bluuebunny/crossref_metadata_2025 huggingface dataset:
Babesia bigemina in ticks grown on non-bovine hosts and its transmission to these hosts
Authors: Callow L. L.
Published: June 2009

The failure of Boophilus microplus to be cleansed of Babesia bigemina while the ticks were growing on non-bovine hosts, as well as the infection of the non-bovine hosts, was demonstrated in experiments in which infected ticks were released on a number of sheep, a goat and a horse.

Seven of ten batches of ticks, collected from six non-bovine hosts, retained their babesia-infection.

Blood subinoculated into cattle from seven of nine sheep and from the horse showed that these animals carried B. bigemina whilst the ticks were feeding on them. This suggested that ticks may have become reinfected from the non-bovine hosts, a possibility supported by the finding of B. bigemina in blood smears from two of the sheep.

This work was performed at the Animal Research Institute, Yeerongpilly, and in the Department of Parasitology, University of Queensland, and supported by funds from both organizations. I am indebted to Mr G. D. Daly for technical assistance, to Professor J. F. A. Sprent and Dr H. M. D. Hoyte for their interest and help.
The species of coccidia occurring in cattle and sheep in the South-West of England
Authors: Joyner L. P. , Norton C. C. , Davies S. F. M. , Watkins C. V.
Published: June 2009

A series of line drawings of the unsporulated and sporulated oocysts of the species of Eimeria found in cattle and sheep in Britain has been compiled.

The incidence of the different species in faecal samples from animals, of which only a minority were known to be suffering from enteritis or diarrhoea, has been recorded. Samples from sheep frequently contained five or six different species among which those that are believed to be pathogenic (E. arloingi, E. crandallis, E. ninaekohlyakimovae) were the most common.

The samples from cattle most frequently contained two or three species. E. bovis and E. zuerni, which are associated with acute disease, were the most common.
Diplocotyle (Eucestoda), a parasite of Gammarus zaddachi in the estuary of the Yorkshire Esk, Britain
Authors: Stark G. T. C.
Published: June 2009

Stream net samples in the Esk estuary reveal the infection, in winter, of the Gammarus zaddachi zaddachi Spooner, 1947 (Crustacea, Amphipoda) population alone with the plerocercoids of Diplocotyle sp. (Eucestoda, Spathebethriidea). Large plerocercoids are found in both sexes of the gammarids but the parasitized females are significantly larger than the non-infected ones and their fertility may be reduced.

I wish to express my thanks to Professor I. Chester-Jones of the University of Sheffield Department of Zoology in whose laboratories this work was carried out, and to Dr F. Segrove (of the same Department) for advice and constructive criticism.
New species and new records of Nycteribiidae from the Ethiopian, Oriental and Pacific Regions
Authors: Theodor Oskar
Published: June 2009

The present paper deals with material examined since the revision of the family (Theodor, 1967) was sent to the press. Material was sent by Mr F. R. Allison from Ghana, by Dr D. Minter, Mr T, S Jones and Mr J. C. Cunningham from East Africa and by Dr F. Zumpt from South Africa and other localities in Africa. The material collected by the Noona Dan Expedition to the Bismarck Archipelago and the Philippines (1961, 1962) was examined. The collection of Nycteribiidae in the Museo Civico di Storia Naturale in Genoa was examined and several new species were found among the material. The types of Stylidia euxesta Speiser in the collection proved different from the species considered as 8. euxesta in the past and to consist of two species. The types of S. euxesta are redescribed.
Coccidian parasites of the California Banded King Snake, Lampropeltis getulus californiae
Authors: Peenen P. F. D. Van , Birdwell T. L.
Published: June 2009

Three coccidian parasites were found in California Banded King Snakes, Lampropeltis getulus californiae: Isospora crotali, an intestinal Eimeria, and a haemogregarine. Schizogonous stages of the latter occurred predominantly in liver, and were remarkably similar to those described for other blood Coccidia.

Dr Charles E. Shaw of the San Diego Zoological Society identified the snakes, and Dr Gordon Ball, Professor of Zoology at the University of California, Los Angeles, kindly reviewed the manuscript.
The fine-structure of the epimastigote forms of Trypanosoma lewisi in the rectum of the flea, Nosopsyllus fasciatus
Authors: Molyneux David H.
Published: June 2009

The fine-structure of the epimastigote forms of Trypanosoma lewisi in the rectum of the flea, Nosopsyllus fasciatus is described.

The parasites are attached to the rectal wall by penetration of the flagella between the highly folded wall of the rectum, by the wedging of the expanded flagella in these folds and irregularities of the wall and by a zonula adherens functional complex between the flagellar membrane and the cuticle of the rectum.

The parasites remain associated with each other by their flagella. The daughter axonemes produced during division are retained within the parent flagellar membrane; this delayed division of the flagella results in up to four axonemes being found within a single flagellar membrane. The parasites accumulate together in masses in the lumen of the rectum and their surfaces interdigitate resulting in the mass of parasites being retained together.

