bluuebunny/crossref_metadata_2025 huggingface dataset:
The complement-fixation test in Bilharziasis II. Preparation and preservation of antigens from Schistosoma mansoni worms extracted in Coca's solution
Authors: Eliakim M. , Davies A. Michael
Published: June 2009

1. Adult S. mansoni worms were extracted in Coca's solution at various temperatures by different methods. The most potent antigen was obtained by extracting a worm suspension, diluted 1:500, at 37° C. for 1 hr., with vigorous shaking at 10 min. intervals, followed by 23 hr. at 28° C. Second extraction of worm samples gave highly active material and third extractions also contained antigen.

2. Complement-fixation tests, performed with the sera of twenty-five patients with chronic bilharziasis and twenty-five healthy subjects showed that the most specific results were obtained with either the first two extracts of worms, suspended in 100 parts of Coca's solution, and extracted for 1 hr. at 37° C. and 23 hr. at 28° C., or with the first extract of worms, suspended in 500 parts and extracted in the same manner.

3. Samples of an extract in Coca's solution were preserved for 170 days by different methods, and their activity was tested at approximately monthly intervals. The antigen, with or without the addition of 0·1% cysteine, retained its titre for 1 month, when kept in the refrigerator. Freezing, or lyophilization of the extract caused a rapid drop in titre.

4. Titration of extracts of lyophilized worms, from freshly opened ampoules, showed that a constant titre was retained for 3½ months followed by a slight drop after 5–6 months. The worm powder retained its antigenic potency when kept, thoroughly desiccated, in the refrigerator for 4 months, but lost it in 40 days when partial rehydration occurred.
Electron microscopic observations of toxoplasma ‘Nicolle et Manceaux’ grown in tissue cultures (first note)
Authors: Meyer H. , de Andrade Mendonça I.
Published: June 2009

Toxoplasma ‘Nicolle et Manceaux’ has been examined in the electron microscope in in toto preparations from tissue cultures.

The extracellular as well as the intracellular forms of the parasite are too thick for an adequate penetration of the electron beam, and the inner structure of Toxoplasma is not revealed in these preparations.

The whole parasite is covered by a very delicate, transparent mantle which may extend to form large membranes. They show no structure in the electron microscope. No sheath has been observed which protects the shape of the parasite. Most of the free forms have an irregular surface and tend to become flat and large.

Several pictures illustrate the way in which Toxoplasma penetrates the tissue cells. In the beginning of parasitism the limits between cytoplasm and parasite are difficult to recognize. The region of the cytoplasm around the parasite is gradually dissolved and a vacuole is formed.
Immunological response of the hosts to Toxocara canis (Werner, 1782) infection I. Effect of superinfection on naturally infected puppies
Authors: Fernando S. T.
Published: June 2009

Superinfection of naturally infected puppies with large numbers of Toxocara canis eggs induced a self-cure reaction. There was a sharp fall in Toxocara egg output following superinfection in most of the puppies. In most, but not all the puppies, the existing worm burden was eliminated. Eliminated worms were full of fertile eggs, but, in the puppies in which egg production fell sharply without expulsion of the worm burden, egg production by the naturally acquired worms was suppressed only transiently.

Antibody production, measured by the complement-fixation test, was directly related to resistance to superinfection but not to self-cure.

Acquired resistance reduced the pathogenic effects of superinfection, and prevented development of the parasite beyond the second stage.

It is a pleasure to thank Professor P. Seneviratna, University of Ceylon, for his constructive criticisms of the manuscript and the facilities provided.

The writer thanks Mr W. G. Senaratne for technical assistance and typing of the manuscript.

This work was carried out with a special research grant from the University of Ceylon.
A histological description of the uterine bell of Polymorphus minutus (Acanthocephala)
Authors: Whitfield P. J.
Published: June 2009

The cellular and syncytial components of the mature uterine bell of the palaeacanthocephalan, Polymorphus minutus are described, and compared with previous accounts of the histology of uterine bells. Each uterine bell always contains 17 separately distinguishable nuclei. This situation provides a good illustration of the phenomenon of organ eutely, common in Acanthocephala. The luminal spaces of the bell are described and their relevance to the translocation of eggs discussed.

I should like to thank Dr D. W. T. Crompton for his help and encouragement during the course of this work and Dr P. Tate for the provision of facilities. The work was carried out during the tenure of an S.R.C. Research Studentship.
Redescription of Psilochasmus oxyurus (Creplin, 1825) Lühe, 1909 (Trematoda: Psilostomatidae), with proposal to synonymize three other species
Authors: Premvati G.
Published: June 2009

Psilochasmus oxyurus, type species of the genus Psilochasmus Lühe, 1909, has been redescribed from whole mounts and transverse, horizontal and sagittal sections. Twenty-five worms from one common mallard, Anas platyrhynchos L. and 12 from one greater scaup, Nyroca marila L. are considered as conspecific with P. oxyurus, although they show some variations in body size and shape of the testes. Of the other eight known species of Psilochasmus, five have already been synonymized and the remaining three, namely, P. indicus Gupta, 1957, P. alii Jaiswal, 1957, and P. megacetabulus Jaiswal, 1957, are declared synonyms of P. oxyurus.
A study of the Eugregarines of the grass-grub [larva of Costelytra zealandica (White), Melolonthinae], with a description of three new species
Authors: Allison F. R.
Published: June 2009

1. Three new species of eugregarine are described from the mid-gut of the larva of Costelytra zealandica (White).

2. Euspora zealandica occurs in the anterior region of the mid-gut near the gut caeca. Slictospora costelytrae occurs just posteriorly to E. zealandica. Euspora sp. occurs posteriorly to the malpighian tubules, but was found only rarely.

