bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal patterns in the epidemiology of schistosome infections of snails: a model for field data
Authors: Woolhouse M. E. J. , Chandiwana S. K.
Published: June 2009

The prevalence of patent schistosome infections of intermediate host snails often shows seasonal variations. For schistosome, mainlySchistosoma haematobium, infections ofBulinus globosusfield data from Zimbabwe show annual ranges in prevalence from 2% to 30%. In this paper a mathematical model is developed for B. globosus population dynamics and the epidemiology of schistosome infection. The model is a discrete-time analogue of a catalytic model, with an added recruitment term. Snail fecundity and survival are functions of age, infection, and temperature. The pre-patent period of infection is dependent on temperature.Parameter values, and relationships with temperature, are taken from earlier field and laboratory studies. The force-of-infection is estimated from analysis of age-prevalence data. Model predictions, making use of temperature data recorded in the field, are in good agreement with observations over a 2-year period at a study site in Zimbabwe. The key features of interest are a fall in the prevalence of patent infections during the cold season and a rapid rise to a peak early in the hot season. This pattern results from the accumulation of pre-patent infections which fail to develop at low temperatures, but mature en masse, together with new infections, after a few weeks at higher temperatures. Model analysis demonstrates that seasonal patterns in the prevalence of patent infections may be due largely to the influence of temperature on the pre-patent period. Seasonal and year-to-year variations in temperature may therefore have significant epidemiological effects.
Major sperm protein and actin genes in free-living and parasitic nematodes
Authors: Scott A. L. , Dinman J. , Sussman D. J. , Ward S.
Published: June 2009

The DNA from a number of free-living and parasitic nematode species was examined to determine the genomic number and distribution of DNA sequences encoding two evolutionary conserved proteins; the major sperm protein (MSP) and nematode actin. Ascaris and Caenorhabditis MSP cDNA sequences and Ascaris genomic actin sequences were used to probe Southern blots of Eco RI and Hin d III digested nematode DNA. The number of MSP genes varied widely between the 1 MSP gene in Ascaris and the 60 MSP genes in Caenorhabditis. Filarial nematodes appeared to have 1—4 MSP genes while the plant and insect parasitic species showed from 5–12 MSP-hybridizing restriction fragments. Mammalian intestinal parasites showed between 1 and 13 bands hybridizing with the MSP probes. Blots probed to estimate the number of actin genes showed that, with the exception of Ascaris which contains more than 20 germ line sequences that encode actin, all of the nematodes tested had between 3 and 9 bands that hybridized to the Ascaris genomic actin probe. The possible use of highly conserved sequences such as MSP and actin to differentiate between nematode species in diagnostic and taxonomic studies is discussed.
Age-related differences in parasitosis may indicate acquired immunity against microfilariae in cattle naturally infected with Onchocerca ochengi
Authors: Trees A. J. , Wahl G. , Kläger S. , Renz A.
Published: June 2009

Onchocerca ochengi is a common parasite of cattle in savanna areas of West Africa and its adult stages inhabit intradermal nodules. We have exploited the accessibility of the macrofilariae to examine quantitative and qualitative differences in both the macro- and microfilariae (mff) in relation to age in naturally infected cattle. Autochthonous cattle at a site on the Adamawa plateau, North Cameroon, situated near a perennial Simulium damnosum s.l. breeding site, were examined in three age groups (1·5–2·5, n = 34; 3–5, n = 39 and ≥ 8 years old, n = 21). Skin mff densities were assessed from ventral skin biopsies, total body counts of nodules were done by palpation and 1–4 nodules were excised from positive animals, collagenase digested and the numbers and condition of macrofilariae determined. Embryogenesis profiles (embryograms) were done on a representative number of female worms in each age group. The overall prevalence of infection in the study population was 71% for mff and 85% for nodules. Nodule prevalence increased significantly from the 1·5–2·5 to 3–5 years old groups, but no other inter-age prevalences were significantly different. While the mean number of nodules per animal increased with age, geometric means (gm) 3·7, 15·5 and 23·1, the skin mff density maximized in the middle age group and decreased significantly in the old animals (gm 15·8, 44·7 and 11·4 mff/g, difference between latter two parameters significant, P < 0·05). Moreover, there was a significant correlation (P < 0·01) between individual nodule counts and skin mff densities in the mid-aged group but not in the oldest group. Examination of nodules showed that nodule counts equated to numbers of female worms, since almost all of 133 nodules examined contained only 1 live female worm. Although the proportion of old female (and male) worms increased with the age groups – 2 (0), 30 (28) and 54 (32)% – the proportion of gravid females (52·8, 48·8 and 58·0%) and the mean number of viable embryos in these females (82·5 × 103, 76·0 × 103 and 102·1 × 103) did not change with age. Thus, due to the higher nodule counts, a calculated productivity index reflecting the potential mff production per animal was 8 times higher in the ≥ 8-year-old animals than in the youngest and 3 times higher than in the middle group, which sharply contrasts with the decline in skin mff density. Although further research is required, these findings may indicate acquired immunity directed against microfilariae. They demonstrate the potential of O. ochengi infections in cattle to investigate a number of aspects of the host–parasite relationship which may have relevance to human onchocerciasis.
Effects of storage time and temperature on amylopectin levels and oocyst production of Eimeria meleagrimitis oocysts
Authors: Augustine P. C.
Published: June 2009

