bluuebunny/crossref_metadata_2025 huggingface dataset:
Infestation of littorinids by larval Digenea around a small fishing port
Authors: Matthews P. M. , Montgomery W. I. , Hanna R. E. B.
Published: June 2009

Larval Digenea infectingLittorina rudis, L. littoreaandL. obtusataaround Portavogie harbour, Co. Down, were examined. High levels of infection were found among the littorinids collected from sites on the harbour shore, though levels of infection varied somewhat with position on the shore. There was a direct relationship between size of the snail host and likelihood of infection. There was a negative association between certain pairs of helminth species in the same host, particularly where the rediae ofCryptocotyle linguaorHimasthlasp. were involved. Infection rates in gastropods declined away from the harbour and it is concluded that the high infection rate centres around the harbour were probably due to the increased concentration of definitive hosts, mainly seagulls, attracted to this area by dumping of raw fish offal. The infection ofPholis gunnelluswith the metacercariae ofC. linguawas also examined. Older fish were more heavily infected than younger fish but no direct relationship was found between high snail infection rates and highP. gunnellusinfection rates.
Fine structural observations on oocyte development in monogeneans
Authors: Halton D. W. , Stranock S. D. , Hardcastle Anne
Published: June 2009

The ultrastructural changes accompanying oocyte differentiation in the ovaries of the monogeneans, Diclidophora merlangi, Diplozoon paradoxum and Calicotyle kröyeri have been described. In each case, oogenesis in the ovary proceeds as far as meiotic prophase in the primary oocyte. A three-stage sequence of development based on oocyte morphology is proposed: (1) Oogonia and early, immature primary oocytes are typically undifferentiated, with chromatin-laden nuclei occupying most of the cell volume. The cytoplasm contains small clumps of mitochrondria and unattached ribosomal aggregates. There is evidence of mitosis and, in later stages, meiotic prophase is indicated by the appearance of nuclear synaptonemal complexes. (2) Maturing primary oocytes are characterized by increased nucleolar volume associated with the production of RNA for export to the cytoplasm. An organized GER and Golgi apparatus are established and involved in the synthesis and packaging of membrane-limited cortical granules. Annulate lamellae and nucleolus-like bodies appear in the cytoplasm and, with development, the cells increase in size and, peripherally, become interdigitated. (3) Mature primary oocytes represent a resting phase when cellular activity is minimal. Golgi disappear and the ER fragments or becomes reduced in dimensions. Mitochondria and free ribo-somes are numerous and cortical granules move to the cell periphery. The cells separate and, when mature, are released from the ovary. There are minor species differences in oocyte ultrastructure and development.
Boophilus microplus: the effect of host resistance on larval attachments and growth
Authors: Kemp D. H. , Koudstaal D. , Roberts J. A. , Kerr J.D.
Published: June 2009

Growth and behaviour ofBoophilus micropluslarvae on British breed cattle, with different resistance levels to the tick, were studied to elucidate the nature of resistance. On highly resistant animals, larval growth rate was slower for the first 3 days, but by day 4 they had attained the normal weight and the majority were subsequently able to moult.

Using phosphorus-32 labelled larvae, it was found that attachment times were shorter and more time was spent wandering on highly resistant animals during the first 16 h. On the second day, attachments had stabilized, but more detachments were still made from highly resistant animals. This was considered to impose an additional stress as the cattle skin environment can rapidly desiccate larvae. However, the larvae were able to compensate by uptake of fluid from the host.

Loss by repulsion of live larvae from the host or drowning in serous exudate were also not considered of major importance. The nature of rejection is discussed in a further paper.

The distribution of larvae after 24 h suggests that their early behaviour largely determines the areas favoured by adults. Movement to, and accumulation in, favoured areas is discussed.
The mechanism of pyrimethamine resistance inPlasmodium falciparum
Authors: Dieckmann A. , Jung A.
Published: June 2009

The uptake of radioactive pyrimethamine by a sensitive and a resistant strain ofPlasmodium falciparum, the metabolic fate of pyrimethamine inside these parasites and the kinetic properties of dihydrofolate reductase (DHFR) from both strains have been studied. Uptake of the drug was identical in both strains and no metabolite of pyrimethamine was found in either strain. DHFR from the resistant strain was 300 times less sensitive to inhibition by pyrimethamine than the enzyme from the sensitive strain, while the Michaelis constant for dihydrofolate remained unchanged and inhibition was competitive in both cases. Altered properties of plasmodial DHFR are apparently the only mechanism responsible for pyrimethamine resistance in the strain ofPlasmodium falciparumstudied.
Seasonal and age distributions ofBabesia, Hepatozoon, TrypanosomaandGrahamellaspecies inClethrionomys glareolusandApodemus sylvaticuspopulations
Authors: Turner C. M. R.
Published: June 2009