3. A description of the species and the life-cycle of two species are given.

4. The life-cycle of S. costelytrae takes about 8 weeks and that of E. zealandica 6 weeks.

5. Gametocysts will develop only at a humidity of 95–100 %.

6. The bi-associative species, E. zealandica, is more abundant in the 1st and 2nd instars than the large species, S. costelytrae. Both species are equally abundant in the 3rd instars, but the peak for incidence was in May for E. zealandica and June for S. costelytrae. This is related to the longer period of time taken for the life-history of S. costelytrae.

7. The incidence of gregarines builds up in each instar to over 90% then falls off, the time of fall off corresponding with the production of gametocysts which pass out with the faeces of the grub.

8. The gregarines mostly complete their cycle before the instars moult. This is borne out by the observation that cysts were not found in the smallest size group of each instar. There were many cases in the larger size group of all three instars where cysts only occurred.

9. Gametocysts are produced mainly in the autumn.

10. Gregarines were not found in grubs approaching metamorphosis (prepupae) nor in pupae nor adults.

11. It seems unlikely from the results that the gregarines have an adverse effect on the grubs as, in general, it was found that the larger grubs had the greater number of gregarines present, but further work on this is needed.

12. The life-history of the gregarines is closely correlated with the life-history of the beetle.

13. The presence of the gregarines only in the larval stages is related to the different habitat and behaviour of larva and adult.

I am grateful to the University Grants Committee for financial support.
Propagation of Plasmodium berghei and P. vinckei in mouse erythrocytes injected into chick embryos
Authors: Hawking Frank , Gammage Kenneth
Published: June 2009

Mouse blood infected with Plasmodium berghei berghei, P. vinckei vinckei or P. vinckei chabaudi, was injected intravenously into 10-day-old chick embryos, and 4 days later further mouse erythrocytes were injected; after 7 days the infection was passed to another embryo with more mouse erythrocytes, and so on. By this procedure, P. berghei was propagated for 39 days through 6 embryos, P. vinckei vinckei for over 45 days through 7 embryos, and P. vinckei chabaudi for over 67 days through 10 embryos. The plasmodia multiplied only in mouse erythrocytes; they invaded a few avian erythrocytes but did not proceed to schizogony in them. P. falciparum, P. knowlesi and P. cynomolgi did not survive in chick embryos longer than 2–3 days. Babesia rodhaini was maintained by this procedure for 9 days through 2 embryos.
Damage to adult Schistosoma mansoni after transfer to a hyperimmune host
Authors: Hockley D. J. , Smithers S. R.
Published: June 2009

Adult S. mansoni from a recently infected rhesus monkey (Macaca mulatta) were transferred into the hepatic portal systems of a normal rhesus and of a rhesus which had acquired complete resistance to the parasite. The worms were recovered after 2 days and examined by light and electron microscopy.

The worms recovered from the normal monkey were undamaged. Most of the worms recovered from the hyperimmune monkey were alive but had localized aggregations of host cells on their surfaces. Small areas of the tegument of these worms showed structural and degenerative changes, namely an increase in density and vacuolation of the tegument; the formation of small, round, membrane-bounded cytoplasmic bodies within vacuoles in the tegument; the breakdown of the outer membrane of the tegument and release of the cytoplasmic contents; and finally the complete disappearance of the tegument exposing the underlying muscle fibres. Host monocytes and polymorphonuclear leucocytes were closely applied to severely damaged parts of the tegument; the host cells appeared to be phagocytic. The other tissues of the worms were normal. Apparently the above damage is a result of the host's immune reaction which is directed against the tegument of the worms. Worms grown in mice and subsequently transferred to monkeys immunized against mouse antigens are similarly damaged, but in this case the damage occurs more rapidly.
Transamination in homogenates of rediae of Cryptocotyle lingua and of sporocysts of Cercaria emasculans Pelseneer, 1900
Authors: Watts Stuart D. M.
Published: June 2009

Transaminase activity in homogenates of larval Digenea indicates that alanine aspartic acid, glutamic acid and their α-keto acid analogues could form an important link between carbohydrate and nitrogen metabolism. As few amino acids participate in transamination it is doubtful whether this process plays a major role in protein synthesis.
Absence of immunity between Trypanosoma musculi and intra-erythrocytic protozoa in mice
Authors: Cox F. E. G.
Published: June 2009

Mice which have recovered from, infections with Trypanosoma musculi exhibit no immunity to challenge with the malaria parasites, Plasmodium v. vinckei, P. v. chabaudi, P. b. berghei, P. b. yoelii or P. atheruri, the piroplasms Babesia rodhaini or B. microti or the dactylosomid Anihemosoma garnhami. Recovery from infections with any one of these parasites confers no immunity against T. musculi. These results indicate that heterologous immunity between intra-erythrocytic protozoa does not extend to trypanosomes.
Histochemistry of the lung mite pigment in infections ofPneumonyssussp. in non-human Primates
Authors: Brack M.
Published: June 2009

Histochemical analyses of the pigment accompanying lung mite infections in Old World monkeys indicate that, contrary to other endogeneous pigments, this pigment is not homogenous, but consists of at least three components. One fraction is formed by fine granular or amorphous cleavage products of mucin substances, the second portion appears to be large granules of haemosiderin and/or lipofuscin, and the third component consists of needle-like crystals of unknown chemical nature. The source and nature of the pigment are discussed.

