bluuebunny/crossref_metadata_2025 huggingface dataset:
Rejection ofEimeriaby foreign hosts
Authors: Long P. L. , Millard B. J.
Published: June 2009

Oocysts ofEimeria maximainoculated into guinea fowl do not develop. Infection occurs when intestinal mucosa or liver tissue from guinea fowl givenE. maximais transferred to susceptible chickens. By transferring material at different times after inoculation, it was shown that most of the stages are lost between 6 and 12 h and few, if any, survive to 48 h.

Sporozoites ofE. tenellahad low infectivity after 48 h contactin vitrowith peritoneal macrophages from guinea fowls and turkeys. Sporozoites ofE. grenierifrom the guinea fowl appeared to be destroyed within macrophages taken from chickens.
Hybridization between Brugia patei, B. pahangi and sub-periodic B. malayi
Authors: Suswillo R. R. , Denham D. A. , McGreevy P. B. , Nelson G. S.
Published: June 2009

Virgin females of Brugia malayi, B. pahangi and B. patei were mated with males of species other than their own to determine whether they would hybridize. Microfilariae were produced in all but one cross (that between B. pahangi males and B. malayi females). Hybrid infective larvae, produced in mosquitoes and inoculated intraperitoneally into jirds, grew to adults but these were unable to produce microfilariae because hybrid males did not produce spermatozoa. Hybrid females were fertile and produced microfilariae when crossed with males of their parental species.
Seasonal variation in the population dynamics ofCaryophyllaeus laticeps
Authors: Anderson R. M.
Published: June 2009

The biological parameters which generate seasonal fluctuations in the size of populations ofCaryophyllaeus laticepsare examined in detail. A mathematical model is formulated to describe the dynamics of the adult parasite within the fish hostAbramis brama, and the predictions of the model are compared with observed population data.

The seasonality of parasite population size is shown to be caused by the combined effects of a temperature dependent mortality rate and fluctuations in host feeding activity, which controls the immigration rate of larval parasites. The observed overdispersed distribution of adult parasite numbers within the host population is shown to be generated by variability in feeding habits between individual members of the fish population.

The theoretical population model is used as a framework for the investigation of, among other factors, the comparative influences of the immigration and death rates on the dynamics of the adult parasite, the future behaviour of the system under altered environmental conditions and the importance of chance effects in the dynamics of individual parasite populations within a single host.

The stability of the dynamics of the complete life-cycle ofC. laticepsis discussed in relation to the inherent biological complexity of host/helminth parasite interactions.
The effect of moisture stress upon the hatching of Nematodirus battus larvae
Authors: Parkin J. T.
Published: June 2009

An experiment was carried out to investigate the effect of soil moisture stress upon the hatching behaviour of Nematodirus battus. The method involved the use of polyethylene glycol solutions to maintain a steady osmotic pressure around a soil containing N. battus eggs, which were ready to hatch. Different concentrations of polyethylene glycol (creating different moisture stresses) were found to affect the numbers and the rate of egg hatching markedly.
Fine structure and development of schizonts, merozoites and macrogamonts of Eimeria acervulina in the goblet cells of the duodenal epithelium of experimentally infected birds
Authors: Michael E.
Published: June 2009

The fine structure of trophozoites, schizonts, merozoites and macrogamonts of Eimeria acervulina found in goblet cells of the duodenal epithelium of chicks is described and compared with the corresponding stages formed in other epithelial cells. Complete schizogony, with the formation of mature merozoites, occurred freely in goblet cells. Developing macrogamonts (but no microgamonts) were rarely found in goblet cells.
The stages observed were confined to the cytoplasm of the host cell above the Golgi apparatus and were usually seen between the mucous granules. The stages seen appeared normal, and contained similar structures to corresponding stages developing in other cells.
The finding of developing stages of E. acervulina in goblet cells provides further evidence that site specificity of Eimeria at the cellular level is not as strict as previously thought.
Maintenance of Theileria parva parva infection in an endemic area of Kenya
Authors: Young A. S. , Leitch B. L. , Newson R. M. , Cunningham M. P.
Published: June 2009

The maintenance of Theileria parva parva infection in an endemic area of Kenya on the shore of Lake Victoria was studied in the field and laboratory. High prevalences of antibodies against T. parva and T. mutans and intra-erythrocytic piroplasms were detected in local zebu (Bos indicus) cattle. The mean infection rate of Theileria parasites in the tick, Rhipicephalus appendiculatus, in field collections was 1·1 %. Most of the infection was attributed to T. parva parva by application of field ticks to susceptible cattle. Five cattle, all about 1·5 years old, were purchased from local owners and transported to the laboratory. All five had oscillating antibody titres against T. parva and T. mutans and had patent theilerial infections during the subsequent 13 months. Uninfected R. appendiculatus nymphs were applied to cattle at 0, 3, 6, 9 and 13 months after transport to Muguga, and 18 out of 23 batches transmitted T. parva parva infection to cattle when 100 resultant R. appendiculatus adults were applied. Infection rates in the tick batches were usually low, with 1 salivary gland acinus infected/tick. Hence, a frequent carrier state of naturally infected cattle has been demonstrated for T. parva parva for the first time, and it is likely that this carrier state is of great importance in maintenance of T. parva parva infection in the field.
Evasion of macrophage microbicidal mechanisms by mature sporozoites ofPlasmodium yoelii yoelii
Authors: Smith Judith E. , Alexander James
Published: June 2009

