bluuebunny/crossref_metadata_2025 huggingface dataset:
The chemical nature and evolutionary significance of monogenean attachment sclerites
Authors: Lyons Kathleen M.
Published: June 2009

The chemical and physical nature of monogenean attachment sclerites has been investigated by chromatography, histochemistry, solubility studies and X-ray diffraction, and these sclerites have been shown to be scleroproteinaceous and not, as the bulk of the literature suggests, chitinous in composition.

Hooks sclerites (i.e. marginal hooks and hamuli), which are the most primitive type of monogenean attachment sclerites and arise early on ontogeny, have been shown to be keratinous; clamp sclerites, accessory bars and the spines arming the pseudohaptors and squamodisks of certain genera which appear to have been acquired later in the phylogeny of the group to supplement the efficiency of the haptoral hooks, contain no cystine sulphur.

While the chemical nature of the non-cystine-containing skeletal structures has not been fully elucidated, clamp substance was found to differ from that of the other scleroproteins with which it was compared, namely sclerotin, vertebrate elastin, reticulin, collagen and keratin. Clamp substance does not appear to be quinonetanned; acid proteins maybe important in the stabilization of this scleroprotein.

Evidence for the occurrence of a variety of S–S bearing scleroproteins throughout the invertebrates has been collated and the problems involved in adequately defining a keratin have been discussed. The implications of the apparent affinity of monogenean hook protein to vertebrate keratins, which in general are intracellular and epidermal derivatives have been considered and some speculations have been made about the possible differences in the development of hook and clamp structures.

Contrary to the prevalent opinion that monogenean sclerites are ‘cuticularizations’, evidence has been presented that these structures are in fact deeply seated and unlikely to be derivations of a superficial cuticle.

The chemical differences elucidated between the median and lateral sclerites of the chimaericolid adhesive organ have encouraged speculation on the evolution of the different types of attachment organ throughout the polyopisthocotylineans.

Outside the Monogenea, studies on the sulphur content of digenean spines and stylets and on the larval hooklets of the ‘cestodarians’Gyrocotyle, AmphilinaandArchigetes, and of eucestodes, have helped to substantiate the view that the cestodes and monogeneans are more closely related to each other than either of these groups is related to the digeneans.

I wish to thank the Director and staff of the Plymouth Laboratory and in particular Mr J. E. Green, for invaluable assistance. I am also indebted to Dr R. W. H. Small for his guidance on X-ray diffraction technique, to Dr J. Morris of the M.R.C. Skin Unit for his advice on the chromatography and to Dr J. Llewellyn for his interest and helpful criticism throughout.
Physiological studies on trematodes: phosphatase systems inGastrothylax crumenifer
Authors: Goil Madan M.
Published: June 2009

Biochemical studies on the phosphatase systems ofGastrothylax crumeniferhave been made. The maximum activity of the phosphatase enzyme was found to be at 5 pH. The action of magnesium and fluoride ions on the acid phosphatase activity shows that both act as inhibitors. The day-to-day variation in the phosphatase activity of the samples, as measured by block differences, was found to be significant at different pH levels. The heat denatured extract showed low and fairly constant acid phosphatase activity.
Some Microphallids collected in Kenya
Authors: Canaris Albert G.
Published: June 2009

African representatives in the family Microphallidae (Trematoda) are recorded, and descriptions of five new species are given. Collections made on the Kenya coast showed: (Aves) Crocethia alba infected with Microphallus kenyensis sp.nov.; Encocotyle africanus sp.nov., and Maritrema sethsmithi sp.nov.; Tringa hypoleucos and Numenius phaeopus infected with Diacetabulum curvicolon Belopolskaia, 1952; (Reptilia, Scincidae) Ablepharus boutonii africanus infected with Levinseniella heardi sp.nov., Maritrema sethsmithi sp.nov. and Maritreminoides ablephari sp.nov.

Patti Hirst and Alma Smith assisted with preparation of the plates. R. W. Heard III and S. Deblock loaned material and made helpful comments on the reproductive structures in the genus Levenseniella.
Studies on gut ultrastructure and digestive physiology in Cosmocerca ornata (Nematoda: Ascaridida)
Authors: Colam J. Barry
Published: June 2009

Histological, histochemical and ultrastructural methods have been used to study gut structure and digestive physiology in Cosmocerca ornata (Dujardin, 1845). The nematode is parasitic in the small intestine and rectum of Rana temporaria, and feeds solely upon the gut contents of the host, primarily bacteria and cellular debris rather than fluid material.

Only a small buccal capsule is present and no host tissue is ingested. Rigid channels at the tips of the oesophageal radii and a spiral arrangement of the corpus lumen are probably concerned in expressing any fluid in the food while retaining the particulate matter. The latter is then shredded by three large valvular flaps projecting into the lumen of the posterior oesophageal bulb. One gland is present in each sector of the bulb. There is some evidence that two secretions are produced in each subventral sector, an electron-dense one posteriorly which is released into the lumen below the valve flaps, and an electron-lucid one synthesized more anteriorly which is released in the anterior region of the bulb. Only one secretion is produced in the dorsal gland, similar to that in the anterior subventral sector, and which is poured into the lumen of the posterior corpus. The intestine is not differentiated into distinct regions and contains no gland cells. A prominent striated border of microvilli is present, varying from 25 μm in the foregut to 0·5 μm in the hindgut. They have a prominent core composed of minute fibrils and an outer glycocalyx covering.