The financial assistance of the Agricultural Research Council is gratefully acknowledged. My sincere thanks are due also to my supervisor Dr Tate for his help, encouragement and enthusiasm through the course of this work.
The fine structure and method of feeding of the tissue parasitizing stages ofHistomonas meleagridis
Authors: Lee D. L. , Long P. L. , Millard B. J. , Bradley J.
Published: June 2009

The structure, method of feeding and relationship with the host cells of the tissue parasitizing stages ofHistomonas meleagridishave been studied by means of light microscopy, cytochemistry and electron microscopy. The invasive stage is amoeboid, lacks flagella but has what appears to be remnants of the flagella apparatus, and feeds by phagocytosis. The vegetative stage is a round quiescent form. It apparently feeds by secreting proteolytic enzymes, which carry out extra-corporeal digestion of the host's tissues, and then taking up small particles of disrupted host cells by means of pinocytosis and probably by diffusion. The vegetative stage also contains remnants of flagella apparatus. Neither the invasive stage nor the vegetative stage contains mitochondria and succinic dehydrogenase is absent. It is concluded that there is no resistant stage.

The reaction of the host's tissues to the parasites has been briefly described.

The authors are grateful to Dr C. C. D. Shute for permission to use the electron microscope, to Mrs B. Fisher and Mr M. Shirley for technical assistance and to Mr P. Rogers for assistance with the photography.
The collection of bird fleas from Fair Isle in 1956
Authors: Stansfield G.
Published: June 2009

In 1951 the laboratory examination of birds at Fair Isle Bird Observatory was extended to include the collection of ectoparasites. The fleas collected during the years 1951–55 have been recorded by Rothschild (1958).
Studies on the origin of the sticky coat on the eggs of the nematode Thelastoma bulhõesi (Magalhães, 1900)
Authors: Lee D. L.
Published: June 2009

1. The eggs of Thelastoma bulhõesi are shown to have a sticky outer coat of acid mucopolysaccharide.

2. The acid mucopolysaccharide is secreted by the lower uterus wall and by the vagina uterina.

3. A protein substance of unknown function has been observed in invaginations in the ovijector of T. bulhõesi.

4. This protein substance appears to be secreted by the lower part of the vagina uterina and passed along into the ovijector.

5. Possible functions of the mucopolysaccharide coat on the eggs, and of the protein substance in the ovijector, are discussed.

I wish to express my thanks to Dr P. Tate for many invaluable suggestions and for his constant encouragement during this investigation.
Echinobothrium acanthinophyllum, n.sp. from the spiral valve of Raja montagui Fowler
Authors: Rees Gwendolen
Published: June 2009

1. Echinobothrium acanthinophyllum sp.nov. occurs in the spiral valve of Raja montagui Fowler. E. affine Diesing was also present.

2. E. acanthinophyllum possesses 23 large hooks in each apical group flanked by 4 small hooks on either side. There are 13 spines in each of the 8 longitudinal rows on the cephalic peduncle and 13 testes in each proglottid. The ripe eggs aggregate into clusters of 8–10, which fill the gravid uterus.

3. Euzet's key is revised to include the 9 species of the genus.
Some cyclophyllidean cestodes from carnivores in Southern Rhodesia
Authors: Mettrick D. F. , Beverley-Burton Mary
Published: June 2009

Three new species of cestodes are described. They are: Joyeuxiella paucitestis sp.nov. from the Rusty Spotted Genet, Genetta rubiginosa; Diplopylidium paurodex sp.nov. from the Rusty Spotted Genet, Genetta rubiginosa; Taenia crocutae sp.nov. from the Spotted Hyaena, Crocuta crocuta.

Re-descriptions are given of Joyeuxiella fuhrmanni (Baer, 1924), Fuhrmann, 1935, and Taenia ingwei Ortlepp, 1938, with particular reference to differences between the original descriptions and those based upon the present material.
Chromosome cycle in the gregarine Stylocephalus mesomorphi Dev.
Authors: Desai R. N.
Published: June 2009

The gregarine Stylocephalus mesomorphi has a diploid chromosome number of 8. The diploid stage is represented only by the zygote nucleus before the metagamic divisions start. The other stages in the entire life history of this gregarine are haploid.

The mitotic chromosomes are four in number, one being the longest, two of medium size and the fourth the smallest.

I am grateful to Professor J. C. Uttangi, Head of the Zoology Department, Karnatak Science College, Dharwar, for the encouragement he gave me throughout this work. I am also greatly indebted to my colleague Dr M. J. Devadhar, for having given me many valuable suggestions.
On a new nematode Spirocaudata bispiculatum gen.nov. sp.nov. (Ancyracanthidae) from the kœl, Eudynamys scolopacea
Authors: Sharma R. K.
Published: June 2009

Three male and four female parasites were recovered from the gizzard of a koel, Eudynamys scolopacea Linnaeus (Cuculiformes). In all, about forty birds were examined and only one was found infected. The present account is based on a study of three male and three female specimens, one female specimen being slightly damaged.
The effects of various treatments on the surfaces of the cercariae and schistosomula ofSchistosoma mansoni
Authors: Kusel J. R.
Published: June 2009