Sporozoites ofPlasmodium yoelii yoeliiwere incubated for 40 min with BALB/c peritoneal macrophages in the presence of nitro-blue tetrazolium (NBT). While immature oocyst sporozoites triggered the macrophage respiratory burst, as visualized microscopically by the localized reduction of NBT to insoluble formazan, 97·6% of mature salivary gland sporozoites did not induce such a response. The macrophage oxidative response was also induced by 82·7% of heat-inactivated and 95·7% of trypsin-treated salivary gland sporozoites. The relationship of these results to the infectivity and immunogenicity of malarial sporozoites is discussed.
Immunization of calves againstSchistosoma bovisusing irradiated cercariae or schistosomula ofS. bovis
Authors: Bushara H. O. , Hussein M. F. , Saad A. M. , Taylor M. G. , Dargie J. D. , Marshall T. F. De C. , Nelson G. S.
Published: June 2009

Fourteen 9-month-old zebu calves were immunized with 10000 irradiatedSchistosoma bovisschistosomula given in 1–3 intramuscular or subcutaneous doses, and 4 more calves were immunized with 10000 irradiated cercariae administered percutaneously in a single dose. Eight weeks after the beginning of the experiment these calves, together with four non-immunized controls were challenged percutaneously with 10000 normalS. boviscercariae/calf. Comparative clinical, parasitological, pathological and pathophysiological observations subsequently revealed significant differences between the vaccinated and non-vaccinated calves. The vaccinated calves showed significantly higher growth rates, and a superior body composition as indicated by their lower total body water content. The beneficial effects of vaccination were also shown by significantly lower faecal egg outputs in the vaccinated calves and by their lower tissue egg and adult worm counts. The reduced tissue egg counts were also reflected in the milder histopathological changes seen in the vaccinated calves. The vaccinated calves had significantly higher packed cell and circulating red blood cell volumes than the challenged controls, longer red blood cell half lives, and somewhat lower blood volumes and rates of red blood cell synthesis. No untoward clinical effects that could be attributed to vaccination were recorded. These results indicate that zebu cattle can be effectively protected againstS. bovisby vaccination with irradiated organisms. We are now evaluating this type of vaccine in a field trial in an enzootic area in the Sudan.
Attenuation of Eimeria mivati ( = mitis) by selection for precocious development
Authors: McDonald V. , Ballingall S.
Published: June 2009

By selection for early development of oocysts during serial passage through chickens the pre-patent period of the Houghton (H) strain of Eimeria mivati ( = mitis) was reduced by over 20 h. The precocious parasite is less pathogenic than the H strain and has a reduced reproductive potential. Chicks inoculated with the precocious parasite were protected against challenge with the H strain. The pathogenicity, immunogenicity and reproduction of precocious E. mivati and an attenuated egg-adapted line of E. mivati were compared. Although the precocious parasite produced more oocysts than the egg-adapted parasite in chickens, neither parasite induced loss of weight and both were immunogenic.
In vitroinhibition ofPlasmodium falciparummerozoite invasion by human plasma fibronectin
Authors: Ouaissi M. A. , Dutoit E. , Vernes A. , Guerret-Stocker S. , Capron A.
Published: June 2009

Human fibronectin isolated from citrated blood was tested for its ability to bind toPlasmodium falciparumby an indirect immunofluorescent assay using rabbit antiserum to human fibronectin. A positive reaction was observed on merozoites inside schizont-infected erythrocytes. The binding was not observed on non-parasitized red blood cells. The effect of human fibronectin onP.falciparumgrowth was further studied using anin vitroinhibition assay; 50% inhibition of parasite multiplication was obtained with approximately 100 μg/ml of human fibronectin. Slight inhibition was observed below 10 μg/ml. The significance of this finding is discussed.
Resistance againstSchistosoma mansoniinduced by highly irradiated infections: studies on species specificity of immunization and attempts to transfer resistance
Authors: Bickle Q. D. , Andrews B. J. , Doenhoff M. J. , Ford M. J. , Taylor M. G.
Published: June 2009

Significant levels of resistance againstSchistosoma mansoaichallenge were developed by mice exposed to highly irradiated (20 krad.) cercariae of the homologous species (53–67%), whereas vaccination withS. bovis, S. haematobiurnorS.japonicunifailed to confer significant levels of resistance (–5–12%), thus confirming the specificity ofthe immunizing procedure. Attempts to transfer resistance to naive recipients by injection of serum and of spleen or lymph node cells from donor mice vaccinated with highly irradiated cercariae were largely unsuccessful. However, significant levels of resistance could be transferred to mice by injection of serum from rabbits exposed to irradiated cercariae. Comparable levels of resistance were conferred by injection of serum at the time of challenge (34–69%) or 5–6 days later (31–56%). Tn contrast, sera from rabbits injected with solubleegg antigen or homogenized cercariae failed to confer protection upon recipient mice. Sera from vaccinated mice, vaccinated rabbits and antigen-injected rabbits all caused cell adherence to skin-transformed schistosomula hut neither the level of adherence nor the serum titre correlated with the ability to confer protection to mice.
Schistosoma mansoni: effect of maintenancein vitroon the physiology and biochemistry of adult worms
Authors: Mercer J. G. , Chappell L. H.
Published: June 2009

