bluuebunny/crossref_metadata_2025_split huggingface dataset:
Host specificity and rejection ofSchistocephalus solidus
Authors: Orr T. S. C. , Hopkins C. A. , Charles G. H. 
Published: June 2009

1. Procercoids ofSchistocephalus solidusreared in copepods were found to infect marine and freshwater varieties ofGasterosteus aculeatus, andPungitius pungitius, but notBarbus ‘Schuberti’.2. In primary infections growth ofS. solidusplerocercoids inP. pungitiuswas much slower than inG. aculeatusand ceased after 6–8 days; plerocercoids were dead by day 11 at 19·5 °C, and by day 14 at 10 °C.3. A challenge infection, following two previous infections given 14 and 28 days before, becomes established inG. aculeatus, but inP. pungitiusplerocercoids are rejected within 3–5 days.4. The possible rejection mechanism involved inP. pungitiusto primary and tertiary infections is discussed and electronmicrographic evidence presented of a degenerative change in the tegument visible by 8 days in a primary infection. Prior to 8 days the survival and growth ofS. solidusplerocercoids surgically transferred toG. aculeatus, indicated no irreversible damage had occurred.
A morphological and histochemical study of Trichuris suis (Schrank, 1788) with special reference to the host-parasite relationship
Authors: Jenkins T. 
Published: June 2009

Adult forms of the pig whipworm, T. suis, are able to establish intimate contact with the host's tissues by the formation of a tunnel-like construction which covers a section of the thread-like oesophageal region. The extreme anterior oral end and the stouter posterior region are not covered and lie free in the lumen of the caecum. The attachment tunnel is composed of host mucosal cells and goblet cell secretion and its possible mode of construction is discussed. Host tissue not directly involved in tunnel formation appears unharmed by the presence of the parasite. T. suis is therefore not a serious pathogen under natural conditions.It has been demonstrated that characteristic structures of the trichuroid oesophageal region, e.g. bacillary band and stichosome are metabolically active. The former penetrates the layered cuticle in the form of columnar protrusions originating in the hypodermis. Each hypodermal column represents a gland cell or bacifiary cell, which displays enzymic activity, e.g. acid phosphatase, non-specific esterase, glucose-6-phosphatase, succinate dehydrogenase, cytochrome oxidase and β-d-glucosidase. Its possible function at the host-parasite interface and in the metabolism of the whipworm is discussed. The layered cuticle is proteinaceous and enzymically inert.Glandular activity is also displayed by the stichosome surrounding the capillary-like oesophagus. This evidence confirms earlier suggestions that the stichosome is a series of oesophageal glands.Although the bacillary band may be involved in nutrient uptake the evidence obtained indicates that this is via the mouth which is favourably placed for the ingestion of mucoid material which was detected in the oesophagus. This may be subjected to preliminary hydrolysis by the enzymes present in the oesophagus and stichosome.
Host-finding behaviour of the rabbit flea, Spilopsyllus cuniculi with special reference to the significance of urine as an attractant
Authors: Vaughan J. A. , Mead-Briggs A. R. 
Published: June 2009

Both fed and unfed rabbit fleas can move relatively slowly upwind towards a host. The speed of movement is too slow for direct host location from more than a few cm.Fleas are strongly attracted to a urine bait, will remain gathered around it, and can move rapidly on to a host when one is present.The attraction is produced by physiologically realistic amounts of urine, little increase being obtained from volumes greater than 15 ml, even over a tenfold range. The range of movement of fleas towards a urine bait obtained in our experiments was greater than 6 m but less than 9 m. The maximum survival time in pasture during summer and autumn was between 14 and 21 days.The attractants are contained in urine and not in faeces, and are not restricted to the urine of rabbits or even of lagomorphs. Strong attraction was obtained towards hare and rat urines, and a low degree of attraction towards dog and human urine. Concentrated homogenates of rabbit anal glands gave low attraction.
The role of the choriothete in tsetse flies
Authors: Roberts Michael J. 
Published: June 2009