I am grateful for the technical assistance of Mrs J. A. Silva and the support by Drs R. T. Damian, S. S. Kalter, R. E. Kuntz and B. J. Myers; Southwest Foundation for Research and Education, San Antonio, Texas.

This study was funded in part by U.S.P.H.S. Grants RR-00361, RR-00278 and RR-00451 and WHO Grant Z2/181/27.
Haemonchus contortus-the effect on lambs of prolonged exposure to daily and weekly doses of infective larvae
Authors: Pradhan S. L. , Johnstone I. L.
Published: June 2009

Thirty-five lambs (14 weeks old), the progeny of Border Leicester rams mated with Border Leicester × Merino ewes, were divided at random into two groups. Seventeen lambs in Group A received 3500 Haemonchus contortus larvae weekly and 18 lambs in Group B received 500 larvae each day: the dosage was decreased to 1400 larvae weekly and 200 larvae per day after 8 weeks.

Pathogenicity was found to be higher when the lambs were infected with a small number of larvae daily (daily group) than when the same number of larvae were given in one dose at weekly intervals (weekly group). The period of survival was consistently shorter in the former group.

No significant difference in faecal egg counts was observed between the two groups.

Reduction in food intake per head per day and in live weight were more pronounced in the ‘daily group’ than in group dosed weekly. The discrepancy in food consumption and live weight between these two treatments was more apparent at the end of the experiment.

Some resistance was observed in both groups but the level of resistance was not high.

Accumulation of inhibited larvae was apparent after 104 days in the ‘weekly group’ and after 78 days in the ‘daily group’. An infection arising from a large number of larvae given at weekly intervals induced a mild form of resistance leading to an accumulation of inhibited larvae at the end of the experiment. This was less apparent in lambs infected with the same number of larvae given each day.

Interference with ovulation in adult females was recorded in both treatments. Sex discrimination against the female population both in the extent of elimination of adults and in the retardation of development of fourth-stage larvae was recorded and the intensity of discrimination was more pronounced with the weekly regime of larger doses than with the same number of larvae but given in daily doses. The worms were eliminated sporadically and not continuously. A challenge infection of 10000 larvae given to two lambs in the ‘weekly’ regime treatment on the 107th day initiated a partial selfcure reaction demonstrated by an immediate fall in faecal eggs per gram (i.e. Epg) but the egg count returned to the original value in 28 days.
An egg-adapted (attenuated) line of Eimeria necatrix: further studies on its reproduction, pathogenicity and immunogenicity
Authors: Shirley M. W. , Bellatti M. A. , Millard B. J.
Published: June 2009

An egg-adapted line of Eimeria necatrix has now been passaged 40 times in the chorio-allantoic membranes of embryonated eggs. Between the 21st and 40th passage in eggs the parasite was subjected to a selection for precocious development, and its pre-patent period in this host is now 123–125 h. The parasite continued to adapt to the chorio-allantoie this tissue caused the growth of the host embryo to be markedly stunted. In chickens, both the reproduction and the pathogenicity of the egg-adapted line decreased with increasing numbers of passages in eggs. A comparison of teh immunogenicity of te egg-adapted line and its parent strain in chickens kept on litter, showed that substantially more oocysts of the egg-adapted line had to be given to induce complete protection.
Intermediary carbohydrate metabolism in protoscoleces ofEchinococcus granulosus(horse and sheep strains) andE. multilocularis
Authors: McManus D. P. , Smyth J. D.
Published: June 2009

With few exceptions, the specific activities of the glycolytic enzymes and the steady-state content of glycolytic and associated intermediates in protoscoleces of the horse (E.g.H) and sheep (E.g.S) strains ofEchinococcus granulosusand the closely relatedE. multilocularis(E.m.) are very similar. Phosphorylase, hexokinase, phosphofructokinase and pyruvate kinase catalyse non-equilibrium reactions and the patterns of activity for pyruvate kinase, phosphoenolpyruvate carboxykinase and malic enzyme are similar in the three organisms. The levels of tricarboxylic acid cycle intermediates inE.g.H., E.g.S. andE.m. are of the same order as those reported in tissues with an active cycle. Each has a complete sequence of cycle enzymes but there are substantial differences between the three parasites with regard to the activity of individual enzymes, The activities of NAD and NADP-linked isocitrate dehydrogenases are significantly lower inE.g.H. than inE.g.S. and particularly inE.m. which suggests that the tricarboxylic acid cycle may play a more important role in carbohydrate metabolism and energy production in the latter parasites. Nevertheless, the three organisms utilize fermentative pathways for alternative energy production, fix carbon dioxide via phosphoenolpyruvate carboxykinase and have a partial reversed tricarboxylic acid cycle. It is speculated thatin vivomore carbon will be channelled towards oxaloacetate than pyruvate at the phosphoenolpyruvate branch point. The steady state content of ATP and the ATP/AMP ratios are low in the three organisms, suggesting a low rate of ATP utilization in each.
Epidermal fine structure and development in the oncomiracidium larva of Entobdella soleae (Monogenea)
Authors: Lyons Kathleen M.
Published: June 2009