In Medium 199 supplemented with calf serum (+ 10%), adultSchistosoma mansoniproduced a mean total of 400 eggs/worm pair during maintenance for 10 daysin vitro. During the period of egg depositionin vitro, the dry weight of worm pairs decreased by 35%. Biomass decreases were proportionally greater in female worms than in males. Declines in the dry weight of female worms were mainly due to decreases in protein content, while biomass decreases in males resulted from losses of both protein and glycogen. Glucose was depleted from the maintenance medium at a rate of approximately 200 μg/worm pair/day during each of the first 3 daysin vitro, while concentrations of glucose in the medium of above 1 g/litre did not affect the degree of glycogen depletion observed in adultS. mansoniduring culture for 24 h. The contribution of the loss of schistosome gut contentsin vitroto the observed changes is discussed. The work described represents part of an attempt at logical design ofin vitroculture.
Immunity to coccidiosis: stages of the life-cycle ofEimeria maximawhich induce, and are affected by, the response of the host
Authors: Rose M. Elaine , Hesketh Patricia
Published: June 2009

An attempt was made to determine the relative importance of the different life-cycle stages ofEimeria maximain the induction of immunity and also those stages most affected by the immune response of the host. In one experiment the life-cycle was controlled by chemotherapy but in all other experiments partial life-cycles were induced by transfers of infected mucosa between hosts.

The results indicated that the second generation schizont stage is probably that most concerned in the induction of protective immunity and that sexual stages are most susceptible to immune inhibition. After initial inhibition in the immune host the earlier asexual stages were able to resume development when transferred to a susceptible host. The longer the period of exposure to the immune environment, the less able was the parasite to recover.
Studies on the induction of permeability inAscaris lumbricoideseggs
Authors: Barrett J.
Published: June 2009

The initial process in the hatching mechanism ofAscariseggs is the sudden onset of permeability in the previously impermeable ascaroside membrane. During this change the ascaroside membrane remains intact and no chemical changes can be detected. Using the molecular probe 1-anilino-8-naphthalene sulphonic acid no conformational changes were detected in the ascaroside membrane during the induction of permeability. It is suggested that either the permeability change is due to a very localized chemical or conformational change, not detectable by conventional analytical techniques, or the change is due to mechanical damage of the ascaroside membrane, brought about by the activity of the infective larva.
Parr Tate, 1901–1985
Authors: Crompton D. W. T.
Published: June 2009

During my third year as an undergraduate reading Zoology at Cambridge, I found a relatively large parasite inside one of the Asellus aquaticus that had been allocated to me for the afternoon's practical work. After we had failed to identify even the group of animals to which it belonged, someone suggested that I should take my find to The Molteno Institute on the Downing Site. There I was ushered into Room 3 where I first met Dr Tate. After listening to my account he looked at my specimen and said, ‘Now just one second …’ in his rich Irish accent. As I later came to know, so much of his teaching or advice began with that highly characteristic phrase. He told me that I had found an acanthocephalan worm in its intermediate host, and when I returned some days later to tell him the results of my search of the literature, he suggested that I should work on the Acanthocephala under his supervision for the Ph.D. Degree after my graduation. I never regretted for one moment my decision to take up his offer. He maintained close contact with me, as he did with all his former research students, and the last letter I received from him was dated 16 September 1985, written just a few weeks before his death on 7 November 1985 in hospital in Cork. During the 24 years of our association I was never on Christian-name terms with him. He was always ‘Dr Tate’ or, when talking with equally close mutual associates like Donald Lee, David Molyneux, John Barrett, Vaughan Southgate or Roger Tatchell, we referred to him as ‘P.T.’. He had great integrity and fairness in all that he did and an ability of seeming to know exactly what you were thinking. These attributes, coupled with his extraordinarily wide parasitological knowledge, generated our respect. He also had a delightful sense of fun and even his sarcasm was kind and gentle. Our children loved him and his steady supply of sweets for those who visited him in Room 3 and the book tokens that came without fail every Christmas were expressions of his kindness.
Population dynamics in echinococcosis and cysticercosis: comparison of the response of Echinococcus granulosus, Taenia hydatigena and T. ovis to control
Authors: Gemmell M. A. , Lawson J. R. , Roberts M. G. , Kerin B. R. , Mason C. J.
Published: June 2009

A comparative study has been made of the progress in the control of ovine echinococcosis caused by Echinococcus granulosus and the ovine cysticercoses caused by Taenia hydatigena and T. ovis in New Zealand. The methods of control included an educational and a dog-dosing programme. In the Styx field trial, the Otago/Southland Surveillance Programme and the national control programme, E. granulosus declined towards extinction. In contrast, this same control effort transformed the cysticercoses from hyper-endemic to endemic status with focal epidemics. In this unstable state, the density-dependent constraint was negligible and superinfection occurred.
Increased exposure of parasite antigens at the surface of adult male Schistosoma mansoni exposed to praziquantel in vitro
Authors: Harnett W. , Kusel J. R.
Published: June 2009