The anatomy of the choriothete and its relation to certain features of the tsetse uterus, such as the previously unnoticed radial, uterine ridges, are described. The results of this study suggest that the choriothete is an organ for support of the developing embryo or larva and this role is taken over by the uterine ridges when the larva reaches a sufficient size. The choriothete then appears to degenerate due to stretching of the uterus until the beginning of the next breeding cycle.Hatching takes place with the aid of a labral egg-tooth as in some other dipteran larvae and does not require the additional presence of the choriothete.The uterine ridges also help to form a pool of milk gland secretion around the anterior end of the second-instar larva by locking its body wall to that of the uterus.I am grateful to Dr E. J. Popham and Col. H. W. Mulligan for reading the text and would like to thank Dr T. A. M. Nash of the Tsetse Research Laboratory, Bristol, for the provision of tsetse material. The work was carried out during tenure of a grant from the Ministry of Overseas Development.
Cyclical transmission of pathogenic Trypanosoma species by gamma-irradiated sterile male Glossina morsitans morsitans
Authors: Moloo S. K. 
Published: June 2009

SUMMARYInvestigations were conducted on the infection rates and transmission charecteristics of sterile male Glossina morsitans morsitans for Trypanosoma vivax, T. congolense and T. brucei. Pupae were irradiated after the first flush of female emergences with 7, 10 or 13 krad. in a 137caesium radiation source under ambient conditions. The emergent males were fed on a T. viuax-infected goat at peak parasitaemia. They were subsequently mated at 8 days old with 3-day-old normal, virgin females. A batch of sexually fertile males which had been infected as tenerals on the goat at the same time were similarly mated to serve as controls. All the tsetse were maintained on rabbits' ears; the survival and reproductive performance were monitored for seven age-group periods of 9 days each. The sterility rates of the males were 73, 91 and 98% for the 7, 10 and 13 krad. doses of radiation; the percentage of T. vivax infection rates were 78·3, 82·3 and 74·4, respectively. For the control males, the fecundity of the mated females was 90% and the infection rate was 75·7%. In all other experiments, the 10 krad. dose was selected since both the survival and the sterility of the irradiated males were good. The T. vivax-challenged cows and goats died with symptoms of anaemia. There was no difference in the transmission characteristics between sterile and fertile vectors. There was also no significant difference between the sterile and normal males in the infection rates and the transmission frequency of T. congolense and T. brucei to cattle, goats and mice. These results indicate that release of sterile male tsetse in tsetse control programmes will potentially increase the trypanosomiasis risk in the affected area. Consideration must therefore be given to integrating adequate surveillance and chemotherapeutic measures for protection of man and his domestic livestock in the region during the period of such tsetse control campaigns.
Nippostrongylus brasiliensis: the distribution of primary worm populations within the small intestine of neonatal rats
Authors: Jenkins D. Conwil 
Published: June 2009

When neonatal rats were exposed to a small (200 larvae) primary infection of Nippostrongylus brasiliensis the worms that became established in the intestine were found in the mid-jejunum on both the seventh and the fourteenth day after infection. By day 21 most of the worms had migrated to the duodenum where they remained subsequently.When similar rats were exposed to a heavy primary infection (1500 larvae) the worms were found to be distributed along the length of the duodenum and jejunum by the seventh day. By day 28, however, a proportion of worms equal to that formerly located in the jejunum had been expelled, leaving a population of about 300 worms in the duodenum.It is suggested that the increased longevity of those worms that survive the effects of host immunity is dependent on their location at the duodenal site. The possibility is raised that the duodenum may be an immunologically privileged site for N. brasiliensis in young rats.
Salivarian trypanosome infections in cattle in Ikoma, South Mara District, Tanzania
Authors: Mwambu P. M. , Mayende J. S. P. 
Published: June 2009

