bluuebunny/crossref_metadata_2025 huggingface dataset:
Hymenolepis diminuta: influence of metacestodes on synthesis and secretion of fat body protein and its ovarian sequestration in the intermediate host,Tenebrio molitor
Authors: Hurd Hilary , Arme C.
Published: June 2009

FemaleTenebrio molitorinfected with metacestodes ofHymenolepis diminutaexhibit elevated concentrations of female-specific proteins in their haemolymph and the origin of these has been investigated. Following a 4 hin vitroincubation with [14C]leucine, fat bodies from non-infected females secreted 13 times more protein than those from females 12 days post-infection. A comparison of the uptakein vivoof radio-isotope labelled amino acids by ovaries from non-infected and infected beetles of various ages revealed no differences; however, a 51·5% decrease in protein sequestration was detected in females 12 days post-infection. Electrophoresis of homogenates of radio-isotope labelled ovaries demonstrated that the majority of label was associated with vitellin sub-units. It is suggested that the decrease in vitellogenin sequestration associated with infection results in an increase in the haemolymph concentration of these proteins despite a concomitant reduction in their secretion by fat bodies. Both fat body synthesis and ovarian sequestration are under juvenile hormone control and it is proposed that metacestodes ofH. diminutamay cause a reduction in the concentration of this hormone in the intermediate host.
Trypanosoma musculi in CBA mice: trypanocidal mechanism eliminating dividing forms
Authors: Desbiens C. , Viens P.
Published: June 2009

Large inocula of dividing form-enriched Trypanosoma musculi parasites, harvested from the peritoneal cavity of infected CBA mice, were given intravenously to mice at various times during the infection. Mice infected for 10 or 15 days (including T cell-deprived, infected mice) eliminated dividing parasites from the blood within a few min, whereas those at earlier stages (1 or 5 days) were less efficient. The initial control of T. musculi parasitaemia thus appears to be due to a trypanocidal mechanism rather than reproduction-inhibiting factor (ablastin).
Effects of mermithid parasitism on the haemolymph composition of the larval blackflies Prosimulium mixtum/fuscum and Simulium venustum
Authors: Gordon R. , Condon W. J. , Edgar W. J. , Babie Sally J.
Published: June 2009

Haemolymph of larval blackflies Prosimulium mixtum/fuscum and Simulium venustum parasitized by the mermithid nematode Neomesomermis flumenalis was compared with that of non-parasitized hosts with respect to protein, amino acid and carbohydrate composition. The mermithid depleted most protein fractions in a non-selective manner in both host species. In P. mixtum/fuscum, the levels of most amino compounds were reduced by mermithid parasitism, but these metabolites were approximately evenly divided into three categories (decreased, increased, unaffected by parasitism) in S. venustum. The mermithid caused a significant decrease of haemolymph glucose levels in both host species but did not affect blood trehalose concentrations. These effects of parasitism are discussed in relation to the nematode's nutritional requirements.
Transmission of Theileria parva by a population of Rhipicephalus appendiculatus under simulated natural conditions
Authors: Young A. S. , Leitch B. L. , Dolan T. T. , Newson R. M. , Ngumi P. N. , Omwoyo P. L.
Published: June 2009

A 2 hectare paddock on the Muguga Estate, Kiambu District of Kenya (altitude 2100 m) free of Theileria parva-iniected ticks was seeded by applying Rhipicephalus appendiculatus nymphs to cattle infected with Theileria parva (Kiambu 4). It was estimated that over 50000 engorged nymphs fell onto the pasture from 4 cattle with high parasitaemias during the cold season (June). Samples of these ticks were placed in plastic cylinders under the vegetation in the paddock and sexual stages of T. parva were detected in gut lumen smears in these samples up to 21 days alter repletion. Zygotes were first observed to transform into kinetes on day 55 and parasites were first detected in salivary glands of adults on day 64. Moulting of the nymphs started on day 60 after repletion and was completed by day 87. Cattle introduced into the paddock showed their first infestation with adult R. appendiculatus on day 64 after repletion of the nymphs and the infestation level gradually increased. On day 76 after repletion, 17% of a sample of adult ticks infesting cattle showed salivary gland infections with T. parva and this increased to over 70% by day 150. From day 360 onwards, a decrease in both the percentage of ticks infected and the number of salivary gland acini infected/tick was noted. In addition, T. parva infections within the salivary glands required a longer period of feeding in the older ticks before they developed into sporozoites. Cycling of Theileria through ticks was prevented by the removal of female ticks before they completed repletion. Lethal challenge levels of T. parva for cattle existed in the paddock up to day 547 after repletion, after which introduced cattle showed no infection or only a sub-lethal infection. Cattle introduced into the paddock on day 808 after repletion showed no evidence of T. parva infection. The tick infestation of introduced cattle decreased markedly from day 368 and infestation had virtually ceased by day 808
Transmission of Theileria annulata (Dschunkowsky & Luhs, 1904) by Hyalomma excavatum (Koch, 1844)
Authors: Samish M. , Pipano E.
Published: June 2009