The development of the epidermis of the oncomiracidium larva of Entobdella soleae was studied in embryos dissected from the egg and processed for electron microscopy. At first (7- to 8-day embryos at 15 °C) the embryo is covered with a nucleated primary epidermis of flattened cells which are closely associated with the viteUine cells and may take up nutrients from them. This layer is either replaced by or develops into the secondary epidermis which consists of ciliated cellular regions joined by an apparently syncytial interciliary cytoplasmic layer. Both ciliated cells and interciliary cytoplasm are at first nucleated but later both lose their nuclei. There may be a turnover of ciliated epidermal cells at the surface of young embryos. Between days 16–20 a discontinuous presumptive adult epidermis appears beneath the ciliated cells which has connexions to cell bodies lying in the parenchyma. This layer, apparently fuses with the syncytial (?) interciliary regions which have by this time lost their nuclei. After shedding of the ciliated cells, the presumptive adult epidermis spreads out to form a continuous syncytial covering to the post-larva. The ciliated epidermal cells apparently lose their nuclei between days 20 and hatching. This may be associated with the ‘programmed life’ of the ciliated cells. Details of the food reserves and morphology of the ciliated cells are discussed in connexion with the energetics of these cells.
A comparative account of the effects of betamethasone on mice infected with Plasmodium vinckei chabaudi and Plasmodium berghei yoelii
Authors: Cox F. E. G.
Published: June 2009

The malaria parasites, Plasmodium berghei yoelii and P. vinckei chabaudi, run comparable courses of infection in mice. When mice were treated with betamethasone infections with P. v. chabaudi were enhanced while those of P. b. yoelii were depressed. Antibody levels in betamethasone-treated mice infected with either P. b. yoelii or P. v. chabaudi were depressed to similar extents. The differences in parasitaemias in the two different infections are attributed to the suppression of reticulocyte production by betamethasone. P. b. yoelii preferentially invades reticulocytes and the patterns of parasitaemia follow the level of reticulocytes in the blood. P. v. chabaudi has no preference for reticulocytes and the pattern of parasitaemia is influenced by the depressed immunological response of the host.
The role of the foreign surface and female parasitoid secretions on the immune response of an insect
Authors: Vinson S. Bradleigh
Published: June 2009

Most successful parasitoids are able to avoid the encapsulation reaction of their host. A similar avoidance was observed with particles of a weakly acidic cation exchanger which was not encapsulated following its injection into the haemocoele of an insect. The ionic nature of the surface of the acidic cation exchanger and the two species of parasitoid eggs appeared to be similar. A weakly basic anion exchanger was readily encapsulated following injections into the haemocoele of a host. The encapsulation of the basic anion exchanger was prevented by coating the surface with fluid from the calyx region of the female parasitoid ovary. The importance of the fluid from the calyx region of the parasitoid and the ionic nature of the surface in avoiding the encapsulation reaction of the hosts haemocytes is discussed.
The effect of immune inhibition on pleomorphism in Trypanosoma brucei rhodesiense
Authors: Ormerod W. E. , Venkatesan S. , Carpenter R. G. , Gardner Angela
Published: June 2009

The effect of immune inhibition on the pleomorphism of Trypanosoma brucei was studied by counting trypomastigotes and their granules on agar. A statistical analysis is presented. Busulphan 32 mg/kg, given 24 h before inoculation, caused an inhibition of the infection detectable at 72 h, but not thereafter. Immune inhibition caused by busulphan was associated with increased numbers both of agranular forms and forms containing lipid (type II) granules. After 96 h, treatment did not alter the proportion of agranular to granular forms. The remission was delayed 24 h in treated rats, the remaining trypomastigotes being more sluggish, more fragile and containing more numerous granules of increased size. We conclude that the remission is not produced by the immune reaction but by an innate process of dissolution of the ageing trypomastigotes.
Observations on migratory behaviour and development of Baylisascaris tasmaniensis
Authors: Sprent J. F. A. , Lamina J. , McKeown Ann
Published: June 2009

The development of larvae of Baylisascaris tasmaniensis to the adult stage is described, using laboratory mice and the Tasmanian devil as experimental hosts. The first moult occurred in the egg, the second moult occurred in mouse tissues at 1–2 weeks after ingestion of embryonated eggs. Larvae migrated to liver, lungs, brain, eyes and kidneys, but most larvae were found in the mesenteric tissues and wall of the intestine. Larvae grew to a length of 0·5–1·0 mm in mice, although some attained a length of 2 mm or more in infections over a year in duration.
Connective tissue changes in rabbits infected with Trypanosoma (Trypanozoon) brucei
Authors: Goodwin L. G. , Guy M. W. , Brooker B. E.
Published: June 2009

The effects of Trypanosoma (Trypanozoon) brucei infection have been studied in actively growing connective tissue in rabbits.
Studies on the relationship between Eimeria acervulina and Eimeria mivati
Authors: Long P. L.
Published: June 2009

Two strains each of Eimeria acervulina and Eimeria mivati were examined for their ability to develop in the chorioallantoic membrane (CAM) of chicken embryos and the caeca of chickens. It was found that between 100 and 1000 times more sporozoites of E. acervulina were needed to produce infections in the caeca and the embryo CAM respectively. The reproduction of both species in infections of chickens was similar and a high degree of cross-protection occurred.

