bluuebunny/crossref_metadata_2025 huggingface dataset:
The development ofHymenolepis diminutain primary and secondary infections in mice
Authors: Hopkins C. Adrian , Subramanian G. , Stallard Helen
Published: June 2009

Over 90% ofHymenolepis diminutacysts administered by stomach tube become established in CFLP, and Porton strains of mice. The rate of growth of single worm infections in terms of dry weight and length was determined. The rate of growth ofH. diminutain mice is slower than in rats even in worms only a few mm long. In most mice growth ceases abruptly on day 10±1 day when the worm is 4–30 cm long, destrobilation usually occurs leaving a scolex and neck often 0·5–2 mm in length. Destrobilated worms can survive for at least 47 days but little if any regrowth occurs unless the worms are surgically transplanted into rats or previously uninfected mice. Normal growth appears to be resumed within hours in both recipient hosts. The cause of destrobilation is probably not physiological; position of establishment and forward migration during growth of the worm in mice is similar to that in a rat. Destrobilation occurs well before the worm fills the small intestine lengthwise. Strong evidence of an immunological response being involved is given by the fate of a secondary infection given 22 and 28 days after the primary. Lower % recoveries were recorded in secondary infections killed 6–9 days later, and the worms were severely stunted. The various lines of evidence are discussed and it is concluded no reasonable doubt exists thatH. diminutais rejected by CFLP and Porton mice as a result of an immunological response.
Characteristics of parasite populations in endemic trichostrongylidosis
Authors: Whitlock J. H. , Crofton H. D. , Georgi J. R.
Published: June 2009

Worm counts, faecal egg counts and erythrocyte losses are recorded for lambs which were exposed on a naturally infected pasture for different periods in different years. After each exposure period the lambs were kept under conditions in which no further infection could occur; at varying times, usually after the infections had had time to maturo, the lambs were killed and examined. A detailed analysis of the results is given. It is concluded that the negative binomial distribution of worms among sheep within a flock is not a reflexion of the pasture distribution of infective stages but is the result of a combination of Poisson distributions, these distributions being generated by genetic subsets within the flock. There is a remarkable correlation between the numbers of Haemonchus present and the numbers of worms of the other genera. It is suggested that there are host-mediated common elements in the biomass regulating parameters of mixed trichostrongyle infections and that there is a resource-allocating device. Three main hypotheses are proposed. The hypotheses are:
(1) The dimensional constraints on the host-parasite system are the results of various kinds of pace-setters or biological clocks. In each annual cycle the parent worms programme the rate of development through each generation.
(2) The rate of development of the worms is tied stochastically or deterministically to the rate of senescence and death.
(3) The rate of development and death for each trichostrongyle is set at the start of each season by a host factor which acts on a comparable area of the genome in each trichostrongyle.
Methods of testing these hypotheses are discussed and the work related to other systems.
The effect of the cestodeCaryophyllaeus laticepsupon production and respiration of its intermediate host
Authors: Kennedy C. R.
Published: June 2009

A quantitative assessment of the effect of larvalCaryophyllaeus laticepsupon its intermediate host,Psammoryctes barbatus, was obtained by comparing the energy budgets of infected and uninfected tubificids from the same natural populationm throughout the course of a year. Measurements of the energy transformations during growth, reproduction and respiration of tubificids indicated some of the effects of the parasite.

Infection had no influence upon the life-span of the host, but progressively decreased its growth and prevented reproduction. By contrast no significant differences were detected between the respiration rates of infected and uninfected animals. Decrease in the production of infected host tissue became apparent as soon as the parasite was detectable. Over the first 6 months loss in production due to the parasite was 50%, and over the whole life-span 59·9%. The production: respiration ratio of infected tubificids was also lower, but differences in assimilation were probably only small. The overall effects of the parasite upon its host population are slight, and the loss in tubificid nutriment available for fish food due to the parasite is less than 5% and of little economic importance. The way in which the parasite actually influences its host's physiology is discussed, and the effect ofC. laticepsupon its host's energy budget compared with that of a plerocercoid larva on its fish host.

I should like to thank Dr M. Palmer for the loan of her Warburg flasks, Mr J. Harris for taking samples for me when I was unable to do so,'and Mr G. G. Vickers for many helpful comments and discussions on ecological energetics. I am also grateful to Mr G. Baileyfor combusting the samples for me.
Growth and respiration throughout the life-cycle ofNematospiroides dubiusBaylis (1926) (Nematoda: Heligmosomidae): the parasitic stages
Authors: Bryant Victoria
Published: June 2009

The growth of male and female parasitic stages ofNematospiroides dubiusfrom male and female ASH/CS1 mice was measured in terms of dry weight. No sex-linked resistance of mice to infection withN. dubiuswas apparent, as growth was the same in both sexes of host. The growth rate did not alter when moulting occurred.

All parasitic stages ofN. dubiusconsumed oxygenin vitroand oxygen was also shown to be necessary for motility and survival.

The relationship between body size and metabolic rate was established for male and female parasiticN. dubiusand thebvalues indicated that aerobic metabolism is of functional importance to this species.

