bluuebunny/crossref_metadata_2025 huggingface dataset:
The mini-exon gene: a molecular marker for Endotrypanum schaudinni
Authors: Fernandes O. , Degrave W. , Campbell D. A.
Published: June 2009

The mini-exon gene repeats from three different strains of Endotrypanum schaudinni have been amplified by the polymerase chain reaction (PCR). Sequence analysis of the cloned products shows the gene and intergenic region to be identical in two of the strains (LV86 and M6159); the intergenic region from the mini-exon gene of the third strain (LV59) is significantly different. The LV86 gene and an intergenic probe from the LV59 mini-exon gene do not cross-hybridize with the mini-exon gene from New World Leishmania species. These data provide the basis of a PCR assay to detect E. schaudinni and distinguish it from New World Leishmania species, and which should be applicable to epidemiological studies in insect vectors and mammalian reservoirs. The identification of two different mini-exon gene repeats in E. schaudinni isolates is indicative of further strain variation within this species.
Modelling toxoplasma incidence from longitudinal seroprevalence in Stockholm, Sweden
Authors: Nokes D. J. , Forsgren M. , Gille E. , Ljungström I.
Published: June 2009

Age-stratified data on toxoplasma seroprevalence in pregnant women in Stockholm, Sweden for the years 1969, 1979 1987 provide the basis for an analysis of temporal patterns of Toxoplasma gondii infection, and estimation of the risk maternal toxoplasmosis, in this population. A catalytic infection model, in which the rate or force of infection is assumed to be a function of time (and not, as is more usual, age), was employed to describe the observed changes in levels toxoplasma seropositivity. A range of simple incidence functions (up to 3 parameters) were fitted using a method maximum likelihood. The data were significantly better described by a linear or an exponential decay in the rate of infection through time compared with a constant level. More complex incidence functions gave no better data description. Thus, whilst there is strong evidence for declining incidence in Stockholm over the past 4–5 decades, the data do not allow discrimination between different possibilities for the nature of this decline. Based on these modelling results, best estimates of the force of infection in 1987 acting on susceptible women are within the range 0 to 0·0045/susceptible/year (95% confidence limits), yielding a possible risk of maternal toxoplasmosis of between 0 and 2·7 cases/1000 pregnancies. These values are shown to be significantly lower than estimates based upon an assumption of temporal stability in toxoplasma incidence, which may be of practical significance to public health policy.
Experimental onchocerciasis in chimpanzees: cellular responses and antigen recognition after immunization and challenge withOnchocerca volvulusinfective third-stage larvae
Authors: Lüder C. G. K. , Soboslay P. T. , Prince A. M. , Greene B. M. , Lucius R. , Schulz-Key H.
Published: June 2009

summary

Immunization of chimpanzees with radiation-attenuated infective 3rd-stage larvae (L3) ofOnchocerca volvulusdid not induce strong protective immunity against a subsequent challenge infection; only 1 out of 4 immunized animals remained non-patent (i.e. microfilariae-negative) after challenge, and may have been protected. However, during immunization and before challenge, a broad range of adultO. volvulus-derived antigens (OvAg) and also uterus-derived OvAg were recognized by circulating antibodies; moreover, the repertory of antigens recognized increased further in subsequently patent animals after challenge, particularly in the range ofMr12–42 kDa. In the immunized and non-patent chimpanzee, by contrast, serological recognition of uterus-derived OvAg withMr14 kDa and 105 kDa disappeared by 19 months post-challenge (p.c.). During immunization,Acanthocheilonema viteaeL3 antigens ofMr11–12 kDa were strongly recognized only by the non-patent animal, suggesting that recognition of these antigens may have supported resistance to the subsequent challenge infection. In immunized chimpanzees, a substantial increase in the cellular reactivity to OvAg was induced; this, however, declined by 19 months p.c. to levels similar to those seen prior to immunization. At that time, 3 out of 4 immunized animals were patently infected. The effect of exogenous cytokines onin vitro-reactivity of PBMC to OvAg was examined. Addition of exogenous IL-2 alone, IFN-γ alone, and IFN-γ in combination with IL-2, did not augment net cellular responses to OvAg by PBMC from infected and control chimpanzees. In the presence of IL-4 alone, IL-6 alone, IL-2 with IL-4, IL-2 with IL-4 and IFN-γ, or IL-2 with IL-4 and IL-6, the net cellular reactivity to OvAg increased significantly in patent chimpanzees and reached levels similar to non-patent animals. Thus, non-patent chimpanzees maintain high cellular reactivity to OvAg andin vitrocellular unresponsiveness to OvAg on the part of patent chimpanzees is reversible after addition of several cytokines which act individually or synergistically.
Gland cells and secretions in the miracidium of Fasciola hepatica
Authors: Wilson R. A.
Published: June 2009