Digestion is entirely extracellular, bacteria and cellular debris in the ingesta being broken down by a C-esterase present in the oesophageal gland secretions. It is completed by a process of contact digestion with the same enzyme adsorbed on to the glycocalyx. Acid phosphatase, also produced by the oesophageal glands and present on the microvilli, may be concerned in the absorption of the resultant digestion products and any simple solutes in the food made available by host extracellular enzymes. GER and free ribosomes present in the distal regions of the gastrodermis are probably concerned in the assimilation of the absorbed materials into glycogen which is stored in large quantities in the gastrodermis.

This investigation was supported in part by Research Grant AI 06295 of the United States Public Health Service. The final manuscript was prepared during the tenure of a Postdoctoral Fellowship from the British Egg Marketing Board.
Host specificity in Schistocephalus solidus
Authors: Bråten Trond
Published: June 2009

Investigations on the host specificity of plerocercoids of Schistocephalus solidus were carried out using the technique of surgically transferring plerocercoids from the body cavity of Gasterosteus aculeatus to various other fish. Plerocercoids survived in all cases when transferred from G. aculeatus to other G. aculeatus; when tranferred to Pungitius pungitius the worms survived for long periods but failed to grow. Plerocercoids transferred to Coitus gobio, Nemacheilus barbatula, Phoxinus phoxinus, Salmo trutta, Coregonus clupeoides, Perca fluviatilis, Rutilus rutilus and Esox lucius always died within 2–10 days after being transferred. Electron-microscopic examinations of the tegument of plerocercoids transferred to new hosts showed: in G. aculeatus normal appearance throughout the experiment; in P. pungitius degeneration of the microtrichs after 6 days; and in S. trutta complete destruction of the tegument in 7 days.

Plerocercoids of the genus Diphyllobothrium survived the transfer from Gasterosteus aculeatus to Salmo trutta and continued to grow in their new host.

Infection of fish with S. solidus by feeding infected copepods and by aspetic injection of procercoids into the body cavity of the fish were also tried. Gasterosteus aculeatus became infected using both these methods but it was not possible to infect Pungitius pungitius.
The dynamics of the host–parasite relationship
Authors: Wagland B. M. , Dineen J. K.
Published: June 2009

A group of thirty-nine Merino-Border Leicester cross-bred lambs were given six sensitizing doses each of 3000 infective Haemonchus contortus larvae. Previous studies showed that this treatment produced a state of immunological exhaustion (Dineen & Wagland, 1966a). In the present study the regeneration of the immunological response was followed by challenging the sensitized animals and previously uninfected control animals with 3000 infective larvae at 2, 4, 8 and 16 weeks after termination of the sensitizing infections with an anthelmintic. Faecal egg counts were carried out on infected animals twice weekly throughout the course of the experiment, and differential worm counts were performed on groups of animals slaughtered 48 days after challenge.

The results show that maximum regeneration of the immune response occurred when periods of 4 and 8 weeks were permitted to elapse between removal of the sensitizing infections and challenge. At 16 weeks the response of the sensitized animals to challenge infection was not significantly different from that of the control animals.

In contrast to results recorded in the previous communication, a high mortality (49%) occurred among the sheep during sensitization. In the earlier experiment the sensitizing infections were given at fortnightly intervals whereas they were given at weekly intervals in the present experiment.

Interpretation of the study is based upon the threshold behaviour of immunological responsiveness in parasite immunity, the occurrence of an immunological latent period and the relationship of this period to the developmental rate of the parasite, the susceptibility of the 4th larval stage to immunological attack, and the immunological privilege of the adult worm. These phenomena have been described in previous communications in the present series.

We are greatly indebted to Mr Emil Teleki and Misses Helen Giller and Lindy Stothart for their excellent technical assistance.
Eimeria phasiani Tyzzer, 1929—a coccidium from the pheasant (Phasianus colchicus). II. Pathogenicity and drug action
Authors: Trigg P. I.
Published: June 2009

Eimeria phasiani was shown to be pathogenic to young pheasant poults. Doses of 100000 or more oocysts proved fatal to birds up to 3 weeks old. Lesser doses produced losses in the live-weight gain of the host.

Two separate strains of E. phasiani were completely susceptible to 0·006% (w/w) Sulphaquinoxaline, but less so to 0·006% (w/w) Amprolium and 0·0125% (w/w) Zoalene.

I should like to express my sincere gratitude to Dr E. U. Canning for her supervision and helpful advice, and to Professor O. W. Richards, F.R.S., for permission to work at the Imperial College Field Station. I am also grateful to Mr T. H. Blank, of the Eley Game Advisory Service, Fordingbridge, Hants, who gave day-old pheasant chicks for this study.

The work was financed by a scholarship from the Agricultural Research Council.
The function and ecological significance of the pharyngeal ridges occurring in the larvae of some cyclorrhaphous Diptera
Authors: Dowding Valerie M.
Published: June 2009

The anatomy and function of the pharyngeal ridges, which occur in the larvae of saprophagous Cyclorrhapha but are generally absent in biontophagous forms, were investigated.