In order to learn more about the nature of the chemical bonds stabilizing the surface membranes of the cercariae and schistosomula ofSchistosoma mansoni, these organisms were treated with a variety of reagents. The cercarial surface was dissolved by 8 M urea alone (pH 9·0) but was protected from such dissolution if a certain critical concentration of cation or anion was included in the 8 M urea solution. Divalent cations were more effective than monovalent cations in this protective effect. The 8 M urea was also unable to dissolve the cercarial surface at any pH below 5·8. The cercarial surface was very rapidly dissolved by sodium hydroxide solutions at pH 11·4 and above. The divalent cation calcium, if included in the sodium hydroxide solution, slowed down the rate of surface solution by sodium hydroxide. The schistosomular surface was stable to 8 M urea at pH 9·0 but was readily dissolved in 8 M urea at pH 10·7 and 11·7. The schistosomular surface was stable in aqueous sodium hydroxide solutions at pH 12·0. Anionic detergents were very effective in dissolving the cercarial surface at concentrations above 0·001%. Cationic and non-ionic detergents were ineffective at 0·01% or below. A saturated solution of digitonin if diluted 1:100 caused destruction of the cercarial surface. At higher concentrations it caused expansion and stabilization of this surface.

It is suggested that in both the cercarial and the schistosomular surface, bonds between carboxyl (—COO′) and amino (—NH3+) groups are very important in maintaining structure. The origin of the —NH3+ group is possibly from —NH2lysyl group in cercariae, and a guanido group in schistosomula. The suggestion that cations are incorporated into the cercarial surface and stabilize it during and after penetration has been tested by treating schistosomula with EDTA. The EDTA had no visible effect on the surface, nor did it labilize the surface to other reagents.

I should like to thank very warmly Dr S. A. Ibrahim, in whose Department this work was carried out. My grateful thanks are given to the Medical Research Council (U.K.) for a grant. I should also like to thank Mr J. R. Lauder, Mr Ahmed Gandour and Mr Saleh for their help during the work. I am very grateful to Dr J. A. Clegg and Dr S. R. Smithers for helpful discussions.
Studies on immunity to Haemonchus contortus infection: the elimination of a challenge infection by immune sheep
Authors: Bitakaramire P. K.
Published: June 2009

Ten-month-old Blackface sheep double vaccinated with X-irradiated larvae of H. contortus were shown to be highly resistent to individual challenge with 50000 larvae. Compared to unvaccinated sheep, the percentage reductions in the numbers of worms established 6, 9, 12 and 16 days after challenge were 83, 90, 99 and 100 respectively. The immune response was directed against the 3rd and 4th larval stages.

The author wishes to express his thanks to his colleagues at the Wellcome Laboratories for Experimental Parasitology for their co-operation and help during the period of this experiment.

This work was supported by a grant from Allen and Hanburys Ltd., Ware, England.
The importance of the bladder for the development of the cysticercus
Authors: Šlais J.
Published: June 2009

The bladder of the cysticerci, the larvae of cestodes, is a transitory embryonic organ; its morphology is related to its mode of development and the localization of the parasite in its intermediate host. The bladder makes possible the adaptation of the cysticercus to unusual conditions of its development. A certain degree of analogy between the trophoblast of the mammalian embryo and the bladder of the cysticerci adapted to the development in the tissues of mammals can be drawn.
The hygroreaction of the larvae of the Oriental rat flea Xenopsylla cheopis Rothsch. (Siphonaptera: Pulicidae)
Authors: Yinon U. , Shulov A. , Margalit J.
Published: June 2009

The humidity reaction of the larvae of Xenopsylla cheopis Rothsch. was studied in an air-chamber with a 0–100% relative humidity gradient.

Highly significant differences (P < 0·001) between the reactions in the various R.H. ranges was found. The most preferred relative humidity along this gradient was 100%. Relatively few larvae were collected at each R.H. in the range between 0 and 90% R.H.

The reaction of the larvae under the experimental conditions was seen to be of orthokinetic type.
Repetitive DNA and hybridization patterns demonstrate extensive variability between the sibling species Globodera rostochiensis and G. pallida
Authors: De Jong A. J. , Bakker J. , Roos M. , Gommers F. J.
Published: June 2009

A method is described for the isolation of high molecular weight DNA from females of potato cyst nematodes. Restriction enzyme analyses of repetitive DNA revealed 30 bands specific for Globodera rostochiensis and 8 bands specific for G. pallida. None of the repetitive DNA bands resolved was common to both species. Hybridization patterns, obtained with a DrosophilaβJ-tubulin probe, revealed 4 common bands, 3 bands specific for G. rostochiensis and 12 bands specific for G. pallida.
Experiences with vaccines against cutaneous leishmaniasis: of men and mice
Authors: Modabber Farrokh
Published: June 2009

The need for a vaccine(s) against cutaneous leishmaniasis and the populations at risk for whom such vaccines should be developed are briefly discussed. The current human vaccine studies are reviewed, as are some experimental mouse studies with emphasis onLeishmania majorinfection relevant to vaccine development. Based on the information available from the mouse model and those data which are being sought in human studies, the benign nature of the cutaneous disease, the ease with whichL. majorcan be manipulated to yield the required material, and the ongoing practice of leishmanization which allows rapid evaluation of candidate vaccine(s), it is suggested that a vaccine, at least againstL. major, is imminent in the not too distant future.
Immunological control of ticks and tick-borne parasitic diseases of livestock
Authors: Morrison W. I.
Published: June 2009