Eimeria meleagrimitis oocysts were stored at 4, 22, 32 or 41·5 °C for up to 1 year. Decreases in amylopectin levels (measured as glucose) and viability (measured as oocyst production and mortality in turkeys) of the oocysts were generally related to the length of time in storage and the storage temperature. Oocysts assayed immediately after harvest contained 58·29 ± 0·75 μg of glucose/106 oocysts. When the oocysts were stored at 4 °C for 162 days, the amylopectin level decreased to 65% of the original level. In oocysts stored at 22, 32 and 41·5 °C, amylopectin declined to approximately 20% within 162, 76, and 41 days, respectively. Oocysts stored at 4 °C for 1 year produced more oocysts in turkeys than the original fresh isolate, but caused no mortality. Oocyst production from oocysts stored at 22 and 32°C decreased gradually until, after 9 and 7 months respectively, no patent infections were produced. Oocyst production from oocysts stored at 41·5 °C was markedly reduced within 1 month and was not detected after 4 months.
Eimeria necatrix: the development and characteristics of an egg-adapted (attenuated) line
Authors: Shirley M. W.
Published: June 2009

Sporozoites of Eimeria necatrix inoculated into the allantoic cavities of embryonating eggs completed their life-cycle in the chorio-allantoic membranes and produced fully viable oocysts. Subsequently, as a result of repeated passage in this host, an egg-adapted line was developed and was found to be markedly less pathogenic for chickens than the nonpassaged parent strain. Antigens capable of inducing protective immunity against challenge with low doses of the parent strain were retained, however, indicating a possible use for this egg-adapted (attenuated) line of E. necatrix in the immunization of comercially reared chickens.
Studies on the growth, chemotherapy and enzyme variation of Eimeria acerulina var. diminuta and E. acervulina var. mivati
Authors: Shirley M. W. , Millard B. J. , Long P. L.
Published: June 2009

Eimeria acervulina var. diminuta was serially passaged 12 times in chicken embryos, but growth in cultured chick kidney cells was linmited to 2 generations of schizonts. After 7 embryo passages the sensitivities of E. acervulina var. diminuta and an embryo-adapted strain of E. acervulina var. mivati to the anticoccidial drugs amprolium, methyl parasites were sensitive to all the anticoccidials but E. acervulina var. diminuta was more sensitive to sulphaquinoxaline and amprolium. The chicken-maintained strain of E. acervulina var. diminuta was extremely sensitive to clopidol, sulphaquinoxaline and decoquinate. Electrphoretic analyses of several enzymes from E. acervulina var. diminuta revealed enzyme profiles with similarities and differences to the embryo-adapted strain of E. acervulina var. mivati.
Strain variation within Eimeria meleagrimitis from the turkey
Authors: Long P. L. , Millard B. J. , Shirley M. W.
Published: June 2009

During the course of a field study of coccidiosis in turkeys, Eimeria oocysts were found which had much smaller dimensions than any previously recorded isolate from the turkey. These oocysts were purified by single oocyst infection of a turkey. The first oocysts (mean dimensions 16.15 ×14.75 μm) were recovered 103 h later. Inoculation of between 0·5 and 2.5 ×105 oocysts of this isolate caused severe effects on body weight gain. Cross-immunity studies showed the parasite to be a strain of E. meleagrimitis. Electrophoretic analyses of two enzymes showed that the strain could be differentiated from another strain of E. meleagrimitis. (Weybridge strain B).

The results show that strain variation occurs within the species E. meleagrimitis and extreme caution should be used in identifying species of Eimeria from the turkey by their oocyst characters.
The inheritance of enzyme variants of glutamic-oxaloacetic transaminase in Paragonimus ohirai
Authors: Agatsuma Takeshi , Habe Shigehisa
Published: June 2009

Lung flukes, Paragonimus ohirai, from Kinosaki, Japan, characterized by 3 electrophoretic variants, FF, FS and SS, of glutamic-oxaloacetic transaminase (GOT: EC 2.6.1.1) were crossed in the laboratory. In the case of a cross between FS and SS, a parent, FS, produced 9 SS and 16 FS clones in the offspring, numbers not significantly different from that expected (1:1) from Mendelian inheritance. From the other cross FS × FF, 20 clones originating from the respective 20 miracidia were obtained from a parent FS. The phenotype segregation ratio was 6 FF and 14 FS, which is not significantly different from Mendelian inheritance expectation. Only 3 clones were obtained from the other parent FF, but these segregated in a ratio of 2 FS: 1 FF. These breeding data indicate that the GOT isozymes of P. ohirai are controlled by 2 codominant alleles, GotF and Gots at a single locus whose products aggregate randomly, forming a dimer.
Genetic influences upon eosinophilia and resistance in mice infected withMesocestoides corti
Authors: Lammas D. A. , Mitchell L. A. , Wakelin D.
Published: June 2009