Theileria annulata was transmitted transtadially by an Israeli strain of Hyalomma excavatum from larvae to nymphs and from nymphs to adults. However, the adults developing from larvae which engorged on infected calves and fed during the nymphal stage on non-infected calves, rabbits or gerbils (Meriones tristrami), did not transmit theileriosis. Suspensions of infected unfed nymphs or adults did not produce theileriosis but both nymphs and adults of the same batch became infective to cattle after 2 days of feeding. Suspensions of salivary glands or of whole ticks derived from infected adults that remained attached to rabbits for more than 7 days, were not infective to cattle.
Seasonal fluctuations and hypobiosis of gastro-intestinal nematodes of Awassi lambs in Iraq
Authors: Altaif K. I. , Issa W. H.
Published: June 2009

The results of an epidemiological study involving the estimation of worm counts of gastro-intestinal nematodes of lambs, during the period December 1978 to November 1979, in the Baghdad area are reported. Ostertagia spp. and Trichostrongylus spp. were the most abundant nematodes in the weaned lambs used in this study. Ostertagia spp. infection was present throughout the period of observation, the level of infection being the highest during early summer (May–June). Trichostrongylus spp. infection, however, reached a peak during July–August. In the tracer lambs the maximum population of Ostertagia spp. was found during February–March, while that of Trichostrongylus spp. could be observed only after mid-June. Other nematodes encountered were Haemonchus contortus and Trichuris sp. but they were only present in small numbers. The proportion of inhibited larvae of Ostertagia spp. was markedly high during the dry summer months. Little inhibition was noticed during autumn and the early winter months. It appears that if the seasonal inhibition of Ostertagia spp. in Iraq is brought about by an environmental stimulus acting upon pre-parasitic larval stages, that stimulus cannot be chilling or falling temperatures, as observed in temperate northern zones.
Echinococcus granulosus equinus: an ultrastructural study of murine tissue response to hydatid cysts
Authors: Richards K. Sylvia , Arme C. , Bridges Janine F.
Published: June 2009

Peritoneal hydatids of Echinococcus granulosus equinus of 9 months standing in BALB/c mice occurred as free cysts or cysts within cyst masses. Both showed wide variation in size and in host tissue response, and all had a well-developed laminated layer separating the host tissue response from the germinal layer. In the smallest cyst-mass cysts the host tissue response was present as remnants of the initial cellular attack involving eosinophils. Slightly larger cyst-mass cysts possessed a primary macrophage invasion which phagocytosed the remnants of the initial attack and also, though to little effect, the laminated layer material. In the largest cyst-mass cysts a second macrophage invasion, of monocyte origin, had commenced and transformation stages of these cells to macrophages were observed. No fibroblasts surrounded individual cyst-mass cysts but they were present around the cyst mass, encapsulating it and possibly preventing further host cell invasion. Thus, the host tissue response around individual cyst-mass cysts remained ‘preserved’ at an early stage such as existed at the time of encapsulation. Small free cysts showed a primary macrophage invasion and transformation stages of cells of a secondary infiltration of peritoneal origin. Peripheral to the macrophages were fibroblasts demonstrating limited fibrinogenesis, and each cyst was surrounded by a layer of mesothelial cells. Large free cysts, also delimited by a mesothelial layer, possessed peripheral connective tissue, a deep fibrous layer and a monolayer of very compressed macrophages lying adjacent to the laminated layer. It is emphasized that an understanding of the host tissue response in cysts of different sizes and from different locations is an essential pre-requisite for the design of experimental studies.
Schistosoma mansoni: changes in elemental composition in relation to the age and sexual status of the worms
Authors: Shaw M. K. , Erasmus D. A.
Published: June 2009

Changes during development in the elemental contents (Ca, P, K, Mg and S) of male and femaleSchistosoma mansonifrom both mixed and single sex infections have been measured for the first time. In mixed infections, there is a significant difference between the calcium content of male and female worms; female worms having between 2 and 3 times more calcium. In mature female worms from mixed infections, after an initial rise in the calcium content corresponding to the time when vitelline development occurs, the amount of calcium ranged from 0.36 to 0.65 mg/g dry wt, whereas the amounts in similarly aged male worms ranged between 0.19 and 0.32 mg/g dry wt. While the type of infection does not affect the calcium content of male worms, a significant difference in the calcium levels in female worms from mixed and single sex infections was found. The amount of calcium in females from single sex infections ranged from 0.21 to 0.39 mg/g dry wt and this is considerably less than the levels recorded in females from mixed infections. This difference in calcium content between mixed and single sex infections can be related to the differences in degree of development of the vitelline gland in the two types of female worm. The amounts of phosphorus, potassium, magnesium and sulphur in both male and female worms from both single and mixed infections are similar, although females from mixed infections contained slightly more phosphorus than either females from single sex infections or either type of male worm.
Sphaerospora molnari sp.nov. (Myxozoa:Myxosporea), an agent of gill, skin and blood sphaerosporosis of common carp in Europe
Authors: Lom Jiří , Dyková Iva , Pavlásková Milena , Grupcheva Ginka
Published: June 2009