Four common blood parasites belonging to the generaBabesia, Hepatozoon, TrypanosomaandGrahamellawere detected in sympatric populations ofClethrionomys glareolusandApodemus sylvaticus. Seasonal changes in the abundance of hosts and parasites were monitored in a longitudinal field survey for 18 months. All parasites in both hosts showed similar seasonal patterns with most transmission occurring in summer and autumn and ceasing in winter. Amongst aged subsets of each host population,HepatozoonandGrahamellaspp. were primarily parasites of young animals whereasBabesiaandTrypanosomaspp. generally infected older hosts. Data from the aged subsets were also used to estimate values for the basic reproductive rate,R0, for each parasite. InC. glareolus,R0= 2·0 forB. microti, 2·6 forH. erhardovae, 1·7 forT. evotomysand 2·8 forGrahamellasp. InA. sylvaticusR0= 2·2 forGrahamellasp. These estimates are probably representative only for summer and autumn of each year.
Nutrition of the miteUnionicola intermedia, Koenike and its relationship to the inflammatory response induced in its molluscan hostAnodonta anatina, L.
Authors: Baker R. A.
Published: June 2009

The structure and staining properties of the epithelium of the midgut inUnionicola intermediaare described. Intracellular non-specific esterase, acid and alkaline phosphatase are present and confined to vacuoles. Extracellular enzymes are absent. Nymphal and adult stages ofU.intermediafeed principally on the haemocytes (= amoebocytes) and mucus of their molluscan host,Anodonta anatina. Feulgen-positive material recorded from the lumen and midgut cells of the mites is believed to be derived from the nucleated haemocytes and to undergo intracellular digestion in the midgut cells. Starved mites show steadily decreasing amounts of Feulgen-positive material in the vacuoles. Haemocytes are present in large numbers below the site of attachment of the mites, their presence represents an inflammatory response, and the mite feeds on the products of this response. Large amounts of bound iron are present in the midgut cells but the origin and role of this is unknown.
Tracking radioactive larvae ofStrongyloides rattiin the host
Authors: Wilson P. A. G
Published: June 2009

Infective larvae of homogonicStrongyloides rattigrown in faecal culture with32P or75Se acquired a significant amount of radioactivity which was firmly attached to them. Heating removed most of the32P but left75Se in place. Subcutaneous injection of virgin and nursing mother rats with living and heat-killed radioactive larvae resulted in a pattern of labelling in the small intestine of injected animals and, in the case of75Se, those of suckling pups, which can only be explained if labelled worms follow the natural migratory routes. The use of this tool in migratory studies is discussed, with precautions to allow for flaws in the technique.
Prevalence of Trypanosoma cobitis Mitrophanow, 1883 in fishes from the River Lee
Authors: Letch C. A. , Ball S. J.
Published: June 2009

The prevalence of Trypanosoma cobitis was recorded in species of small fish from the River Lee at Enfield Lock during 33 months of sampling. Trypanosome infections were more numerous during the summer months with 50–70% of bottom-living ‘inactive’ fish, bullheads (Cottus gobio), stone loach (Nemacheilus barbatulus) and gudgeon (Gobio gobio) infected, compared to only 6 and 18% of the more active pelagic fishes, stickle-backs (Gasterosteus aculeatus) and minnows (Phoxinus phoxinus).
Survival characteristics of the free-living cercarial population of the ectoparasitic digenean Transversotrema patialensis (Soparker, 1924)
Authors: Anderson R. M. , Whitfield P. J.
Published: June 2009

The survival characteristics of free-living cercarial populations of Transversotrema patialensis were described and shown to be age-dependent. The maximum life-span was found to be 44 h with a 50% survival at 26 h. Activity and infectivity of the larvae were also characterized by age-dependence, and were demonstrated to be closely correlated with one another. For individual cercariae, both activity and infectivity had dropped to extremely low levels many hours before death occurred. An attempt was made to interrelate activity and infectivity, in a theoretical manner, with the availability of energy reserves.

Conceptual understanding of the biological processes involved was aided by the formulation of simple mathematical models.
Gaps in our armoury against parasites of man
Authors: Rée G. H.
Published: June 2009

The major health problems of the world today relate to infections—viral, bacterial or parasitological. Malaria, schistosomiasis and filariasis are a risk to at least 600 million people and the problems of many of these infections are getting worse owing to ecological changes associated with industrial development and burgeoning populations which have increased out of proportion to increases in health resources.
Parasite population biology and host nutrition: dietary fructose and Moniliformis (Acanthocephala)
Authors: Keymer Anne , Crompton D. W. T. , Walters D. E.
Published: June 2009

Experiments were carried out to investigate the possible influence of host-dietary fructose concentration on the relationship between worm burden and the fecundity of Moniliformis dubius. Worm length was found to be dependent both on the fructose concentration of the host's diet and on worm burden. The number of free ovaries/female worm was found to increase linearly with increasing dietary fructose concentration but was independent of worm burden. The length of the ovaries increased with increasing dietary fructose concentration and decreased in response to increases in worm density. The magnitude of the density-dependent reduction in the volume of ovarian tissue/female was decreased in worms from rats fed on diets containing low concentrations of fructose. The numbers of eggs present in the body cavities of the female worms was found to be positively correlated with dietary fructose concentration. At 5 weeks post-infection, mature eggs (containing fully developed acanthor larvae) were found in the body cavities of female worms from rats whose diets contained 3 and 12% fructose, but not in those from rats whose diets contained 1 and 2% fructose (w/w). The experimental results are discussed in the wider context of the influence of host nutrition on parasite population biology.
A comparative study of the life-histories of mammalian schistosomes
Authors: Loker Eric S.
Published: June 2009