Parasitic diseases inflict major losses on livestock production throughout the world. Currently, control of the diseases relies largely on prophylactic or therapeutic application of anti-parasitic drugs. In many instances, these measures are only partially effective. Moreover, they must be applied frequently, are therefore costly and time-consuming, and lead to the selection of drug resistance within the parasite populations. Thus, it has been recognized for several decades that effective methods of vaccination against parasitic diseases would have a major impact on livestock production. However, despite considerable efforts over the last 30 years, only a few parasite vaccines are currently in use and all of these involve the administration of live organisms.
Acquired immunity toTrichuris murisin the albino laboratory mouse
Authors: Wakelin D.
Published: June 2009

After infection with the nematodeTrichuris muris70–75% of mice of the Schofield strain developed an immunity to the parasite and eliminated the worms between the 16th and 19th days after infection. In these mice the acquired immunity persisted for at least 3 months and prevented the establishment of subsequent infections.

In 25–30% of the mice immunity was not produced and infections developed into mature worms. These non-resistant mice remained susceptible to further infection.

The development and action of the immune response were suppressed completely by the administration of cortisone acetate.
The structure of Mehlis's gland complex and histochemistry of Artyfechinostomum mehrai (Faruqui) (Trematoda: Echinostomatidae) from a girl at Andhra Pradesh, India
Authors: Rao K. Hanumantha
Published: June 2009

1. The functional anatomy of the ducts associated with Mehlis's gland in the echinostome Artyfechinostomum mehrai (Faruqui) recovered from a girl has been described.

2. The mechanism and histochemistry of egg-shell formation are described and discussed.

Appreciation is extended to Dr V. S. Raghunathan, M.D., Physician and Superintendent, and Dr T. Sreenivasan, M.D., of King George Hospital, Visakhapatnam, for their kind co-operation and the gift of specimens of A. mehrai. My thanks are due to Professor P. N. Ganapati for facilities and encouragement.
Virulence of lizard malaria: the evolutionary ecology of an ancient parasite—host association
Authors: Schall J. J.
Published: June 2009

The negative consequences of parasitic infection (virulence) were examined for two lizard malaria parasite—host associa tions:Plasmodium agamae and P. giganteum, parasites of the rainbow lizard,Agama agania, in Sierra Leone, West Africa; andP. mexicanumin the western fence lizard, Sceloporus occidentalis, in northern California. These malaria species vary greatly in their reproductive characteristics:P. agamaeproduces only 8 merozoites per schizont,P. giganteumyields over 100, andP. mexicanuman intermediate number. All three parasites appear to have had an ancient association with their host. In fence lizards, infection with malaria is associated with increased numbers of immature erythrocytes, decreased haemoglobin levels, decreased maximal oxygen consumption, and decreased running stamina. Not affected were numbers of erythrocytes, resting metabolic rate, and sprint running speed which is supported by anaerobic means in lizards. Infected male fence lizards had smaller testes, stored less fat in preparation for winter dormancy, were more often socially submissive and, unexpectedly, were more extravagantly coloured on the ventral surface (a sexually dimorphic trait) than non-infected males. Females also stored less fat and produced smaller clutches of eggs, a directly observed reduction in fitness. Infected fence lizards do not develop behavioural fevers.P. mexicanumappears to have broad thermal buffering abilities and thermal tolerance; the parasite's population growth was unaffected by experimental alterations in the lizard's body temperature. The data are less complete forA. agama, but infected lizards suffered similar haematological and physiological effects. Infected animals may be socially submissive because they appear to gather less insect prey, possibly a result of being forced into inferior territories. Infection does not reduce clutch size in rainbow lizards, but may lengthen the time between clutches. These results are compared with predictions emerging from several models of the evolution of parasite virulence. The lack of behavioural fevers in fence lizards may represent a physiological constraint by the lizards in evolving a thermal tolerance large enough to allow elimination of the parasite via fever. Such constraints may be important in determining the outcome of parasite—host coevolution. Some theory predicts low virulence in old parasite—host systems and higher virulence in parasites with greater reproductive output. However, in conflict with this argument, all three malarial species exhibited similar high costs to their hosts.
Parasite—host coevolution
Authors: May R. M. , Anderson R. M.
Published: June 2009

In this paper we wish to develop three themes, each having to do with evolutionary aspects of associations between hosts and parasites (with parasite defined broadly, to include viruses, bacteria and protozoans, along with the more conventionally defined helminth and arthropod parasites). The three themes are: the evolution of virulence; the population dynamics and population genetics of host–parasite associations; and invasions by, or ‘emergence’ of, new parasites.
Studies on the adult and diplostomulum ofDiplostomum(Dolichorchis)leonensis(Strigeida: Trematoda)
Authors: Williams M. O.
Published: June 2009

Large number of fishes of the family Cryprinodontidae collected from a stream at Hastings, Sierra Leone, were found with a diplostomulum encysting on the skin and in the musculature.

Infected pieces of fish were fed to day-old chicks and cattle-egrets, and adult stages of a worm, considered to be new species and namedDiplostomum(Dolichorchis)leonensis, were obtained.

Morphological details of the diplostomulum and the adult worm are described.