Sphaerospora molnari sp.nov. is described from the gills, skin and nasal pits of yearling carp (Cyprinus carpio L.) from ponds in the South Bohemian pond region of Czechoslovakia and one infected specimen from the river Danube in Bulgaria. Small vegetative stages, often massively pervading the infected tissue, produce 1 spore each. Spores are sub-spherical, 10·3 × 10·5 μm in size, with almost spherical polar capsules of equal size. The polar filaments are wound in wide coils that are almost parallel with the longitudinal axis of the spore. There are 2 uninucleate sporoplasm cells. Developmental stages and spores are also found in circulating blood. In the gills, S. molnari invades stratified epithelium of gill filaments and secondary lamellae causing branchial lesions and must be regarded as a serious pathogen of yearling carp. A new name, Sphaerospora chinensis sp.nov. is proposed for S. branchialis Lee & Nie in Chen (1973), pre-occupied by S. branchialis Razmashkin and Skrip-chenko, 1967.
Site segregation by species of Acanthocephala in fish, with special reference to eels,Anguilla anguilla
Authors: Kennedy C. R.
Published: June 2009

Site specificity and distribution of 5 species offreshwater acanthocephalansAcanthocephalus clavula, A. lucii, A. anguillae, Pomphorhynchus laevisandEchinorhynchus trultaeand I marine species,E. gadi, were studied in the intestines of several species of fish, especiallyAnguilla anguilla. When data are presented in the conventional manner with results from all fish and all parasites in a sample combined, each species exhibited a preference for a particular region of the intestine which altered in some species in relation to host identity and sex and abundance of parasite. Each species could nevertheless inhabit most of the length of the intestine and there was a considerable degree of overlap in most cases between the distributions of species in the same host, but the mean position of each species differed significantly from that of any other and the species appeared to exhibit site segregation and resource partitioning along the length of the intestine. In individual fish, fidelity of site location and distribution is poor and may bear little or no relationship to the position and distribution of the parasites in the population as a whole, and it is concluded that the concepts of site specificity and segregation are most applicable at the population level. Mixed species infections are very rarely encountered in Britain since most freshwater localities contain, or are almost completely dominated by, only a single species of acanthocephalan. The results are discussed in relation to current ideas on the role of interspecific competition in determining site segregation and community structure of parasites. It appears that site specificity in fish acanthocephala is not related to the probability of mating, or site segregation to interspecific competition past or present. Acanthocephalan communities do not exist as such; the normal situation is chance assemblages, with vacant niches, little organization, few or no interactions and little fidelity between habitats.
Synthesis of macromolecules by the epithelial surfaces ofSchistosoma mansoni: an autoradiographic study
Authors: Wilson R. A. , Barnes P. E.
Published: June 2009

The use of tritiated leucine as a marker for protein synthesis and of tritiated glucosamine as a marker for polysaccharide/glycoprotein synthesis, is described. Adult worms were pulse-labelled by incubation in medium containing the substrate. Labelled worms were then incubated in chase medium, without labelled substrate, for varying lengths of time before fixation. The distribution of label which had been incorporated into macromolecules in the worm tissues, was examined by light and electron microscope autoradiography. It was estimated that the tegument and tegument cell bodies were the source of 67–80%, and the gut epithelium of 20–33%, of exportable leucine-containing protein. Conversely, the gut epithelium was the source of 72%, and the tegument cells 28%, of exportable glucosamine-containing polysaccharide. The specific activity of labelled protein reached a peak in the tegument cytoplasm after 1.5 h of chase incubation. Half of the labelled protein was secreted into the worm's environment by 3 h of chase incubation. The half-life of secretory protein in gut cells appears to be around 2 h. Labelled protein disappears from the gut lumen relatively rapidly but labelled polysaceharide remains in the lumen at high specific activity for at least 24 h. The major carbohydrate labelled may be the glycocalyx on the luminal surface of the gut epithelial cells. The results suggest that the bulk of worm secretions have a rapid turnover with a half-life of a few hours. Against this background of rapid mass secretion a slower process of membrane turnover would be difficult to detect and quantitatively small.
The effect of the expulsion phase ofTrichinella spiralisonHymenolepis diminutainfection in rats
Authors: Christie P. R. , Wakelin D. , Wilson M. M.
Published: June 2009

The effect of the intestinal changes brought about by the expulsion ofTrichinella spiralisin rats was studied in relation to the growth and survival of a concurrent infection withHymenolepis diminuta, a cestode not normally rejected by the rat in low-level infections. Growth ofH.diminutawas stunted in rats givenT.spiralisjust before, or after, infection withH.diminuta, the stunting being more pronounced when the cestode was given closer to the period of inflammation. There was no loss of the cestode from dual-infected rats and no evidence for destrobilation was found. LowerT.spiralisburdens had a correspondingly weaker effect on growth ofH.diminuta, and stunting was abolished by administration of the anti-inflammatory drug cortisone acetate. It is concluded that the stunting ofH.diminutais probably due to the non-specific inflammatory component of the rat's response toT.spiralisinfection.
Eimeria maxima: the use of enzyme markers to detect the genetic transfer of drug resistance between lines
Authors: Rollinson D. , Joyner L. P. , Norton C. C.
Published: June 2009

Eimeria maxima (Weybridge) and E. maxima (indentata) were distinguished by the electrophoretic mobility of phosphoglucomutase. This enzyme was used as a marker to detect the transfer of methyl benzoquate resistance between resistant and sensitive lines of these parasites.
Detection of ecdysteroids in the human trematode,Schistosoma mansoni
Authors: Torpier G. , Hirn M. , Nirde P. , De Reggi M. , Capron A.
Published: June 2009