The size/metabolism relationship for the whole life-cycle was established.
The ultrastructure of the cysticercoid of Tatria octacantha Rees, 1973 (Cyclophyllidea: Amabiliidae) from the haemocoele of the damsel-fly nymphs Pyrrhosoma nymphula, Sulz and Enallagma cyathigerum, Charp
Authors: Rees Gwendolen
Published: June 2009

The cysticercoid of Tatria octacantha Rees, 1973 from the haemocoele of damsel-fly nymphs consists of an outer and inner cyst. The tegument of the outer surface of the outer cyst bears long slender microvilli which increase the surface area presumably for absorption. The tegument on the inner surface bears electron-dense microvilli and contains vesicles embedded in an electron-dense material. The contents of the vesicles resemble those of the central cavity in which the inner cyst floats freely. Nutrients absorbed by the outer cyst pass into the central cavity where they are available to the inner cyst.
The survival ofTrichuris murisin wild populations of its natural hosts
Authors: Behnke J. M. , Wakelin D.
Published: June 2009

The results of experimental infections ofTrichuris murisin wild field mice (Apodemus sylvaticus) and laboratory-bred wild house mice (Mus musculus) showed that the parasite elicited an immune response similar to that previously described in strains of laboratory mice. Experiments in laboratory mice showed that the parasite was able to become sexually mature only when small single infections or repeated low-level infections were given. A survey of a population of 43 wild house mice naturally infected withT. murisshowed that the pattern of small worm burdens in the majority of mice was consistent with a situation of repeated low-level infection, except in the case of six female mice which harboured larger mature worm burdens. It is suggested that in these mice pregnancy and/or lactation may have suppressed the immune response, allowing the accumulation of a worm burden in excess of the threshold for worm expulsion.
Effects of different infection rates on the oocyst production ofEimeria acervulinaorEimeria tenellain the chicken
Authors: Williams R. B.
Published: June 2009

Experiments using chicks of specified strain, age and sex raised under identical conditions on the same diet and infected with known strains of coccidia are described. The relationships between the infection rates and resulting oocyst productions ofEimeria acervulinaandE. tenellaare presented graphically and are used to demonstrate a crowding effect. Possible contributory factors to the crowding effect and possible reasons for the differences between theE. acervulinaoocyst production of unmedicated birds or birds medicated with decoquinate are discussed. It is suggested that standard curves for normal infection rate — reproductive potential relationships under strictly specified conditions may be of value in choosing appropriate infection rates for critical experimental work to assess the effects of anticoccidial compounds on oocyst production.
The immunity arising from continuous low-level infection withEimeria tenella
Authors: Joyner L. P. , Norton C. C.
Published: June 2009

Daily infection with doses of approximately five oocysts ofEimeria tenellaproduced an infection with an extended patency which ceased by the time the birds had received about 140 oocysts. Total oocyst production was comparable with that in birds given the same number of oocysts in a single dose, but the immunity to subsequent heavy challenge was significantly greater. Continuous exposure to low-level infections may be more comparable to the field situation and the present results suggest how birds can acquire a strong immunity without showing evidence of clinical disease.
The life-cycle of Bucephalus haimeanus Lacaze-Duthiers, 1854 from Cardium edule L.
Authors: Matthews R. A.
Published: June 2009

Bucephalus haimeanus is shown to be an estuarine species. The cercaria from Cardium edule is briefly redescribed to include details of the nephridial system. The metacercaria is described for the first time, having been obtained experimentally in Pomatoschistus microps and Pleuronectes platessa. In Pomatoschistus microps it survives at least 10 months, development within this host being completed within 2 months. The main site of infection is the liver. Migration is completed within 1 h and in some instances within 10 min. During this period the metacercaria actively feeds on host tissue, the gut being greatly distended with food on encystment. A hyaline cyst wall is maintained throughout the remaining life of the metacercaria. ‘O’ group plaice are highly susceptible to invasion by B. haimeanus during early summer and 100% infections were recorded in catches from Ynys-las, Dovey Estuary, in June. Experiments showed that only 2% of the metacercariae survived more than two weeks and that ‘l’ group plaice were non-susceptible to infection. Plaice are therefore considered accidental hosts. The metacercaria was linked with the adult stage from Morone labrax on the basis of comparative morphology and the ecology of the hosts, the bass entering the estuarine habitat during the summer months. The adult is considered synonymous with Bucephalus minimus Stossich, 1887.
Development ofAncylostoma ceylanicumLooss, 1911 (Hamster strain) in the albino mouse,Mus musculus, with and without cortisone
Authors: Ray D. K. , Bhopale K. K. , Shrivastava V. B.
Published: June 2009

Complete development ofAncylostoma ceylanicum(Hamster strain) is reported for the first time in mice. A patent infection (viz. ova in faeces) could be established only under the influence of hydrocortisone acetate. Cultures made from the faeces containing eggs produced viable larvae which were infective to mice.
Hatching rhythms in three species ofDiclidophora(Monogenea) with observations on host behaviour
Authors: Macdonald Sheila
Published: June 2009