The distribution and fine structure of gland cells in the miracidium of Fasciola hepatica is described. There is a large flask-shaped, multinucleate, apical gland lying ventrally in the anterior. On each side of this are pairs of uninucleate accessory gland cells. Both apical gland and accessory gland cells communicate with the tip of the apical papilla. A third group of vesiculated gland cells opens by ducts at the base of the apical papilla. The miracidium is covered with a surface mucous coat and this appears to be directly extruded from the underlying ciliated epithelial cells. The findings are discussed with relevance to attachment to, and penetration of, the snail intermediate host.
Eimeria species: studies using rRNA and rDNA probes
Authors: Ellis J. , Bumstead J.
Published: June 2009

rRNA and a heterologous cloned rDNA probe have been used to detect the rRNA genes of Eimeria species which infe the chicken, and has allowed the isolation and preliminary characterization of cloned rDNA sequences from a genomic DNA library of Eimeria tenella. It is demonstrated that rRNA and rDNA probes can be used to identify individual Eimeria species by the restriction fragment patterns detected after Southern hybridization. In addition, studies have shown that the large and small subunit rRNAs are expressed throughout sporulation.
Speciation of echinostomes: evidence for the existence of two sympatric sibling species in the complex Echinoparyphium recurvatum (von Linstow 1873) (Digenea: Echinostomatidae)
Authors: McCarthy A. M.
Published: June 2009

Evidence for the existence of 2 first intermediate host-specific sibling species of the 45 collar-spined echinostome Echinoparyphium recurvatum is presented. Experimental studies on their life-cycles were carried out under controlled laboratory conditions. The two entities were found to be morphologically indistinguishable in all major respects, yet they exhibited distinct biological characteristics. One of the sibling species utilizes the freshwater lymnaeid pulmonate snail Lymnaea peregra as first intermediate host, and the adults occur in the anterior small intestine of the wildfowl experimental definitive host Anas platyrhynchos. The other utilizes the freshwater mesogastropod prosobranch snail Valvata piscinalis as first intermediate host, and the adults occur in the posterior small intestine and rectum of A. platyrhynchos. The existence of the two sibling species in sympatry may be explained by the fact that the life-cycles of the two forms represent two distinct cycles of transmission serving to reduce excessive competition between them.
Seasonal variations in the parasite infections in a population of three-spined sticklebacks,Gasterosteus aculeatusL.
Authors: Pennycuick Linda
Published: June 2009

A population of three-spined sticklebacks,Gasterosteus aculealus, from a pond in Somerset was sampled about every three weeks for 19 months, a total of 1863 fish being collected. Three species of parasites were found in the fish:Schistocephalus solidus,Diplostomum gasterosteiandEchinorhynchus clavula.

Seasonal changes in the incidence and intensity of the three parasitic infections are described. In general the infections increased in summer and autumn and decreased in winter and spring, although inSchistocephalusthe differences in the level of infection between the two years were greater than between seasons.

The largest increases in theSchistocephalusandEchinorhynchusinfections occurred in August and September and in theDiplostomuminfection in May and June. These increases could be related to the feeding activity of the sticklebacks and to the abundance and level of infection of theCyclops,AsellusandLimnaea peregerpopulations.

Reduction in the sizes of the infections was by predation and death of heavily infected fish in the case ofSchistocephalusandDiplostomumand mainly by death of individual worms inEchinorhynchus.

These mechanisms are shown to be adapted to the life cycles of the parasites.

I am most grateful to Dr H. D. Crofton for his help and encouragement during this investigation and to Dr R. A. Avery for useful discussions and advice. This work was supported by a Science Research Council research studentship and a NATO studentship.
On the morphology, growth and identification of the pre-infective larvae of some horse strongylids
Authors: Ogbourne C. P.
Published: June 2009

Descriptions are given of the first and second-stage larvae of Strongylus edentatus, S. vulgaris, S. equinus and Trichonema nassatum and newly hatched larvae of Trichonema catinatum and Triodontophorus serratus. Information has been obtained on the growth of pre-infective larvae and on the structural changes which occur during the first ecdysis. Most of the species of newly hatched larvae studied can be differentiated on the basis of differences in appearance, dimensions and other morphological features. The advantages of differential diagnosis of horse strongylid infection using first-stage larvae rather than infective larvae are discussed.

My thanks are due to Dr H. D. Crofton for his constructive criticism and advice and to Professor H. E. Hinton, F.R.S. for the provision of laboratory facilities.This work would not have been possible without the willing co-operation of Mr L. J. Potter from whose slaughterhouse the parasites were collected. I am also indebted to the Horse Race Betting Levy Board for their financial assistance.
The pathological effects of sporocysts, rediae and metacercariae on the digestive gland of Bithynia tentaculata (Mollusca: Gastropoda)
Authors: Reader Trevor A. J.
Published: June 2009

The uninfected digestive gland of Bithynia tentaculata consists of three main cell types: ‘absorptive’ cells, ‘thin’ cells and ‘secretory’ cells. With infection by sporocysts, rediae, or metacercaria, pressure effects caused a reduction in the lumen of the digestive gland tubules and this probably resulted in a starvation autolysis. Some tubules recovered from infection and in such cases there was a reduction in the height of the epithelium. A migration of the digestive gland nuclei was only evident in redial infections and this may have been due to the toxic effects of rediae. In addition, rediae directly ingested host digestive gland tissue.The digestive gland was reduced to about two-thirds of its normal size in all heavily infected snails. Secretory cells of the gland were more resistant to infection than were the absorptive or thin cells.