The author wishes to express his gratitude to Dr G. Dubois for his interest and advice in connexion with the study, to Miss M. R. Coker who prepared the diagrams; and to Messrs F. Deen, T. Alhassan and M. Seisay for technical help.
Chairman's Concluding Remarks
Authors: Barrett J.
Published: June 2009

Although structurally simple, the nervous systems of parasitic helminths are biochemically complex. As well as the classical transmitters, the nervous systems of helminths contain a range of regulatory peptides and so far some 29 different peptides have been described. The only group of compounds thought to be transmitters in free-living organisms which have not yet been shown to be transmitters in helminths are the purines. There is evidence in helminths, as in vertebrates, for the co-localization, in the same cell, of classical transmitters and peptidergic molecules and for the non-neuronal occurrence of some regulatory peptides. Co-localization would effectively increase the number of transmitter types, since compounds could be released in different combinations. How such a selective release might be achieved is unknown. Different regulatory peptides are localized in different parts of the helminth nervous system, but it is quite probable that more than one peptide can occur in the same cell. Whether the relative proportions of the different peptides change under different physiological or developmental conditions is not known. The classical transmitters similarly show a differential distribution. It is presumed that the regulatory peptides in helminths, as in other organisms, are synthesized by post-translational modification of a high molecular weight precursor protein and that the peptides are not recycled but are removed from their site of action by specific peptidases. The latter are located near the receptor sites and may be membrane-bound. In vertebrates the precursor molecules usually contain several different peptides with different biological functions and processing of the precursor often shows tissue-specific variations.
Studies on the absorption of amino acids by larval tapeworms (Cyclophyllidea: Taenia crassiceps)
Authors: Haynes W. D. G. , Taylor Angela E. R.
Published: June 2009

Larvae of Taenia crassiceps have been shown to absorb L-valine and L-methionine by a process of active transport. Uptake is maximal at about 43 °C and a pH of about neutrality, and concentration against a gradient has been demonstrated. In advanced larvae, the absorption mechanism has been shown to be specific for neutral aliphatic amino acids, with an uncharged amino group in the α-position. Competitive inhibitions of uptake have been demonstrated in the presence of other amino acids.

Comparison has been made with a mechanism present in Hymenolepis diminuta for the uptake of neutral amino acids, demonstrated by Read et al. (1963), and the absorption of L-methionine by the two species has been compared in detail.

The uptake of valine and methionine by the two types of larvae has been compared in detail: the presence of two types of sites for the uptake of these aminoacids has been suggested.

The absorption of the L-isomers of glutamic acid, proline, serine, glycine and leucine has been demonstrated in advanced larvae. Separate mechanisms for the uptake of acidic amino acids, basic amino acids and neutral aromatic amino acids have been suggested.

Thanks are due to Professor G. Chapman, in whose department this work was carried out, and to Miss E. Clarry for her willing assistance. We would also like to thank Dr G. Ayrey, of the Queen Elizabeth College Isotope Unit, for his valuable help, especially in the development of a technique for the simultaneous counting of 14C and 3H. The work was supported by a research grant from the Wellcome Trustees, to whom we are most grateful.
Notes onAscaris and Toxascaris, with a definition ofBaylisascarisgen.nov.
Authors: Sprent J. F. A.
Published: June 2009

The family Ascarididae, as defined by Hartwich (1957) and emended by Osche (1958), comprises species in the generaAscaris, Toxascaris, ParascarisandLagochilascaris, all occurring in terrestrial mammals. Other ascaridoids of terrestrial mammals occur in Crossophoridae and Toxocaridae, the latter includingToxocaraandNeoascaris(see Hartwich, 1957; Sprent, 1957; Osche, 1958).
Death of schistosome cercariae during penetration of the skin
Authors: Rai S. L. , Clegg J. A.
Published: June 2009

The seagull, a natural host ofAustrobilharzia terrigalensis, was infected with cercariae through a small area of breast skin; 40% of the schistosomula recovered from the skin shortly afterwards were dead. In budgerigar skin 29% of the schistosomula were dead, but mortality in the skin of ducklings was much higher (85%). The budgerigar is a useful laboratory host for this schistosome, but ducklings are completely resistant to experimental infection mainly because of the barrier effect of the skin.

Rapid recovery of schistosomula from budgerigar skin established that the majority of deaths occurred during the first 15 min after application of cercariae. In sections of skin fixed after 10 min nearly all the schistosomula were in the epidermis between the narrowstratum corneumand the living cells of the Malpighian layer. In seagull and budgerigar skin most schistosomula succeeded in crossing the Malpighian layer in the next 5 min, but in ducklings nearly all schistosomula completely failed to penetrate this layer.

In vitroexperiments in which cercariae were allowed to penetrate through several layers of dead epidermis, isolated from dried budgerigar skin, into balanced saline, showed that schistosomula are not killed by host cells or a soluble toxic substance. The possibility that the epidermis contains an insoluble toxic substance could not be excluded.

The proportion of schistosomula which died during penetration of dead epidermis was related to the number of layers in the barrier, suggesting that schistosomula may die owing to exhaustion caused by the intense activity of penetration.

About 30% of the glycogen reserves of cercariae were utilized during penetration of budgerigar skin. In dead schistosomula the glycogen reserve had been reduced by 80%, but the significance of this observation is uncertain because much of the glycogen may have been autolysed after death of the schistosomula. Exposure of cercariae to glucose before penetration did not affect the proportion which died in the skin.