Eggs of three species ofDiclidophorawere incubated in alternating 12 h periods of light and darkness at 13°C. Eggs ofD. merlangicollected at Arbroath hatched during the illumination period with most larvae being recovered in the first 4–6 h; some evidence of a seasonal difference in hatching of these eggs was found. Eggs ofD. merlangicollected at Plymouth hatched with a peak of larval recovery in the 2 h period before the light came on. Eggs ofD. luscaehatched over ‘dusk’ while those ofD. denticulatahatched after the light was switched off. Neither mechanical disturbance nor the proximity of host tissue caused hatching inD. merlangiorD. luscae. Observations on the behaviour of the host fishes suggest that the hatching rhythms are adapted to specific host behaviour patterns.
Nippostrongylus brasiliensis: further properties of antibody-damaged worms and induction of comparable damage by maintaining worms in vitro
Authors: Love R. J. , Ogilvie Bridget M. , McLaren Diane J.
Published: June 2009

When adult Nippostrongylus brasiliensis were maintained in vitro they became damaged. Using the criteria of ultrastructural morphology, acetylcholinesterase isoenzyme pattern and the behaviour of the worms after transfer to a normal rat, this damage appeared to be similar to that produced by the in vivo action of antibodies.

Antibodies were shown to be responsible for the anterior migration of adult worms which occurs during primary infections in mature rats and in the prolonged infections seen in lactating and immature rats.

Antibody damaged worms and worms unaffected by antibodies were equally able to stimulate the immune response required for worm expulsion. Apparently antibody damage is not required for the initiation of the second immune component necessary for expulsion of this parasite.
The nature of age immunity toPlasmodium bergheiin the rat
Authors: Smalley M. E.
Published: June 2009

The intensity ofPlasmodium bergheiinfections decreases as the age of the rat host increases. The nature of this ‘age immunity’ was investigated. No experimental support was found for innate resistance involving either serum non-antibody factors or changes in the erythrocytes that inhibit parasites in older rats. A cross reacting immune response active againstP. bergheiwas not found. Evidence is presented which shows that rats less than 7 weeks old lack at least part of the functional immunological apparatus by which older rats produce a protective immune response. It is suggested that the defect might involve T lymphocytes.
Drug screening in cell culture for the detection of anticoccidial activity
Authors: Ryley John F. , Wilson Robert G.
Published: June 2009

Methods for screening compounds against Eimeria tenella in cell culture and in the chicken are described. An analysis for incidence of anticoccidial activity and host cell toxicity has been made of 11550 compounds screened in vitro, and some correlation of activity in vitro and in vivo has been attempted. The results show that screening compounds in tissue (cell) culture is not a satisfactory or reliable alternative to screening in chickens, although in vitro studies undoubtedly have a part to play in the evaluation of an active drug.
Molluscs interfering with the capacity of Fasciola hepatica miracidia to infect Lymnaea truncatula
Authors: Christensen Niels Ørnbjerg , Nansen Peter , Frandsen Flemming
Published: June 2009

Fasciola hepatica miracidia labelled with radioselenium were used to study aspects of their host-finding capacity by determining radioactivity subsequently taken up by exposed ‘target’ snails (Lymnaea truncatula). Possible interfering effects exercised by a number of non-host snails and bivalves were examined in linear test channels. The infection rate (radioactivity) among ‘target’ snails was markedly lowered when non-host Lymnaea species (L. pereger, L. palustris, L. stagnalis) were interposed as ‘decoys’. The prosobranch Bithynia tentaculata and the bivalve Sphaeriwm corneum exhibited a slight decoy effect whereas pulmonate species like Anisus vortex, Gyraulus albus, Planorbis planorbis, Physa fontinalis did not interfere with miracidial host-finding.

Other experiments showed that miracidia are more strongly attracted towards L. truncatula than L. pereger. Miracidia are not able to penetrate intact egg clusters of L. truncatula.
Further studies on the use of chicken embryo infections for the study of drug resistance in Eimeria tenella
Authors: Chapman H. D.
Published: June 2009

Infections in the chicken embryo have been used to study the development of drug resistance in an embryo adapted strain of E. tenella. Resistance was developed to decoquinate, clopidol and robenidine by serially passaging this strain, but evidence for the development of resistance to amprolium was inconclusive. Resistance to decoquinate developed more readily than to the other drugs. Attempts to increase resistance to clopidol, robenidine and amprolium by increasing the sporozoite inoculum and by the use of a mutagenic agent were unsuccesful. No cross-resistance was found between the 4 drugs.

Drug resistant lines of the Houghton strain (H) of E. tenella, made resistant to the 4 anticoccidial drugs by passage in chickens, were found to be resistant when evaluated using chicken embryo infections. Lines made resistant to decoquinate were not controlled by any concentration of this drug, suggesting that resistance, once developed, was absolute and not dependent on drug concentration. Lines made resistant to robenidine, clopidol and amprolium, however, were controlled by higher drug concentrations suggesting that in this case resistance was dependent on drug concentration.
Some observations on the sexual differentiation of Eimeria tenella using single sporozoite infections in chicken embryos
Authors: Shirley M. W. , Millard B. J.
Published: June 2009

Unsporulated oocysts were recovered from the allantoic cavity of 5 chicken embryos inoculated with a single sporozoite of Eimeria tenella; some of these oocysts sporulated. Both macrogametes and microgametes are required for the formation of viable oocysts. The results conclusively demonstrate the bisexual nature of the sporozoite, suggest that sexual differentiation is influenced by environmental factors, and show that true clones of Eimeria can be established from individual sporozoites.
Immune responses to infections with coccidia in chickens: gut hypersensitivity
Authors: Rose M. Elaine , Long P. L. , Bradley J. W. A.
Published: June 2009

Sporulated oocysts or oocyst hulls of Eimeria acervulina given via the crop, and oocyst juice or sporozoites inoculated directly into the in testinal lumen, were tested for their effects on the hypersensitivity of the intestines of immunized and susceptible birds. Only viable sporozoites consistently caused an increase in the permeability of the immunized intestine to macromolecules, shown by the leakage of intravenously injected dye. Repulsion of epithelium and disruption of the villi were seen more often in immunized than in susceptible chickens but there was no correlation with treatment or with dye leakage.