798 cattle from the Ikoma area, Musoma district, were examined for evidence of trypanosomiasis and the predominant trypanosome species involved.From the results, the extent of cattle trypanosomiasis in Ikoma and the predominance of congolense-type infections as compared with vivax-type infections was established.The need to use more than one method in the diagnosis of animal trypanosomiasis is emphasized from the results presented in Table 3.The direct relationship between the poor health of the cattle and T. congolense infections demonstrates the economic importance of this trypanosome species as compared with T. vivax. This relationship also supports results of earlier work showing that in East Africa congolense-type infections produce more serious clinical trypanosomiasis in cattle than do vivax-type infections. This is important when drawing up a treatment programme.
The specific immunoglobulin response in cattle immunized with isolated Theileria parva antigens
Authors: Wagner G. G. , Duffus W. P. H. , Burridge M. J. 
Published: June 2009

Cattle were inoculated with purified Theileria parva piroplasm and/or schizont antigen. Two similar inoculations were given 10 days apart. Serum samples were regularly collected and the indirect haemagglutination (IHA), indirect immunofluorescence (IFA), complement-fixation (CF) and immunodiffusion (ID) tests were used to detect T. parva antibodies. Selected sera were separated by Sephadex G 200 and fractions examined for specific immunoglobulin activity.With the IHA test specific antibody first appeared 4 days post inoculation (dpi) and reached high titres by 8 dpi. With the IFA and CF tests specific antibody also appeared 4 dpi and reached high titres by 8–14 and 10–14 dpi respectively. Specific ID activity was detected as early as 6 dpi and persisted for the length of the experiment.On fractionation of the sera both the IHA and CF tests indicated a sequential production of T. parva IgM and 7S Ig. However, in cattle inoculated with schizont antigen only, a significant 7S Ig component was not detected by the IHA test until 16 dpi, but was demonstrated by the CF test 7 dpi. The IFA test, however, detected anti T. parva activity almost exclusively in the 7S Ig fractions. All cattle were challenged 35–42 dpi with infective T. parva stabilate and all cattle proved fully susceptible. The lack of protection by high titres of specific T. parva immunoglobulin is discussed, together with the data on the differential immunoglobulin response, in relation to previous results.
Structure and invasive behaviour ofPlasmodium knowlesimerozoitesin vitro
Authors: Bannister L. H. , Butcher G. A. , Dennis E. D. , Mitchell G. H. 
Published: June 2009

The structure and invasive behaviour of extracellular erythrocytic merozoites prepared by a cell sieving method have been studied with the electron microscope.Free merozoites contain organelles similar to those described in late schizonts ofPlasmodium knowlesi. Their surface is lined by a coat of short filaments. On mixing with fresh red cells, merozoites at first adhere, then cause the red cell surface to invaginate rapidly, often with the formation of narrow membranous channels in the red cell interior. As the merozoite enters the invagination it forms an attachment by its cell coat to the rim of the pit, and finally leaves this coat behind as it is enclosed in a red cell vacuole. Dense, rounded intracellular bodies then move to the merozoite periphery, and apparently rupture to cause further localized invagination of the red cell vacuole. The merozoite finally loses its rhoptries, the pellicle is reduced to a single membrane and the parasite becomes a trophozoite. Invasion is complete by 1 min after adhesion, and the trophozoite is formed by 10 min.
Some influences of population density on Hymenolepis diminuta in rats
Authors: Hesselberg Carl Aage , Andreassen Jørn 
Published: June 2009

When measured 56 days postinfection the length, wet weight and dry-weight of Hymenolepis diminuta were all found to decrease with increasing number of cysticercoids given up to 20. The mean position of the worms in 10, 12 and 20 worm infections is significantly posterior to that of 1, 2 and 5 worm infections and the worms are attached over a wider area of the intestine.Egg production by the worms was followed up to day 56 postinfection; the number of eggs produced per worm and even per rat decreased with increasing population density. Thus the best way to get most eggs and to maintain the parasite in the laboratory is to have rats infected with only one tapeworm.Rats given 1–20 cysticercoids showed a mean recovery of 100–65%, while rats given 40–200 cysticercoids showed a mean recovery ranging from 13 to 2%. In addition to ‘normal’ worms, defined as worms > 10 mm, small, most probably destrobilated, worms were found. In the 50 and 100 cysticercoid infections, worm recoveries were, respectively, 8% ‘normal’, 16% small, and 2% ‘normal’, 5% small. From the significantly lower recovery from heavy infections it is concluded that a deleterious factor is operating during the 8 weeks after the infection.
Flight muscle ultrastructure of susceptible and refractory mosquitoes parasitized by larvalBrugia pahangi
Authors: Lehane M. J. , Laurence B. R. 
Published: June 2009