It was found that oocysts of E. mivati differed in size and shape depending upon whether they were produced from infections of embryos or chickens. When maintained by passage in chickens they assumed size and shape characteristics of E. acervulina.

These findings, with the known similarity of the life-cycle stages, pathogenicity and pathology, indicate that E. mivati is not sufficiently different from E. acervulina to be a distinct species. It is suggested that it is best referred to as E. acervulina var. mivati.
A proposed site of fluid secretion in the salivary gland of the ixodid tickDermacentor andersoni
Authors: Meredith Joan , Kaufman William R.
Published: June 2009

The histology and ultrastructure of the salivary gland inDermacentor andersoniare presented with particular emphasis on those aspects relating to fluid secretion. We suggest that the group III acinus contributes most of the fluid portion of the saliva (i.e. water and small molecules) and that the main cell-type involved is what we name the ‘water-cell’. The granule-cells possibly secrete the cement by which the tick secures its mouthparts to the host, and the ‘vacuolar cell’ possibly produces a protein-rich secretion. The function of the group I acinus remains obscure.
Eimeria tenella: experimental studies on the development of resistance to robenidine
Authors: Chapman H. D.
Published: June 2009

The development of resistance by the Houghton strain (H) of E. tenella to robenidine has been studied, in the laboratory, by serially passaging the strain in chickens fed increasing concentrations of drug. Resistance to robenidine developed more readily in experiments using larger numbers of birds with higher numbers of oocysts in the inoculum. Both these factors increased the parasite population and increased the chance of selecting parasites resistant to the drug. E. tenella (H) was made resistant to 264 ppm robenidine and showed no cross-resistance to other anticoccidial agents. Resistance arose in a series of ‘steps’ as the concentration of drug was increased. E. tenella (H) was continuously passaged at concentrations ranging from 2 to 33 ppm of robenidine. After 16 passages, lines passaged at 2, 4 and 8 ppm were not resistant to 33 ppm robenidine, suggesting that the degree of resistance developed was dependent upon the drug selection pressure.
Transferred drug-resistance in Eimeria maxima
Authors: Joyner L. P. , Norton C. C.
Published: June 2009

A series of experiments is described in which two drug-resistant strains of Eimeria maxima were passaged together in untreated chicks. The resultant oocysts were then inoculated into chicks treated with both drugs. When strains resistant to methyl benzoquate and sulphaquinoxaline or clopidol and sulphaquinoxaline were used the resultant infections were not controlled by the double treatment, indicating the acquisition of resistance factors by one strain from the other. When strains resistant to clopidol and methyl benzoquate were used the phenomenon was not observed.
The mode of hatching of the monogeneanEntobdella soleae, a skin parasite of the common sole (Solea solea)
Authors: Kearn Graham C.
Published: June 2009

Observations have been made on the hatching behaviour of the larva of the monogeneanEntobdella soleaeand on the effects of various enzymes on the opercular cement of the egg. These observations indicate that hatching is brought about by a proteolytic hatching fluid which is produced by two pairs of ventral head glands and spread over the inner surface of the opercular joint by rotation of the larva about its longitudinal axis. After hatching there is no trace of the ventral head glands. Similar glands are present before hatching in the oncomiracidium ofE. hippoglossi.
Isolation of host-cell nuclei from chick intestinal cells infected with second-generation schizonts ofEimeria necatrix
Authors: Fernando M. A. , Pasternak J.
Published: June 2009

A procedure is described for the preparation of purified nuclei of chick intestinal cells infected withEimeria necatrix. During second-generation schizogony the host-cell membrane becomes resistant to homogenization, hypotonic shock and ultrasonication. However, brief treatment with a low concentration of trypsin (0·001 ) will disrupt the cell membrane. Thereafter, the nuclei can be selectively harvested from contaminating nuclear types and schizonts by a series of centrifugations. Electron microscopy and Feulgen—DNA microspectrophotometry showed that the nuclear preparations retained their integrity with little, if any, loss of DNA. Chemical determinations confirmed that host-cell nuclear DNA synthesis was stimulated by conccidial infection and further established that quantitatively there was a coincident increase in the amount of host nuclear RNA during schizogony. It is now feasible to examine directly the effects of coccidial infection upon the host's nuclear apparatus.
Egg size and form as taxonomic criteria in Diphyllobothrium (Cestoda, Pseudophyllidea)
Authors: Andersen Karin , Halvorsen Odd
Published: June 2009

The size and form (length, width, and length: width ratio) of eggs of Diphyllobothrium dendriticum, D. ditremum and D. laturn vary considerably among individual worms within each species. The size of eggs varies with host species and a decrease in egg size with increasing intensity of infestation is indicated. The egg size of D. laturn increases during the first 10–12 days of egg production. For single worm infections in golden hamsters the mean egg length and width of D. ditremum are significantly smaller than the corresponding means of D. dendriticum and D. latum, while D. latum has significantly wider eggs than D. dendriticum. As taxonomic characteristics, egg size and form may contribute to species delimitation at the population level. For identification at the individual level the best possible accuracy is about 80%. This accuracy is considerably reduced when variation in host species and intensities of infestations are introduced. Scanning electron microscope studies did not reveal any differences among eggs of the three species.
Morphological and histochemical obervations on the ovarian balls of Centrorhynchus corvi (Acanthocephala)
Authors: Parshad V. R. , Guraya S. S.
Published: June 2009