The hypersensitive response of immune intestines challenged with a heterologous organism was approximately half as intense as the response to homologous challenge.

The significance of these findings in relation to immunity to coccidiosis is discussed.
Studies on the biology ofProtopolystoma xenopodis(Monogenoidea): the oncomiracidium and life-cycle
Authors: Tinsley R. C. , Owen R. Wynne
Published: June 2009

Protopolystoma xenopodis(Price, 1943) Bychowsky, 1957 is a parasite of the African clawed toads, species ofXenopus. Adult worms in the host's urinary bladder produce up to 15 eggs/24 h; these are voided with the urine and hatch after 20–24 days (at 26 °C). The swimming oncomiracidia enter the cloaca of the toad and travel via the urinary ducts to the kidneys. Larval development in the kidneys lasts 8–12 weeks (at 22 °C) and the juvenile parasites then migrate to the urinary bladder where maturity is reached after a further 3–4 weeks,i.e. 3–4 months after invasion. Egg production is continuous and parasite longevity has been found to exceed1½ years. Rarely, the adult worms may undertake a return migration from bladder to kidneys.

The morphology of the oncomiracidium is described and compared with available accounts of other polystomatid genera. Consideration of data for the genusPolystomasuggests that the arrangement of the epidermal ciliary cells is relatively constant at the inter-specific level. Comparison ofProtopolystomawithPolystoma,DiplorchisandOculotremareveals that whilst the ciliary cell patterns are clearly related there are important differences in both cell number and disposition at the inter-generic level. Differences are also evident in the distribution of epidermal sensillae inProtopolystomaandPolystoma.Protopolystomais distinguished from all other polystomatids infecting anuran hosts by the presence of two pairs of haptoral hamuli.
In vitro oncospheral agglutination given by immune sera from mice infected, and rabbits injected, with eggs of Hymenolepis nana
Authors: Ito Akira
Published: June 2009

Oncospheral agglutination given by sera immunized with Hymenolepisnana eggs is described as a new way of assessing H. nana infection. All sera of mice which possessed acquired protective immunity against reinfection by H. nana eggs had the potency to induce oncospheral agglutination in vitro. Only oncospheres, which had been hatched, agglutinated, no agglutination occurred in sera from uninfected mice. Oncospheral agglutination was carried out by mixing 0·1 ml of serial two-fold dilutions of serum and 0·1 ml of Hanks' balanced salt solution containing about 600 hatched oncospheres. Titre of agglutinins was indicated as a reciprocal of the final dilution capable of giving agglutination clusters made of three or more oncospheres. Agglutinins developed within 14 days after a primary infection with 500 shell-free eggs. There was no rapid increase of agglutinins within 4 days following a secondary infection. The titre increase coincided with the increase in dosages of eggs. Agglutinins were thought to be immunoglobulins, because the potency of the serum to agglutinate oncospheres was extinguished after absorption of globulins with rabbit anti-mouse globulin serum.

Agglutinins were produced in rabbits by intravenous injections of shell-free eggs. The titres of the rabbit sera were much higher than those of mouse sera.
An experimental investigation of a direct life-cycle inReighardia sternae(Diesing, 1864), a pentastomid parasite of the herring gull (Larus argentatus)
Authors: Banaja A. A. , James J. L. , Riley J.
Published: June 2009

A direct life-cycle inReighardia sternae, a cephalobaenid pentastomid of gulls was investigated: the work was prompted by a report of eggs and larvae recovered from the stomach and intestine of a naturally infected gull.

Infective pentastomid eggs were obtained by surgically transplanting maturing femaleReighardia, taken from freshly shot wild gulls, into captive recipients. Faecal material from birds thus artificially infected was collected daily and examined for eggs. Eggs were force fed to 33 hand-reared (from eggs or nestlings) juvenile gulls which were selected at random and sacrificed at intervals thereafter and examined for pentastomids.

One hour after infection, primary larvae appear in the body cavity where they moult immediately. They grow steadily and by 27–35 days are sexually differentiated, and by 66 days have copulated. Fertilized females take a further 116 days to produce eggs by which time they are 7·6 cm long.