Praziquantel is a broad-spectrum anthelmintic active against schistosome species which are major parasites of man. Two major effects on Schistosoma mansoni have been demonstrated; (i) spastic paralysis of the parasite musculature, possibly arising as a consequence of an influx of Ca2+ into the worm (Pax, Bennett & Fetterer, 1978; Coles, 1979) and (ii) vacuolation and degeneration of the worm tegument (Becker, Mehlhorn, Andrews, Thomas & Eckert, 1980). These events may contribute to the elimination of schistosomes in vivo, but this elimination may partly be dependent on the host immune response as infected T-cell-deprived mice are less able than immunologically intact animals to reduce their worm burdens following drug treatment (Doenhoff, Harrison, Sabah, Murare, Dunne & Hassounah, 1982). This latter observation raises the possibility that praziquantel may lower the ability of the parasite to evade host immunity by increasing the exposure of parasite antigens capable of acting as targets for host antibody, or antibody-armed cells at the worm surface. Consistent with this idea is the observation that adult schistosomes in praziquantel-treated mice are invaded a few hours after treatment by host granulocytes (Mehlhorn, Becker, Andrews, Thomas & Frenkel, 1981).
A preliminary study of the nature of infection and immunity in chickens given an attenuated line of Eimeria acervulina
Authors: McDonald V. , Ballingall S. , Shirley M. W.
Published: June 2009

The Houghton (H) strain of Eimeria acervulina was attenuated by serial passage through chickens of the first oocysts produced during infection. This selection pressure resulted in a reduction in the pre-patent period of the parasite, shown to be due to the selection of a line predominantly with only 3 instead of 4 generations of schizonts. The precocious line had a reproductive potential much lower than that of the parent strain and it was significantly less pathogenic. Chickens given oocysts of the precocious line were almost completely immune to challenge with the Houghton strain.
An analysis of variations in the age structure of Fasciola hepatica populations in sheep
Authors: Smith Gary
Published: June 2009

The processes which govern the age structure of Fasciola hepatica populations in sheep were investigated by means of a simple mathematical model. The mortality of the metacercariae on the pasture was shown to be a factor of major importance. The mortality rate depends on the micro-climate that prevails at the pasture surface, and thus the age distribution curve of a population of flukes is also determined in part by the weather. This has important implications for the chemotherapy of fascioliasis: flukicides are not equally effective over the whole range of age-classes of parasite and so the factors which govern the age distribution curve of the parasite population within individual hosts ultimately determine the efficiency of chemotherapy.
Monoclonal antibodies against surface antigens of schistosomula of Schistosoma mansoni
Authors: Taylor D. W. , Butterworth A. F.
Published: June 2009

Monoclonal antibodies have been produced after fusion of NS-1 murine myeloma cells with spleen cells from mice immunized either by chronic primary infection or with irradiated cercariae: in both cases, animals were challenged with live cercariae 7 days before fusion. The initial cultures were screened for anti-schistosomular antibodies both by a radioimmunoassay with whole schistosomulum extracts and by immunofluorescence. There was no correlation between the two techniques and subsequent screening was carried out by immunofluorescence. Cloning was carried out in soft agar and 7 cloned cell lines, from 5 initial cultures, were selected for detailed study. Products of 6 of these 7 lines were monoclonal, as judged by isoelectricfocusing of [35S]methionine-labelled supernatant fluids, and their binding to live schistosomula was specific. None of the antibodies showed detectable activity in mediating eosinophil- or complement-dependent damage to schistosomula in vitro. However, 2 antibodies were successfully used to isolate surface proteins with an apparent molecular weight of 24000 on SDS-polyacrylamide gel electrophoresis.
Daily egg production of Ascaris lumbricoides: the distribution of eggs in the faeces and the variability of egg counts
Authors: Sinniah B.
Published: June 2009

Fifteen children aged from 6 to 12 years who were infected with Ascaris lumbricoides were selected for the study. The number of eggs/g (e.p.g.) of stool was determined using Beaver's direct smear technique, Stoll's dilution egg count technique and Katz's modified thick smear technique. Beaver's direct smear method consistently gave a higher e.p.g. than the other two methods. Results of this study show that Katz's modified thick smear technique was the best of the three methods used. The e.p.g. depends on several factors: the amount of stool passed daily, the concentration of eggs within a stool sample, the daily egg output, the worm load, the age of the worm and the technique used for determining the egg load. The daily average egg output/female A. lumbricoides was estimated to be 238722 (range 134462–358 750) with an average e.p.g. of 3540. The estimation of worm load based on egg count is useful in determining the intensity of infection in an individual. The male/female worm ratio was estimated to be 1: 1·4.
Factors influencing the assessment of anticoccidial activity in cell culture
Authors: Latter Victoria S. , Wilson R. G.
Published: June 2009