Unlike in other acanthocephalans, the overian balls of Centrorhynchus corvi are complex and are composed of 24–30 ovarian ball units. Each ovarian ball unit consists of three structural and functional units – the oogonial syncytium, developing oogenetic cells and the supporting syncytium – complementary to the ovarian balls of other acanthocephalans. Three metamorphic stages of the nuclei in the oogonial syncytium are described, depending on the nuclear morphology, chromatin structure and appearance of the nucleolus. Third-stage nuclei bulge out at the periphery of the oogonial syncytium and are surrounded by its cytoplasm and a thin membrane. Ultimately these are separated from the oogonial syncytium to from oogonia containing small amounts of cytoplasmic components derived from the oogonial syncytium. Nuclei of the young oogonia, oognia at the budding stage, and 3rd-stage nuclei of the oogonial syncytium all possess nucleoli and are similar also in their nuclear dimensions and cytochemical affinities. Nuclear resemblances, and cytoplasmic similarities of the oogonia and oogonial syncytium with regard to the presence of lipids, RNA and proteins support the concept of the origin of oogonia from the oogonial syncytium.

The free oogonia divide mitotically in the cellular zone where they undergo a single mitotic division and the resulting oocytes enter the prophase of meiosis. I. The meiotic primary oocytes in contrast to the permeiotic primary oocytes of other acanthoscephalans enter the growth phase which is closely accompanied by the accumulation of various ooplasmic components such as basophilic yolk nucleus which is composed of RNA, proteins, lipoproteins and phospholipids. Histochemical features of the oogonial and supporting syncytium are described.
The effect of natural worm loss on the estimate of anthelmintic activity in an anthelmintic test with Haemonchus contortus
Authors: Turton J. A. , Clark C. J.
Published: June 2009

An anthelmintic test was carried out in lambs against fourth-stage larvae of Haemonchus contortus to determine whether a natural loss of worms from either untreated control animals or from animals treated with anthelmintic affected the estimated activity of the anthelmintic.

Thirty-two lambs were each infected with 1500 larvae of H. contortus on 4 consecutive days and divided into 4 groups of 8 animals. Two groups of lambs were treated with anthelmintic on day 7, the first group being slaughtered on day 9 and the second on day 29. An untreated control group was slaughtered 7 days after infection and a second control group was killed 29 days after infection.

The numbers of worms recovered indicated that in the untreated control lambs there was an estimated daily loss of about 7% of the parasite population between the first day of infection and day 29, and in the lambs given anthelmintic an estimated daily loss of about 2% of the worm population was indicated between days 9 and 29. If the rate of worm loss is not the same in the untreated control hosts and in the treated animals, the estimate of anthelmintic efficacy will vary according to the time of autopsy. To minimize the possibility of an incorrect result occurring in an anthelmintic trial due to a natural loss of worms, it is recommended that the untreated control and the treated lambs are slaughtered on the same day, and that the autopsy is carried out as soon as possible after anthelmintic therapy.
Experiments with defined multispecific coccidial infections in lambs
Authors: Catchpole Janet , Norton C. C. , Joyner L. P.
Published: June 2009

The behaviour of four species of Eimeria was studied in lambs which were given either monospecific or multispecific infections. In the presence of other species the patency of oocyst production of E. ovina and E. weybridgensis was extended and the total number of oocysts produced by all species except E. ninakohlyakimovae was increased. Clinical symptoms were observed only in lambs which received E. ninakohlyakimovae.
The Fowl (Gallus domesticus) and a lepidopteran (Setomorpha rutella) as experimental hosts forTetrameres mohtedai(Nematoda)
Authors: Lim C. W.
Published: June 2009

The life-cycle ofTetrameres mohtedaiin the fowl involving a hitherto unknown intermediate host,Setomorpha rutella, is described and methods for laboratory demonstration are given. Development to infectivity in the intermediate host took less than 2 weeks under laboratory conditions. Infections could be established using infective larvae dissected from the intermediate host. The pre-patent period in the fowl averaged 36 days. Experimental evidence is given for infection of the final host by ingestion of either infected adult or infected larvalSetomorpha. Development of the parasite to the infective stage does not depend on metamorphosis of the intermediate host.
Sex determination and sex differentiation in coccidia: gametogony and oocyst production after monoclonal infection of cats with free-living and intermediate host stages of Isospora (Toxoplasma) gondii
Authors: Cornelissen A. W. C. A. , Overdulve J. P.
Published: June 2009

Clones of single oocysts, single sporocysts, single sporozoites, single proliferative parasites, single cysts and single cystozoites of Isospora (Toxoplasma) gondii (KB-strain) were made under visual control using a de Fonbrune micromanipulator. Cloning was successful in 28, 32, 21, 8, 54 and 7% of the trials, respectively. All clones were used for monoclonal infection in non-immune conventionally reared (CV) or specified pathogen-free (SPF) cats. Pre-patent and patent periods, sporulation percentages of excreted oocysts, mouse infectivity of sporulated oocysts, antibody response and immunity to reinfection of CV cats were determined. For these parameters almost no differences were observed between monoclonal infections and infections described with the non-cloned KB-strain. In all cats autopsied during the patent period, 5–8 days post-infection, macrogametes, microgametes and oocysts were found. Since meiosis occurs during sporulation and since all free-living and intermediate host stages proved to be bisexual, it is concluded that sex differentiation in I. (T) gondii is not determined by segregation of sex chromosomes or sex genes but is caused by some final host factor(s) that induce(s) differential gene expression in genetically identical cells.
Oogenesis and egg-shell formation inAspiculuris tetrapteraSchulz (Nematoda: Oxyuroidea)
Authors: Wharton D. A.
Published: June 2009