The complex migrations undertaken by developing larvae in the gull, and the problems of the mechanism of direct transmission, are discussed.
Heterologous immunity between piroplasms and malaria parasites: the simultaneous elimination of Plasmodium vinckei and Babesia microti from the blood of doubly infected mice
Authors: Cox F. E. G.
Published: June 2009

Mice which have recovered from infections with the avirulent piroplasm Babesia microti are also resistant to challenge with the virulent malaria parasite Plasmodium vinckei. In mice infected with P. vinckei before the peak of the B. microti infection the numbers of malaria parasites in the blood increase until that peak and are then eliminated at the same time as the piroplasms. In mice infected with P. vinckei at or after the peak there is no apparent multiplication and the malaria parasites begin to disappear from the blood immediately. The malaria parasites in doubly infected mice show signs of degeneration similar to those seen in mice pre-treated with Corynebacterium parvum and it is suggested that a common mechanism exists in homologous and heterologous immunity and in immunity following pre-treatment with C. parvum or BCG.
Trypanocidal activity of blood and tissue fluid from normal and infected rabbits treated with curative drugs
Authors: Goodwin L. G. , Tierney Ellen D.
Published: June 2009

A new technique for determining the trypanocidal activity of body fluids has been devised, using very small quantities in the wells of plastic microtest plates.

The activities of blood and tissue fluid of rabbits have been measured after the injection of melarsoprol, suramin, diminazene aceturate and isometamidium chloride. Activity againstTrypanosoma (Trypanozoon)bruceiPersisted in body fluids for a shorter time in treated normal rabbits than in treated rabbits infected with the tryponosome. The difference was caused by the participation of the immune response of the infected animals.

The new technique was sensitive enough to detect these interactions of chemotherapy and immunology and should be of use in the study of new trypanocidal compounds.
The synthesis of a variant-specific antigen byTrypanosoma brucei in vitro
Authors: Taylor D. W. , Cross G. A. M.
Published: June 2009

A variant-specific surface antigen from a cloned population ofTrypanosoma bruceiS 42 has been isolated and partically characterized. [35S]L-methionine was found to be incorporated into this material by cells incubatedin vitroin a chemically defined medium. Incorporation of [35S]L-methionine was inhibited by cycloheximide and puromycin at concentrations which are known to specifically inhibit protein synthesis in other systems. The rate of synthesis of the variant-specific antigenin vitrohas been estimated to be about 8% of the ratein vivo. Newly synthesized [35S]L-methionine-labelled variant-specific antigen was incorporated into the surface coat.
The source and nature of some functional antigens of Trichuris muris
Authors: Jenkins Simon N. , Wakelin D.
Published: June 2009

Vaccination with whole male worm extract (AMA), stichoseome extract (SA) and a short-term inculbation fluid (EXA) of adult Trichuris muris induced a high degree of protective immunity in mice as assessed by reduction in larval worm burden.

Immunodiffusion of AMA against rabbit anti-AMA serum revealed five precipitin lines, one of which was common to both EXA and SA with which only single lines were obtained.

Physico-chemical tests suggested that the antigen is a protein and that carbohydrate, lipid and DNA do not contribute to its antigenicity. Partial fractionation was obtained with ammonium sulphate. All preparations with immunogenic activity showed the common line of EXA on immunodiffusion.

It is concluded that one of the protective immunogens is a protein which can be associated with the precipitin line and originates in the stichosome.
Nuclear size and DNA content in host cells during first-generation schizogony of Eimeria zuernii
Authors: pasternak J. , Fernando M. A. , Stockdale P. H. G. , Weber D.
Published: June 2009

The response of intestinal host-cell nuclei of calves infected with Eimeria zuernii 6 and 8 days post-infection was examined using Feulgen-DNA microspectrophotometry. The results show that nuclear hypertrophy is dissociated from DNA replication. In the light of previous work (Fernando, Pasternak, Barrell & Stockdale, 1974) it is surmised that the specificity of infection of cells by E. zuernii is not stringent, with the major target being non-proliferative cells. At most, 20% of the first-generation schizonts develop within cells that would have had proliferative potential and as a result some non-scheduled DNA synthesis occurs.
Transfer of immunity toTrichinella spiralisin the mouse with mesenteric lymph node cells: time of appearance of effective cells in donors and expression of immunity in recipients
Authors: Wakelin D. , Wilson Margaret M.
Published: June 2009

Cells capable of transferring immunity toTrichinella spiralis, i.e. of accelerating adult worm expulsion, were present in the mesenteric lymph nodes of mice infected for 4, 6 or 8 days, but not in mice infected for only 2 days. The time-course of worm expulsion in mice infected on the day of transfer was similar in recipients of day 8 cells, expulsion becoming marked only when the recipients had been infected for at least 6 days. Transfer of cells 4 or 6 days after infection did not result in an accelerated worm expulsion; transfer 1 or 2 weeks before infection did not enhance the level of immunity in recipient mice. In contrast to the results obtained with mesenteric lymph node cells (MLNC) no immunity was trsnsferred when recipients were given spleen cells taken from donors infected for 8 days. It is suggested that MLNC do not cause worm expulsion directly, but cooperate with another component of the host's defence mechanism. Accelerated expulsion in recipients of cells was accompanied by a premature decline in fecundity of female worms. Evidence is presented to show that worm expulsion and impaired reproduction may represent independent aspects of the immune response toT. spiralis.
Babesia bigemina in Kenya: experimental transmission by Boophilus decoloratus and the production of tick-dervied stabilates
Authors: Morzaria S. P. , Young A. S. , Hudson E. B.
Published: June 2009

A Babesia-free batch of laboratory reared Boophilus decoloratus ticks was infected with a Kenyan strain of Babesia bigemina by feeding them on a steer infected by inoculation of a blood stabilate. The engorged female ticks showed developing stages of B. bigemina in their haemolymph and subsequently their progeny transmitted the parasite to a susceptible splenectomized steer.