Freeze fracture study ofSchistosoma mansonimembrane differentiation enabled us to describe the characteristic features of the tegumental membrane complex at various stages of development of this parasite. The observation of a membrane exuviation during the 10–20 day period of infection of the definitive host led us to search for possible hormonal control. The development of an appropriate radioimmunoassay has allowed the detection of significant production of ecdysteroids in a human platyhelminth. This hormonal material undergoes level variation during the development of post-cercarial stages ofS. mansoniand its precise chemical characterization is presently being investigated.
The activity of acid proteases hydrolysing haemoglobin in parasitic helminths with special reference to interspecific and intraspecific distribution
Authors: Maki Jun , Furuhashi Asami , Yanagisawa Toshio
Published: June 2009

Acid proteases hydrolysing haemoglobin, first described by Timms & Bueding (1959), were studied to investigate the interspecific and intraspecific distribution in adult parasitic helminths. Acid protease activity was detected in a variety of adult helminths, irrespective of their habitats, namely, parasitic nematodes,Angiostrongylus cantonensis, Dirofilaria immitis, Trichuris murisandAscaris suum, a trematode,Paramphistomumsp. and cestodes,Diphyllobothrium erinaceiandHymenolepis nana. Much higher specific activity was observed in the blood nematodes,A. cantonensisandD. immitisthan in the gastro-intestinal helminths examined. The intraspecific distribution of the acid protease activity within organs was studied in those nematodes from which the organs could be anatomically separated. The highest specific activity was observed in the intestine ofA. cantonensis, D. immitisandA. suum. The activity was also found in other organs of these nematodes, namely, the reproductive organs and the body wall, but to a much lesser extent. The pH optima for the hydrolysis of haemoglobin were found to be in the pH range of 3·1 to 4·6. Each of the enzyme solutions from the 7 species of helminths hydrolysed haemoglobin faster than the other proteins examined but some activity on myoglobin, casein, albumin and other proteins was demonstrated. Pepstatin, a potent inhibitor of carboxyl proteases, inhibited the hydrolysis of haemoglobin by the acid proteases of the 7 species of the parasites. Acid protease activity fromA. cantonensisandA. suumwas not inhibited in the presence of thiol-, serine- and metallo-protease inhibitors at a concentration of 10−6M. This fact, together with the inhibitory effect of pepstatin, suggests that the enzyme activity is likely to be due to carboxyl protease(s). Acid proteases such as cathepsin D and pepsin were simultaneously used for comparison of some enzymological characteristics. The substrate specificity of the enzyme solutions from the helminths seemed to resemble that of cathepsin D rather than that of pepsin. The effects of pH and pepstatin on the acid protease activity of the helminths were similar to those on pepsin and cathepsin D.
Development of Theileria parva (Theiler, 1904) in the gut of Rhipicephalus appendiculatus (Neumann, 1901)
Authors: Schein E. , Warnecke M. , Kirmse P.
Published: June 2009

The life-cycle of Theileria parva in the gut of the tick Rhipicephalus appendiculatus was investigated in Giemsa-stained smears and in wet preparations under the phase-contrast microscope. The different developmental stages of T. parva were seen in a large proportion of specially-selected R. appendiculatus tickes. After the intra-erythorcytic merozoites were engorged by the ticks during a blood meal, the following development was observed. (1) In the lumen of the gut of infected nymphs, spindle-shaped microgamonts developed out of the ring-forms. These broke up into several thread-like microgameters after nuclear division and development of thread-like cytoplasmic projections. The ring-froms developed into round-forms of 3–4 μm in diameter which are considered to be macrogametes. (2) From the 6th day after repletion, zygotes with a clear zone in the centre appeared in the epithelial cells of the tick's gut. A steady increase in size and a progressively denser cytoplasm were observed up to the 3rd day after moulting to adult ticks. (3) Subsequently a slightly angular, retort-like stage developed by invagination inside the rounded zygotes, and from the 5th day after moulting this stage developed further into a club-shaped kinete. The kinetes propelled themselves in the gut by active gliding movements.
Schistosoma mansoni: complement activation in human and rodent sera by living parasites of various developmental stages
Authors: Ruppel A. , Rother U. , Vongerichten H. , Diesfeld H. J.
Published: June 2009

LivingSchistosoma mansoniof various developmental stages were studied with respect to their ability to activate the complement system in sera of humans, mice and rats. Immunofluorescence assays demonstrated that binding of human C3 occurred on fresh schistosomula as well as on schistosomula prepared from mouse lymph-nodes or lungs and on adult schistosomes. However, rodent C3 was deposited only on fresh schistosomula. Deposition of human C3 on the worms' surface required activation of the complement system. The alternative pathway was shown to be involved in deposition of human C3 on schistosomes of all ages, whereas activation of the classical pathway was demonstrable only with fresh schistosomula. Immunoelectrophoretic studies demonstrated a dose-dependent cleavage of human C3 and conversion of factor B by living adult schistosomes. The results demonstrate that the ability of living schistosomes to activate complementin vitrois dependent not only on their developmental stage but also on the species of the serum.
Infections with a Malaysian dog strain of Ancylostoma ceylanicum in outbred, inbred and immunocompromised mice
Authors: Carroll S. M. , Grove D. I. , S. H. J. , Mitchella G. F. , Whitten L. K.
Published: June 2009