I am indebted to Dr F. R. Stranack for her supervision and guidance throughout this investigation, and to Dr G. Charles and Dr T. Jenkins for their continued help and advice. This study was carried out during the tenure of a Research Assistantship awarded by the Governors of Portsmouth Polytechnic.
Trypanosoma (Megatrypanum) incertumfromPipistrellus pipistrellus: development and transmission by cimicid bugs
Authors: Gardner R. A. , Molyneux D. H.
Published: June 2009

Trypanosoma (Megatrypanum) incertumPittaluga 1905 was found in 33 out of 206Pipistrellus pipistrelluscaught at various sites in Britain. The trypanosome is described from blood smears. Development took place in laboratory-rearedCimex pipistrelliandCimex lectularius. Epimastigote forms initially multiplied rapidly in the ventriculus and midgut ofCimex. Metacyclic trypanosomes were found in the rectum of both species ofCimexafter 8 days when bugs were maintained at 20 °C and as early as 3 days at 30 °C. Electron microscopy of infected bugs revealed that there was no attachment to epithelial cells of the ventriculus or midgut, but within the rectum epimastigotes were attached by their flagella to the cuticle of the rectum by hemidesmosomes. Transmission was achieved by feeding experimentally infected bugs to bats kept in the laboratory. These bats were negative as judged by xenodiagnosis using laboratory-rearedCimex. Bats which had been caught in the wild demonstrated low-grade or sub-patent parasitaemias (positive in xenodiagnosis) for up to 400 days after the day of capture. Despite an extensive search of impression smears of tissues immediately after trypanosomes first appeared in the blood of experimentally infected bats no multiplicative stages were found.
Host-finding in Trichobilharzia ocellata cercariae: swimming and attachment to the host
Authors: Feiler W. , Haas W.
Published: June 2009

The cercaria of Trichobilharzia ocellata finds and identifies its duck host with a seriesof different behavioural phases. Dispersal and selection of the water surface as microhabitat is achieved by an intermittent swimming behaviour, which is governed by the interplay of passive dropping with forward and backward swimming movements and includes a positive phototactic and a geonegative orientation. Then the cercariae tend to cling to the water surface in an energy-saving resting position. A movement towards the duck feet as the site of entry occurs when shadows evoke forward swimming movements, which are directed away from the source of light, i.e. normally downwards. Forward swimming movements are also stimulated by touch, but only in free-swimming cercariae and not when these are in the resting position. Attachments occur only when a substrate is touched during forward swimming movements. Attachments are stimulated by warm substrates (1 °C temperature difference triggers a nearly maximal response) and by chemical components of duck-foot skin, and the readiness to attach is increased when the forward swimming movement is started by shadow stimuli.
The effects of H-2 and non-H-2 genes on the expulsion of the nematode Trichuris muris from inbred and congenic mice
Authors: Else Kathryn , Wakelin D.
Published: June 2009

Two groups of H-2 congenic strains of mice were compared for their susceptibility to a primary infection with the nematode Trichuris muris. Mice of the BALB genetic background were markedly more resistant than mice of the BIO genetic background, as reflected by the rate of expulsion of T. muris from the large intestine. Within each of the two groups of H-2 congenic strains mice possessing the H-2k haplotype (BALB/k, B10.BR) were more susceptible to infection than mice expressing other haplotypes; B10 background strains expressing H-2b (B10) or H-2q (B10.G) alleles were the most resistant of the four congenic strains studied. Differential resistance was observed within three of the four BIO congenic strains and this is discussed in terms of rate of development of the protective immune response in relation to worm development. The results support the conclusion that both H-2-linked and non-H-2 genes play important roles in controlling the immune response which expels worms from the gut.
Continuous cultivation of intraerythrocytic Plasmodium falciparum in a serum-free medium with the use of a growth-promoting factor
Authors: Asahi H. , Kanazawa T.
Published: June 2009

Serum-free media were used to culture Plasmodium falciparum. A commercial preparation, Daigo's GF21 developed as a growth-promoting factor for many kinds of mammalian cells, and consisting of the 55–70% ammonium sulphate fraction of adult bovine serum, insulin, transferrin, ethanolamine and sodium selenite, was found to sustain growth of the parasite when Daigo's T was employed as a basal medium. The optimal Daigo's GF21 concentration for parasite growth was between 5 and 20% (v/v), with the best results at 10%. Differential counts indicated that Daigo's GF21 is essential for schizogony. Established serum-free medium, GIT, consisting of Daigo's T basal medium and Daigo's GF21, yielded good parasite growth without any supplementation. Growth-promoting factor derived from adult bovine serum in Daigo's GF21 was shown to be crucial to parasite growth. The results presented here will not only be of practical value, but will provide important information about the developmental requirements for the parasite.
Characterization of the modes of action of anti-Pbs21 malaria transmission-blocking immunity: ookinete to oocyst differentiationin vivo
Authors: Ranawaka G. R. R. , Fleck S. L. , Alejo Blanco A. R. , Sinden R. E.
Published: June 2009