A comparative study has been made of the factors influencing the assessment of anticoccidial potency in vitro against Eimeria tenella using established anticoccidials and arprinocid and some of its analogues. Drugs whose potency depended upon medium composition were amprolium, lasalocid and halofuginone. There was a difference in strain sensitivity with robenidine. Host cell type had an important effect on potency of monensin, decoquinate, arprinocid and its analogues. Arprinocid was active in chick liver cell systems but totally inactive in chick kidney cell systems, although its N-oxide was active in both cell types. Arprinocid-containing medium, conditioned by supporting the growth of chick embryo liver cell cultures, had an anticoccidial effect on E. tenella, growing in chick kidney cells. It is deduced that the anticoccidial activity of arprinocid in the chick is due to a metabolite.
Strategies for the use of anthelmintics in livestock and their implications for the development of drug resistance
Authors: Michel J. F.
Published: June 2009

Just as human helminth infections are vitally influenced by the way in which people live, so the helminthiases of domestic animals depend on how these are managed.Veterinary helminthology is a branch of agriculture. The agricultural industry changes quickly, more quickly than the ideas of scientists. Ideas, in their turn change more rapidly than their practical implications are understood. A discussion of anthelmintic use must therefore be partly agricultural, partly historical.
How anthelmintics help us to understand helminths
Authors: Bossche H. Vanden
Published: June 2009

Study of the mode of action of the anti-parasitic ‘hydrogenophore’, closantel, revealed that mitochondria isolated from livers of untreated rats, 13 weeks after infection withFasciola hepaticametacercariae, were uncoupled. This uncoupling of mitochondria might be induced by a product(s) excreted by the liver fluke. The lipid extractable product(s) binds to albumin and has a molecular weight between 500 and 1000 Daltons. A second unexpected finding indicates that closantel affects the motility ofSchistosoma mansoni in vitroby interferin with mitochondrial ATP synthesis. The results obtained are suggestive of a role for aerobic metabolism in the generation of energy required for motility.
The modes of action of some anti-protozoal drugs
Authors: Howells R. E.
Published: June 2009

In spite of the continuing need for new and improved anti-protozoal drugs for use in man, a considerable contraction of industrially based research on anti-protozoal drugs has occurred in recent years. Newton (1983) reviewed the reasons for this decline and presented a compelling argument that fundamental research on the biology of the parasites is essential for the discovery of leads for the development of a new generation of drugs – a rational chemotherapy. The rapid advance in knowledge of the biochemistry of parasitic protozoa which has occurred in recent years has provided a number of potential leads to new drug development and has permitted a greater understanding of the mode of action of many current drugs. The account of these advances which follows is necessarily selective and relates to protozoan parasites of man.
The ultrastructure of the intestine of the redia of Parorchis acanthus Nicoll (Digenea: Philophthalmidae) from the digestive gland of Nucella lapillus L
Authors: Rees F. Gwendolen
Published: June 2009

The intestine of the redia of Parorchis acanthus is lined by a gastrodermis and surrounded by inner longitudinal and outer circular muscles. The gastrodermis consists of alternating rings of dense and lucent cells of similar dimensions, with similar nuclei and with microvilli on the lumenal surface. The dense cells contain ribosomes, dense secretion bodies, vesicles and a few lipid bodies. Ribosomes, dense bodies and lipids are absent from the lucent cells but vesicles are present which, as in the dense cells, pass along the microvilli to be discharged into the lumen. Both types of cells are secretory, absorptive and transportive. The lucent cells, in addition, store glycogen in areas of the cytoplasm devoid of organelles. Tips of processes from the parenchyma cells are engulfed in pockets in the basal plasma membrane, of both, facilitating transport of nutrients from the gastrodermis directly into the parenchyma
The migration, growth and development of Cyclocoelum oculeum (Kossack, 1911) (Trematoda: Cyclocoelidae) in Fulica americana (Gm.)
Authors: McLaughlin J. D. , Marcogliese D.
Published: June 2009

The migration, growth and development of Cyclocoelum oculeum Kossack, 1911 was studied in orally and parenterally exposed coots, Fulica americana (Gm.). Young flukes injected into the body cavity migrate to the sinuses from the body cavity via the air sacs and air passages. Young flukes were first found in the trachea on day 18 post-infection and in the sinuses on day 21. Migration was not synchronous and some flukes were found in the air sacs and trachea of parenterally exposed coots up to 45 days post-infection. Exponential growth and organogenesis began between days 9 and 12. Flukes in the sinuses were consistently larger than flukes of the same age in either the air sacs or trachea. Growth and organogenesis proceeded in the latter flukes but at a slower rate than those in the sinuses.
Allosteric control of pyrimidine transport in Hymenolepis diminuta: an unusual kinetic isotope effect
Authors: Uglem G. L. , Dupre R. K. , Harley J. P.
Published: June 2009

A thymine–uracil transport system is present in the plasma membrane brush-border of the tapeworm, Hymenolepis diminuta. The relation between initial uptake and substrate concentration of either thymine or uracil was sigmoidal when 2-14C-labelled substrates were used. In contrast, absorption kinetics of methy 1-14C- and 3H-labelled substrates were hyperbolic. Since there was no metabolism of the labelled substrates during the incubation period, these differences indicate that the sigmoidal kinetics of pyrimidine transport in this organism is an isotope effect associated with the presence of the 14C label at the 2 position in the pyrimidine ring.
Re-discovery of Haemoproteus kopki (De Mello, 1916) in two geckoes from the Afghan border of Pakistan
Authors: Telford Sam R.
Published: June 2009