The course of infection with a Malaysian dog strain of Ancylostoma ceylanicum was investigated in 15 inbred strains of mice, in outbred and inbred mice immunosuppressed with prednisolone, and in immuno-deficient hypothymic mice. Oral, percutaneous and subcutaneous routes of infection, in both sexes of mice, were assessed. In only one instance was a single small adult male worm found. Following oral infection, larvae migrated from the stomach to the large bowel and then a proportion of worms penetrated the perianal skin. This was followed by the appearance of larvae in the lungs. Living 3rd-stage larvae were seen in the anterior small intestine, perianal skin and lungs for the 6 weeks of the study, with peak recoveries being at 12 h, 8 days and 3 weeks, respectively. It is clear that systemic migration of larvae occurs after oral infection, and it is possible that recirculation may occur. Only a small percentage of larvae penetrated the abdominal skin after being administered percutaneously. In subcutaneous infections, a small proportion of larvae moved rapidly from the site of injection and were recovered from the lungs 2 h after infection. Most larvae, however, migrated from the injection site over the ensuing few days. Living 3rd-stage larvae were seen in the lungs and in the small intestine for the 4 weeks of observation. The strain of A. ceylanicum employed does not complete its development in mice. Nevertheless, this model offers significant potential for studying the immune responses, as well as investigating the means by which these parasites evade host defences.
Cross-reactive surface antigens on three stages ofBrugia malayi,B. pahangiandB. timori
Authors: Maizels R. M. , Partono F. , Oemijati Sri , Denham D. A. , Ogilvie Bridget M.
Published: June 2009

Surface antigens of three stages of three species of the filarial nematode genusBrugiahave been analysed by radio-iodination and immunoprecipitation. These surface antigens have been shown to be characteristic for each stage by polyacrylamide gel electrophoresis. For example, infective larvae and adult worms have relatively complex patterns while microfilariae have few bands which are not found when other stages are radio-isotope labelled by the same technique. The surface antigens ofBrugia malayi,B. timoriandB. pahangiadult worms are all closely homologous, as are the surface antigens of infective larvae of the same three species, and of microfilariae ofB. malayiandB. pahangi. Immunoprecipitation revealed that antibody raised in mice against one stage or species reacted with surface antigens from other stages and species. For example, sera raised againstB. pahangimale adults reacted strongly with surface antigens from all three species. This cross-reactivity was dominant despite the apparent stage-specificity of the surface pattern seen on SDS-PAGE analysis. Moreover, in cross-immunization experiments, infective larvae were able to stimulate a secondary antibody response in mice previously primed with microfilarial surface antigens. The major microfilarial surface antigens (of mol. wt 65−70000 Daltons) were recognized by serum antibody from microfilariae-, infective larvae- or adult-infected animals. Thus, although the dominant antigens from each stage are of different molecular weight, cross-reactions with stage-specific antisera suggest that there must be shared epitopes onBrugiasurface antigens from each stage. Such shared antigenic determinants dominate the immune response, although other evidence, including the differences in molecular weight, indicates the existence of stage-and species-specific components.
Correlation between the morphology and infectivity of Theileria lawrencei developing in the tick Rhipicephalus appendiculatus
Authors: Young A. S. , Purnell R. E. , Kimber C. D. , Payne R. C.
Published: June 2009

Adult Rhipicephalus appendiculatus ticks, infected as nymphs by feeding them on an African buffalo harbouring Theileria lawrencei, were applied to the ears of rabbits.

Equal numbers of the feeding ticks were removed daily from rabbits and either dissected and processed so that parasites in their salivary glands could be examined morphologically and classified, or ground in Eagle's Minimal Essential Medium, to harvest parasites from the ticks in the resultant supernatant fluid. The infectivity of the supernatant fluid was tested by inoculation of aliquots into groups of susceptible cattle.

It was found that supernatant fluids produced from day 0 to day 2 fed ticks were uninfective to cattle but those produced from 3 to 9 days were infective. The most infective supernatant fluid was produced from 6 day fed ticks.

The reactions resulting in cattle were correlated with the number and morphology of parasites in sections of salivary glands and it was found that mature parasites coincided with infectivity of the supernatant fluid to cattle.

From the reactions in cattle inoculated with supernatant fluids from 5 and 6 day fed ticks it was concluded that this method of harvesting parasites was efficient.

Examination of the salivary glands of a representative sample of a T. lawrencei infected tick batch is a potential means of screening material for T. lawrencei stabilates.
The effects of gamma-irradiation on migration and survival of Schistosoma mansoni schistosomula in mice
Authors: Bickle Q. D. , Dobinson T. , James E. R.
Published: June 2009