Schistosomula adapt to the osmotic pressure in the skin, which is one-third that of sea water, and 30 min after penetration they are rapidly killed if returned to sea water. This process of adaptation is not related to mortality of schistosomula during penetration of the skin.

We wish to acknowledge the expert technical assistance of Mrs J. Morgan. This investigation was supported in part by research grant AI-04707 from the National Institute of Allergy and Infectious Diseases, United States Public Health Service.
Kinetic modelling of isometamidium chloride (Samorin) uptake byTrypanosoma congolense
Authors: Sutherland I. A. , Mounsey A. , Eisler M. , Holmes P. H.
Published: June 2009

Clones ofTrypanosoma congolensewhich express resistance to the widely used trypanocide isometamidium chloride accumulate less of the drug than clones which are sensitive to drug treatment. A mathematical model has been developed which was able to predict theoretical lines representing the uptake kinetics in trypanosomes which were sensitive to isometamidium, as well as for resistant trypanosomes in which reduced accumulation was a result of either reduced uptake or enhanced efflux of the drug. Data from drug uptake experiments were then fitted to these theoretical lines. While the value for drug efflux could not be separated from the dissociation constant of the trypanosomes for isometamidium, it was demonstrated that reduced accumulation is not a result of reduced uptake of isometamidium by drug-resistant trypanosomes.
Circulating antibodies to histolysain, the major cysteine proteinase ofEntamoeba histolytica, in amoebic liver abscess patients
Authors: Osorio L. M. , Picóf T. , Luaces A.
Published: June 2009

A solid-phase enzyme immunoassay (EIA) was used to detect circulating antibodies to histolysain, the major cysteine proteinase ofEntamoeba histolytica. Serum samples from 40 healthy controls, 33 asymptomaticE. histolyticacyst passers and 22 patients with amoebic liver abscess were tested. Antibodies to histolysain were found in 72·7% of cases of amoebic liver abscess, 18·1% of the cyst passers and 2·5% of healthy controls, which suggests that a humoral immune response is induced by histolysain during amoebic liver abscess.
The life cycle ofParvatrema homoeotecnumsp.nov.(Trematoda: Digenea) and a review of the family Gymnophallidae Morozov, 1955
Authors: James B. L.
Published: June 2009

1.Parvatrema homoeotecnumsp.nov. from the oystercatcher,Haematopus ostralegus occidentalisNeumann at Aberystwyth is described and compared with other species of the genus.

2. The life cycle of this species is unique. The larval stages occur in the gastropod,Littorina saxatilis(Olivi) subsp.tenebrosa(Montagu) and include germinal sacs which have a structure and development similar to an adult digenean. There are no free-living stages and only one intermediate host.

3. The significance of this unique life cycle is discussed.

4. The family Gymnophallidae Morozov, 1955, is reviewed. Emended definitions are given for the family, subfamilies and genera. Keys, diagnostic features and brief notes of the species are included.

I am very grateful to Dr Gwendolen Rees, who suggested the investigation which led to the discovery of this species, for her advice and indispensable assistance throughout the work and the preparation of this paper. I am also grateful to the late Professor T. A. Stephenson for his interest and for the provision of working facilities; to Mr W. A. Ballantine, Mr A. H. Clarke, Jr., Mr C. Curtis, Miss G. P. F. Evans, Dr V. Fretter, Professor L. A. Harvey, Mr D. H. Jones and Dr J. Lewis who sent me specimens ofLittorina saxatilis; to Professor R. M. Cable and Emerit. Professor G. R. La Rue for helpful suggestions; to Mr J. R. Hirst and Mr D. Hemingway Jones for photographic and technical assistance and to the Department of Scientific and Industrial Research for a grant which made the work possible.
Observations on the life-history of Phyllodistomum srivastavai sp.nov. (Trematoda: Gorgoderidae)
Authors: Rai S. L.
Published: June 2009

Koga (1922) recorded for the first time the occurrence of metacercariae belonging to the genus Phyllodistomum Braun, 1899, in the freshwater shrimp, Palaemon nipponensis from Japan. Later Yogota (1922), Hirata (1928) and Asada (1928) recorded that shrimps in Japan were infected by larvae of several species of Phyllodistomum.
Microtubular organization visualized by immunofluorescence microscopy during erythrocytic schizogony in Plasmodium falciparum and investigation of post-translational modifications of parasite tubulin
Authors: Read M. , Sherwin T. , Holloway S. P. , Gull K. , Hyde J. E.
Published: June 2009

We describe a novel procedure for the immunofluorescent investigation of Plasmodium falciparum. This has allowed us to visualize clearly microtubular structures and their changing conformation through the erythrocytic cell-cycle, to the stage of cytodifferentiation leading to merozoite release. The images of spindle development we observed, together with an analysis of nuclear body numbers in large numbers of parasites, indicate that there is an apparent asynchrony in chromosomal multiplication within a single parasite. Using antibodies specific for post-translational modification of α- tubulin, we also demonstrate that the C-terminal tyrosine-containing epitope of P. falciparum α-tubulin I is similar to that of other organisms. Lysine-40 in the same molecule, a target for highly specific in vivo acetylation in some organisms, is unmodified in the blood stages we examined here. After in vitro acetylation of this residue, however, the epitope to which it contributes was recognized by antibody, showing that the conformation of this part of the molecule is also conserved, despite a lack of primary sequence homology immediately downstream of the target lysine residue.
Decoy effect and host infection by miracidia within snail communities
Authors: Chipev N. H.
Published: June 2009

