. CBA mice showed marked resistance to reinfection with microfilariae. Six days after challenge with a secondary infection recoveries of microfilariae from the ears were only 26% of the level in challenge controls and fell to 3% of the level of controls by day 35. It is concluded that the model ofO. lienalismicrofilariae in CBA mice shows considerable promise as a tool for research into immunological responses to skin-dwelling microfilariae, which are the principal cause of pathology in onchocerciasis.
Inhibited development of Ostertagia ostertagi in Australia related to survival over summer in the host or on pasture
Authors: Smeal M. G. , Donald A. D. 
Published: June 2009

SUMMARYDuring autumn and winter, separate pasture plots were seeded with Ostertagia ostertagi eggs produced by worms which had persisted in the host over summer as inhibited larvae, or which had developed directly from larvae acquired from pasture in late summer. Successive groups of parasite-free calves grazed the plots in spring for 14 days at 4-week intervals and were killed for worm counts 14 days after removal from pasture. The proportion of inhibited early 4th-stage larvae was substantially greater in calves which grazed the plot carrying the progeny of previously inhibited worms. This finding is more easily reconciled with differential survival on pasture over spring and summer of inhibiting and non-inhibiting morphs, than with the concept of a physiological switch from inhibiting to non-inhibiting behaviour in individual larvae.
The development, composition and maintenance of experimental populations of Haemonchus contortus in sheep
Authors: Coadwell W. J. , Ward P. F. V. 
Published: June 2009

SUMMARYClun Forest sheep, aged between 3 and 18 months and worm-free from birth, were given a single dose of 25000 infective larvae of the nematode Haemonchus contortus. The host animals were killed between 4 and 100 days after infection and the nematode populations were examined to determine size and composition. The relation between worm body length, dry weight and age was studied and growth curves were constructed. Variations in the sex ratio for infections of different ages were noted. No evidence was found for a relation between rate of growth and population density. The rate of expulsion was determined and its variability discussed.
Histochemical studies of glycosidase activity in juveniles and adults of the lung fluke Paragonimus
Authors: Fujino T. , Higo H. , Ishii Y. 
Published: June 2009

SUMMARYGlycosidase activities in the adults and juveniles of the lung fluke Paragonimus ohirai and P. westermani adults were demonstrated histo-chemically. For comparative studies, histochemical examination was also made on the adults of the liver fluke Fasciola hepatica. The enzymes examined were N-acetyl-β-glucosaminidase (EC 3.2.1.30), β-glucuronidase (EC 3.2.1.31), β-galactosidase (EC 3.2.1.23), α-glucosidase (EC 3. 2. 1. 20) and β-glucosidase (EC 3.2.1. 21). The distribution of β-glucosaminidase was similar in juveniles and adults. Strong reaction sites for the enzyme were the caecal brush border, tegument, sub-tegumental cells and testes. In contrast, no staining reaction occurred in the caeca of F. hepatica, although the tegument and parenchymal cells were weakly stained, β-glucuronidase activity was associated only with the luminal surface of the caeca in the juveniles. However, luminal contents also appeared stained and this might suggest that the activity in the caeca is not endogenous. β-galactosidase was localized in the caeca, sub-tegumental cells and tegument in both juveniles and adults. No reaction occurred for the other two enzymes, α- and β-glucosidase.
Experimental life-cycle studies of Raillietiella gehyrae Bovien, 1927 and Raillietiella frenatus Ali, Riley and Self, 1981: pentastomid parasites of geckos utilizing insects as intermediate hosts
Authors: Ali J. H. , Riley J. 
Published: June 2009

SUMMARYThe life-cycles of two closely related cephalobaenid pentastomids, Raillietiella gehyrae and Raillietiella frenatus, which utilize geckos as definitive hosts and cockroaches as intermediate hosts, have been investigated in detail. Early development in the fat-body of cockroaches involves 2 moults to an infective, 3rd-stage larva which appears from 42–44 days post-infection. Complete development in geckos involves a further 5 moults in the case of males and 6 for females. Males mature precociously and copulation is a once-in-a-lifetime event which occurs around day 80 post-infection when both sexes are the same size but the uterus of the female is undeveloped. Sperm, stored in the spermathecae, is used to fertilize oocytes which slowly accumulate in the developing saccate uterus. Patency commences when the uterus carries approximately 4000–5500 eggs but only 25–36 % of these contain fully developed primary larvae. Since only mature eggs are deposited, we postulate that the vagina (?) of the female must be equipped with a selective filter that allows through large eggs but retains smaller, immature eggs. Thus the only limit on fecundity is the total number of sperms in the spermathecae and this is precisely the same factor that constrains egg production in the advanced order Porocephalida.