Infections with irradiated Schistosoma mansoni were established by intramuscular (i.m.) injection of mechanically transformed schistosomula. A dose of 2·3 krad. allowed persistence of a small proportion of worms to adulthood, and of these survivors the majority of the female worms were sexually sterile. However, a small proportion of 2·3 krad. irradiated females and a larger proportion of similarly irradiated males were capable of pairing successfully with non-irradiated partners. Radiation in the range 2·3 to 10 krad. resulted in slightly reduced peak recoveries from the lungs while 20 krad. resulted in a much reduced and 40 krad. a virtual absence of survival to the lung stage. Increasing doses of radiation in the range 2·3 to 10 krad. resulted in successively fewer parasites reaching the liver. Thus, the major sites of the radiation-induced mortality appeared to be as follows: 2·3 krad., mainly in the liver; 4 krad., in the lungs and liver; 10 krad., mainly in the lungs; 20 krad., at the injection site and in the lungs and 40 krad., mainly at the injection site. The infections studied here showed reduced survival following exposure to high doses of radiation compared with the infections, established as percutaneously applied cercariae, which have been reported by other workers. Possible reasons for the disparity are discussed.
Ovarian development of Corynosoma semerme (Acanthocephala) during experimental infections in rats
Authors: Peura Raija , Valtonen E. Tellervo , Crompton D. W. T.
Published: June 2009

The general structure and aspects of the development of the ovaries of the palaeacanthocephalan Corynosoma semerme were studied by transmission electron microscopy using worms varying in age from 18 to 90 h obtained from experimental primary infections in hydrocortisone-treated rats instead of seals, which serve as the natural definitive hosts. The observations can be interpreted to show that the immature ovaries become transformed relatively rapidly from cellular spheres to the more complex mature ovaries consisting of the supporting and oogonial syncytia and the germ-line cells. The supporting syncytium developed before the oogonial syncytium. The cytological appearance of ovaries from worms from rats was found to be similar to that of ovaries from mature worms of unknown age from naturally infected seals. Ecological evidence is considered to suggest that the rapid maturation of C. semerme in rats may also occur when the parasite becomes established in seals.
Observations on the antigenicity and serological relationships of stocks ofTrypanosoma congolensefrom East and West Africa
Authors: Luckins A. G. , Gray A. R.
Published: June 2009

Antigenic relationships of 4 stocks ofTrypanosoma congolensefrom different parts of Africa were examined by immunofluorescence (IFAT) and neutralization tests. Antisera to each stock were obtained from rabbits infected with trypanosomes transmitted byGlossina morsitans. Trypanosomes for use as antigens were obtained from local skin reactions developing on rabbits infected with 2 of the stocks. Using the IFAT and antisera at end-point dilutions approximately 40% of the trypanosomes fluoresced strongly and a further 30% less intensely with homologous antisera, indicating antigenic heterogeneity among the trypanosomes developing in the skin. Using antisera at low dilutions some samples gave cross-reactions with trypanosomes of heterologous stocks, but at higher dilutions there were no cross-reactions with either of the antigens. The lack of cross-reactions at high antiserum dilutions was interpreted as indicating antigenic differences between the 4 trypanosome stocks. Using neutralization tests only homologous antisera reduced the infectivity of trypanosome suspensions. Overall, these observations indicated that there were at least 3 different strains ofT. congolenseamong the 4 stocks examined.
Characterization ofTrypanosoma congolenseserodemes in stocks isolated from cattle introduced onto a ranch in Kilifi, Kenya
Authors: Masake R. A. , Nantulya V. M. , Musoke A. J. , Moloo S. K. , Nguli K.
Published: June 2009

A herd of 20 cattle was introduced on a ranch in Kilifi, Coast Province of Kenya, where they were in contact withGlossina austenifor 6 months. In total, 65 trypanosome isolates were made from these animals. Examination of the isolates revealed that 61 wereTrypanosoma congolenseand 4 wereT. theileri. Out of the 61T. congolenseisolates, 55 were successfully passaged and cloned in mice to provide trypanosome populations for further analyses. The stocks and their clones were inoculated into goats on which teneralG. morsitans centraliswere later fed in order to provide metacyclics for use in serodeme analysis. Identification of serodemes was carried out by indirect immunofluorescence and neutralization using antimetacyclic hyperimmune sera prepared in mice against metacyclics of cloned trypanosome populations. So far 4 serodemes have been identified in 8 stocks and 7 clones. Each of the 9 stocks contained a mixture of at least 2 of the 4 serodemes identified. Furthermore, stocks isolated sequentially from individual animals contained the same serodemes despite repeated treatment with a curative dose (6 mg/kg body weight) of Berenil between isolations. From the latter finding, it can be inferred that the 4 serodemes were present on the ranch throughout the study period.
Inhibition of development of Ostertagia ostertagi – effect of temperature on the infective larval stage
Authors: Smeal M. G. , Donald A. D.
Published: June 2009

Populations of Ostertagia ostertagi established from fresh larvae and from larvae stored at 4 °C for up to 12 weeks contained about 10% inhibited early 4th-stage larvae. This value rose to 21% after 16 weeks, due to an increase in numbers of inhibited larvae while adult numbers remained unchanged. Storage at 15 °C had no effect. In the case of larvae stored at 4 °C for 8 weeks, increasing the larval dose to 90000 had no significant effect on the proportion of the dose which was inhibited. The response to low temperature storage was much weaker than in previously reported studies on British populations, which accords with our earlier conclusion that low temperature cannot be the effective stimulus for inhibition in Australia.
Distinction of African trypanosome species using nucleic acid hybridization
Authors: Massamba N. N. , Williams R. O.
Published: June 2009