The genetic influences upon host variation in eosinophilia and resistance to helminth infection, and the relationship between these parameters, was investigated in 9 inbred and 3 hybrid strains of mice infected withMesocestoides corti.Blood, bone marrow, spleen and peritoneal fluid eosinophilia were far higher in SJL mice than in any other inbred strain. SWR, NIH, C3H and BALB/c mice were high responders toM. cortiwhereas CBA and 3 congenic strains sharing the B10 background (C57BL/10, B10.S, B10.G) were low responders. Some of the genes for high eosinophil responsiveness appeared to be dominant, as F1hybrids from high and low response parental strains were intermediate to high in response to infection. SJL and NIH strains were highly susceptible to infection withM. corti, larval burdens at 21 days after infection with 100 tetrathyridia being considerably higher (>1000) than all other strains. BALB/c (≃ 700 larvae) were designated susceptible, SWR (>400 larvae) were resistant and the BIO congenics (<400 larvae) were highly resistant. Genes influencing resistance also appeared to be dominant, as F1hybrids between resistant and susceptible parental strains were intermediate to resistant on infection. The overall response patterns indicate a direct correlation between susceptibility to infection and high eosinophil responsiveness, but this relationship is not consistent in all strains.
Two- and three-dimensional locomotion of the nematodeNippostrongylus brasiliensis
Authors: Lee D. L. , Biggs W. D.
Published: June 2009

Locomotion of adultNippostrongylus brasiliensishas been studied in saline, in 0.6% agar, in sodium alginate of different viscosities and amongst sand grains in these media. In saline the nematode formed two-dimensional waves but there was little forward progression. Amongst sand grains in saline the nematode moved forwards by thrusting against sand grains, but thigmokinetic behaviour later resulted in quiescence. In 0.6% agar and in alginates of weak viscosity the nematode produced two-dimensional waves and sometimes a three-dimensional helical wave which resulted in forward movement. The formation of three-dimensional waves and the distance travelled increased with increasing viscosity up to 4% sodium alginate and also amongst sand gains in these media. In 8% sodium alginate the nematode became coiled like a spring but remained almost stationary. The three-dimensional wave is formed with torsion and obtains thrust from the viscous medium. In the intestine of the host thrust will be obtained from the mucus and villi of the intestinal mucosa. The ability of this nematode to move by two-and three-dimensional undulatory propulsion is probably related to its complex ridged cuticle. Attention is drawn to the role that increased viscosity of mucus may play in entrapping nematodes during their immune rejection.
Mitochondrial DNA andAscarismicroepidemiology: the composition of parasite populations from individual hosts, families and villages
Authors: Anderson T. J. C. , Romero-Abal M. E. , Jaenike J.
Published: June 2009

Patterns of genetic subdivision in parasite populations can provide important insights into transmission processes and complement information obtained using traditional epidemiological techniques. We describe mitochondrial sequence variation in 265Ascariscollected from 62 individual hosts (humans and pigs) from 35 households in 3 Guatemalan locations. Restriction mapping of individual worms revealed 42 distinct mitochondrial genotypes. We ask whether the mitochondrial genotypes found in worms from individual hosts, from families of hosts and from villages represent random samples from the totalAscarispopulation. Patterns of genetic subdivision were quantified using F-statistics, while deviations from the null hypothesis of randomness were evaluated by a simple resampling procedure. The analysis revealed significant deviations from panmixia. Parasite populations were strongly structured at the level of the individual host in both humans and pigs: parasites bearing the same mitochondrial genotype were found more frequently than would be expected by chance within hosts. Significant heterogeneity was also observed among populations from different villages, but not from different families within a village. The clustering of related parasites within hosts suggests a similar clustering of related infective stages in the environment and may explain why sex ratios inAscarisare female-biased. We discuss aspects ofAscarisbiology which may lead to the observed patterns.
The migration of infective larvae of Brugia pahangi within the mosquito, Aedes aegypti
Authors: Lindsay S. W.
Published: June 2009

The course of the migration of infective larvae of Brugiapahangi within the mosquito, Aedes aegypti, is described. The presence of blood or eggs in the abdomens of mosquitoes at a time when the infective larvae are beginning their migration out of the thorax leads to a significant increase in the proportion of larvae accumulating in the abdomen. The evidence supports the hypothesis that infective larvae may accumulate in the labium as a direct consequence of the insect's internal anatomy i.e. infective larvae on moving into a confined space tend to remain there. In addition, the rate at which infective larvae migrate into the labium is shown to be density dependent.
Changes in metabolism and behaviour of the freshwater copepod Cyclops strenuus abyssorum infected with Diphyllobothrium spp
Authors: Pasternak A. F. , Huntingford F. A. , Crompton D. W. T.
Published: June 2009

In a population of copepods (Cyclops strenuus abyssorum), with a naturally high prevalence of infection with procercoids of Diphyllobothrium spp., no difference in body size was found between infected and uninfected hosts. However, a significant reduction in the reproductive capacity of infected females was observed, 87% of uninfected females having developed eggs in their gonads and sacs compared with 21% of infected females. The feeding rate of infected copepods was relatively high soon after infection occurred, but gradually decreased to less than half that of uninfected animals. Respiration rate was also lower in infected copepods. Infected copepods showed reduced motility and impaired escape responses, which is likely to make them more susceptible to predation.
Adhesion ofPasteuria penetransto the cuticle of root-knot nematodes (Meloidogynespp.) inhibited by fibronectin: a study of electrostatic and hydrophobic interactions
Authors: Davies K. G. , Afolabi P. , O'Shea P.
Published: June 2009