Available data in the literature pertaining to the life-history characteristics of all known species of mammalian schistosomes have been gathered, and correlations between such variables as length of pre-patent period, adult worm size, rate of progeny production and progeny size have been explored. Accommodation of the schistosome life-cycle to the constraints imposed by certain host characteristics such as life-expectancy and size is discussed. Of the 23 known species of mammalian schistosomes, 20 species apparently rely to a major extent on relatively large-bodied and long-lived mammals such as primates, ungulates and proboscideans for their transmission. Only 1 species,Schistosomatium douthitti, is exclusively dependent on rodents for its transmission.S. douthittiattains maturity within its definitive host faster than any other mammalian schistosome, and is the only species known to be capable of producing viable eggs by facultative parthenogenesis. For all species of mammalian schistosomes, adult worm size, as estimated by female length, is positively correlated with the number of uterine eggs contained within the female (r= 0·682). For the 7 species for which data exist, rate of egg production/worm pair/day is positively correlated with uterine egg counts (r= 0·873) and inversely correlated with egg length (r= −0·787) and miracidium length (r= −0·953). Length of the pre-patent period is positively correlated with egg length (r= 0·503). With respect to the molluscan host, the number of cercariae produced by snails is positively correlated with the shell size of the snail (r= 0·657). For the 5 species for which data exist, the rate of egg production is inversely correlated with shell size of the intermediate host (r= −0·955) and the common logarithm of the number of cercariae produced (r= −0·893). Comparisons between species suggest that exceptionally low rates of cercariae production in the intermediate host may be compensated for by rapid rates of egg production in the definitive host, implying a degree of integration in the schistosome life-cycle not previously appreciated. Most species of mammalian schistosomes have long-lived definitive hosts, and snail hosts capable of producing many cercariae; compensatory relationships are therefore less obvious in such species. Additional quantitative data on all aspects of schistosome life-histories, particularly rate and duration of egg production, are needed to confirm or refute the relationships discussed above.
Circadian variation in the distribution ofHymenolepis diminuta(Cestoda) and 5-hydroxytryptamine levels in the gastro-intestinal tract of the laboratory rat
Authors: Cho C. H , Mettrick D. F.
Published: June 2009

The circadian migration ofHymenolepis diminutain the small intestine of the rat may be correlated with a circadian variation in 5-hydroxytryptamine levels present in worm tissue, in the intestinal lumen, in the intestinal mucosa, with the amount of food present in the small intestine and in arterial blood. The 5-HT and food levels in uninfected animals were also determined. The 16.00 h stage in the circadian cycle marks both the commencement of host feeding, followed by rising 5-HT levels in both worm and host tissues, and initiation of an anteriad migration of worm biomass. It was found that 5-HT levels in the intestine of parasitized animals were significantly higher than in the intestine of uninfected controls. This is the first report of circadian variation in mucosal and luminal 5-HT levels. The similarity in the circadian patterns of worm migration and worm luminal, mucosal and blood 5-HT levels were striking. Fasting eliminated the circadian rise in intestinal 5-HT levels and the worms did not migrate. Luminal 5-HT levels were significantly lower in fasted animals than in the comparable rats fedad libitum. When the intestine was ligatured at the pyloric sphincter, worm anteriad migration still occurred after feeding, indicating that the presence of exogenous food in the intestine is not a factor in the initial migration of the worms.
Density-dependent mechanisms in the regulation of intestinal helminth populations
Authors: Keymer Anne
Published: June 2009

The regulation of helminth populations tends to occur primarily as a result of limitations imposed on the build up of parasite subpopulations within individual hosts (Anderson & May, 1979; May & Anderson, 1979). Considering the relevance of these factors to the success or otherwise of intestinal helminth control programmes, it is perhaps surprising that more information is not yet available concerning the particular mechanisms which may be responsible, and in particular, the population consequences of the immune responses which such parasites may precipitate. Density-dependence in a single rate parameter, if operative over the naturally observed numerical range, is sufficient to regulate parasite population flow throughout the life-cycle, whether direct or indirect (Anderson, 1976). For the genera given in Table 1, this could be provided by the observed pattern of parasite mortality and/or fecundity. It is of interest to note, however, that circumstantial evidence cited in the Table suggests that each of the 6 genera is also potentially able to induce host mortality under certain conditions. Whether this acts in a density-dependent manner in natural infections is almost entirely unknown. Rapid reproduction may be of great selective advantage to intestinal helminths, even if it is necessarily accompanied by pathogenicity (see Anderson, 1981). If the manner in which this pathogenicity acts in any way enhances the stability of the host-parasite interaction, then perhaps it may have contributed to the selection pressures which have led so many genera to continue to break the rules of the ‘well-adapted’ parasite (see, for example, Noble & Noble, 1971).
A life-cycle stage-specific antigen ofTheileria parvarecognized by anti-macroschizont monoclonal antibodies
Authors: Shapiro S. Z. , Fujisaki K. , Morzaria S. P. , Webster P. , Fujinaga T. , Spooner P. R. , Irvin A. D.
Published: June 2009