The effect of experimental non-host snail (NHS) communities on the infection of Lymnaea truncatula with Paramphistomum daubneyi and Fasciola hepatica miracidia was studied. The results obtained indicated that NHS had variable effects on basic population parameters of host infection. Specifically, NHS were able to produce aggregation of sporocyst number/snail in the experimental host populations. Proposed hypotheses for decoy effect mechanisms failed to explain completely the experimental results. A new mechanism is suggested, based on a distance response of miracidia to snail chemo-attractants, to explain effects of NHS on miracidial host finding behaviour. It is assumed that miracidia have evolved the ability to discriminate among individual snail chemical attractants in a community already at a distance. This attribute of miracidial behaviour allows NHS to induce variations in the effectiveness of individual host localization by miracidia. The resulting aggregation of successful infections/host is assumed to be the specific component of snail decoy effect at the community level. It was also established that NHS affected trematode reproduction in the host inducing a compensatory increase in the intramolluscan population. Intraspecific competition among developmental stages is suggested to be the mechanism of this compensatory reaction.
Field trials in the control of Opisthorchis viverrini with an integrated programme in endemic areas of northeast Thailand
Authors: Saowakontha S. , Pipitgool V. , Pariyanonda S. , Tesana S. , Rojsathaporn K. , Intarakhao C.
Published: June 2009

A control programme of opisthorchiasis was carried out for three years in three villages of northeast Thailand in order to compare the effectiveness of two intervention measures. The intervention measures employed were to give praziquantel treatment to all infected people either once (village I) or twice (village II) per year with the integration of regular health education and sanitation improvement. A control village (village III) received no intervention during the study. Sampling of the population in these villages to estimate prevalence, intensity, reinfection and incidence of infection as well as knowledge of opisthorchiasis and number of latrines was performed at 6 monthly intervals throughout the duration of the study. At the initial assessment, there were no significant differences in the prevalence and intensity of infection of villages I and II. Both values were greatly reduced when assessed 6 months after the initiation of treatment, and the decrease in prevalence and intensity of infection did not differ between villages I and II. The control village (village III), during the first 2 years, exhibited slight variation in the prevalence and intensity, and these decreased considerably in the third year of the study. The reinfection rate per 6 months in villages I and II was nearly equal. The incidence rate per 6 months in the two treated villages was lower than that of the control village. Marked improvement in knowledge of opisthorchiasis, behavioural changes of eating raw fish and increased numbers of latrines was evident in all of the villages during this study. The study showed that the effectiveness of annual drug treatment is similar to that of 6 monthly treatments when combined with regular health education and sanitation improvement.
Intestinal helminth communities of the long-finned pilot whale (Globicephala melas) off the Faroe Islands
Authors: Balbuena J. A. , Raga J. A.
Published: June 2009

The intestines of 170 long-finned pilot whales, Globicephala melas, caught off the Faroe Islands (N.E. Atlantic) were examined for helminth parasites. Eight species were detected but only 4 occurred in at least 10% of the sample. No core or recurrent group of species were identified and no correlations between abundances of species were significant. Diversity values were far below those reported for other endotherms. Colonization by helminths was random, whales not being readily colonized. These features point to largely unpredictable, isolationist infracommunities, there being little potential for inter-specific interactions. Older hosts tended to harbour more diverse infracommunities, offering more opportunities for such interactions. Two hypotheses, which might also apply to other cetaceans, are proposed to account for the depauperate helminth communities of the pilot whale: (i) some ancestral helminth species failed to adapt their cycles to the marine habitat and (ii) the hosts' isolation from land prohibited new infections with helminths of mammals.
Chemotherapy and immunity in opportunistic parasitic infections in AIDS
Authors: Zumla A. , Croft S. L.
Published: June 2009

Parasitic diseases are endemic in parts of the tropics, but there is no convincing evidence that their prevalence or incidence is increasing due to the HIV epidemic. Available scientific data on parasitic infections in patients with the Acquired Immunodeficiency Syndrome (AIDS) suggests a predominance ofPneumocystis carinii, Toxoplasma gondiiandCryptosporidiumspp. For reasons which are unclear, parasitic infections such asPlasmodium falciparum, Strongyloides stercoralisandEntamoeba histolytica, where cell-mediated immune responses are also thought to be significant, do not appear to be opportunists of importance. It is being increasingly recognized that chemotherapy for parasitic diseases has a host-dependent component, although scientific data on this subject remain scanty. The management of opportunistic parasitic infections in patients infected with HIV is dogged by failures and relapses, aptly illustrating the notion of the relationship between chemotherapy and the immune response. This review discusses the immunity and chemotherapy of opportunistic parasite infections in patients infected with the Human Immunodeficiency Virus (HIV).
Resistance to intestinal parasites during murine AIDS: role of alcohol and nutrition in immune dysfunction
Authors: Watson R. R.
Published: June 2009