The ridges extend throughout the length of the ventral aspect of the pharynx and lie in an evagination of its floor. They enclose channels which narrow and disappear posteriorly but are open anteriorly. Each ridge consists of a longitudinal plate projecting dorsally from the floor of the pharynx, the bifurcated upper edge of the plate bears, one on each side, a row of lateral lamellae, each about 0·3 μm thick. They are set vertically at regular intervals of just less than 1 μm. The lateral lamellae of adjacent ridges are closely apposed and completely roof over the channels between the ridges. Anteriorly the upper arms of the ridges are fused together.

The lamellae form a sieve which retains particles of 0·6 μm and above in size as the relaxation of the pharyngeal dilator muscles allows the roof to descend so forcing liquid downward between the lamellae. InCalliphora vicina(Syn.C. erythrocephala) the sieve concentrates a suspension of 2700 particles of 4–7 μm per mm3between five and six times. The natural food consists largely of bacteria.

Fungus spores and pollen grains of selected sizes were used to demonstrate the movements of particulate material in the pharynx and to define the upper size limit of the particles ingested.

Swallowing is effected by simultaneous relaxation of the anterior dilator and transverse muscles of the pharynx, with contraction of the posterior dilator muscles; the transverse muscles are otherwise maintained in a state of contraction closing the posterior exit from the pharynx.

Starved third-instar larvae ofC. vicinacan ingest 50% of their body weight in 6 min.

The larvae of the Cyclorrhapha which possess pharyngeal ridges are essentially particle feeders. The ridges form a sieve by means of which food is concentrated and the amount of non-nutritious liquid ingested is reduced. The lack of pharyngeal ridges in larvae feeding on living material is correlated with the constant and high nutritive value of both the solid and the liquid fractions of the food.

I should like to thank Dr P. Tate for his help and encouragement during the course of this work which was carried out during the tenure of a Postgraduate Studentship awarded by the Agricultural Research Council. Thanks are also due to the staff of the Plant Pathology subdepartment of the Botany School, Cambridge, for their help in obtaining fungus spores of suitable sizes.
Basic concepts and new aspects of vaccine development
Authors: Roitt I. M.
Published: June 2009

I wish to thank the Society for inviting me to give the Introductory Talk in this Symposium. It is going to centre around what might be called ‘epitope specific’ immunization and I want to draw your attention to a number of factors which will be bound to affect any new approach to the development of vaccines. To begin with, it is now clear that complex antigens, such as those associated with parasites, present many different epitopes to the immune system. These epitopes are ‘seen’ by different cell types using different receptors and epitope recognition can activate a number of different effector systems.
An update on candidate malaria vaccines
Authors: Mitchell G. H.
Published: June 2009

The purpose of this work is to review the progress towards malaria vaccination that has been made over the last four or so years, and the prospects and difficulties as they now appear. Although some of the older literature will be referred to as necessary background, it is not treated here in any detail. The reader who wishes for a fuller historical perspective should see, for instance, Brown (1969), Cohen & Mitchell (1978), Desowitz & Miller (1980), Mitchell (1984), Miller, David & Hadley (1984), Heidrich (1986) and, specifically for a consideration of sporozoite vaccination, Nussenzweig & Nussenzweig (1984, 1986). Naturally, any summary of vaccination will lean on the immunology of the disease, but malaria immunology is not reviewed here in its own right. The reader requiring the most recent attempt to cover this field should see the work edited by Perlmann & Wigzell (1988); some individual chapters of that volume will be referred to below.
Sterile immunity, coinfectious immunity and strain differences in Babesia bigemina infections
Authors: Callow L. L.
Published: June 2009

The acquired immunity of twenty-eight splenectomized and twenty-three intact cattle following primary inoculation with either of two strains (the Y and the R strain) of Babesia bigemina was investigated. Some of these animals were carriers, while others had ceased to be infected. Observations were made on the response of splenectomized animals challenged up to four times with the original infecting (homologous) strain and finally with the heterologous strain.

In the splenectomized animals, a total of sixty-three homologous challenges produced parasitaemias in only twenty-seven instances, and these were generally delayed and of lower intensity than in control animals. Fifteen negative transmission tests performed shortly after thirty-two challenges showed that it was difficult to re-establish the homologous strain in some animals that had achieved self-cure. Substantial homologous immunity had developed within 16 weeks of the primary infection in animals which were no longer carrying B. bigemina.

All twenty-one splenectomized animals subjected to heterologous challenge developed well-marked parasitaemias. Nine of these had been highly immune to homologous challenge 2 weeks earlier. Eight of the twenty-one were carriers at the time of challenge and these showed much lower parasitaemias than the self-cured animals which almost invariably were acutely affected.

Challenges of twenty-three intact steers confirmed that the two strains differed immunologically. Six of twelve challenged homologously failed to show detectable parasitaemia, whereas all eleven challenged heterologously developed parasitaemias.
Studies onSchistocephalus solidus
Authors: Sinha D. P. , Hopkins C. A.
Published: June 2009

The growth rate ofSchistocephalus soliduswas measured in culture at 4°, 7°, 12°, 17°, 23°, 27°, 30°, 33°, 35° and 40 °C. Between 7° and 23 °C the rate of growth increased nearly exponentially, with aQ10of 3·6. Between 23° and 27 °C growth rate was maximal; above 27 °C, after 8 days in culture, weight increase was shown only by worms which were too small to mature. Even in these worms the weight increase was very small and was probably due to partial maturation which occurs from 30 °C upwards. The larger the plerocercoid and the higher the temperature up to 40 °C the bigger the percentage weight loss, due to earlier maturation.