Four monoclonal antibodies, raised against macroschizonts ofTheileria parva, were studied to characterize their antigen binding specificity. The indirect fluorescent antibody test showed that the antigen(s) recognized were present in the macroschizont stage of the parasite life-cycle but not in piroplasm, kinete or sporozoite stages. Immunoblot analysis of macroschizont stage antigens suggested that all four antibodies recognized the same antigen. This was a molecule which varied in molecular mass between different parasite stocks, ranging from 68000 to 95000 Da. The antigen was localized by immunoelectron microscopy to the surface of the intracellular macroschizonts.
The relationship between pathology and resistance to reinfection withSchistosoma mansoniin mice: a causal mechanism of resistance in chronic infections
Authors: McHugh S. M. , Coulson Patricia S. , Wilson R. A.
Published: June 2009

The development of resistance in mice to reinfection withSchistosoma mansoniwas recorded during an early chronic infection, and compared with hepatic portal pathological and vascular changes. The latter were assessed using a microsphere injection technique. The degree of acquired resistance was directly dependent on the patent worm burden and the time post-infection. Strong correlations were noted between the development of resistance and the appearance of parasite eggs in the lungs and spleens of infected hosts. Weaker associations were present between resistance and other aspects of the disease pathology, such as portal hypertension and organ weights. The appearance of injected microspheres in the lungs and spleens correlated well with the appearance of eggs in those organs and with the development of resistance. The levels of resistance had risen and microspheres were detected in the lungs, before the development of major extra-hepatic, porta-systemic collateral vessels. It is concluded that intra-hepatic vascular alterations may be a causal factor in the development of resistance, preventing the sequestration of migrating schistosomula in the liver. It is estimated that as much as 70–75% of the recorded resistance can be attributed to this immunologically non-specific mechanism.
Non-specific induction of increased resistance in mice toTrypanosoma congolenseandTrypanosoma bruceiby immunostimulants
Authors: Murray Max , Morrison W. I.
Published: June 2009

Administration of the immunostimulantsCorynebacterium parvum, Bacillus Calmette-Guérin(BCG) orBordetella pertussisprior to, or at the same time as, challenge withTrypanosoma congolensesignificantly increased survival times in mice, both of trypano-susceptible (A/J) and trypano-resistant (C57Bl) strains. The increased survival time was associated with significant alterations in parasitaemia, which included lengthening of the pre-patent period, a delay in the time taken to reach the first peak of parasitaemia and a reduction in the level of parasitaemia. Similar results were obtained when these strains of mice were challenged withTrypanosoma bruceifollowing pre-treatment withC. parvum. Thus, by the use of immunostimulants it was possible to reduce the susceptibility of mice to trypanosomiasis and the hope is that this can also be achieved with domestic livestock.
The blocking of human antibody-dependent, eosinophil-mediated killing ofSchistosoma mansonischistosomula by monoclonal antibodies which cross-react with a polysaccharide-containing egg antigen
Authors: Dunne D. W. , Bickle Q. D. , Worth A. E. Butter , Richardson B. A.
Published: June 2009

Three IgM monoclonal antibodies, M22G11P, M7B7 and M22B3G, which reacted with the surfaceof Schistosoma mansonischistosomula in an indirect fluorescent antibody assay, were found to recognize a polysaccharide-containing egg antigen previously designated K3. The monoclonal antibodies and a monospecific rabbit anti-K3serum also recognized a crossreacting antigen in a crude cercarial antigen preparation. In an eosinophil-mediated schistosomulum killing assay, all three monoclonal antibodies significantly inhibited the level of killing produced by human infection serum. An IgG3 monoclonal antibody, M22C1C, which also recognized the egg antigen K3, did not inhibit eosinophil-mediated killing. However, when lower concentrations of human serum were used in the assay, this monoclonal antibody significantly enhanced the level of killing, despite having no capacity to induce eosinophil-mediated damage in the absence of human infection serum. On the basis of these and other results we suggest the possibility that antibodies toS. mansoniegg antigens which cross-react with the surface of the early post-penetration schistosomulum may influence the effective expression of antibody-dependent, eosinophil-mediated effector mechanisms in human infections.
Reevaluation of the potential ofFasciola hepaticaantigens for immunization againstSchistosoma mansoniinfection
Authors: Ford M. J. , Taylor M. G. , Bickle Q. D.
Published: June 2009

Previous workers have reported that significant resistance toSchistosoma mansonicercarial challenge can be induced in mice by immunization with variousFasciola hepaticaantigen preparations. We have attempted to reproduce these observations and have also carried out similar experiments in rats. In our hands, however, CBA mice did not develop either antibodies against the schistosomular surface, or significant resistance to challenge after immunization with heterologous antigens. Similar results were obtained in Fischer rats, but rats did develop significant resistance after immunization with homologous (schistosomular) antigens, even without adjuvant, and the homologous ‘protective’ antigens could be separated by antibody-affinity chromatography using serum from rats vaccinated with irradiated cercariae. Thus, we found no evidence for the existence of shared ‘protective’ antigens betweenS. mansoniandF. hepatica, and suggest that this is further evidence that where heterologous resistance can be demonstrated between these two parasites, it is probably due to immunologically non-specific mechanisms.
Solubilization and immunoprecipitation of125I-labelled antigens fromPlasmodium knowlesischizont-infected erythrocytes using non-ionic, anionic and zwitterionic detergents
Authors: Howard R. J. , Barnwell J. W.
Published: June 2009