We have performed restriction endonuclease digestion of nuclear DNAs, combined with gel electrophoresis and molecular hybridization to characterize different Trypanosoma brucei brucei stocks and to identify trypanosome species. Cloned DNA complementary to the messenger RNAs (mRNAs) for different variable surface glycoproteins (VSGs) of T. b. brucei stock LUMP 227 was used to examine differences in genomic DNAs from T. b. brucei stocks and from various other trypanosome species. These cDNA reagents differentiated the stocks of T. b. brucei and also distinguished the trypanosome species. Our data also show that a T. b. brucei nuclear DNA fragment used as a probe in molecular hybridization analysis provides an appropriate marker in determining trypanosome species. We have extended our analysis of trypanosome nuclear DNA by developing a simple and rapid spot test, for the identification of trypanosome species, which can be carried out using crude materials such as isolated parasites, infected whole blood and tsetse saliva. The procedure is species-specific, sensitive to the level of 104 organisms and is suitable for use under field conditions. Thus, with appropriate sequences for hybridization, the procedure has obvious applications for the diagnosis of African trypanosomiasis.
Parasite development and host responses during the establishment ofTrypanosoma bruceiinfection transmitted by tsetse fly
Authors: Barry J. D. , Emery D. L.
Published: June 2009

Following inoculation ofTrypanosoma bruceiinto large mammals by the tsetse fly a local skin reaction, the ‘chancre’, develops due to trypanosome proliferation. We have cannulated the afferent and efferent lymphatics of the draining lymph node in goats and examined the onset of a cellular reaction, the emigration of the parasite from the chancre and the development of both antigenic variation and the specific immune response. The chancre first became detectable by day 3 post-infection, peaked by day 6 and then subsided. Lymphocyte output increased 6- to 8-fold by day 10 and the number of lymphoblasts increased 50-fold in this period. Both then declined. Trypanosomes were detected in lymph 1–2 days before the chancre, peaked by days 5–6, declined during development of the chancre and then peaked again. The bloodstream population appeared by days 4–5 and displayed different kinetics from that in lymph. Recirculation of parasites through the lymphatics ensued. Lymph-borne trypanosome populations were highly pleomorphic. Parasites in lymph expressed firstly a mixture of the Variable Antigen Types (VATs) which are found characteristically in the tsetse fly, this being followed by a mixture of other VATs. The two groups overlapped in appearance. In the bloodstream the same sequence of events occurred although 2 or 3 days later. The specific antibody response, as measured by radioimmunoassay and agglutination, arose within a few days of the first detection of each VAT. Activities appeared first in the lymph and then in plasma.
Chimaerocestos prudhoeigen. et sp. nov., representing a new family of tetraphyllideans and the first record of strobilate tapeworms from a holocephalan
Authors: Williams H. H. , Bray R. A.
Published: June 2009

Chimaerocestos prudhoeigen. et sp. nov. fromRhinochimaera atlanticain the North Atlantic off north-eastern Scotland represents a new family, the Chimaerocestidae, of tetraphyllideans and is the first record of a strobilate tapeworm from a holocephalan. The main taxonomic features are described and figured along with aspects of the ecology and mode of attachment to the gut mucosa. The lobed annular ovary and distribution of the vitellarium in two fields are characteristic features. About 15 eggs are deposited together in capsules.C. prudhoeiis discussed in relation to other unusual fish tapeworms and the evolutionary biology of tapeworms, and to our scant knowledge of the holocephalans.
Migrational responses of Hymenolepis diminuta to surgical alteration of gastro-intestinal secretions
Authors: Sukhdeo M. V. K. , Mettrick D. F.
Published: June 2009

The effects of the direction of gut flow, of injections of glucose and saline into different regions of the small intestine and of surgical re-routing or ligature of gastric, biliary and pancreatic secretions into the small intestine have been correlated with changes in the migratory response of the rat tapeworm Hymenolepis diminuta. Reversing the normal anterior to distal flow of luminal contents in the small intestine did not affect worm migration following feeding. Injections of a glucose-saline solution into the duodenum did not initiate a migratory response; similar injections into the mid- and posterior regions of the small intestine resulted in migrational responses similar to those following intragastric glucose feeding. Re-routing gastric secretions to the distal duodenum inhibited anterior migration of the worms beyond the new point of entry of gastric juices. Results following re-routing and ligation of the biliary and pancreatic secretions suggest that there is a potent cue to anteriad migration in the pancreatic secretions. Biliary secretions also appear to contain an additional migratory cue to worm migration. In order of importance the factors stimulating/inhibiting worm migration are pancreatic > gastric > biliary > glucose. The results support the hypothesis that the factors affecting worm distribution in the small intestine are interactive and synergistic, involve other luminal factors, such as 5- hydroxytryptamine and the physico-chemical gradients, and are of a regional nature such that the migratory response of a particular worm is directly related to its position in the small intestine when the cues to relocation are received.
The large-scale preparation of purified sporozoites of Eimeria spp. by metrizamide density-gradient centrifugation
Authors: Wisher M. H. , Rose M. E.
Published: June 2009

A method is described for the reproducible purification of greater than 1·0 × 108 sporozoites of Eimeria spp. by centrifugation on metrizamide density-gradients. The mean contamination of the purified sporozoite fraction by sporocysts and sporocyst debris was less than 6% and the recovered sporozoites were fully viable, infective and ultrastructurally intact.
Effect of copper and zinc upon the survival and infectivity of Echinoparyphium recurvatum cercariae
Authors: Evans N. A.
Published: June 2009