Incubation of plerocercoids for 4 days at 35 °C, although inducing maturation and suppressing somatic growth, did not destroy the ability of the worm to grow when returned to 23 °C.

Two hypotheses to explain the pattern of morphogenesis inSchistocephalusplerocercoids and adults are propounded; the evidence favours the existence of two enzyme systems, one controlling somatic growth with peak efficiency near 23 °C and the other controlling maturation with peak efficiency near 40 °C.

The authors gratefully acknowledge financial support for this work from Shell International Petroleum Company Limited. It is also a pleasure to thank Miss Patricia Grant for technical help.
Metaclevelandella termitis, a new genus and species of Heterotrichous ciliate (family Clevelandellidae) found in the Indian termite Capritermes incola Wasm.
Authors: Uttangi J. C. , Desai R. N.
Published: June 2009

The paper records the description of the morphology and taxonomy of a new genus and species of a Heterotrichous ciliate (family Clevelandellidae) found in the gut of the non-xylophagous termite Capritermes incola Wasm. (Termitidae) from Dharwar (India).
Two new species of the genus Amplicaecum Baylis from Malayan amphibians
Authors: Yuen P. H.
Published: June 2009

This paper records two new species of Amplicaecum from Malayan amphibians for which the following names are proposed: Amplicaecum communis sp.nov. and A. sandoshami sp.nov. A. communis is a common parasite in a number of Malayan amphibians, but A. sandoshami has been found only in Megophrys sp.
Amblyomma calabyi n.sp. from Western Australia (Acarina: Ixodidae)
Authors: Roberts F. H. S.
Published: June 2009

The new species of Amblyomma described in this paper was collected and forwarded to the author for identification by Mr J. H. Calaby, Wildlife Section, C.S.I.R.O. This is the fourth species of the genus to be recorded from Western Australia, the others being A. australiense Neumann, A. albolimbatum Neumann, and A. triguttatum Koch (Roberts, 1953).
A morphological and biometrical study of the blood forms ofTrypanosoma suisOchmann, 1905
Authors: Stephen L. E.
Published: June 2009

The status ofTrypanosoma suiswas held in doubt from the time it was first seen in 1905 until it was re-discovered and carefully studied in the Belgian Congo in 1954.

A description is given of the morphology of single and dividing forms ofT. suisas seen in stained thin films made from the blood of infected pigs, and a selection of these is illustrated by line drawings. Briefly this trypanosome is short and stumpy with a free flagellum.

A biometrical study was made on 200 organisms, showing a normal length distribution with a range from 8·5 to 18·5μ, and mean = 14·43μ.

The monomorphism of the trypanosome is verified, and—because of its development in the salivary glands ofGlossina—its systematic position as a monomorphic subgroup of theBruceigroup is confirmed.

I am much indebted to Dr C. A. Hoare, F.R.S., for the loan of the blood films used in this study and for his interest in the work. I am also grateful to Professor P. C. C. Garnham for providing me with accommodation and equipment at the London School of Hygiene and Tropical Medicine.
The life cycle of the monogeneanEntobdella soleae, a skin parasite of the common sole
Authors: Kearn G. C.
Published: June 2009

The life cycle ofEntobdella soleae, a monogenean skin-parasite of a marine bottom-living flatfish (Solea solea) has been described and related to the habits of the host, which buries itself in the sediment for some time each day and when not buried rarely moves more than a few centimetres from the sea bottom.

The eggs of the parasite are laid by specimens attached to the lower surface of the host and are anchored to sand grains on the sea bottom by an egg stalk bearing sticky droplets. The anchoring device may prevent the eggs from being carried by water currents vertically or laterally out of the region inhabited by soles.

The free-swimming oncomiracidium which hatches from the egg invades the anterior part of the upper surface of the fish, which is the only part exposed when the fish is buried in the sand. After a short period of development on the upper surface the parasite emigrates to the lower surface where sexual maturity is reached.

Adult parasites, which are distributed randomly on the lower surface, are orientated with the adhesive organ upstream with respect to water currents produced by the forward locomotion of the host, but the parasites are capable of moving from place to place on the lower surface of the fish. This movement of the parasite may be connected with the nature of the food.

I wish to thank the Director and Staff of the Plymouth Laboratory and in particular Mr J. E. Green, for invaluable assistance. I am also very grateful to Dr J. Llewellyn for advice and criticism. The work was conducted during the tenure of a Fishery Research Training Grant from the Development Commission.
The evolutionary biology of parasitism: Preface
Authors: Keymer A. E. , Read A. F.
Published: June 2009

Parasitism was recognized as a potent evolutionary force by Haldane as early as 1949 but was then largely ignored by evolutionary biologists until the mid-1970s. Interest has since been rekindled, and parasites have now been attributed major roles in areas of evolutionary biology as fundamental and diverse as social behaviour, sexual reproduction, ornamentation and speciation. These ideas have their roots in evolutionary theory, and parasitologists have as yet contributed little to their development and testing. Likewise, evolutionary biologists have been slow to assimilate the parasitological literature. This year's BSP Autumn Symposium was thus organized with the aim of promoting constructive interchange between the two disciplines.
Reproduction in the daughter sporocyst of Cercaria bucephalopsis haimeana (Lacaze-Duthiers, 1854) (Bucephalidae) and Cercaria dichotoma Lebour, 1911 (non Müller) (Gymnophallidae)
Authors: James B. L. , Bowers E. A.
Published: June 2009