The ovary ofAspiculuris tetrapterahas a prominent terminal cap cell. This is considered to be part of the ovarian epithelium. Oogonia detach from the short rachis and increase in size from 6 to 60 μm; accumulating hyaline granules, shell granules and glycogen. The hyaline granules persist in the egg cytoplasm after shell formation has been completed and are considered to be lipoprotein yolk. The shell granules contribute to the non-chitin fraction of the chitinous layer. A classification of the cytoplasmic inclusions of the nematode oocyte is proposed. Upon fertilization a vitelline membrane is formed which constitutes the vitelline layer of the egg-shell. The chitinous layer is secreted in the perivitelline space, between the vitelline layer and the egg oolemma. Upon completion of chitinous layer synthesis, the egg cytoplasm contracts away from its inner surface. The material of the lipid layer is secreted at the surface of the egg cytoplasm and adheres to the inner surface of the chitinous layer. During secretion of the chitinous and lipid layers by the egg cytoplasm, the uterine cells secrete the unit membrane-like external uterine layer and the crystalline internal uterine layer. A complex system of interconnecting spaces develops in the internal uterine layer. This system is open to the exterior via breaks in the external uterine layer. There is no direct involvement of the uterine cells in the formation of this structure.
Effects of a thermal effluent on the incidence and abundance of the gill and intestinal metazoan parasites of the black bullhead
Authors: Boxrucker J. C.
Published: June 2009

Effects of thermal effluent on the incidence and abundance of gill and intestinal metazoan parasites of the black bullhead,Ictalurus melas, were investigated. A total of 472 bullheads from a thermal outfall area and an unaltered area of Lake Monona, Dane County, Wisconsin were examined. All parasites underwent a seasonal cycle in abundance with peak infections occurring in summer, except for the acanthocephalan,Pomphorhynchus bulbocolli, which underwent a seasonal cycle in abundance in the reference area but not in the outfall area. Thermal effluent had little effect on the incidence of the parasites. Differences in abundance between the outfall and reference areas were observed for all parasites but these differences were not always consistent nor statistically significant.P. bulbocolliwas more abundant in the reference area than in the outfall area in summer (P≤ 0·05). The monogenean,Cleidodiscussp. was more abundant in the reference area than in the outfall area in August (P≤ 0·05). The infections of the gill copepod,Achtheres ambloplitis, were higher in the reference area than in the outfall area in spring, June, August, and September (P≤ 0·05). Availability of infective larvae and variability in host feeding patterns were suggested as the controlling factors of the patterns of abundance observed.
Diplocystis tipulaesp.nov. (Sporozoa: Eugregarinorida), a parasite ofTipula paludosaMeigen (Diptera: Tipulidae)
Authors: Sherlock P. L.
Published: June 2009

Stages seen in the life-cycle ofDiplocystis tipulaesp.nov. parasitic inTipula paludosaMg., included a structure that was probably a trophozoite within the midgut epithelium of one host larva and gamonts that developed on the midgut wall in the haemocoele of the larvae. Syzygy occurred, usually in pairs, when the gamonts were about 200–300 μm in diameter. Initially, syzygous gamonts were bilobed but they quickly became spherical and were enclosed by a fine membrane to form a gametocyst 450–550 μm in diameter. Early stages of gametogony were seen in one pupa; sporogony occurred in pupae and adults. The mean size of the round–oval oocysts was 7·14 × 6·26 μm. Individuals ofTipula oleraceaL. are also susceptible to infection withD. tipulae. This gregarine is considered to be a new species, independent of the gregarines of the gut lumen.
A reappraisal of the taxonomic status of Eimeria mivati Edgar and Seibold 1964, by enzyme electrophoresis and cross-immunity tests
Authors: Shirley M. W.
Published: June 2009

An examination of 2 strains of Eimeria acervulina var. mivati (since 1973 E. mivati has been regarded as a variant of E. acervulina) showed that previous confusion over the taxonomic status of E. mivati arose because the investigations were done using laboratory cultures of E. mivati which were contaminated with E. acervulina.

Electrophoretic analyses of enzymes, host specificity and cross-immunity tests have revealed that:

(1) The 1971 Houghton strain of E. acervulina var. mivati was a mixture of 2 parasites. (a) Passage of this strain in embryonating eggs resulted in a selection against that parasite previously characterized as E. acervulina. (b) The parasite which did reproduce in eggs did not immunize chickens against subsequent challenge with E. acervulina. This parasite is most likely E. mivati. (c) E. mivati recovered from eggs did, however, immunize chickens against challenge with a new field strain which was morphologically identical to E. mivati and characterized by the same electrophoretic forms of 2 enzymes.