The impact of immune sera, and peripheral blood cells (PBC) from mice immunized withPlasmodium bergheiookinetes; and of purified immunoglobulin or Fab fragments from anti-Pbs21 monoclonal antibody 13.1, upon establishment of oocyst infections in the mosquito was studied. Infections were initiated either from gametocyte-infected mice, or membrane feeders which contained either gametocytes or mature ookinetes. PBC from ookinete-immunized mice presented with non-immune serum failed to show any transmission-blocking activity. Anti-ookinete serum, intact anti-Pbs21 monoclonal antibody 13.1 or its Fab fragments, all inhibited oocyst formation significantly. When gametocyte-infected mice or gametocytes in membrane feeds were used, inhibition did not directly correlate with antibody concentration. In membrane feeders that contained ookinetes and antibody, concentration-dependent inhibition usually occurred. The efficacy of purified 13.1 IgG was dependent upon the ookinete concentration. The ookinete plasmalemma and cytoplasm were significantly disturbed after 12h in bloodmeals that contained antibody 13.1, but not in the isotype controls. These changes may have caused the observed failure of the ookinete to migrate as rapidly as the controls from the destructive environment of the bloodmeal.
Platyhelminth FMRFamide-related peptides (FaRPs) contract Schistosoma mansoni (Trematoda: Digenea) muscle fibres in vitro
Authors: Day T. A. , Maule A. G. , Shaw C. , Halton D. W. , Moore S. , Bennett J. L. , Pax R. A.
Published: June 2009

Molluscan FMRFamide and two recently discovered platyhelminth FMRFamide-related peptides (FaRPs), GNFFRFamide from the cestode Moniezia expansa and RYIRFamide from the terrestrial turbellarian Artioposthia triangulata, cause dose-dependent contractions of individual muscle fibres from Schistosoma mansoni in vitro. The most potent FaRP tested was the turbellarian peptide RYIRFamide, which produced a concentration-dependent effect between 10−9 and 10−7 M. FMRFamide and GNFFRFamide were less potent, inducing contractions between 10−8–10−6 M and 10−7–10−5 M respectively. The contractile effect of each of these peptides was blocked by the presence of 1 µM FMR-DFamide. FMRF free acid did not elicit contraction of the muscle fibres. The FaRP-induced contractions did not occur if the Ca2+ was omitted and 0·5 µM EGTA was added to the extracellular medium. The FaRP-induced contractions were not blocked by the Ca2+ channel blockers nicardipine, verapamil or diltiazem, although high K+-induced contractions of these fibres were blocked by nicardipine. These data indicate the presence of FaRP receptors on schistosome muscle fibres and demonstrate their ability to mediate muscle contraction. The action of these endogenous flatworm peptides on schistosome muscle is the first demonstration of a direct excitatory effect of any putative neurotransmitter on the muscle of a flatworm, and establishes a role for FaRPs in neuromuscular transmission in trematodes. In addition, it provides the first evidence that the peptidergic nervous system is a rational target for chemotherapeutic attack in parasitic platyhelmiths.
Amino acid catabolism in the nematodesHeligmosomoides polygyrusandPanagrellus redivivus. 1. Removal of the amino group
Authors: Grantham Barbara D. , Barrett J.
Published: June 2009

The major transaminase inHeligmosomoides polygyrus, Panagrellus redivivusand rat liver was the 2-oxoglutarate-glutamate system, with relatively few amino acids acting as donors for the pyruvate-alanine and oxaloacetate–aspartate systems. The relative effectiveness of the different amino acid donors in the three transaminase systems was similar in all three tissues. BothH. polygyrusandP. redivivuscan oxidatively deaminate a range of L-amino acids, although D-amino acid oxidase activity was low. Serine and threonine dehydratase activity and histidase activity were present inH. polygyrusandP. redivivusand both nematodes were also able to deaminate glutamine, asparagine and arginine. When NAD(H) was the cofactor the glutamate dehydrogenases ofH. polygyrusandP. redivivusshowed similar regulatory properties to the mammalian enzyme. However, with NADP(H) the results were anomalous. The capacity of both nematodes to transaminate and oxidatively deaminate amino acids was broadly similar and comparable to mammalian tissue. Glutamate dehydrogenase is probably the major route for deamination in these nematodes. A complete sequence of urea cycle enzymes could not be demonstrated in eitherP. redivivusorH. polygyrus.
The influence of Blastocrithidia triatomae (Trypanosomatidae) on the reduviid bug Triatoma infestans: in vivo and in vitro diuresis and production of diuretic hormone
Authors: Schnitker Antonia , Schaub G. A. , Maddrell S. H. P.
Published: June 2009

The homoxenous flagellate Blastocrithidia triatomae disturbs excretion in Triatoma infestans. During the first 4 and 24 h after feeding, infected 5th instars excreted approximately a 2·5-fold smaller volume of urine. Consequently, about double the normal volume of haemolymph could be obtained from these infected bugs 24 h after feeding. Surprisingly, the in vitro secretion rates of Malpighian tubules from uninfected and infected bugs were nearly identical. In addition, the storage and release of diuretic hormone in infected bugs was sufficient to induce normal secretion rates by isolated Malpighian tubules. Therefore, the previously observed ultrastructural alterations in the upper Malpighian tubules of infected bugs do not result in a disturbed in vitro secretion, although in vivo excretion is reduced.
Susceptibility of goats to tsetse-transmitted challenge withTrypanosoma vivaxfrom East and West Africa
Authors: Vos G. J. , Moloo S. K. , Gardiner P. R.
Published: June 2009