The germ-cell cycle and method of reproduction in the daughter sporocysts of the bucephalid Cercaria bucephalopsis haimeana (Lacaze-Duthiers, 1854) and the gymnophallid Cercaria dichotoma Lebour, 1911 (non Müller) from the edible cockle, Cardium edule L., have been investigated by the examination of stained sections. A review is given of the principal interpretative theories which attempt to explain the nature of the reproduction and the homology of the germinal sacs of the Digenea. It is suggested that the life-cycle includes a cyclic alternation of homologous generations. Of these, the miracidium/mother-sporocyst and the daughter germinal-sac generations usually reproduce by apomictic parthenogenesis but polyembryony may also occur secondarily in some species.

We are very grateful to Dr Gwendolen Rees and Professor E. W. Knight-Jones for considerable help with the manuscript.
Electron-microscope studies of Fasciola hepatica II. The interrelationship of the parenchyma with other organ systems
Authors: Gallagher S. S. E. , Threadgold L. T.
Published: June 2009

The structural relationship between cells of the parenchyma and those of the alimentary and excretory systems, and tegument are described.

Junctional complexes are formed in areas of close cell apposition. They occur laterally on invaginations of parenchymal processes which are embedded in the epithelial cells of the alimentary and excretory systems, and on flat plaques between parenchymal cells and the tegument.

The ultrastructure of the complexes has been resolved and a three-dimensional interpretation is put forward. It is suggested that the complex is a type of desmosome.

The findings reported here add support to the suggestion made in a previous paper that the parenchyma may function as a transport system in this fluke.

We wish to acknowledge grants from the Wellcome Trust and the S.R.C. for the purchase of an Akashi TRS 50 and an A.E.I. EM 6B electron-microscope respectively. This research and that reported in a previous paper were carried out while one of us (S.S.E.G.) was in receipt of a Training Studentship Grant from the Wellcome Trust.

We also wish to thank Mr W. Ferguson and Mr A. Lyness for photographic and technical assistance.
The in vitro effect of hexachlorophene on some enzymes in the liver fluke, Fasciola hepatica L.
Authors: Thorsell Walborg
Published: June 2009

The effect of hexachlorophene, a fasciolicide, on some enzyme systems in the liver fluke was studied. The enzymes were adenosine triphosphatase, succinate oxidase and cholinesterase. Adenosine triphosphatase was activated, whereas succinate oxidase and cholinesterase were inhibited when homogenized flukes were incubated in some concentrations of hexachlorophene. Of the three enzyme systems studied in flukes killed by hexachlorophene, only the succinate system showed reduced activity, whereas the other two showed almost normal activities. The study indicates that biochemical changes are associated with the effect of hexachlorophene on the liver fluke.

Thanks are due to Dr C. Grant for critical examination of the language, to Miss Maarja Kippar for valuable help with the experiments and to Mrs Astrid Holmström for the typing of the manuscript.

This work was supported by grants A 1108/B 904 and A 1635/B 1299 from Jordbrukets Forskningsråd.
The course of infection and egg production ofPolymorphus minutus(Acanthocephala) in domestic ducks
Authors: Crompton D. W. T. , Whitfield P. J.
Published: June 2009

Laboratory infections ofPolymorphus minutusin domestic ducks have been studied, and the parasites have been found to move posteriorly for a distance of about 4% of the host's intestinal length during the course of the infection.

No evidence has been found for male and female worms having different attachment zones.

Worms which had become attached anterior to a position 60% along the intestinal length were considered to be more likely to move or be expelled from the host before other worms in the population.

Growth of male and female worms was studied by weight measurements. The growth rates of worms of both sexes are similar during the first week of the infection, but by the third week the weight of female worms is more than twice that of male worms.

Mature eggs were first found in the host's faeces from 22 to 25 days after the beginning of the infection. Egg release continued for a variable period depending on the number of female worms present in the host.

The average peak rates of egg production were 1700, 2000 and 700 eggs/day/ worm for the three cases studied.

Eggs were estimated to remain for 50–100 min in the duck's intestine after being released by the worms but before being passed out of the host.

The introduction of a Perspex cannula into the small intestine of a domestic duck does not disturb the environment ofP. minutus.