Attempts were made to produce stabilates from pre-fed larvae and nymphs derived from infected batches of B. decoloratus. Only the stabilates derived from the nymphs pre-fed either on cattle or rabbits produced B. bigemina infection when inoculated intravenously into susceptible cattle.
Inhibited development in Ostertagia ostertagi infections – a diapause phenomenon in a nematode
Authors: Armour J. , Bruce R. G.
Published: June 2009

Experiments are described which show that in a recently isolated field strain of the cattle nematode, Ostertagia ostertagi, the primary stimulus to the induction of inhibited development at the early fourth larval stage (EL4) in the host is chilling of the infective larvae (L3). Thus exposure of L3 to a temperature of 4 °C for 8 weeks prior to their oral administration to calves resulted in a mean of 66% of the established worm burden becoming inhibited at the EL4 stage. This provides an explanation for the seasonal occurrence in Britain of inhibited EL4 stages of O. ostertagi in cattle during the cold climate of late autumn and winter.

If the L3 stages were exposed to chilling for a prolonged period (> 19 weeks), prior to infection of calves, then the prevalence of inhibited EL4 stages amongst the worms established declined. After 33 weeks chilling the worm population consisted almost entirely of adults and only 2% inhibited EL4 stages. This suggested that a selective mortality of inhibition prone L3 was taking place and explained why under natural grazing conditions inhibition prone L3 were not available on the pasture in spring.

The duration of inhibition at the EL4 stage in calves infected with chilled L3 was consistently between 16 and 18 weeks and maturation of the majority of the inhibited larvae occurred spontaneously after such a period and irrespective of season. This period is equivalent to the duration of a normal winter in Britain when conditions unsuitable for the free living development of O. ostertagi larvae prevail.

The induction of inhibition by the environmental stimulus of chilling, the fixed period for the duration of inhibition within the host and the spontaneous maturation of the inhibited larvae are characteristic of a true diapause.
The metabolism of glucose byHaemonchus contortus, in vitro
Authors: Ward P. F. V.
Published: June 2009

AdultHaemonchus contortusobtained from freshly killed sheep were incubated in a medium similar to Tyrode's saline containing known amounts of D-[U-14C]glucose. The worms appeared to remain in a healthy condition throughout the incubations which lasted for up to 6 h. All the radioactivity was recovered either within the worms or in the incubation vessel in the form of CO2, excretory products and unmetabolized glucose. An oxygen electrode in the incubation liquid showed that, because of their rapid oxygen consumption, the worms were under anaerobic conditions during all or nearly all of the incubation period, despite the presence of oxygen in the gas phase of the vessel. In terms both of quantity and radioactivity the main excretory products in solution were propan-1-ol, propionate and acetate. Smaller amounts of ethanol, lactate and succinate were excreted. Much radioactivity was associated with the expired CO2. At the end of the incubations glucose other than the initial radioactive glucose was detected indicating that the absorption of glucose byH. contortusis complex and needs further investigation. The present experiments suggest that the rate of absorption depends on the worm's need for nutrients. The results are compared with those found for other parasitic nematodes, particularlyAscaris lumbricoides, Heterakis gallinaeandTrichuris vulpis.The importance of CO2fixation in the utilization of energy from glucose byH. contortusis discussed.
A freeze fracture study of the developing tegumental outer membrane ofSchistosoma mansoni
Authors: McLaren Diane J. , Hockley D. J. , Goldring O. L. , Hammond B. J.
Published: June 2009

The freeze fracture technique has been used to quantify changes in the integral components of the double outer membrane ofSchistosoma mansoniduring the 6-week period of development within the mouse. The intramembraneous particle (IMP) density on the P1face begins to rise Within 6 h of host penetration, reaches a maximum at day 4 and then falls rapidly after day 9, so that it is at a low level between 3 and 6 weeks. The E1 face IMP density follows the same course as that of the P1 face except that maximum particle density is recorded on day 1 and the counts begin to fall on day 5. The IMP density on the P1face remains at a consistently low level throughout development. The E2face IMP density rises gradually to a peak at day 4, when the parasites have migrated to the lungs, and remains thereafter at a similar level, so that by 6 weeks the E2face has a higher IMP density than the other three fracture faces. The E2face IMP show a marked increase in size on day 4. Morphological studies indicate that a different type of inclusion body makes a transient appearance in the tegument of the lung worms, and immunocytochemical techniques show the lung worms to be nonimmunogenic. It is suggested, therefore, that the E2face IMP may represent complexes of parasite antigens and acquired host antigens. The tegumental membranes of cultured specimens have also been examined by freeze fracturing and the IMP densities compared with those obtained fromin vivoparasites; the cultured schistosomula have a lower E2face particle density than thein vivospecimens.
The activity of methyl benzoquate and clopidol against Eimeria maxima: synergy and drug resistance
Authors: Joyner L. P. , Norton C. C.
Published: June 2009