To determine if, as is the case withTrypanosoma bruceiandT. congolense, serodemes ofT. vivaxcould be distinguished on the basis of immunity to the metacyclic stages of the parasite, attempts were made to immunize goats by infection with infected tsetse, followed by chemotherapy or eventual ‘self-cure’. Thirty goats were infected by tsetse with either clones or stocks ofT. vivaxfrom East or West Africa. Twenty-four goats were treated with diminazene aceturate (Berenil, Hoechst A.G.) 2–6 weeks after infection and 6 goats were allowed to self-cure. Infection, followed by treatment, induced immunity to a first homologous challenge by infected tsetse in only 2 of 24 goats (one immune to the East African stock, and the other to a clone of the West African stock). Immunity to a clone of the East African stock was induced in 3 or 4 animals after a second infection and treatment and in the fourth animal of the group following a third infection and treatment. One of 2 goats infected with the clone of the East African stock was immune to challenge at 16 weeks, following self-cure without treatment, and 1 of 4 goats infected with the parent stock was similarly immune when challenged at 40 weeks post-infection. Goats susceptible to infection with East AfricanT. vivaxshowed evidence of partial immunity by delayed pre-patent periods and depressed parasitaemias after challenge. Goats infected with the relatively more virulent West AfricanT. vivaxwere, however, completely susceptible to infection after homologous challenge, and showed only a slight delay in pre-patent period. A similar result was obtained in a further 8 goats primed and challenged by large numbers of tsetse (20 or 100 infected tsetse/goat) with the West AfricanT. vivax. In further experiments using a very short treatment interval, infections following challenge were clearly shown to be the result of a lack of immunity rather than relapse following treatment. Lytic antibody activity to cultured metacyclic trypanosomes could not be detected during infection but such activity against bloodstream forms was detected after 2 weeks of infection. It is suggested that the primary reason for the erratic induction of immunity toT. vivaxemploying this methodology is the low number of metacyclics transmitted by infected tsetse, and thus poor antigenic stimulus encountered by goats upon tsetse challenge.
Characterization of two species ofLepeophtheirus(Copepoda, Caligidae) from flatfishes. Description ofLepeophtheirus europaensissp. nov
Authors: Zeddam J.-L. , Berrebi P. , Renaud F. , Raibaut A. , Gabrion C.
Published: June 2009

In the eastern Mediterranean, the copepodLepeophtheirus thompsoniBaird, 1850, has been reported to infest turbot, brill and flounder. By combining several methods, including enzyme electrophoresis, we show that this species is found only in turbot. By contrast, brill and flounder are infested by a species ofLepeophtheirusthat corresponds to no other species reported in the literature. We propose that the species be designated asL. europaensisand we describe the characteristics of the gravid female. This study was extended to the Atlantic populations of flatfishes and includes an investigation ofL. pectoralis(Muller, 1776), which infects flounder in the North Sea; we also confirmed the presence ofL. thompsoni(Baird, 1850) over the whole geographic range of turbot. Lastly, we discuss the specificity and distribution of these species along the European coasts.
A model of tsetse-transmitted animal trypanosomiasis
Authors: Milligan P. J. M. , Baker R. D.
Published: June 2009

The data needed to develop analytical models of trypanosomiasis transmission have become available only recently. By making some simplifying assumptions, models of the dynamics of the disease in vector, cattle and wild mammal populations can be constructed in order to determine criteria for successful disease control by mass and targetted chemotherapy, and by vector control. The heterogeneity in transmission due to tsetse fly feeding preferences and the variability of immunological characteristics among the vertebrate hosts account for differences in prevalence ofTrypanosoma vivaxandT. congolense, and also lead to an increase in the basic reproductive rates of the parasites and a corresponding decrease in the vector population density threshold for disease eradication or persistence. The long life-span of the vectors relative to the duration of the parasites' developmental period lead to high infection rates in the vector and high values of R0. The efficacy of chemotherapeutic regimes depends on the relationship between treatment rate and the duration of prophylaxis conferred by the drugs used. The model's predictions of the effects of vector control are shown to be in broad agreement with published field data for Mkwaja Ranch, Tanzania. Vector control programmes are frequently blighted by reinvasion, and the implications of this are discussed in terms of a model for fly immigration. With immigration of vectors, the disease is always endemic, though the infection rate in the fly population is modified by the effect of differential mortalities inside and outside the controlled area on cohorts of incubating flies. Sensitivity analysis of the model, using Monte-Carlo methods, enables an assessment of the relative importance of the parameters to be made. The results emphasize the need for studies of the wild animal reservoir to be carried out alongside entomological surveys. The relative accuracy with which field measurements need to be made in order to minimize the uncertainty in predictions of trypanosomiasis prevalence is discussed.
Decreased predator avoidance in parasitized mice: neuromodulatory correlates
Authors: Kavaliers M. , Colwell D. D.
Published: June 2009