(2) A strain of E. acervulina var. mivati from the USA was also a mixture of E. acervulina and E. mivati.
Experimental studies of infection dynamics: infection of the definitive host by the cercariae of Transversotrema patialense
Authors: Anderson R. M. , Whitfield P. J. , Dobson A. P.
Published: June 2009

The number of cercariae of Transversotrema patialense which attach to the fish host Brachydanio rerio, during a fixed exposure period, is shown to be directly proportional to cercarial density within an experimental infection arena. The distribution of successful infections/host is shown to change from a random pattern to an over-dispersed form as cercarial exposure density or duration of host exposure to infection increases. A stochastic simulation model is used to demonstrate that small differences in host susceptibility to infection, within a population of hosts, can generate patterns of dispersion in parasite numbers/host similar to those observed in the experimental studies. Differences in host behaviour, during the period of exposure to infection, are thought to generate variability in host susceptibility to cercarial infection.
Effects of Aureo-S-700R on sporulation, viability and infectivity of ovine coccidial oocysts
Authors: Ajayi Jerry A.
Published: June 2009

Sporulation rates of normal oocysts and oocysts isolated from lambs infected with coccidia and fed Aureo-S-700R for 25 days were studied at different temperatures. The viability and infectivity of the latter were also investigated.

Temperatures of 5 and 10 °C inhibited sporulation of oocysts, but when the same oocysts were subsequently incubated at 25 °C, they sporulated. At 35 and 40 °C, sporulation was initially fast, but death and degeneration of oocysts occurred at these temperatures after 3 days.

Normal oocysts sporulated faster and in greater numbers than oocysts isolated from medicated lambs; both kinds of oocysts sporulated best between 20 and 25 °C.

Lambs inoculated with oocysts from medicated lambs passed fewer oocysts for a shorter period of time than lambs inoculated with normal oocysts. The former lambs gained more weight, passed better formed faeces, ate better and had higher PCV and haemoglobin values than the latter.
Eimeria tenella: immunogenicity of the first generation of schizogony
Authors: McDonald V. , Rose M. Elaine , Jeffers T. K.
Published: June 2009

The life-cycle of a precocious and attenuated line (WisF96) of Eimeria tenella, derived from the Wisconsin (Wis) strain, contained only the first of the three generations of schizogony undergone by the parent strain. The reproductive capacity of WisF96 was less than that of the parent strain by a factor of about 2000, but inoculation of chickens on two occasions with a large number of its oocysts induced resistance against challenge with oocysts, or with second-generation merozoites of Wis. The immunizing abilities of the attenuated line and its parent were compared by priming groups of chickens with numbers of oocysts of WisF96 or Wis, designed to produce infections of equal magnitude in terms of oocyst production (standard inocula), and then challenging with oocysts of Wis. The results suggested that an equivalent parasite mass of WisF96 was more immunogenic than Wis. This was confirmed by the finding that, even when the priming dose of Wis was increased 10-fold, the standard inoculum of WisF96 still produced the greater protective effect. These results indicate that the first generation of schizogony of E. tenella is highly immunogenic.
Plasmodium falciparum: regional differences in lectin and cationized ferritin binding to the surface of the malaria-infected human erythrocyte
Authors: Sherman I. W. , Greenan Jane R. T.
Published: June 2009

The distribution of anionic residues on the surface of erythrocytes infected withPlasmodium falciparumwas studied using cationized ferritin (CF) and transmission electron microscopy. CF staining of uninfected erythrocytes or erythrocytes infected with a knobless variant resulted in a dense and uniform distribution of ferritin particles; however, when red cells infected with a knob-inducing variant were exposed to CF, aggregates of ferritin particles were observed in the region of membrane elevation. Lectin binding to the erythrocyte surface was visualized by transmission electron microscopy using ferritin-conjugated lectins and lectin-fetuin-gold. No differences were observed in the lectin-binding patterns of malaria-infected or uninfected erythrocytes using WGA (wheat-germ agglutinin), RCA (ricin), andLimax flavuslectin. In distinct contrast to the uniform distribution of ferritin particles seen with these lectins was the appearance of clusters of ferritin-ConA over the knobby regions. Localized aggregates of ConA were not seen in knob-free areas or on the surface of red cells infected with a knobless variant. No significant differences were found in the agglutination reactions of normal and infected cells with theCancer antennariuslectin specific forO-acylated sialic acids.
Analysis of trypanosome variable antigen types in cultures of metacyclic and mammalian forms of Trypanosoma congolense
Authors: Luckins A. G. , Frame I. A. , Gray M. A. , Crowe J. S. , Ross C. A.
Published: June 2009

Cultured metacyclic forms of Trypanosoma congolense display a characteristic repertoire of metacyclic variable antigen types (M-VATs) similar to that exhibited in vitro in the tsetse fly. There appeared to be no change in expression of M-VATs in cultures of two stocks of T. congolense even after several passages, cryopreservation or long-term cultivation in vitro. Metacyclic forms transformed into mammalian forms when transferred to cultures of bovine aorta endothelial cells and whilst one stock retained expression of M-VATs without change even after 4 months, the other stock underwent antigenic variation within 14 days of transfer. Analysis of the M-VAT composition of mammalian forms of this stock using monoclonal antibodies showed that although the proportion of mammalian forms expressing certain M-VATs declined considerably, trypanosomes expressing one M-VAT increased proportionally to comprise 50 % of the population. In contrast, only small changes were seen in antigen expression in cultures of metacyclic trypanosomes from which mammalian-form cultures were derived. It was possible to produce in vitro, loss and reacquisition of variable antigen surface coat, similar to the differentiation process occurring when bloodstream trypanosomes are ingested by the tsetse fly and eventually develop into metacyclic forms.