Plasmodium knowlesimalaria-infected erythrocytes were radio-iodinated and several non-ionic, anionic and zwitterionic detergents were compared in their capacity to extract the labelled membrane proteins. The use of these detergents for antigen identification was tested by immunoprecipitation, after addition of Triton X-100 to some detergent extracts, using hyperimmune monkey antiserum and protein A-Sepharose.125I-labelled antigens were specifically immunoprecipitated with all detergents tested, including the anionic detergents sodium dodecyl sulphate (SDS), deoxycholate and cholate; the zwitterions Zwittergent-312 and -314, CHAPS and Empigen BB, as well as several non-ionic detergents. The SDS-polyacrylamide gel electrophoresis patterns of125I-labelled antigens varied after extraction with different detergents, there being no consistent pattern for detergents of a particular class. A total of 14125I-labelled antigens were identified, 11 of them using Triton X-100. Some minor antigens identified with Triton X-100 were immunoprecipitated in greater amount after extraction in other detergents. Most importantly, two antigens Mr200000 and 180000 were detected only after extraction with deoxycholate or SDS.
The development of the tegument and cercomer of the polycephalic larvae (cercoscolices) ofParicterotaenia paradoxa(Rudolphi, 1802) (Cestoda: Dilepididae) at the ultrastructural level
Authors: MacKinnon Barbara M. , Burt M. D. B.
Published: June 2009

The development of the tegument and cercomer ofParicterotaenia paradoxapolycephalic larvae was examined using electron microscopy. Larvae are formed by budding from the inner surface of the tegument of the degenerating hexacanth embryo. A new secondary tegument formed around the larvae is probably produced from the original hexacanth sub-tegumental cells. Microvilli covering the surface of young larvae are converted directly into microtriches, as the larvae develop, by addition of electron-dense material to the proximal part of the microvillus. Remnants of the original microvillus are visible at the distal surface of each new microthrix, but they eventually degenerate. The cercomer homologue is represented by scattered follicular cells, bearing microvilli, lying just within the containing cyst wall. The continuity of tegumentary tissue from one developmental stage to the next is discussed.
Nippostrongylus brasiliensis: the effect of mitochondnal inhibitors on life-cycle stages
Authors: Fry M. , Jenkins D. C.
Published: June 2009

The effects of mitochondrial inhibitors on the in vitro development of Nippostrongylus brasiliensis have been studied in free-living and parasitic life-cycle stages. Mitochondrial inhibitors were chosen as being representative of established electron transport inhibitors and oxidative phosphorylation inhibitors and uncouplers of the classical mammalian respiratory chain. All mitochondrial inhibitors tested were highly effective in killing or retarding development of free-living stages of N. brasiliensis. Free-living stages were particularly susceptible to such inhibitors upon hatching of embryonated eggs to 1st-stage larvae. Concentrations of inhibitors effective against free-living stages were consistent with their level of inhibition against isolated mitochondria from embryonated eggs and 3rd-stage infective larvae. Results suggest an absolute requirement in the development of free-living stages for the mammalian-like respiratory chain and associated oxidative phosphorylation. Electron transport inhibitors were effective in retarding at least the initial development of 4th-stage larvae to adults, but only antimycin A and azide produced a lasting effect leading to worm death. Oxidative phosphorylation inhibitors and uncouplers were ineffective against developing parasitic stages of N. brasiliensis. Experiments on whole-worm respiration indicated that most electron transport inhibitors were able to penetrate the adult worm, but oxidative phosphorylation inhibitors were without effect on whole-worm respiration. Results suggest that the mammalian-like electron transport chain is a necessary requirement to adult N. brasiliensis, but oxidative phosphorylation in the adult worm may not be required for development and survival in vitro although it could be necessary to support the parasite in vivo.
Hammondia heydorniinfection in sheep, goats, moose, dogs and coyotes
Authors: Dubey J. P. , Williams C. S. F.
Published: June 2009

The transmission ofHammondia heydorniamong sheep, goats, cattle, dogs and coyotes is described. Oocysts ofH. heydorni, obtained from dog faeces by feeding naturally infected goat meat, were fed to an experimental goat. After 312 days tissues from this animal were fed to 2 dogs. One dog, which received goat muscle, shed oocysts, whereas the other dog which received brain, spleen, kidneys, lungs and liver did not. Oocysts from the dog fed goat muscle were fed to an experimental sheep. After 73 days sheep tissues were fed to a dog and a coyote, both of which shed oocysts 5–8 days later. A second isolate ofH. heydorniwas obtained by feeding naturally infected beef to a coyote. These oocysts were fed to a single goat and sheep and after 71 days, muscle from these 2 animals was fed to 2 dogs and 2 coyotes, all of which shed oocysts 5–8 days later. None of the animals inoculated withH. heydornibecame ill and noHammondia-like organisms were found in tissue sections from the herbivores. Another dog shedH. heydorni-like occysts between 7 and 10 days after ingesting naturally infected muscles from a moose. These results indicate thatH. heydorniinfects goats, sheep, moose and coyotes in addition to cattle and dogs.
The isolation and characterization of human and bovine strains of Babesia divergens from Drumnadrochit, Scotland
Authors: Lewis D. , Purnell R. E. , Shaw S. R. , Revington J. P.
Published: June 2009