We are most grateful to Dr R. C. Campbell, School of Agriculture, University of Cambridge, for all his help and advice about the statistical analysis employed in this work, to Mr J. A. F. Fozzard, Department of Anatomy, for taking the radiograph, to Dr P. Tate for helpful discussions, and to the S.R.C. for a grant for P.J.W.
Fluorescent lipid uptake and transport in adult Schistosoma mansoni
Authors: Moffat D. , Kusel J. R.
Published: June 2009

Fluorescent lipophilic compounds can be used to label the surface membrane of Schistosoma mansoni by adding the compound in small amounts of organic solvents to aqueous medium in vitro. Under these conditions it is difficult to follow routes of distribution of the label. Here we have absorbed nitrobenzoxadiazolamine methylamino–(NBD)–ceramides to positively charged Dowex beads, and incubated the labelled beads with living parasites. The NBD–ceramide transfers to the surface membrane as a patch 50–100 μm in diameter, after which the label can be seen localized in the gut and in a very concentrated form in organelles within the oesophageal gland cells. Subsequently the labelled compound can be found in organelles within other body cells, including subtegumental cells. We show that the labelled ceramide has been transported from the patch in the surface membrane through internal membrane systems to the destination in the gut and oesophageal gland and not transported through the gut via the external medium. A different pattern was observed when NBD–cholesterol was used. The pharynx was rapidly labelled when NBD–cholesterol was added in medium with or without serum or attached to red blood cells only. Diffuse labelling of the surface membrane and oesophageal gland occurred. We have demonstrated a novel route of lipid transport within the parasite. The route requires the surface membrane to have very specialized regions to facilitate such transport.
The egg, oncomiracidium and larval development ofEntobdella soleae, a monogenean skin parasite of the common sole
Authors: Kearn G. C.
Published: June 2009

The form of the egg, the structure of the oncomiracidium and the subsequent development ofEntobdella soleae, a monogenean skin parasite of the common sole, are described. The reproductive organs develop in a constant sequence and the parasite is protandrous. Glands of Goto were observed in post-oncomiracidia of all ages.

The early embryo ofE. soleaepossesses eight pairs of marginal hooklets and two pairs of hamuli. One pair of hooklets, centrally situated on the adhesive organ, undergoes metamorphosis and becomes the pair of accessory sclerites associated with the hamuli in the adult.

My thanks are due to Dr J. Llewellyn for continued advice and criticism. The work was conducted during the tenure of a Fishery Research Training Grant from the Development Commission.
The attachment of the monogenean Diplozoon paradoxum to the gills of Rutilus rutilus L. II. Structure and mechanism of the adhesive apparatus.
Authors: Owen I. L.
Published: June 2009

The adhesive apparatus of Diplozoon paradoxum consists of four pairs of clamps and a pair of small hooks which apparently persists from the larval stage. The sclerotized framework which supports each clamp bears great resemblance to that of a Discocotyle clamp but certain differences, particularly in the fair-lead region, may make it mechanically more efficient.

A clamp of Diplozoon paradoxum operates on an extrinsic muscle-tendon-fair-lead-hinged-jaws principle as do the clamps of Discocotyle, Plectanocotyle and Kuhnia. It appears likely that other species of Diplozoon will be found to possess this clamping mechanism despite statements to the contrary.

It is a pleasure to record my thanks to Dr F. G. Rees, University College of Wales, Aberystwyth, for her encouragement and guidance and to Dr J. Llewellyn, University of Birmingham, for his valuable help and critical reading of the manuscript. This work was done while receiving a grant from the Department of Scientific and Industrial Research.
A new species of Lobochona, L. insularum sp.nov. (Ciliata: Chonotrichida) on a gribble from Hawaii
Authors: Matsudo Hitoshi , Mohr John Luther
Published: June 2009

Lobochona insularum sp.nov., a collar ciliate (Chonotrichida), an ectocommensal on the pleopodal bristles of a gribble from Hawaii, is described. L. insularum differs from the previously described chonotrichidan ectocommensals of the gribbles, L. limnoriae on Limnoria lignorum and Lobochona prorates on Limnoria tripunctata, in the outlines of the body and of the marginal lappets of the collar.

This work was supported by a grant from the National Science Foundation. Various facilities were made available by the Allan Hancock Foundation of the University of Southern California.

Acknowledgement is given to Dr Bayard H. McConnaughey, who discovered the organism and prepared the slides.
Host strain, H-2 genotype and immunocompetence do not affect the survival or development of Onchocerca lienalis infective larvae implanted within micropore chambers into mice or rats
Authors: Taylor M. J. , Van Es R. P. , Townson S. , Bianco A. E.
Published: June 2009

The survival, growth and development of Onchocerca lienalis 3rd-stage (L3) larvae implanted into mice within micropore chambers has been studied with a view to developing a vaccination model for studies of protective immunity in onchocerciasis. The influence of host genetics on worm recoveries and development (growth and moulting rate) was analysed in a panel of inbred mice (CBA, BALB/c, DBA/2, SJL, 129J, C57BL/10 (B10), C3H/He and NIH), together with mice of BALB and B10 backgrounds with different major histocompatibility complex (H-2) genes (BALB/c, BALB.K, BALB.B and B10, B10.D2/n, B10.BR, B10.S). Parasite recoveries and development were similar in all mouse genotypes tested. They were unaffected by procedures designed to block or modulate phagocytic cell function with carbon or carrageenan, or to suppress inflammation by treatment with hydrocortisone acetate. A comparison of chambers sealed with membranes designed to admit (5·0 μm pore size) or exclude (0·2 μm pore size) host cells demonstrated no effect on the percentage recovery of living larvae, although dead larvae were more frequently retrieved when cells were excluded. Recoveries and rates of development of larvae implanted into immunodeficient scid mice and athymic Hooded rats were similar to those recorded in immunocompetent controls. We conclude that host genetic factors and immunocompetence are not significant determinants of survival, growth or development of O. lienalis larvae implanted within micropore chambers into naive mice. Despite its limitations, the use of this system merits further investigation as an approach to the study of protective immunity against developing larvae in onchocerciasis.
Comparative studies ofTrypanosoma (Duttonella) vivaxisolates from Colombia
Authors: Dirie M. F. , Otte M. J. , Thatthi R. , Gardiner P. R
Published: June 2009