Haemoproteus kopki (De Mello, 1916) is reported from the geckoes Teratoscincus scincus and T. microlepis collected in three localities on the Afghan border of Pakistan. A detailed description of H. kopki is provided in correlation with the courses of an initial, acute infection and a relapsed, chronic infection. Haemoproteus kopki is characterized by large round or oval gametocytes which show sexual dimorphism in distribution of pigment: macrogametocytes show pigment dispersed in dark granules throughout the cytoplasm, while pigment in microgametocytes is aggregated into large, round golden masses within vacuoles in one, or rarely two foci. Other sexual differences exist in gametocyte dimensions. Gametocytes produced in the relapse infection grew much more slowly than did those of the initial infection, and never attained a comparable size despite being observed for twice the length of time. Despite a maximum parasitaemia of 53·8% in the initial infection, increased erythropoiesis did not occur. No asexual stages were found in tissues examined. The presence of mixed infections of H. kopki, Leishmania sp. and microfilariae in a harsh sand dune habitat with presumably limited dipteran fauna suggests their having a common vector in intimate association with the burrows inhabited by the geckoes.
Suppression of the immune response to Trichuris muris in lactating mice
Authors: Selby Gwendoline R. , Wakelin D.
Published: June 2009

Mice infected with Trichuris muris during lactation were unable to expel the infection at the normal time, but expulsion occurred when lactation was terminated. Suppression of expulsion was uniform in mice suckling more than five young but variable with smaller litters. Mice exposed to a primary infection while lactating were shown to have serum antibodies capable of passively transferring immunity to recipient mice and showed near normal immunity to a secondary infection given after lactation had ceased.

Acquired immunity to T. muris was also suppressed by lactation, but the worms which became established in lactating resistant mice were fewer and smaller than those in non-lactating, non-resistant controls.

It is suggested that the suppressive effect of lactation in this hostparasite relationship is exerted on the second, lymphoid cell-mediated phase of worm expulsion.
Evasion of the insect immune response by Moniliformis dubius(Acanthocephala): further observations on the origin of the envelope
Authors: Lackie Ann M. , Lackie J.M.
Published: June 2009

The envelope around larvae of Moniliformis dubius appears to protect the parasite against immune recognition and encapsulation by the insect host's haemocytes. The origin of this envelope has been the subject of controversy although most evidence suggests it is parasite-derived. If host-derived, the envelope would be expected to share surface properties with host tissue. Thus, experiments were undertaken, transplanting parasites and host tissue to other insects and using haemocytic encapsulation as an assay for immune recognition, in order to compare the response to host tissue and to the parasite's envelope. Parasites without their envelopes, and pieces of tissue (ventral nerve cord) from the experimental host (the locust Schistocerca gregaria) were recognized as foreign and encapsulated in the cockroach, Periplaneta americana. The majority of parasites with their envelopes were unencapsulated or only partially encapsulated on transfer to their normal host, P. americana, indicating that the envelope does not have surface similarity to locust tissue. Cockroach-derived parasites with or without envelopes were not encapsulated in S. gregaria, suggesting that the larva itself can evade or inhibit the locust's recognition mechanism. However, since larvae which develop in S. gregaria are enclosed in an envelope, the formation of the envelope would seem to be an inherent feature of the parasite's development.
A monoclonal antibody toBabesia divergenswhich inhibits merozoite invasion
Authors: Winger Caroline M. , Canning Elizabeth U. , Culverhouse J. D.
Published: June 2009

A monoclonal antibody-producing hybridoma cell line has been raised against merozoites ofBabesia divergens. This antibody is strongly reactive against merozoites in an enzyme-linked immunosorbent assay (ELISA) and is also positive in an indirect fluorescent antibody test (IFAT) on preparations of live merozoites. The antibody recognizes an antigen, of molecular weight (Mr) 50–60 K by Western blot analysis on SDS–polyacrylamide gel electrophoresis (SDS–PAGE) gels. Merozoite neutralization assays show that the antibody significantly inhibits merozoite invasion of bovine erythrocytes.
Control of insects by bacteria
Authors: Burges H. D.
Published: June 2009

All bacteria in microbial insecticides are species ofBacillusand form spores since they have to survive in the environment and on the shelf. They can be formulated as wettable powders, suspensions and dusts for application with conventional pest control machinery. All are safe to man and virtually all non-target organisms. Development costs are relatively low, but host specificity greatly restricts markets, the largest beingca. 2000 tons per annum in the West forB. thuringiensis. All act only after ingestion, a disadvantage because there is no contact action and usually only larvae are attacked. Three main groups have special features that determine their commercial success.

TheB. popilliaegroup is produced onlyin vivowhich limits production by three small firms. The Japanese beetle has been controlled in grassland in the warm parts of the USA by single applications of spores in heaps, spaced 2 m each way. The bacterium spreads slowly to untreated areas, is very persistent and kills only by infection.