Strains of Babesia divergens of human and bovine origin were isolated from the same locality in Scotland. A morphometric comparison was then made between Babesia divergens parasites in blood smears made from groups of 3 splenectomized calves reacting to the inoculation of these strains. The various forms taken by the parasites of each strain were seen to be divisible into 7 categories and representatives of each category were found for each strain. More amoeboid forms were found in blood smears from calves infected with the strain of bovine origin but otherwise the frequencies of occurrence of different forms coincided. The dimensions of 3 forms of the parasites of each strain were compared and theparasites of human origin were found to be significantly larger. The reactions of the groups of calves to inoculation of the 2 strains of B. divergens were seen to be very similar, although inoculation of the bovine strain had a slightly greater effect on the animals' haematology as indicated by an increase in erythrocyte mean corpuscular volume.
Analysis of proteins synthesizedin vitroby the erythrocytic stages ofPlasmodium knowlesi
Authors: McColm A. A. , Shakespeare P. G. , Trigg P. I.
Published: June 2009

Studies were performed to identify specific parasite proteins synthesized withinPlasmodium knowlesi-infected rhesus erythrocytes. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of whole parasites freed from the host erythrocyte by immune lysis, of membranous and cytoplasmic parasite fractions, and of isolated merozoites, detected several parasite-specific components after Coomassie Blue staining of the separated proteins. However, significant contamination with host erythrocyte material generally occurred, particularly in the whole parasite and parasite membrane preparations. Improved identification of plasmodial proteins was subsequently afforded by a radioisotope labelling technique in which parasitized erythrocytes were cultivatedin vitrowith [3H] isoleucine prior to electrophoretic analysis. Of 11 principal labelled peaks ranging in molecular weight from approximately 17000 to 145000 which were detected upon electrophoresis of whole parasites harvested from culture, all were observed in the cytoplasmic fraction while at least 5 were also associated with the membranous cell fraction. Analysis of different developmental stages of the intra-erythrocytic parasite revealed no significant stage-specific qualitative variations in the electrophoretic profiles. Quantitatively, however, the middle to late trophozoites incorporated more [3H] isoleucine into protein than the other intra-erythrocytic stages. Analysis of merozoites purified from labelled schizonts showed a protein pattern similar to the other stages. This confirmed that host components did not contribute to the labelling pattern and that none of the labelled proteins were specific to the residual cytoplasm remaining after merozoite formation.
Release of radio-isotope labelled antigens fromPlasmodium knowlesiduring merozoite re-invasionin vitro
Authors: McColm A. A. , Trigg P. I.
Published: June 2009

Labelled antigens sharing determinants with both membrane and cytoplasmic fractions ofPlasmodium knowlesiwere detected in culture medium afterin vitroincubation of schizont-stage parasites previously pulse-labelled with [3H]isoleucine. Release of antigens occurred only during schizont rupture and merozoite re-invasion. Antigenic material accounted for up to a third of the total trichloroacetic acid-insoluble radioactivity released by the cells. Absorption experiments indicated that approximately two-thirds of this antibody-precipitable material shared determinants with parasite membrane antigens, with a similar quantity sharing determinants with cytoplasmic proteins. Using antisera derived against 2 different antigenic variants ofP. knowlesi, no evidence for the release of variant-specific antigens was obtained. Centrifugal analysis revealed that the majority of the radio-isotope labelled antigens were particulate in nature; however, some appeared to exist in true solution.
The contribution ofAscaris lumbricoidesto malnutrition in children
Authors: Stephenson Lani S.
Published: June 2009

There is a need for more applied and experimental research to determine more precisely the relationships between nutrition, particularly childhood malnutrition, and intestinal parasitic infections, particularlyAscarisinfection. Nevertheless, it is clear that in certain communitiesAscarisinfection is associated with poor growth in malnourished children and that deworming improves growth. Periodic deworming of children using a mass treatment approach may be needed to control soil-transmitted helminths in areas where parasites and protein energy malnutrition are highly prevalent. The main aims of treatment should be to reduce parasite loads below the level of clinical significance for the individual child and to reduce future environmental contamination with infective faeces for the sake of the community.
Schistosoma mansoni: development of primary infections in mice genetically deficient or intact in the fifth component of complement
Authors: Ruppel A. , Rother U. , Diesfeld H. J.
Published: June 2009

The influence of the late components of complement (C) on percutaneous primary infections withSchistosoma mansoniwas studied in inbred mice genetically deficient or intact in C5. Worm recoveries were diminished in C5-deficient male mice as compared to C5-intact animals. Twenty-four-day-old parasites were also shorter following growth in C5-deficient animals. At 7 weeks after infection, female schistosomes, but not male parasites, were shorter and fewer eggs/schistosome pair were deposited in the livers of C5-deficient as compared to C5-intact male mice. In addition to the presence of C5, the mouse sex was found to influence the outcome of an infection. Schistosomes showed a reduced infection rate and were relatively stunted after 24 days of growth in female mice of the two strains as compared to male mice of the corresponding strains. The results suggest that C5 plays no role in defence against a primary infection in mice.
Processes influencing the distribution of parasite numbers within host populations with special emphasis on parasite-induced host mortalities
Authors: Anderson R. M. , Gordon D. M.
Published: June 2009