Pasteuria penetransis a bacterium with the potential to control plant-parasitic nematode populations; the mechanism of spore adhesion, however, is poorly understood. Attachment assays were performed in media supplemented with various concentrations of fibronectin and in the presence and absence of KSCN which modulates hydrophobic interactions. A reduction in the strength of the hydrophobic effect prevented spores from binding to the cuticle as did 20 μg/ml fibronectin. It was also shown directly utilizing a newly-developed technique which utilizes 3-hexadecanoyl-7-hydro-coumarin as an indicator of the fibronectin binding to the spore surface that the presence of KSCN prohibited binding. This effect was interpreted to indicate that the reduction of binding was the direct result of the influence of hydrophobic interactions between the fibronectin and the spore surface. Western blot analysis of cuticle extracts ofMeloidogyne incognitaandCaenorhabditis elegansrevealed small amounts of fibronectin to be present. Fibronectin, or a similar receptor, present in the cuticle could be responsible for the adhesion ofP. penetransby hydrophobic interactions.
Studies on the life-cycle of Himasthla militaris (Trematoda: Echinostomatidae): influence of salinity and temperature on egg development and miracidial emergence
Authors: Vanoverschelde R.
Published: June 2009

In this study we examined the influence of salinity and temperature on egg development and miracidial emergence of the digenean, Himasthla militaris. In the range 2·1 to 34‰ salinity the eggs developed normally (i.e. no significant difference in the percentage embryonation), and miracidial emergence was only markedly inhibited in water with a salinity of 34‰. At 12 °C embryonation ceased; at 20 and 30 °C egg development as well as miracidial emergence occurred, but at 20 °C both processes progressed at a slower rate than at 30 °C.
The effect of irradiation on the susceptibility of Rhipicephalus appendiculatus ticks to Theileria parva infection
Authors: Young A. S. , Leitch B. L. , Irvin A. D. , Dobbelaere D. A. E.
Published: June 2009

Irradiation doses of 800 rad. or less had no detectable effect on the subsequent development of unfed nymphal Rhipicephalus appendiculatus ticks. Doses of 1600 rad. or above impaired feeding and moulting and delayed the subsequent development of unfed nymphs. At 6400 rad. no ticks completed their moult. Unfed nymphal R. appendiculatus irradiated at 0, 400, 800 and 1600 rad. were applied to 3 cattle infected with T. parva (Kiambu 4). The Theileria infections in the salivary glands of the resultant adult ticks were assessed and it was found that irradiation doses of 800 rad. or less had little effect on the Theileria infections, but an–irradiation dose of 1600 rad. greatly reduced the level of infection. The numbers of salivary gland acini in ticks of this group were reduced but the percentage of infected acini was similar.
Detection and characterization of DNA polymerase activity inToxoplasma gondii
Authors: Makioka A. , Stavros B. , Ellis J. T. , Johnson A. M.
Published: June 2009

A DNA polymerase activity has been detected and characterized in crude extracts from tachzoites ofToxoplasma gondii. The enzyme has a sedimentation coefficient of 6·4 S, corresponding to an approximate molecular weight of 150000 assuming a globular shape. Like mammalian DNA polymerase α, the DNA polymerase ofT. gondiiwas sensitive toN-ethylmaleimide and inhibited by high ionic strength. However, the enzyme activity was not inhibited by aphidicolin which is an inhibitor of mammalian DNA polymerases α, δ and ε and also cytosine-β-D-arabinofuranoside-5′-triphosphate which is an inhibitor of α polymerase. The activity was inhibited by 2′,3′-dideoxythymidine-5′-triphosphate which is an inhibitor of mammalian DNA polymerase β and γ. Magnesium ions (Mg2+) were absolutely required for activity and its optimal concentration was 6 mM. The optimum potassium (K+) concentration was 50 mM and a higher concentration of K+markedly inhibited the activity. Activity was optimal at pH 8. Monoclonal antibodies against human DNA polymerase did not bind to DNA polymerase ofT. gondii. Thus theT. gondiienzyme differs from the human enzymes and may be a useful target for the design of toxoplasmacidal drugs.
Identification of a fibronectin-like molecule onEimeria tenella
Authors: Lopez-Bernad F. , Cacho E. Del , Gallego M. , Quilez J. , Sanchez-Acedo C.
Published: June 2009

The attachment ofEimeria tenellato its target cells as an obligatory intracellular pathogen is essential for the development of disease. Previous reports have established that other intracellular protozoa parasites have either fibronectin, an adhesion protein, or fibronectin receptors, both of which are involved in the interaction with the host cells. In this current research, studies have been undertaken to visualize a surface component that may be involved in the attachment ofE. tenellato host cells. For this purpose, monoclonal antibodies, both anti-chicken and anti-human fibronectin, and also anti-chicken integrin were used. Our results show a fibronectin-like molecule with an apparent molecular weight of 110 kDa in mature schizonts and microgametes. Staining with serum directed against chicken integrin revealed immunoreactivity within mature schizonts. Both the fibronectin-like molecule and the integrin may play an important role in the parasite stage-cell interaction and the promotion of parasite uptake.
Studies on two new Cephaline gregarines from the intestine of Indian insects, Gryllodes sigillatus and Liogryllus bimaculatus
Authors: Narain Narsingh
Published: June 2009

A description is given of two new Cephaline gregarines from Indian crickets collected at Lucknow and Jalaun, United Provinces.

One of these, Stenophora gryllodes-sigillatae sp.nov., from the gut of Gryllodes sigillatus, has solitary slender trophozoites up to 194μ long. Its epimerite is rounded in young forms and absent or represented by its remnant in adults. The nucleus has two chromosomes. Cysts are rounded, invested in a very thin membrane and without sporoducts.