TheB. thuringiensisgroup kills larvae of Lepidoptera, mosquitoes and blackflies, mainly by gut poisoning with a protein crystal toxin. It rapidly paralyses mouthparts and gut, stopping crop damage. It is readily produced by deep liquid fermentation, but does not persist and needs repeated application during the pest season. Products containing no beta exotoxin can be applied at unlimited dosage to food crops up to harvest. Only one application is needed for stored grain. After 20 years' use of strains against Lepidoptera, a different strain is now used commercially against mosquitoes and blackflies (only 5 years after its discovery), although improvements in formulation for aquatic application are needed. A recent new product based on the beta exotoxin is used in Finland only against flies in pig houses because it has some vertebrate toxicity.

TheB. sphaericusgroup is similar toB. thuringiensis, except that its proteinaceous toxin is different, is situated in the spore wall in strain 1593, and attacks only mosquitoes. Now at the pilot production stage, its commercial future depends on whether it is more potent thanB. thuringiensisagainst certain species and whether it can recycle to give effective extended mosquito control in some environments.

Intensive selection from natural isolates has improved potency 100 to 600 fold. This selective effort must be maintained and improved by genetic manipulation, which can be used to develop greater potential, particularly since DNA coding for the crystal toxin is carried on plasmids. This also gives speculative hope that the toxin may be incorporated into natural aquatic bacteria for mosquito control and into plants for protection against lepidopterous larvae. A great advantage is that these bacteria do not harm beneficial fauna to cause pest resurgence. At present, the main use lies in integrated pest control systems, although bacteria are not likely to supplant chemical insecticides on a large scale in the near future.
Excystation of Notocotylus attenuatus (Rudolphi, 1809) Kossack, 1911 (Trematoda: Notocotylidae) and their localization in the caecum of the domestic fowl
Authors: Radlett A. J.
Published: June 2009

Studies on the biology of Notocotylus attenuatus in the domestic fowl were undertaken with the aim of determining where in the alimentary system the metacercariae excyst and how soon the juvenile worms become established in the caecum of the host. The metacercariae were found to excyst in the lower intestine and juvenile worms were recovered from the caecum after 4 h. Thereafter, as the worms increased in size they changed their position relative to the viii and also moved down the caecum, coming to lie in the blind ending region as the worms approached maturity.
Observations on the development and survival of the free-living stages ofHyostrongylus rubidusboth in their natural environments out-of-doors and under controlled conditions in the laboratory
Authors: Rose J. H. , Small A. J.
Published: June 2009

Faeces containing eggs ofHyostrongylus rubiduswere deposited on grass plots each month throughout 1980. Eggs in faeces deposited on plots from May to October developed into infective larvae but in May development was completed only in artificially moistened faeces, the weather was warm and dry and natural faeces dried out rapidly resulting in the death of eggs and pre-infective larvae. For the remainder of this period the weather was sufficiently warm and wet for development to be completed. More eggs developed into infective larvae on plots with well-grown herbage than on plots with short herbage. In April a few eggs survived and developed into lst-stage larvae but no further development took place. In the laboratory development was completed at temperatures ranging from 10 to 27 °C but no development took place at 4 °C. Out-of-doors infective larvae survived on herbage for up to 10 months while in the laboratory, infective larvae suspended in tap water survived even longer at 10 and 22 °C, but the larvae were rapidly killed by continuous freezing and by desiccation when the relative humidity was less than 95%. The relationship between climatic conditions and the development and survival of the free-living stages is discussed and a comparison made with the free-living stages ofOesophagostomum dentatum.
Rohdella siamensis gen. et sp.nov. (Aspidogastridae: Rohdellinae subfam.nov.) from fresh water fishes in Thailand, with a reorganization of the classification of the subclass Aspidogastrea
Authors: Gibson D. I. , Chinabut S.
Published: June 2009

Rohdella siamensis, a new genus and species of aspidogastrean, is described from freshwater fishes in Thailand. A new subfamily, the Rohdellinae, is erected to accommodate this worm on the grounds that it differs from all known aspidogastreans in that the male and female ducts unite to form an hermaphroditic duct, with the result that the intromittent organ is a sinus-organ and not a cirrus. A new classification of the subclass Aspidogastrea is presented. Two orders are recognized: the Aspidogastrida, containing a single family, the Aspidogastridae, which in turn contains 3 subfamilies, the Aspidogastrinae, the Cotylaspidinae and the Rohdellinae subfam.nov.; and the Stychocotylida ord.nov., containing 3 families, the Stichocotylidae, the Multicalycidae fam.nov. and the Rugogastridae. The systematic position of the Stichocotylida, and especially the Rugogastridae, is commented upon.
A stereological analysis of the tegumental mitochondria in Corrigia vitta (Trematoda: Dicrocoeliidae)
Authors: Robinson R. D. , Halton D. W.
Published: June 2009

The tegumental mitochondria from the anterior, mid-ventral and mid-dorsal regions of the body surface of Corrigia vitta have been analysed using stereological and statistical methods. Mitochondria from the ventral tegument were more numerous and contained a greater density of cristae than either the anterior or dorsal tegumental mitochondria. A close association between the size and numbers of mitochondria in the anterior regions of tegument appears to be important in maintaining a relatively constant mitochondrial volume fraction. Results are discussed with respect to worm surface function in the intact host-parasite system.
Eimeria tenella: in vitro development in irradiated bovine kidney cells
Authors: Crane M. St J. , Schmatz D. M. , Stevens S. , Habbersett Mary C. , Murray P. K.
Published: June 2009