A murine AIDS model with many similarities to human AIDS, LP-BM5 Murine Leukaemia, suppresses T and B cell numbers and functions in the intestine. This permits chronic colonization by Giardia and Cryptosporidium. Cocaine and the nutrient alcohol, which are immunosuppressive, further reduce resistance to intestinal parasites and intestinal lymphocyte numbers. Protein undernutrition, vitamin E supplementation, and alcohol use further modify immune dysfunction induced by the murine retrovirus infection. This suggests that both undernutrition and nutrient supplementation could affect parasite resistance during AIDS. Thus this murine model of human AIDS has great potential to accelerate studies of the role of nutrients in immune dysfunction and resistance to intestinal parasites.
Preface
Authors: Smith J. E. , Chappell L. H.
Published: June 2009

As stated by Jennie Blackwell in her introduction to this symposium, the surface of protozoan parasites has long been the province of immunologists, driven by interest in the diagnostic and vaccine potential of surface molecules. This preoccupation with vaccines led to the generation of a great deal of sequence data for surface molecules but gave few clues as to their function.
Evolutionary ecology of vertically transmitted parasites: transovarial transmission of a microsporidian sex ratio distorter inGammarus duebeni
Authors: Dunn A. M. , Hatcher M. J. , Terry R. S. , Tofts C.
Published: June 2009

Vertically transmitted parasites are transmitted from generation to generation of hosts usually via the host's gametes. Owing to gamete size dimorphism, the major transmission route is transovarial and selection (on the parasite) favours strategies which increase the relative frequency of the transmitting (female) host sex. These strategies impose unusual selection pressures on the host, and coevolution between hosts and vertically transmitted parasites has been implicated in speciation, in the evolution of symbiosis, and in the evolution of novel systems of host reproduction and sex determination. We review the evolutionary implications of vertically transmitted parasites in arthropods before focusing on strategies of transmission of a parasitic sex ratio distorter inGammarus duebeni. The efficiency of parasite transmission to new hosts is a key factor underlying the relationship between vertically transmitted parasites and their hosts. Vertically transmitted parasites must overcome 2 bottlenecks in order to ensure successful infection of future host generations: first, transmission from adult to gamete; and secondly, transmission to the germ-line of the infected host. We investigate these 2 processes with regard to transovarial transmission by a microsporidian parasite inGammarus duebeni. Parasite transmission from adult to eggs is highly efficient, with 96% of eggs of infected mothers inheriting the infection, whereas transmission to germ-line within infected embryos is relatively inefficient (72%). We measure parasite distribution between cells of developing embryos, and use these distributions to infer possible mechanisms of parasite transmission to germ-line. Parasite distribution within the embryo is dependent on host cell lineage, and is not consistent with unbiased segregation between daughter cells. These results indicate that parasites segregate together at host cell division, and may reflect a strategy of differential segregation to the host germ-line. We consider alternative parasite strategies at the cell-level in terms of their evolutionary implications.
The effect of homogenates and excretory/secretory products ofNippostrongylus brasiliensisand of acetylcholinesterase on the amplitude and frequency of contraction of uninfected rat intestinein vitro
Authors: Foster N. , Dean E. J. , Lee D. L.
Published: June 2009

Whole worm homogenates and excretory/secretory (E/S) products of adultNippostrongylus brasiliensissignificantly decreased the amplitude of contractions of segments of uninfected rat intestine maintained in an organ bath, with significantly larger volumes of E/S products being required to bring about a similar decrease to that caused by the whole worm homogenate. Boiled samples of homogenate and E/S products significantly decreased the amplitude of contractions of uninfected rat intestine, but larger volumes were needed than with unboiled samples. Frequency of contraction was unaltered by homogenates or E/S products. When electric eel AChE was injected into the lumen of segments of uninfected rat intestine maintained in an organ bath there was no significant decrease in the amplitude of contractions. These results suggest that substances present in the E/S products ofN. brasiliensissignificantly reduce the amplitude of contractions of uninfected rat intestinein vitroand that the biochemical holdfast responsible for this phenomenon may not be AChE.
Isolation and characterization of a species-specific multicopy DNA sequence fromEntamoeba histolytica
Authors: Mittal V. , Bhattacharya A. , Bhattacharya S.
Published: June 2009

A genomic library ofEntamoeba histolytica(pathogenic strain HM-1: IMSS) was screened to detect repetitive DNA clones other than those from the highly abundant ribosomal DNA (rDNA). One such clone (HMc) had a 2·3 kb insert which hybridized with the main genome and not the rDNA circle. Southern hybridization ofE. histolyticagenomic DNA, digested withEcoRI and probed with HMc, showed multiple bands. The banding pattern was identical in all axenic pathogenic strains tested. Differences, however, existed when the banding pattern of a pathogenic strain was compared with that of a non-pathogenic strain. HMc was present in about 25–30 copies per genome in strain HM-1: IMSS. Nucleotide sequence analysis of HMc revealed a partial open reading frame which hybridized with a 1·35 kb poly A+transcript in Northern blots. The deduced amino acid sequence did not, however, show significant homology with known proteins. The HMc sequence was found only inE. histolyticaas it hybridized with 5 different axenic strains ofE. histolyticabut did not recognize other closely related species ofEntamoeba. It has thus the potential to be used as a species-specific DNA probe.