The second, Bulbocephalus indicus sp.nov., from the gut of Liogryllus bimaculatus, is characterized by solitary elongated sporadins; the neck is short and a bulbous epimerite is always present. The body, measuring up to 175μ in length and up to 30μ in breadth, presents a striated appearance. Cysts are oval, covered by a very thin membrane, and have no sporoducts.

The author is very grateful to Dr S. M. Das, under whose able guidance this work was carried out. His thanks are also due to the Department of Zoology, University of Lucknow, for providing the laboratory facilities.
Three British species of the genus Metaradiophrya including one new speciesM. gardneri
Authors: Rees B.
Published: June 2009

The species of Astomatous ciliates of the genus Metaradiophrya dealt with in the present paper inhabit the intestine of three species of earthworms. They are, together with their hosts, as follows:
Trematodes of fishes from the Red Sea. 10. On three new Cryptogonimidae including two new genera
Authors: Nagaty H. F. , Aal Tahia M. Abdel
Published: June 2009

The three trematode specimens described in this paper were collected by the senior author at the Marine Biological Station, Ghardaga, Red Sea; they are deposited in the collections of the Department of Parasitology, Ein-Shams University, Cairo, U.A.R.
Observations on the occurrence of Dictyocotyle coeliaca and Calicotyle kroyeri (Trematoda: Monogenea)
Authors: Williams H. Harford
Published: June 2009

Dictyocotyle coeliaca is recorded for the first time from Raja fullonica and R. batis. It is suggested that normally D. coeliaca may be restricted to waters deeper than about 50 fathoms and that this should be considered in attempts to incubate its eggs in the laboratory. No Calicotyle kroyeri were present in female R. radiata which contained eggs in their uteri and a brief account is given of the apparent differential distribution of the species in male and female rays. Up to 64 specimens of C. kroyeri per fish are recorded from the cloacae of R. radiata (previous records refer to an average of about four specimens per host). In a brief discussion of the controversial papers on these two monogeneans reasons are given for retaining the two in separate genera.

I am most grateful to the following for providing excellent facilities for the work. The Director and staff, in particular Dr B. B. Rae and Dr Z. Kabata, Marine Laboratory, Aberdeen; the Director and Staff, Plymouth Marine Laboratory; Professor James Brough, University College, Cardiff; the Director, Commonwealth Bureau of Helminthology; and Mr H. Atkinson of Messrs J. Marr and Son, Fleetwood. Additional specimens were provided by Mr J. Slinn, Marine Biological Station, Port Erin, and by Mr J. W. Smith of this Bureau.
An immunocytochemical study with Fasciola hepatica
Authors: Thorpe E.
Published: June 2009

The results are described of a study of the distribution of the antigens in F. hepatica at various stages of development, and in the liver and spleen of experimentally infected rats using globulins labelled with fluorescein isothiocyanate, from rats and sheep infected with F. hepatica.

Possible uses of this technique in aiding the diagnosis of fascioliasis are indicated.

I wish to thank Dr A. W. J. Broome for a supply of the metacercariae of F. hepatica, and Dr J. S. S. Lowe who kindly isolated and labelled the globulins with fluorescein isothiocyanate. Miss Enid Eccleston gave valuable technical assistance.
Rhipicephalus reichenowi Zumpt, 1943: a re-description of the male and female and descriptions of the nymph and larva, together with an account of its known hosts and distribution
Authors: Walker Jane B.
Published: June 2009

The male and female of Rhipicephalus reichenowi are re-described and the nymph and larva are described for the first time. The affinities of the species within the genus are discussed.

Its developmental periods under laboratory conditions are given and all known records of its hosts and distribution in the field are noted.

The author wishes to thank the Director of the East African Veterinary Research Organization for permission to publish this paper. She is also most grateful to everyone who submitted field collections of this species to her and to Dr Hoogstraal for permission to quote unpublished information; to Dr G. Theiler for her helpful suggestions during the preparation of the manuscript, and to Mr G. M. Kohls, Dr C. M. Clifford and Dr H. Hoogstraal, who also checked the manuscript before publication.
Resistance to diamino-diphenylsulphone in Plasmodium gallinaceum
Authors: Bishop Ann
Published: June 2009

A fourfold enhancement of resistance to diamino-diphenylsulphone has been produced over a period of 15 months in strain A of P. gallinaceum by subjecting the strain, maintained in a state of patent infection, to increasing doses of the drug.

The DDS-resistant strain was cross-resistant to the minimum effective dose of sulphadiazine and slightly resistant to twice this dose, but it showed only a slight enhancement of resistance to pyrimethamine and proguanil.

The antimalarial action of DDS was antagonized by p–A.B. in the ratio of 100 to 1. DDS, in the minimum effective dose, was antagonized completely by folic acid if given in equal doses, but not by smaller doses of the antagonist; the antagonism was not competitive.

The relationship of cross-resistance between p–A.B.-inhibited sulphonamides and proguanil and pyrimethamine is discussed.
Distribution of the nematode Labiostrongylus longispicularis (Wood) within the stomach of the Red Kangaroo Megaleia rufa (Desmarest)
Authors: Dudzinski M. L. , Mykytowycz R.
Published: June 2009

The distribution of two stages of the nematode Labiostrongylus longispicularis (Wood) in thirty-eight stomachs of the Red Kangaroo, Megaleia rufa (Desmarest) has been analysed statistically.