Although parasites are reported to alter host responses to predators, little is known about the neurochemical mechanisms involved. Using an odour preference test, we examined the effects of an acute, subclinical infection with the naturally occurring, single host, enteric protozoan parasite, Eimeria vermiformis, on the responses of male laboratory mice, Mus musculus, to a predator. Uninfected mice avoided the odour of a predatory cat, spending a minimal amount of time in a Y-maze in the vicinity of the cat odour. In contrast, mice infected with E. vermiformis, spent a significantly greater amount of time in the proximity of the cat odour, showing a reduced avoidance of the cat odour and a reduction in predator-induced fear or anxiety. This was not related to augmented opioid activity and decreased pain sensitivity in the infected mice, as neither treatment with the exogenous opiate, morphine, nor restraint stress-induced augmentation of endogenous opioid activity, had any significant effects on the responses of uninfected mice to cat odour. The altered responses of the infected mice to the cat odour were reduced by peripheral administration of the gamma-aminobutyric A (GABAA) antagonists, bicuculline and picrotoxin, but were not significantly affected by either the benzodiazepine antagonist, Ro 15–1788, the opiate antagonist, naloxone, or the excitatory amino acid, N-methyl-D-aspartate (NMDA) antagonist, MK-801. These results indicate that infection with E. vermiformis in mice reduces the avoidance of predator odour through neurochemical systems associated with anxiety involving, at least in part, GABAA receptor mechanisms.
Replication, differentiation, growth and the virulence ofTrypanosoma bruceiinfections
Authors: Turner C. M. R. , Aslam N. , Dye C.
Published: June 2009

This study had 2 objectives: first, to investigate how the processes of slender form replication, of differentiation from dividing slender to non-dividing stumpy forms, and of stumpy mortality, combine to determine the initial (acute-phase) growth rate ofTrypanosoma bruceipopulations; second, to determine how acute-phase growth rates influence parasite densities during the subsequent, chronic phase of infection. During the acute phase, slender and stumpy populations both grew approximately exponentially, the latter more slowly than the former. Mathematical models showed how this difference in slender and stumpy growth rates can be explained in terms of heterogeneous replication and differentiation rates. Stumpy life-expectancy was determined for one stock and found to be age-dependent with a half-life of 48–72 h, much larger than observed population doubling times of 5–10 h. A comparison of cloned stocks showed that the highest parasite densities during the chronic phase were associated with the highest acute-phase growth rates of both the whole parasite population and of the subpopulation of slender forms. By contrast, high chronic-phase parasitaemias artificially produced following rapid syringe passage were associated with low acute-phase growth rates of slender forms. Syringe-passaging is a laboratory procedure which selects for virulent parasites, but these parasites behave differently from naturally virulent stocks.
Investigation of the chemosensory function of amphids of Syngamus trachea using electrophysiological techniques
Authors: Riga E. , Perry R. N. , Barrett J. , Johnston M. R. L.
Published: June 2009

Syngamus trachea, the gape nematode, has been used as a model to study the chemosensory function of amphids. Extracellular electrophysiological recordings were performed directly on amphids. The amphids were stimulated by blood serum from a host bird and by D-tryptophan. The spike frequency produced by the amphid increased significantly after the application of the serum and the application of D-tryptophan. Two types of amphidial neurones responded to the presence of the stimuli. These extracellular recordings have verified the chemosensory function of the amphids.
Isolates of Trichuris muris vary in their ability to elicit protective immune responses to infection in mice
Authors: Bellaby T. , Robinson K. , Wakelin D. , Behnke J. M.
Published: June 2009

Much of what is currently known of the host-parasite interaction between mice and the parasitic nematode Trichuris muris has come from experiments using a single parasite isolate (E/N). This isolate has been compared with 2 others which, on morphological criteria, belong to the same species. In 3 inbred strains of mouse that show distinct, genetically determined response phenotypes, there was a consistent pattern in terms of parasite survival time regardless of host strain, E/K worms being expelled early, E/N expelled later and S worms very late or not at all. High-responder CBA mice expelled E/K and E/N worms earlier than low-responder C57 B1/10 mice. B10.BR mice were permissive to S isolate infection, mounted a very late response to E/N worms but expelled E/K worms effectively by day 25. The differential response of mice to these isolates provides an experimental system for identifying the basis of variation in this host-parasite relationship.
A new species of Cotugnia (Cestoda Davaineidae) from the domestic pigeon in India
Authors: Malviya H.C. , Dutt S.C.
Published: June 2009

Cotugnia columbae sp.nov. from the domestic pigeon is described and compared with other species of the genus. The tapeworm measures 108–130 mm in length and 2·236 mm in maximum breadth. The rostellum bears 200 hooks, 7·7–10·6 μm. long arranged in two rows. Testes number 105–130 and the cirrus pouch measures 0·354–0·376 x 0·054–0·065 mm.

We are grateful to Dr C. M. Singh, Director, Indian Veterinary Research Institute, and to Dr H. D. Srivastava, erstwhile Assistant Director and Head of the Division of Parasitology, for their interest in these studies and for the provision of the necesssary facilities.
Zumptiella coreaensis, a new species of nasal mite from the Korean squirrel, Sciurus vulgaris coreae Sowerby, 1921
Authors: Ah Hyong-Sun
Published: June 2009

A new halarachnid mite, Zumptiella coreaensis, is described from female and male specimens obtained from the nasal cavities of the Korean squirrel, Sciurus vulgaris coreae, collected from Korea. A key to the species of the genus Zumptiella is presented.
On the morphology of the hitherto undescribed male of Spinitectus oviflagellis Fourment, 1884 (Nematoda: Rhabdochonidae)
Authors: Rahman Habibur
Published: June 2009

Male specimens found with females of Spinitectus oviflagellis Fourment, 1884, in the intestine of Gadus merlangus have been described and compared with two other males of Spinitectus. Considering the differences they are regarded as males of S. oviflagellis.
Sporulation of Amblyospora (Microspora) in female Culex salinarius: induction by 20-hydroxyecdysone
Authors: Lord J. C. , Hall D. W.
Published: June 2009