The characterization of fourTrypanosoma vivaxisolates from Colombia in South America showed that although minor phenotypic differences existed between them, these parasites are antigenically related and belong to a single serodeme. Characterization by isoenzyme assay, karyotyping and DNA probe analysis, showed the Colombian isolates to be more similar to the West African than to KenyanT. vivax. There was, however, little serological cross-reactivity between South American and African groups ofT. vivax. Although theT. vivaxisolates from Colombia were pathogenic for dairy calves which showed the typical sign of progressive emaciation, these parasites failed to infect mice or tsetseand could not be cultivated as bloodstream formsin vitro.This study represents initial attempts to establish the phenotypic and serological diversity amongstT. vivaxisolates from South America.
Temporal changes in glucose and carbohydrate metabolism in the oncospheres of the cyclophyllidean tapeworm, Hymenolepis diminuta
Authors: Pappas P. W. , Durka G. M.
Published: June 2009

When incubated in vitro for 24 h, oncospheres of Hymenolepis diminuta absorb and metabolize radioactive glucose. Between 0 and 12 h post-activation, oncospheres absorb glucose, but glucose is neither metabolized into other carbohydrates nor incorporated into the ethanol-precipitable fraction (which would contain glycogen). Between 12 and 24 h post-activation glucose is incorporated into a number of higher molecular weight carbohydrates that are demonstrable in ethanol extracts of the larvae, as well as the incubation media. Furthermore, measurable amounts of radioactivity are incorporated into the ethanol-precipitable carbohydrate fraction of oncospheres. To determine if these temporal changes in carbohydrate metabolism occurred spontaneously following activation, oncospheres were pre-incubated for 12 h (0–12 h post-activation) in the absence or presence of glucose, and then transferred to media containing radioactive glucose for an additional 12 h (12–24 h post-activation). In these latter experiments, glucose absorption and metabolism between 12 and 24 h post-activation were virtually identical to glucose metabolism in oncospheres that were incubated in radioactive glucose for 0–12 h immediately following activation. Thus, these data do not support the hypothesis that the temporal shift in carbohydrate metabolism occurs spontaneously.
Population genetics and dynamics ofPlasmodium falciparum: an ecological view
Authors: Day K. P. , Koella J. C. , Nee S. , Gupta S. , Read A. F.
Published: June 2009

Molecular characterization of thePlasmodium falciparumgenome has led to identification of polymorphic loci and the mechanisms generating genetic diversity in this parasite. This information has resulted in the development of molecular methods to type parasite diversity in the field. Consequently, we are now in a position to describe the population genetics and dynamics ofP. falciparum. The limited number of field studies that have been conducted to date have revealed an extraordinary degree of genetic diversity in natural parasite populations. Heterozygous recombination which occurs during meiosis appears to be one mechanism for generating genetic diversity. The rate at which such recombination occurs in natural parasite populations defines the genetic structure of the parasite population and can influence the ability of the parasite to respond to selection pressure. The high frequency of single genotype infections and the female-biased gametocyte sex ratios found in hyperendemic malaria areas suggest that self-fertilization occurs frequently. Population- wide surveys of allele frequencies in endemic areas have, however, shown no evidence of linkage disequilibrium and are consistent with a panmictic population structure. We argue that these studies have only sampled symptomatic infections, within which rare or recombinant genotypes may be disproportionately represented. They also take no account of the spatial structure ofP. falciparumpopulations. Systematic investigations of the amount of heterozygosity in small areas as part of population-wide surveys are required to define the genetic structure ofP. falciparumpopulations. Population dynamic studies which consider genetic heterogeneity ofP. falciparumhave shown fluctuations of different serotypes in space and time. The host immune response appears to play an important role in generating these dynamics. Integrated field and laboratory studies, which consider the interaction between population genetics and dynamics, will be necessary to describe the population biology ofP. falciparum.
Ascariasis and childhood malnutrition
Authors: Hlaing Thein
Published: June 2009

The present review will examine epidemiological perspectives and be confined mainly to the results of those field studies published since 1975 in order to provide concrete scientific evidence of the effect of ascariasis on childhood malnutrition, particularly on growth. The field studies were done in many developing countries from Africa, Asia and Latin America, using cross-sectional and intervention studies in which anthelmintics were employed, with different dosing frequency and follow-up periods ranging from 33 days to 2 years. In general, a better nutritional status in terms of growth, lactose tolerance, vitamins A and C, and albumin levels were observed amongAscaris–free or treated than amongAscaris–infected or untreated children even in cross-sectional or non-randomized studies. More importantly, the improvement in weight or height after chemotherapeutic treatment was found to be significant particularly in those randomized controlled studies with an initially high prevalence of ascariasis and malnutrition, a low prevalence of other intestinal parasites, repetitive and regular treatments of children with tetramisole, levamisole or pyrantel, within a period of 12 or 24 months. Reasons for failures to detect improved growth in some studies are provided. This review strongly indicates thatA. lumbricoidesinfection definitely retards childhood growth.
Parasitic infection and chronic energy deficiency in adults
Authors: Shetty P. S. , Shetty N.
Published: June 2009