Synergy between clopidol and methyl benzoquate against Eimeria maxima was shown to be supra-additive. Collateral sensitivity to these drugs could not be demonstrated in resistant lines of this parasite. Resistance to methyl benzoquate and clopidol was not transferred when lines of E. maxima, resistant to the respective drugs, were propagated together. The failure to demonstrate this phenomenon was judged not to be due to synergy between the drugs. Attempts to induce simultaneous resistance to both drugs failed, although resistance to methyl benzoquate was readily acquired by a line of E. maxima resistant to clopidol. Induced resistance to clopidol in a methyl benzoquate-resistant line required numerous passages.
The ultrastructural development of the schistosome egg granuloma in mice
Authors: Smith Mary D.
Published: June 2009

Hepatic granulomas from mice infected with Schistosoma mansoni for periods of 8 weeks to 1 year were studied by electron microscopy. The different cell types present in the granulomas suggested that whilst a delayed hypersensitivity response predominated during early stages of infection an Arthus-type reaction associated with delayed hypersensi-tivity occurred at later stages of infection.
A genetic investigation of virulence in a rodent malaria parasite
Authors: Walliker D. , Sanderson A. , Yoeli M. , Hargreaves B. J.
Published: June 2009

The genetic basis of virulence in a line (YM) of Plasmodium yoelii yoelii was investigated in a cross with a mild line (A/C). The blood forms of the virulent line developed extensively in mature erythrocytes of mice, causing death of the host within 7 days; infections with the mild line were normally restricted to reticulocytes, infected animals recovering after three weeks. Lines YM and A/C differed additionally in enzyme and drug-sensitivity markers. Studies on infections established from each line alone from sporozoite mixtures of the two lines and from the cross between the lines showed that the appearance of virulence had been caused by a genetic change in the parasite, and not by other factors such as a concurrent infection with another organism. An analysis of the characters of 56 clones derived from the cross showed that the virulence character had undergone recombination with the other markers, and appeared to be inherited in Mendelian fashion. Three clones exhibited atypical virulence, although it was not clear whether this had been produced by genetic recombination.
Population biology of Paragonimus kellicotti metacercariae in central Ohio
Authors: Stromberg P. C. , Toussant M. J. , Dubey J. P.
Published: June 2009

The distribution of Paragonimus kellicotti metacercariae in a mixed population of crayfish from a small central Ohio stream was studied for two seasons. The distribution of worms in crayfish approximates the negative binomial distribution. Prevalence and intensity of infection increased with crayfish body weight. Although no difference in intensity of infection was noted between male and female crayfish, the prevalence of infection was higher in males. The data demonstrate a seasonal recruitment of metacercariae into the crayfish only during late summer and autumn. Metacercariae can live for over 1 year but some die and become mineralized. There is no apparent detrimental effect of P. kellicotti infection on the crayfish. The seasonal timing of life-cycle events is postulated.
Host–parasite relationships of Zygocotyle lunata (Trematoda) in the domestic chick
Authors: Fried B. , Nelson P. D.
Published: June 2009

Domestic chicks were infected with Zygocotyle lunata to determine gross and histopathological effects on the caecal tissues, to observe the method of feeding by worms and to examine the effects of crowding on the growth and development of the worm. Caecal weights and dimensions were significantly reduced in infected chicks. Caecal debris, abundant in control chicks, stained positive for proteins, polysaccharides, acid mucopolysaccharides and neutral fats. Caecal debris was rarely seen in infected chicks. The lumen of the intestinal caeca of the worms contained acellular material which showed protease activity and stained positive for proteins, polysaccharides and acid mucopolysaccharides. Histopathological effects of the infection showed a disruption of the architecture of host caecal mucosa, worm to worm attachment, tissue plugs in the worm acetabulum, and an engorgement of host mucosal tissue with erythrocytes. Stunting due to worm crowding was very evident and by 2 weeks post-infection, worms from single-worm infections were sexually mature and more than twice the length of immature flukes obtained from chicks infected with 100–500 cysts.
Differences in the chemical composition and carbohydrate metabolism of Echinococcus granulosus (horse and sheep strains) and E. multilocularis
Authors: McManus D. P. , Smyth J. D.
Published: June 2009

Metabolic studies in vitro and studies on chemical composition indicate basic biochemical differences between the horse and sheep strains of Echinococcus granulosus and between these and the closely related species, E. multilocularis. The horse strain of E. granulosus has a similar level of DNA, but significantly more polysaccharides and lipids, with less RNA and protein than the sheep strain. E. multilocularis has significantly more lipids and DNA but less polysaccharides than the horse and sheep strains of E. granulosus, more RNA and protein than the horse strain but similar protein to and less RNA than the sheep strain. Incubations under air and under 95% N2-5% CO2 for 3 h show that only E. multilocularis takes up glucose, that all three forms consume different amounts of oxygen and endogenous glycogen and produce different concentrations of lactate, succinate, acetate, malate, pyruvate, propionate and ethanol as end products of carbohydrate metabolism.
Acquisition of host antigens by youngSchistosoma mansoniin mice: correlation with failure to bind antibodyin vitro
Authors: McLaren Diane J. , Clegg J. A. , Smithers S. R.
Published: June 2009