Amblyospora sp. is a microsporidian parasite which is transovarially transmitted from an infected female Culex salinarius to her progeny. This transmission is dependent on synchronization of sporulation of the parasite and ovarian development of the host, both of which are initiated when the mosquito takes a blood meal. We induced sporulation in the absence of a blood meal and, with or without prior ovariectomy, by injection of 20-hydroxyecdysone, a hormone whose precursor, ecdysone, is produced by the ovaries of blood-fed mosquitoes. Sporulation in response to a blood meal was prevented by ovariectomy of the host prior to blood feeding or by decapitation immediately after feeding.
The tissue response of Yellow Perch, Perca flavescens Mitchill to infections with the metacercarial cyst of Apophallus brevis Ransom, 1920
Authors: Pike A. W. , Burt M. D. B.
Published: June 2009

Apophallus brevis metacercariae localize in parasite-produced cysts mainly in the myotomes of Perca flavescens. The host response induced by this parasite is very intense and leads to the formation of an elaborate host-formed capsule of material which is very similar if not identical to host bone. This capsule is pierced by two canals situated at opposite poles in the cyst and enables the parasite to escape from this host capsule on being ingested by a definitive host. Successive layers of melanocytes and connective tissue, containing lipid droplets, are also present around the bony capsule. Histochemically this bony capsule and the fish bone are virtually identical but there are slight organizational differences in the capsule tissues compared to the fish bone. It is postulated that the formation and arrangement of the capsule may be influenced by the parasite and may not therefore be a defensive development by the host.
An automated large-scale culture system of Plasmodium falciparum using tangential flow filtration for medium change
Authors: Ponnudurai T. , Lensen A. H. W. , Meuwissen J. H. E. Th.
Published: June 2009

Asexual stages and mature gametocytes of Plasmodium falciparum have been produced in a 500 ml suspension culture system containing 6–10% red cells. Medium change was automated and was accomplished using a tangential flow filtration unit. The rate of multiplication of the parasite (isolate NF 54) was consistently high when compared with static cultures and ranged from 6·4 × to 15·3 × per cycle in 8 experiments. Mature gametocytes were present in up to 2% of red cells in 14-day-old cultures. Only minor modifications would be required to further scale-up the volume of the culture.
Concluding remarks: variation and polymorphism in parasite phenotype – implications for the selection of potential intervention strategies
Authors: Sinden R. E.
Published: June 2009

Work reported at this meeting has described the exploitation of variation in parasite phenotype in disciplines ranging from molecular taxonomy and drug development, through the understanding of host-parasite interaction, to the evolution of parasite populations and determining the potential efficacy of vaccine programmes.
The ‘head’ and ‘body’ races of Pediculus humanus L.
Authors: Busvine J. R.
Published: June 2009

1. Measurements were made of the head length, head width, total body length, antenna length, length and breadth of 3rd antennal segment of head and body lice from natural infestations. In all measurements (except the last) the means were significantly different for. the two forms, but in all cases there was considerable overlap.

2. Head lice reared continuously on the body for forty-three generations (over 2 years) did not change systematically in size. Body lice reared under similar conditions were likewise constant.

3. There was a highly significant difference between mean measurements of all the samples of head lice reared for up to 2 years on the body when compared with body lice reared for a similar period in the same way. The means for lice worn 24 hr. per day were less than those worn 12 hr. per day in both strains. An experiment showed that this is probably due to a difference in average temperature.

4. The mean live weights of head and body strains were even more distinct than linear dimensions on the several occasions when these were recorded.

5. Measurements of the dimensions of the opercula of the eggs of the two races and the numbers of air cells in them were distributed in the same way as the body measurements: that is, distinct means but overlapping individuals.

6. Ventral abdominal muscles in wild head lice are typically confined to segment 5. (The forty specimens examined adhered to this rule.) In wild body lice, muscles are usually also present in segment 4 as well.

7. Hybrids (female body x male head louse) were fertile for several generations. In size, the F1 generation was intermediate, but the F2 and F3 generations became identical with the body louse strain.

8. Eggs of the body louse strain hatched at the same time as those of the head strain, but the body strain reached a significantly higher percentage hatch.

9. The times of moulting during development were studied in both races in relation to differing opportunities to feed (24, 12, 6 and 3 hr. per day). The two strains showed very similar reactions in regard to speed of development, but throughout there was a higher pre-imaginal mortality in the head strain.

10. Head lice were shown to be considerably more susceptible to starvation than body lice.

11. If adults of the two strains are mixed, there is no tendency towards homogeneous mating. Of the mixed matings, those between body louse males and head louse females are much more common than the reverse.

12. Female head lice show a slight difference in their egg-laying preferences when offered a choice of hair, voile and tape.

My thanks are due to Prof. P. A. Buxton, F.R.S., for a number of helpful suggestions based on his extensive knowledge of louse biology and to Dr J. O. Irwin for critical comments on the statistical issues.
An essentially synthetic liquid medium for Entamoeba histolytica
Authors: Hansen Eder L. , Anderson Hamilton H.
Published: June 2009

An essentially synthetic medium has been developed for the cultivation of Entamoeba histolytica in association with organism t. It consists of buffered saline solution containing trace minerals, twelve amino acids, ten synthetic vitamins of the B complex, nucleic acid, cholesterol and rice starch. Cultures have been carried continuously in this medium for a period of eleven months.