The paper examines the factors which generate various patterns of dispersion in the distribution of parasites within their host populations. Particular emphasis is placed on the role played by chance elements in the growth and decay of parasite populations and on the influence of different types of demographic processes. It is argued that observed distributions are dynamic, rather than static, entities generated by opposing forces, some acting to create over-dispersion and others acting to generate under-dispersion. Monte Carlo simulation experiments, based on probability models of the growth and decay of host and parasite populations, are used to study the dynamics of parasite dispersion. Attention is specifically focused on the role played by parasite-induced host mortality. It is shown that, for certain types of host–parasite associations, convex curves of mean parasite abundance in relation to age (age-intensity curves), concomitant with a decline in the degree of dispersion in the older age classes of hosts, may be evidence of the induction of host mortality by parasite infection. Empirical evidence is examined in light of this prediction. In general, however, simulation studies highlight the technical difficulties inherent in establishing clear evidence of parasite-induced host mortality from ecological studies of hosts and parasites in their natural habitats.
Analysis of six serum components from rats infected with tetrathyridia ofMesocestoides corti
Authors: Chernin J. , Morinan A.
Published: June 2009

The serum from rats infected intraperitoneally (i.p.) and subcutaneously (s.c.) with the tetrathyridia ofMesocestoides cortiwas analysed for α-amylase, alkaline phosphatase, γ-glutamyltransferase, glucose, corticosterone and total proteins. A histochemical analysis for hepatic alkaline phosphatase was also carried out. A significant decrease in activity of serum alkaline phosphatase was detected in both the i.p. and s.c. infections, whereas a large increase in hepatic alkaline phosphatase was observed in i.p. infections. A significant increase in serum cortiscosterone was found in both the i.p. and s.c. infections. No changes were detected in the other four components. The relevance of these findings is discussed with respect to the host–parasite relationship.
The pathogenicity and development within the host fish of Myxobolus cyprini Doflein, 1898
Authors: Molnar Kálmán , Kovács-Gayer Éva
Published: June 2009

Myxobolus cyprini has, until now, been considered an ‘organo-cosmopolitan’ parasite of the common carp (Cyprinus carpio) and less frequently of other carps, producing spores in various organs in small plasmodia and possible in cysts. The present observations of naturally infected common carp fry and two-summer carp have revealed that M. cyprini is a specific muscle parasite, developing intracellularly in the muscle fibres of the skeletal muscle. The sarcoplasm of the infected muscle fibres is filled with developmental stages, followed by spores of M. cyprini, which are held together in a 1–1·5 mm long pseudocyst by the sarcolemma of the muscle fibre. After maturation of the spores and disintegration of the pseudocysts the spores are transported in the bloodstream to different parts of the body where they are retained in the capillaries.
The isotypes of antibody responsible for the ‘late’ passive transfer of immunity in rats vaccinated with highly irradiated cercariae
Authors: Ford M. J. , Dissous C. , Pierce R. J. , Taylor M. G. , Bickle Q. D. , Capron A.
Published: June 2009

The roles of different antibody isotypes in the transfer of protection with serum from rats vaccinated with irradiated cercariae were investigated by immunoadsorption of IgG, IgG2a and IgG2c, and by heating at 56°C to remove IgE. Only depletion of IgG2a reduced the levels of vaccine-induced immunity transferred, whereas immunity transferred by infection serum was reduced by both IgG2a and IgE depletion. It was also shown that exposure to irradiated parasites did not lead to either specific or non-specific induction of an IgE response. The successful passive-transfer experiments using serum from non-resistant 25 week-infected rats into recipient animals demonstrated that the waning of resistance observed in 25 week-infected rats was not due to a failure of the humoral response to protective antigens.
Characterization of surface proteins and glycoproteins on red blood cells from mice infected with haemosporidia:Babesia rodhainiinfections of BALB/c mice
Authors: Howard R. J. , Smith Patricia M. , Mitchell G. F.
Published: June 2009

Infection of intact (nu/+) or hypothymic (nu/nu) BALB/c mice with the lethal intra-erythrocytic parasite,Babesia rodhaini, induced several changes in the surface proteins of red cells from infected blood. Lactoperoxidase-catalysed radio-iodination was used to compare the surface proteins on normal mouse erythrocytes and the total red cells from infected blood at different levels of parasitaemia. At very low parasitaemia, when only 2·5% of the red cells contained parasites, we observed significant changes in the profile of radio-iodinated proteins separated by SDS-polyacrylamide gel electrophoresis. These changes included the appearance of a group of high molecular weight proteins, and a protein with an apparent molecular weight (Mr) of 60 000, both of which were absent from normal erythrocytes. The major labelled band on the erythrocyte surface (Mr92 000) also appeared to be less heavily labelled during infection. The magnitude of these differences in surface proteins increased as the parasitaemia rose, until the new bands dominated the radioactivity profile with blood of greater than 50% parasitaemia. Several control experiments established that the radio-iodinated proteins were surface molecules on intact cells and that artifactual proteolysis did not contribute to the observed differences. The results suggest that changes in the surface proteins occur onallred cells in the blood of infected mice. The results of labelling the surface glycoproteins by oxidation with periodate or galactose oxidase, followed by NaB3H4reduction, have varied with the isolate ofB. rodhaini. With the isolate currently in use, no significant differences were observed in the labelled surface glycoproteins of normal erythrocytes and red cells from infected blood of high parasitaemia, whereas an earlier isolate exhibited a marked decrease of glycoprotein labelling of both infected and uninfected red cells.
Characterization of surface proteins and glycoproteins on red blood cells from mice infected with haemosporidia:Plasmodium bergheiinfections of BALB/c mice
Authors: Howard R. J. , Smith Patricia M. , Mitchell G. F.
Published: June 2009