A quadratic regression was used where y = log of mean worm densities of stomach sections + 1 and x = numerical values of the mid-positions of the sections. The analysis revealed significant maxima in the proximity of the cardiac region. The maxima in stomachs with relatively large numbers of worms were found to be further away from the pylorus than in the stomachs with small numbers of worms. The mean maximum densities were about fifty worms per 100 g of stomach content in highly infected animals and about eight in low infections. It is suggested that freshly chewed food or saliva may be a factor regulating the distribution of worms.

The parasite was absent from the stomach's pyloric region where the pH is low.

Sex and size of the worm were independent of its position in the stomach.

The average number of eggs per adult female in the different stomach sections roughly corresponded to the density of worms in these sections, but the sample material was inadequate to show that this relationship was statistically significant.

The mean number of fertilized eggs per female worm was 3300.

Thanks are due to Professor E. J. Williams of the University of Melbourne and Mr B. V. Fennessy of the Division of Wildlife Research, C.S.I.R.O., for reading and criticizing the manuscript, and to Messrs E. R. Hesterman and C. Kogon for technical assistance.
Dichelyne trionyxi sp.nov. and Dichelyne wallagoni sp.nov., two new species of the family Cucullanidae Cobbold, 1864
Authors: Chakravarty G. K. , Majumdar G.
Published: June 2009

When specimens of the turtle, Trionyx gangeticus, and of the fish, Wallago attu, were purchased in a local market and examined, nematodes were found in the intestines of both these hosts. Two males were found in the intestine of the turtle, and a male and three females in the intestine of the fish. Examination of these nematodes showed that they all belonged to the genus Dichelyne Jägerskiöld, 1902, but that none of them belonged to any known species of this genus. The genus Dichelyne was regarded by Yorke & Maplestone (1926) as being synonymous with the genus Cucullanus, O. F. Mueller, 1777, but was later re-instated as a distinct genus by J. F. Mueller (1934), who reduced the genus Dacnitoides Ward & Magath, 1916, to synonymy with Dichelyne. In the light of these emendations the genus Dichelyne now includes the following species: D. fossor Jägerskiöld, 1902, 1909; D. cotylophora (Ward & Magath, 1916), J. F. Mueller, 1934; D. robusta Van Cleave & Mueller, 1932; D. fastigatus Chandler, 1937; and D. diplocaecum Chandler, 1937.
Studies on monocystid gregarines. Three Monocystis species including two new species M. cambrensis and M. lanceata
Authors: Rees B.
Published: June 2009

The three species of gregarines described in the present paper—Monocystis cambrensis sp.nov., M. lanceata sp.nov. and M. elongata (Phillips & Mackinnon, 1946), Loubatières, 1949—are all parasites of British earthworms. The observations upon which these descriptions are based form part of a larger survey of the monocystid fauna of several British earthworms. The methods used are fully described in a previous paper (Rees, 196).
Besnoitia (Protozoa: Toxoplasmea) in lizards
Authors: Garnham P. C. C.
Published: June 2009

Besnoitia sauriana sp.nov. is described from the tissues and organs of Basiliscus vittatus, with the type locality Baking Pot, British Honduras. It is placed in a new family, Besnoitiidae in the order Toxoplasmea.

The proliferative stage is thought to take place in the alveoli of the lungs. The cystic stage begins as the greatly altered host cell, containing a single round or oval body. The host-cell membrane becomes greatly thickened, the nuclei multiply and enlarge and the cytoplasm assumes a granular texture. The parasites (‘spores’) multiply by binary fission, enclosed in a fine membrane, within this cell, which eventually they entirely fill.

The ‘spores’ easily contaminate the blood and may be mistaken for Schellackia or Toxoplasma in blood smears of infected lizards.
The uptake of 14C-Chlorella protein by larval Taenia crassiceps (Cestoda)
Authors: Esch Gerald W. , Kuhn Raymond E.
Published: June 2009

Larval Taenia crassiceps of the ORF and KBS strains have been shown to accumulate whole 14C-Chlorella proteins in the bladder fluid. Precipitation by trichloroacetic acid removed 70% of the radioactivity indicating the 14C-Chlorella proteins had not been catabolized during movement into the bladder fluid.
Structural differences in the egg envelopes of Haemonchus contortus and Trichostrongylus colubriformis (Nematoda: Trichostrongylidae)
Authors: Waller P. J.
Published: June 2009

Many studies have been carried out on the structure and chemical composition of trematode and cestode egg envelopes. Among the nematodes, much work has been done on the eggs of ascarids but there have been few studies on the egg envelopes of species in the Superfamily Trichostrongyloidea. Zawadowsky et al. (1929) reported on the biology of five species of this family, namely Trichostrongylus instabilis (T. colubriformis), T. extenuatus (T. axei), T. probolurus, Cooperia pectinata and Ostertagia mentulata. They described the egg envelope as consisting of three or possibly four layers. The physical and chemical properties of these layers were investigated and these workers concluded that the structure of the egg envelope was similar to that of Ascaris. However, the solubility of the inner layer differed from that of Ascaris in dissolving only partially in absolute alcohol and very little in ether.
Some observations on the morphology and developmental stages of Trypanosoma avium bakeri ssp.nov. from the red-whiskered bulbul (Otocompsa jocosa Linn.)
Authors: Chatterjee D. K. , Ray H. N.
Published: June 2009

Trypanosoma avium bakeri ssp.nov. has been recorded from naturally infected red-whiskered bulbuls (Otocompsa jocosa Linn.). This trypanosome resembles T. avium Danilewsky, 1885 in general morphological features but it is larger in every respect. The parasite can also infect chicks, black-breasted quails and pigeons.