We are greatly indebted for materials used in this study to the following: Drs M. S. Dunn, J. J. Eiler, D. M. Greenberg, L. D. Greenberg, E. E. Howe, H. D. Lightbody, H. S. Loring, H. Molitor, E. D. Stewart and E. L. R. Stokstad.

The authors wish to acknowledge the valuable advice and material aid provided by Drs Gladys Emerson and Gilberto G. Villela during the initial phase of this study.
Cultivation of Trypanosoma cruzi in tissue cultures: a four-year study
Authors: Meyer H. , Oliveira M. Xavier De
Published: June 2009

Trypanosoma cruzi is easily cultivated in tissue cultures of chick embryos, but it was not possible to infect chicks with trypanosomes cultivated for more than 2 years in chicken cells.

The trypanosome cycle takes place in one cell unit.

The number of trypanosomes formed in one cycle depends on the volume of the host cell.

The transformation of the leishmania form into the flagellate form begins when the cell is full of parasites, and occurs in 12–24 hr.

The intracellular trypanosome, immediately after the crithidia form, is broad and short, the thin form probably being a later phase of the evolution of the parasite.

Division of the adult trypanosome, or mating between the thin and broad forms, was never seen.

At the beginning of the infection the cells with-stand the parasites and continue to proliferate, but finally they are destroyed.
On larvae and nymphs of some species of Palestinian Hyalomma
Authors: Feldman-Muehsam B.
Published: June 2009

The taxonomy of larval and nymphal stages of H. savignyi, H. detritum, H. marginatum, H. dromedarii and the nymph of H. aegyptium are described.

The material for the first four species was obtained from laboratory-bred specimens. The bionomics of these species was studied in the laboratory. Their behaviour under natural conditions still remains to be studied.
Notes on the biology of the copepod Mytilicola intestinalis Steuer
Authors: Grainger J. N. R.
Published: June 2009

1. The free-swimming larvae of Mytilicola intestinalis can develop in theabsence of external food. Approximate figures are given for the duration of the free-living and early parasitic stages.

2. Four of the twenty-one samples of Mytilus edulis collected from various parts of Ireland were infected with Mytilicola intestinalis. All the four mussel beds found to be infected were in the neighbourhood of ports.

3. 72·0% of the Mytilicola which were found inhabited the part of the recurrent intestine which is embedded in the digestive gland.

4. There is a significant correlation between mussel length and number of Mytilicola per mussel.

5. There is a significant decrease in the numbers of Mytilicola per mussel between November to December and May to June. It is almost certain that this represents a real decrease in the copepod population, especially in the mussels larger than 55 mm., due to a death-rate which is sufficient to more than offset the increment due to new infection during November to January. In certain chosen size groups of mussels there is also an apparent decrease as a result of mussel growth in the summer, a time when new infection is very small.

6. In the 50–69 mm. mussel group the number of adult Mytilicola per mussel was lowest in September. The number of immature stages was highest in November and December and lowest from May to August. Egg-bearing copepods were found through out the year. There was an excess of males in the adult population throughout the year.

The writer is very indebted to the various people who assisted in collecting mussel samples especially the Irish Sea Fisheries Association; to Miss M. Davidson, B.A., who made a bacteriological examination of a mussel sample; to Dr J. P. Harding for informing him of the specimens of Mytilicola intestinalis in the British Museum collection; and to Prof. J. Brontë Gatenby and Dr J. D. Smyth of Trinity College, Dublin (where this work was carried out), for their suggestions and advice.
Experimental production of pure mixed strains of Entamoeba histolytica
Authors: Neal R. A.
Published: June 2009

1. Dobell's observations on the production of pure mixed strains of Entamoeba histolytica have been repeated and confirmed.

2. It has been demonstrated that the method devised by Rao did not sterilize the cysts of E. histolytica but merely killed all non-sporing organisms, while the spores of all spore-forming bacteria were unaffected.
Ixodes frontalis Panzer, 1795. A review of the species
Authors: Arthur D. R.
Published: June 2009

The identification of Ixodes frontalis Panzer, 1795, from earlier descriptions presented great difficulty, more particularly as the species is rare. There are two specimens in the British Museum (Natural History), and the description by Schulze (1933) is from a single specimen in the Sofia Museum. The rarity of the species led Schulze to write that ‘Die Art ist in Deutschland seit den Zeiten Panzers nicht mehr wiedergefunden worden’. Senevet (1937), who considers I. frontalis synonymous with I. brunneus Koch, 1844, wrote that the species occurred in St Genies-de-Malgoires in France, but this information was taken from Nuttall, Warburton, Cooper & Robinson (1911).
Five new species of larval mites (Acarina: Trombiculinae)
Authors: Radford Charles D.
Published: June 2009

Prior to 1939 our knowledge of the mites of the sub-family Trombiculinae was limited to about a dozen species, whose life history had been the subject of investigations by Nagayo and his associates in Japan, Walch in the Dutch East Indies and Gater, Fletcher, Lesslar and Lewthwaite in Malaya.