At concentrations ranging from 0·1 to 10·0 mg/l, copper and zinc reduced both the longevity and infectivity of Echinoparyphium recurvatum cercariae. Concentrations of 10·0 mg/l copper and zinc in hard water reduced the time to 50% mortality of cercariae from 30·5 h to 8·5 h and 15·5 h respectively. Copper-induced effects upon cercarial infectivity were particularly severe and exposures of cercariae to 0·5 mg/l of this metal for as little as 15 min caused significant reductions in their ability to infect molluscan 2nd intermediate hosts. Water hardness had a marked influence on copper toxicity but had a much lower effect on the toxicity of zinc. Metal concentrations found to exert a profound influence on parasite transmission in the present laboratory-based study have been found to occur in natural, albeit polluted, freshwater habitats.
Localized skin changes at the site of immunization with highly irradiated cercariae of Schistosoma mansoni are associated with enhanced resistance to a challenge infection
Authors: Miller Kathleen L. , Smithers S. R.
Published: June 2009

The level of immunity to a percutaneous cercarial challenge with Schistosoma mansoni was assayed 4–6 weeks after immunization of mice with highly irradiated (20 krad.) cercariae or schistosomula. When immunization and challenge occurred through the same skin site, resistance, particularly that which occurred in the skin, was greater than that observed when immunization and challenge occurred in different sites. The enhanced resistance is believed to be due to localized changes in the skin; 4 weeks after exposure to irradiated cercariae, abdominal skin is characterized by a thickened epidermis, changes in the ground substance and a cellular infiltration of the dermis. A convenient mouse model is described in which one or both ear pinnae are exposed to irradiated cercariae and a percutaneous challenge is given via the abdomen, thus eliminating the effects of local skin changes. In this model, the majority of the challenge infection which succumbs to the immune response appears to be killed in the skin.
The distribution of cephalic sense organs in four species ofRaillietiella(Pentastomida: Cephalobaenida)
Authors: Ali J. H. , Riley J.
Published: June 2009

Scanning electron microscope observations of the frontal papillae and peribuccal cuticle of four species of raillietiellid pentastomids have shown an array of sensilla which are grouped in characteristic patterns. The arrangement of sensilla is remarkably uniform within the species studied and it cannot be used in specific diagnosis. Possible functions are suggested.
Characterization of phenol oxidase in a pseudophyllidean cestode Penetrocephalus ganapatii
Authors: Jayabaskaran C. , Ramalingam K.
Published: June 2009

The biochemical characteristics of phenol oxidase obtained from Penetrocephalus ganapatii have been investigated using manometric and electrophoretic techniques. Phenol oxidase was found to have maximum activity at pH 7·4, the Michaelis constant for dopamine was 189 μM and the enzyme was stable between 20 and 40°C. Potassium cyanide, sodium diethyldithiocarbamate and phenylthiourea strongly suppressed enzyme activity. The Ki values for potassium cyanide, diethyldithiocarbamate and phenylthiourea were 33μM, 700 μM and 938 μM respectively. The properties of soluble and insoluble enzymes to various phenolic substrates are discussed.
Immunochemical studies on pathotypes of the potato cyst nematodes, Globodera rostochiensis and G. pallida
Authors: Fox P. C. , Atkinson H. J.
Published: June 2009

The potential of antigenic differences for discriminating pathotypes of the potato cyst nematodes Globodera pallida and G. rostochiensis has been examined by the use of an antiserum raised to a homogenate of potato cyst nematode larvae. Species-specific antigens were detected among reference pathotypes but more variability was detected among field populations, and cluster analysis was used to interpret the precipitation are pattern produced by Laurell crossed-immunoelectrophoresis. A division into species was seen with this analysis but no definite pathotype groupings were detected. Cross-reaction with other cyst-nematode species was limited to general non-specific precipitation. The antigens were all proteinaceous, did not arise from micro-organisms within the cyst and were mainly hydrophilic with an acidic isoelectric point. Peptidase and acid phosphatase activity was detected in some precipitation arcs but this was not species specific.
Population effects of parasite survival of host death: experimental studies of the interaction of Ichthyophthirius multifiliis and its fish host
Authors: McCallum H. I.
Published: June 2009

Current models of the regulation of host populations by parasite infection assume that death of a host results in death of all the parasites contained within or on the host. This assumption acts as a density-dependent constraint on parasite population growth and contributes to the stability of the interaction between host and parasite populations. The protozoan Ichthyophthirius multifiliis, a parasite of freshwater fish, is one of a number of pathogens in which the reproductive capacity of an individual is not entirely destroyed by the death of its host. The effect of host death on the reproductive potential of I. multifiliis was investigated with a series of short-term experiments examining (i) the relationship between parasite burden and host mortality, (ii) parasite survival on the host and (iii) the relationship between parasite age and the number of infective stages released/parasite. Results of a series of experimental epidemics in which host numbers were maintained constant showed large oscillations in parasite numbers. Deterministic models ignoring the age structure of the parasite population were unable to reproduce the behaviour observed in the experimental epidemics. Using the results of the short-term experiments, a difference equation model was developed. This model was able to qualitatively reproduce the observed epidemic behaviour.