The surface proteins and glycoproteins of red cells fromPlasmodium berghei-infected blood have been radio-isotope labelled and compared with those of normal mouse erythrocytes using the following protein labelling probes: lactoperoxidase-catalysed radio-iodination of tyrosyl residues, periodate oxidation and NaB3H4reduction of sialic acid and oxidation of galactosyl/N-acetylgalactosaminyl residues by galactose oxidase with subsequent NaB3H4reduction. DuringP.bergheiinfection, new tyrosyl-labelled proteins with apparent molecular weights (Mr) of 60000, 54000, 40000 and 27500 appeared on the surface of most, if not all, red cells in the blood. Purified multinucleate cells (mostly reticulocytes) differed only in that they also had a surface protein withMrof 83000. However, this molecule is thought to be specific to mouse reticulocytes rather than derived from parasites. In contrast to the relatively minor changes detected with radio-iodination, striking changes inglycoproteinradio-isotope labelling resulted from infection. All of the red cells in infected blood of greater than 20% parasitaemia lost their periodate-sensitive glycoprotein sialic acid. With some samples there was little change in glycoprotein labelling by the galactose oxidase method, provided neuraminidase was also added. Modification of the exocyclic hydroxyls of sialic acid is postulated to account for this. Other blood samples exhibited a dramatic loss of galactose oxidase-dependent labelling. It is suggested that these observations may relate to the excessive red cell destruction of uninfected as well as infected cells which has been inferred in many haemosporidial infections, including malaria.
Characterization of surface proteins and glycoproteins on red blood cells from mice infected with haemosporidia:Plasmodium yoeliiinfections of BALB/c mice
Authors: Howard R. J. , Smith Patricia M. , Mitchell G. F.
Published: June 2009

Lactoperoxidase-catalysed radio-iodination was used to compare the surface proteins on red cells fromPlasmodium yoelii-infected and normal BALB/c mice. The profile of radio-iodinated proteins separated by SDS-polyacrylamide gel electrophoresis was different for infected blood of similar parasitaemia from mice inoculated with different doses of the parasite. Inoculation with the lower dose resulted in the appearance of a major radio-iodinated protein of apparent molecular weight (Mr) 76000 which was labelled to a similar extent on uninfected red cells from infected blood and purified multinucleate infected cells. Several minor radio-iodinated bands, with identical mobilities to the minor bands on normal BALB/c erythrocytes, were also present on red cells from this infected blood. In contrast, the higher inoculation dose produced changes in the minor labelled bands, and the band withMrof 76000 was absent. In this case, the minor radio-iodinated proteins of the normal BALB/c erythrocyte (with Mr of 65000, 57000, 48000, 38000 and 32000) were replaced by a series of bands withMrof 60000, 50000, 43000 and 28000 on both uninfected and infected red cells. These differences with inoculation dose may be related to the different duration of these infections, the development of anaemia and the extent of pathological changes at the erythrocyte surface.P. yoeliiinfection caused a marked loss in periodate-dependent labelling of sialoglycoproteins on most, if not all, red cells in infected blood. There was also a large decrease in galactose oxidase-dependent glycoprotein labelling with or without neuraminidase treatment. These changes in the carbohydrate groups on red cell membrane glycoproteins may be linked to the excessive loss of both uninfected and infected red cells during some malaria infections.
Copepod parasites ofPsychrolutes(Pisces: Scorpaeniformes) from deep water in the eastern Pacific
Authors: Ho Ju-Shey
Published: June 2009

Chondracanthus yaneziAtria andNeobrachiella amphipacificasp. nov. are described based on material collected fromPsychrolutes phrictusStein and Bond trawled off northern California.N. amphipacificais also recorded fromPsychrolutes sioNelson trawled off northern Chile. Both host species are deep water forms ofPsychrolutes.
The importance of parasite load in the killing ofPlasmodium vinckeiin mice treated withCorynebacterium parvumor alloxan monohydrate
Authors: Cox F. E. G. , Millott Stephanie M.
Published: June 2009

Mice pre-treated withCorynebacterium parvumand later challenged withPlasmodium vinckeibecome infected but do not die whereas control mice do. When pre-treated mice were challenged with 1, 10, 1 × 102, 1 × 104, 1 × 105or 1 × 106parasites, the pre-patent periods correlated directly with the number of parasites injected, but the subsequent parasitaemias reached similar levels. This suggests that parasite killing, resulting from pre-treatment withC. parvum, is not triggered until the parasite load has reached a particular threshold. The injection of alloxan monohydrate, which brings about the release of toxic oxygen inter mediates thought to be involved in non-specific immunity, has little effect onP. vinckeiinfections until the parasitaemia is relatively high. This indicates that oxygen-mediated parasite killing also does not occur until the parasitaemia has reached a particular threshold. It is suggested that it is only at relatively high parasitaemias that the factors involved in parasite killing are able to enter the infected red blood cells.