The initial infection and first-generation development of Eimeria tenella was quantified using a cloned MDBK (Madin-Darby Bovine Kidney) cell line, irradiated with gamma radiation prior to infection, as the host cell. Irradiated cell cultures were found to be more susceptible to infection and had a greater capacity to support parasite development than non-irradiated cultures. It was suggested that the larger proportion of cells in the G2 phase of the cell cycle, the larger individual cell size and the inhibition of cell division in the irradiated cultures were all factors contributing to the increased susceptibility to infection and capacity to support parasite growth and development. The application of this technique (host cell irradiation) to the cultivation of other intracellular, protozoan parasites is discussed.
The ultrastructural development of the oocyst wall of Eimeria maxima
Authors: Pittilo R. M. , Ball S. J.
Published: June 2009

Oocyst wall formation in Eimeria maxima was studied during the macrogamete stage in intestinal cells of the chick and in unsporulated oocysts isolated from faeces. The outer of the 2 membranes bounding the mature macrogamete separated from the surface but remained as a veil surrounding the developing oocyst throughout the whole intracellular process. Wall-forming bodies Type I were initially applied to the limiting membrane of the zygote cytoplasm; a layer of material similar to their contents was then formed around the zygote. As this occurred a new double membrane was formed surrounding the oocyst cytoplasm. The outer wall layer was initially homogenous in appearance but later developed into 2 zones, an outer amorphous region and an inner osmiophilic region. The inner layer of the oocyst wall was formed from the contents of the wallforming bodies Type II which dispersed between the outer wall and the limiting membranes of the oocyst cytoplasm. There was evidence of an additional membrane formed external to the outer wall. The outer membranes were not present around the wall of oocysts passed in the faeces of chicks, but the same wall zonation was evident, although the inner osmiophilic zone of the outer wall layer was markedly thinner in comparison with the same zone seen in the tissues.
The development of Theileria = Cytauxzoon taurotragi (Martin and Brocklesby, 1960) from eland in its tick vector Rhipicephalus appendiculatus
Authors: Young A. S. , Grootenhuis J. G. , Leitch B. L. , Schein E.
Published: June 2009

The sexual cycle of Theileria taurotragi was identified in the gut lumen of replete Rhipicephalus appendiculatus nymphs maintained at 28°C which had fed on eland with rising parasitaemias. Macro- and microgametes developed from ring-form piroplasms within 24 h after repletion. The microgamonts were elongate with 2 or more lateral projections. The nuclei of the microgamonts divided into 4 and the microgamonts differentiated into 4 thread-like microgametes each with a central nucleus. Round macrogametes developed at the same time and stages indicative of the fusion of the macro- and microgametes were observed after 48 h. The resultant zygotes were detected in the gut wall cells by day 4, many being rounded and vacuolated with a peripheral nucleus. By day 7 the zygote cytoplasm became dense and they lay in clusters still within the cells. Binucleate zygotes were observed at this stage. The zygotes increased in size and by day 12 began to transform into kinetes by invagination. By the time the nymphs moulted into adults (about day 14), the kinete straightened to a broad anterior end and a tapering posterior with a mean length of 22·1 μm. Kinetes were detected in the haemolymph by day 16. By day 20 the kinetes had penetrated the salivary gland acinar cells where they underwent schizogony until the infected acinar cells were filled with multinucleated sporoblasts. The nuclei of the infected acinar cells became greatly enlarged soon after penetration of the kinete. Division of the sporoblast nuclei was stimulated by feeding of the adult ticks. From the 2nd day of attachment of the ticks to rabbits the sporoblasts underwent a process of schizogony to produce cytomeres. Each nucleus of the cytomere divided to produce several small nuclei which differentiated into uninucleated sporozoites.
Copepod parasites of deep-sea benthic fishes from the western North Atlantic
Authors: Ho Ju-Shey
Published: June 2009

Nine species of parasitic copepods are reported, with 3 of them being new to science. They are: (1) Chondracanthodes deflexus Wilson from Antimora rostrata Günther, Coryphaenoides (Chalinura) brevibarbis (Goode and Bean), Coryphaenoides (Nematonurus) armatus (Hector), Coryphaenoides (Chalinura) leptolepis (Günther), and Coryphaenoides (Lionurus) carapinus (Goode and Bean); (2) Chondracanthodes radiatus (Müller) from Macrourus berglax Lacepede; (3) Lernaeopodina pectinata sp.nov. from Alepocephalus agassizi (Goode and Bean); (4) Neobrachiella pinguis (Wilson) from Antimora rostrata Günther; (5) Clavella adunca (Strøm) from Macrourus berglax Lacepede; (6) Sphyrion lumpi (Krøyer) from Antimora rostrata Günther; (7) Lophoura gracilis Wilson from Synaphobranchus kaupii Johnson; (8) Lophoura pentaloba sp.nov. from Coryphaenoides (Nematonurus) armatus (Hector) and Nezumia bairdii (Goode and Bean) and (9) Lophoura tetraphylla sp.nov. from Antimora rostrata Günther. The infected fishes were collected with trawls from depths of 828 to 4815 m in the New York Bight and 403 to 1294 m near the Grand Banks (south of Newfoundland).