The division stages of the parasite are also very interesting. Considering the different morphological criteria, division stages and loose host specificity, the parasite is designated as subspecies of T. avium.

For the first time division stages of an avian trypanosome have been studied in detail in the peripheral circulation and bone marrow of the bird. The parasite multiplied by longitudinal binary fission and two types of plasmotomy.

Our thanks are due to Dr S. Mookerjee, Professor and Head of the Department of Zoology, Presidency College, Calcutta for providing the necessary laboratory facilities and constant encouragement and for going through the manuscript and to Dr J. R. Baker, Department of Medical Protozoology, London School of Hygiene and Tropical Medicine, for his valuable suggestions in the preparation of this article. The financial support provided by the Indian Council of Medical Research (for H.N.R.) and the University Grants Commission (for D.K.C.) is gratefully acknowledged.
Variables in the radiation-attenuation of helminth larvae: the effect of differences in quality of radiation
Authors: Kassai T. , Fitzpatrick B. , Mulligan W.
Published: June 2009

A comparison has been made of the attenuating effect on N. brasiliensis larvae of X-rays (HVL, 8 mm Al) and γ-rays from 60Co over the range 10–80 kr. In the dose range where attenuation was manifested as a decrease in total worm burden the γ-rays had an RBE (relative biological effect) of 0-7 relative to the X-rays as unity.

Because of the enhancement of infectivity occurring at low radiation doses, attenuation in this region is better assessed in terms of alteration to the sex-ratio of the parasite rather than effect on total population.

This work was supported by grants from the Agricultural Research Council and the Horse Race Betting Levy Board, and was carried out during the tenure by one of the authors (T. Kassai) of a British Council exchange scholarship.

Thanks are due to Dr T. Martin Young and Mr J. S. Orr of the Radiotherapy Department, Western Infirmary, Glasgow, for access to radiation sources and helpful advice.
Studies on the morphology and life-cycle ofDiplostomum (Diplostomum) gasterostei(Strigeida: Trematoda)
Authors: Williams Modupè O.
Published: June 2009

One of a large number ofLymnaea peregra(Mull.) from a pond near Glasgow was found to be infested withCercaria diplostomi gasterostei.

C. d. gastrosteihas been found to penetrateGasterosteus aculeatusand develop into a diplostomulum in the retina of the eyes.

Large numbers ofG. aculeatusfrom the pond have been found withDiplostomulum gasterosteioccurring in the retina.

Infested heads of fish were fed to domestic ducklings and pigeons, and adult stages of a worm considered to be a new species and namedD. gasterosteiwere obtained.

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

The author wishes to thank Dr C. A. Hopkins for reading and criticising the manuscript, Dr D. A. Erasmus and Dr G. Rees for valuable suggestions. My thanks are due also to the technical staff of the Department who assisted me in the collection of snails and fishes, and to Mr Francis Deen who did the sectioning of the specimens. This work was in part supported by a grant from Shell Oil Company (London).
Acquired immunity toPlasmodium vinckeiin mice
Authors: Cox F. E. G.
Published: June 2009

Plasmodium vinckeiinfections, which usually kill mice within 7 days, can be terminated in the majority of cases by a single injection of chloroquine phosphate equivalent to 10 mg/100 g body weight. After such drug treatment the parasites disappear from the blood for 6–11 days, after which a recrudescence with a low peak occurs. Most animals overcome this second parasitaemia and the parasites finally disappear completely. After recovery, mice exhibit an immune response to a challenge infection and, after a short period of parasitaemia during which a low peak is reached, the animals recover completely. This immunity, once acquired, apparently persists for the lifetime of the host. The establishment of the immune state depends on the period of patent parasitaemia during the primary infection and the longer this period the greater is the chance of a solid immunity developing. Immunity may be exhibited by mice treated with chloroquine as early as the 3rd day of infection. Killed parasites have no immunizing effect. Mice splenectomized before infection are capable of an immune response, and mice splenectomized after radical cure are also able to overcome a challenge infection. In both these cases more than one injection of chloroquine is required. The immunity produced in mice is that of the true sterile type, equivalent to that produced againstP. bergheiin rats, and is species-specific, conferring no resistance to infection withP. berghei. P. vinckeiinfections in mice provide a useful immunological model for laboratory studies. The immune response is predictable and easy to induce, and this parasite is therefore superior toP. bergheifor immunological studies. Attention is drawn to the fact that inP. vinckeithe infection is brought under control by the immune response and not by the antimalarial drug; therefore this ought to be taken into consideration in the assessment of drug trials.
Cultivationin vitroofEndolimax blattaeLucas, 1927 from the cockroach hind gut
Authors: Warhurst David C.
Published: June 2009

Endolimax blattae, a small amoeba living in the cockroach hind gut, was cultivatedin vitrofor the first time.

Growth and encystment took place in diphasic serum-saline media with or without the addition of starch.

E. blattaegrew well at 25 and 37°C. At the latter temperature the flagellates andBlastocystiswhich contaminated recently isolated strains were eliminated.

More amoebae and cysts were produced in cultures supplied with starch than in those without starch, and there seemed to be a relationship between depletion of starch and onset of encystment.

The results are discussed with reference to conditions in the natural environment.