Young schistosomes collected after penetration through isolated mouse skin (3 h schistosomula) were cultured in medium containing immune rhesus monkey serum with a high titre of antibody known to kill schistosomula in the presence of complement. Morphological signs of damage in electron micrographs were confined to the surface tegument of the schistosomula. Antibodies in immune rhesus serum were shown to bind to the surface membrane of 3 h schistosomula using an antibody-enzyme bridge technique involving labelling with horseradish peroxidase and histochemical localization of the enzyme at the ultrastructural level. Schistosomula recovered from the lungs of mice 4 days after infection did not bind monkey antibodies at the surface and these 4-day schistosomula are not susceptible to damage by immune serumin vitro. Mouse erythrocyte antigens were detected on the surface of 4-day schistosomula using an appropriate antibody-enzyme bridge but these host antigens could not be found on 3 h schistosomula. This correlation between the presence of mouse host antigens on the surface of schistosomula and the inability of immune monkey antibodies to bind to the surface membrane is consistent with the hypothesis that host antigens are acquired by young schistosomes and serve to protect the surface membrane against antibody-mediated damage.
Transmission of microsporidia, especially Orthosoma operophterae (Canning, 1960) between generations of winter moth Operophtera brumata (L) (Lepidoptera: Geometridae)
Authors: Canning Elizabeth U. , Barker Rosalind J. , Page A. M. , Nicholas J. P.
Published: June 2009

The transmission mechanisms of microsporidia between generations of Operophtera brumata, a geometrid moth with an univoltine life-cycle, have been investigated. The parasites, Orthosoma operophterae, Pleistophora operophterae and Nosema wistmansi were present in moths collected from Wistman's Wood on Dartmoor. An infection rate of 100% was found in eggs laid by moderately or heavily infected female moths. Thus, 100% infection was found in eggs laid by 78 out of 90 infected females. Lower prevalences were found in eggs laid by the remaining 12 and these moths were subsequently shown to have very light infections. Male moths do not pass on this infection to progeny. The development of O. operophterae was followed during embryonation. The microsporidia do not invade the cells of the developing larva but are restricted to the yolk, where spores accumulate in abundance after earlier merogonies. When the larva is mature and ready to hatch, spores are ingested with the remains of the yolk, as the larva eats its way through the egg-shell. Spores are then found in the meconium in the lumen of the gut. These spores are infective and, once the gut of the larva has become functional, are responsible for infecting the tissues of the larvae which harbour them, as well as healthy larvae reared with them. Spores of O. operophterae held in the natural environment for 7 months from winter until mid-summer still retained infectivity and those contaminating the environment from the bodies of one generation must contribute to transmission between generations.
Mitochondrial membrane fluorescence and temperature adaptation in Schistocephalus solidus (Cestoda: Pseudophyllidea)
Authors: Walker R. W. , Barrett J.
Published: June 2009

The fluorescent probe 1-anilino-8-naphthalene suiphonic acid (ANS) was used to investigate the effect of temperature on the physical state of the mitochondrial membranes of adult and larval schistocephalus solzdus together with that of their hosts Gasterosteus aculeatus and Gallus domesticus. Arrhenius plots of ANS/membrane fluorescence for S. solidus plerocercoids was linear over the temperature range 15 to 58 °C, while that for the adult was biphasic with a discontinuity at 39·9 °C. This was interpreted as a physical change which occurred in the adult membrane but not in the plerocercoid membrane and pointed to an alteration in membrane composition during infection. Gasierosteus aculeatus showed a linear Arrhenius plot for membrane fluorescence, irrespective of acclimation temperature. Gallus domesticus showed a discontinuity in the Arrhenius plot for membrane fluorescence at 46·9 °C, outside the normal physiological temperature range.
The inheritance of thiabendazole resistance in Haemonchus contortus
Authors: Le Jambre L. F. , Royal W. M. , Martin P. J.
Published: June 2009

Haemonchus contortus worm populations isolated from naturally infected sheep at the Pastoral Research Laboratory, Armidale, N.S.W., were found to contain approximately 20% of worms resistant to a 50 mg/kg dose of thiabendazole. Following 3 generations of selection with 50 mg/kg thiabendazole the number of worms removed by the anthelmintic was too small to detect differences between treated and control groups. After more than 15 generations of selection, matings between males from the selected strain and non-resistant females produced resistant males and females in equal numbers. Thus, thiabendazole resistance does not appear to be sex-linked. A dose–response assay on the F2 adults indicated that worms from female resistant × male non-resistant crosses were more resistant than F2 adults of the reciprocal cross. An in vitro technique that identified thiabendazole-resistant eggs by their ability to hatch in a solution containing thiabendazole and 0·1% NaCl solution was also used to study the inheritance of resistance. F1 eggs had similar LC50's to the resistant parents. F2 and back-cross eggs from an original mating of thiabendazole-resistant females × non-resistant males had a higher LC50 than F2 and back-cross eggs from the reciprocal mating, indicating a degree of matroclinous inheritance of resistance. However, the resistant parents had tolerances to thiabendazole exceeding those of F2. F3 eggs had a resistance distribution that ranged from that of the resistant to the non-resistant parent. No significant deviation from linearity was observed in any of the dose–response lines. These results indicate that thiabendazole resistance in H. contortus worms is inherited as an autosomal and semi-dominant trait.