Interactions between infection and nutrition have been well recognized for several years now since they contribute directly to the health of individuals and communities. Malnourished individuals are specially prone to developing infections while infections themselves can lead to profound changes in the nutritional status of the individual. Health workers in developing countries in the tropics have long recognized the mutually aggravating interactions of malnutrition and infection. The importance of this synergistic relationship between infection and nu-tritional status has been studied extensively in the case of young children. The nutritional status of a young child is a critical determinant of both c morbidity and mortality resulting from a wide range of infections: bacterial, viral, or parasitic. Chandra (1983), in his review on the relationship of nutrition, immunity and infection has categorized the wide range of infectious agents (bacterial, viral, fungal and parasitic) into those that are definitely, variably or minimally influenced by the nutritional status of the child.
Persistence and transmission of tick-borne viruses:Ixodes ricinusand louping-ill virus in red grouse populations
Authors: Hudson P. J. , Norman R. , Laurenson M. K. , Newborn D. , Gaunt M. , Jones L. , Reid H. , Gould E. , Bowers R. , Dobson A.
Published: June 2009

The population dynamics of tick-borne disease agents and in particular the mechanisms which influence their persistence are examined with reference to the flavivirus that causes louping-ill in red grouse and sheep. Pockets of infection cause heavy mortality and the infection probably persists as a consequence of immigration of susceptible hosts. Seroprevalence is positively associated with temporal variations in vectors per host, although variation between areas is associated with the abundance of mountain hares. The presence of alternative tick hosts, particularly large mammals, provides additional hosts for increasing tick abundance. Grouse alone can not support the vectors and the pathogen but both can persist when a non-viraemic mammalian host supports the tick population and a sufficiently high number of nymphs bite grouse. These alternative hosts may also amplify virus through non-viraemic transmission by the process of co-feeding, although the relative significance of this has yet to be determined. Another possible route of infection is through the ingestion of vectors when feeding or preening. Trans-ovarial transmission is a potentially important mechanism for virus persistence but has not been recorded with louping-ill andIxodes ricinus. The influence of non-viraemic hosts, both in the multiplication of vectors and the amplification of virus through non-viraemic transmission are considered significant for virus persistence.
Rate and course of sporulation of oocysts ofEimeria acervulinaunder different environmental conditions
Authors: Graat E. A. M. , Henken A. M. , Ploeger H. W. , Noordhuizen J. P. T. M. , Vertommen M. H.
Published: June 2009

An experiment was conducted to determine the rate and maximum percentage of sporulation ofEimeria acervulinaoocysts at various environmental conditions relating to temperature (21 versus 33 °C) and relative humidity (RH) (40 versus 80%). Measurements were made during 44 h after excretion of oocysts in 3 substrates: dry litter, clammy litter and pure faeces respectively. Maximum sporulation percentage in both dry (22·6%) and clammy litter (19·5%) was higher (P< 0·005) than in pure faeces (11·6%). Neither temperature nor RH had a significant influence on percentage of oocysts that sporulated. Under these simulated practical conditions approximately 25% of all oocysts sporulated, whereas sporulation under optimal conditions (29 °C, aeration, 2% K2Cr2O7) showed a higher (68%) sporulation ability of oocysts. At 33 °C sporulation proceeded at a faster pace than at 21 °C (P< 0·005). With respect to RH and substrate, once sporulation started, the rate of increase to maximum percentage was not different. Time of onset of sporulation was influenced by temperature (P< 0·0001) and RH (P< 0·001). Time of onset occurred 15 h later at 21 °C compared with 33 °C and 5 h later at 40% RH compared with 80%. Also, an interaction effect (P< 0·01) was found with effect of RH being stronger at 21 °C compared with 33 °C. It was concluded that the most important aspect in the epidemiology ofE. acervulinaduring a flock cycle is the time of onset of sporulation with temperature being the most important factor.
Burnellus gen.nov. (Digenea: Fellodistomatidae), the life history of the type-species, B. trichofurcatus (Johnston & Angel, 1940), and a note on a related species, Tandanicola bancrofti Johnston, 1927, both from the Australian freshwater catfish, Tandanus tandanus
Authors: Angel L. Madeline
Published: June 2009

A new trematode, Burnellus trichofurcatus, is described from South Australia from the freshwater catfish, Tandanus tandanus. It appears to have affinities with Monodhelmis Dollfus, 1937 and Mehratrema Srivastava, 1939, but is probably most closely related to Tandanicola Johnston, 1927 (Fellodistomatidae: Tandanicolinae). It is assigned to the Fellodistomatidae Nicoll, 1909, as emended by Cable (1953). Cercaria trichofurcata Johnston & Angel, 1940 is shown to be the larval stage. The cyst stage is omitted from the life cycle, with infection of the catfish occurring directly, probably by mouth. Further comments on developmental stages are given. The sporocyst is not branched, as described by Johnston & Angel (1940). The miracidium of Tandanicola bancrofti is reported, and the life history of this species is discussed. The genus is named for Dr R. H. Burnell in recognition of his help, over a number of years, in collecting animals used in these life history studies.

I would also like to acknowledge information and help given me by Dr J. C. Pearson, of the University of Queensland, and information on fish given me by Mr C. J. M. Glover, of the South Australian Museum.