I wish to express my thanks to Professor H. P. Moon, in whose department this work was carried out, for his help and advice, to my supervisor Dr Marjorie G. Guthrie for her advice, encouragement and constructive criticism, and to Dr Ann Bishop, F.R.S., and Dr Elspeth W. McConnachie for their invaluable advice onin vitrocultivation.
Changes in the protein content of the serum and intestinal mucus of sheep with reference to the histology of the gut and immunological response to Oesophagostomum columbianum infections
Authors: Dobson Colin
Published: June 2009

Sheep infected with Oesophagostomum columbianum showed anorexia, loss of weight, diarrhoea and macroscopically obvious oedema and inflammation of the alimentary tract. Arthus-like lesions caused by the larvae developed particularly in the large intestine.

The gross immunological responses of the sheep were associated with antibodies in greater titre within the mucus of the gut than in the serum. Acquired immunity was manifest through an antibody-antigen reaction which was localized mostly in the large intestine and which involved proliferation of the lymphoid tissue of the gut and an increased synthesis of protein. Lower titres of antibody in serum than in mucus may indicate leakage of antibody away from the gut. The direct effects of antibody were established by the respiratory inhibition of the 3rd-stage larvae. The presence of antibody was associated with particularly high concentrations of β globulin after first and β and γ globulins after second infection. Specific antibody was demonstrated in these protein fractions by blockage of electrophoretic movement by larval antigen in the buffer.

The antibody-antigen reaction may act as a trigger which releases the nonspecific effects of excess mucus production and oedema which causes mechanical dislodgement of the infection. The natural and specific respiratory inhibitory effects of mucus on the worm would facilitate this dislodgement process.

The greatest cellular reactions occurred where there was an active infection. Usually these reactions were associated with oedema, hyperaemia and an increase in the size of the mesenteric lymph nodes.
Studies on the morphology, ecology and life-cycle ofMeiogytnnophallus minutus(Cobbold, 1859) comb. nov. (Trematoda: Gymnophallidae)
Authors: Bowers E. A. , James B. L.
Published: June 2009

Meiogymnophallvs minutus(Cobbold, 1859) comb, nov., fromCardium eduleL. andHaematopus ostralegus occidentalisNeumann is shown to be synonymous withLecithodendrium somateriae (nonLevinsen, 1881) Jameson, 1902in partim, Cercaria margaritaeLebour, 1907,Oymnophalloides oedemiae(Jameson & Nicoll, 1913) James, 1964,Cercaria cambrensisCole, 1938, andGymnophallus nereicolaRebecq & Prévot, 1962. The intensity of infestation of cockles, with the metacercariae, increases with the size and particularly with the age of this host and varies with the seasonal migrations of the final host. The connexion between the metacercaria and the adult is demonstrated experimentally. Domestic ducklings used as experimental hosts were susceptible to infection when fed with minced cockles but not when fed on baby chick crumbs.

We are very grateful to Professor E. W. Knight-Jones for the provision of working facilities and for help with the manuscript and to the Science Research Council for a grant to one of us (E.A.B.) which made the work possible.
Studies on Eimeria praecox Johnson, 1930, in the chicken
Authors: Long P. L.
Published: June 2009

E. praeox has been isolated in Britain for the first time and is similar in regard to its oocyst size, prepatent time, life-cycle and the development of host immunity to the reports of Tyzzer et al. (1932). Oocysts had mean dimensions of 20·4 × 17·45 μm and the first oocysts were discharged 83½ h after infection.

Oocyst production and life-cycle studies suggest that at least three generations of schizogony precede gametogony and that at least one further generation of schizogony is needed to explain the oocyst reproduction resulting from a small dose of oocysts. Young chickens 1½–3 weeks of age were not such suitable hosts as older chickens (6 weeks) and the reproduction of the parasite was seriously reduced when large numbers (e.g. 105, 106) were used to infect chickens. A high degree of resistance to reinfection occurred after a single exposure to infection.

Sporozoite infections of the caeca or cloaca resulted in the infection of the usual small intestine site; there was no development at the site of inoculation and attempts to infect the embryo allantois did not succeed.

I wish to thank Dr M. Elaine Rose for the surgery required for the caecal infections, for her interest throughout and for help with the manuscript; Dr R. F. Gordon for help with the manuscript and permission to publish and Mr B. J. Millard for skilled technical assistance.
The Wellcome Trust Lecture
Authors: Mitchell G. F.
Published: June 2009

The modern biology era in which molecular analyses dominate and immunology, cell biology and molecular genetics are prominent, has created unprecedented opportunities for the vaccine developer. The need for new and improved vaccines against many infectious disease agents is also great, no more so than for the protozoan and helminth parasite scourges of the rural poor in the tropical, less-industrially developed world. Despite the opportunities and needs, no vaccine against any human parasite yet exists nor does any molecular vaccine against any parasite; this chapter is a general discussion on the reasons for this state of affairs that assuredly will change soon.
Chairman's concluding remarks
Authors: Ogilvie Bridget M.
Published: June 2009

This meeting included talks which covered both the principles and problems of vaccine development and others that extensively reviewed the present state of progress towards the goal of antigenically defined parasite vaccines for human and veterinary use. Several speakers, particularly Drs Morrison and Gutteridge, pointed out that in comparison with bacteria and viruses there are few vaccines available against parasites and these consist of attenuated organisms for veterinary infections. Therefore, despite the intensity of effort, better defined vaccines for parasites still elude us.