On parasitization with larvalBrugia pahangithe infected flight muscle fibres of ‘resistant’Anopheles labranchiae atroparvusundergo the following ultrastructural changes. The fibres become almost totally devoid of glycogen, their sarcoplasmic reticulum becomes elongate and closely associated with muscle fibrils. These fibrils degenerate and vesicles appear both within the degenerate fibril and within elements of the sarcoplasmic reticulum. Vesicles accumulate around the worm and degenerate to a uniform mass which eventually becomes melanized from its inner edge (next to the parasite) outwards.The infected flight muscle fibres of both ‘resistant’Aedes aegyptiand ‘susceptible’Aedes togoiare almost totally devoid of glycogen granules, but show no other ultrastructural change from the uninfected state.
Changes in the adenylate energy charge ofNippostrorigylus brasiliensisandNematodirus battusduring the development of immunity to these nematodes in their hosts
Authors: Ballantyne A. J. , Sharpe M. J. , Lee D. L. 
Published: June 2009

SummaryInfection of rats with 2000 infective juveniles ofNippostrongylus brasiliensisand of lambs with 60000 infective juveniles ofNematodirus battusresults in a well-marked immunity to these nematodes in their respective hosts. There is a fall in the adenylate energy charge value of these nematodes during the course of these infections, reaching values of 0·37 in males and 0·27 in females ofN. brasiliensis, and 0·31 in males and 0·23 in females ofN. battustowards the end of the infections. In hosts given relatively small numbers of infective juveniles, the values for the nematodes removed from the hosts late in the infection remain at a relatively high level. These results indicate that the immune response of the host may affect the energy status of these nematodes, and this could help to explain their subsequent expulsion from the immune host.
Strongyloides ratti in virgin female rats: studies of oestrous cycle effects and general variability
Authors: Wilson P. A. G. , Cameron Maureen , Scott D. S. 
Published: June 2009

SummaryThere were no differences in mean intestinal worm burdens 8 days after subcutaneous injection of 4000 infective larvae of Strongyloides ratti into rats in dioestrus, pro-oestrus, oestrus and metoestrus. Thus, changes in the hormonal environment of the migrating larvae dependent on the oestrous cycle did not alter the worms' destination or affect their potential for development. In particular, the results are prima facie evidence that prolactin is not, on its own, responsible for the re-orientation of larvae in the tissues of nursing mothers. Other sources of variability in experimental S. ratti infections are analysed and the ‘exact dose’ technique offered as a corrective for some procedural errors.
The life-cycle of Rasajeyna nannyla n.gen., n.sp., a coccidian pathogen of Tipula paludosa Meigen
Authors: Beesley J. E. 
Published: June 2009

A coccidium belonging to the family Adeleidae was discovered in the mid-gut cells of Tipula paludosa. A new genus Rasajeyna and a new species nannyla are established because this pathogen differs from previously described coccidia. A diagnosis of R. nannyla is given.The endogenous phase of R. nannyla is restricted to larvae. The oocysts, which are the external phase of the parasite, are swallowed by the leatherjackets and excyst in the anterior mid-gut. The sporozoites, 36·5 µm (± 5·4 µm, 95% confidence limits) long, 15·7 µm (± 1·8 µm, 95% confidence limits) wide, each containing a refractile body, enter the anterior mid-gut cells where the 1st schizogony occurs. The refractile bodies are retained during the early nuclear divisions. The sausage-shaped merozoites, 28·2 µm (± 4·3 µm, 95% confidence limits) long, 7·1 µm (± 0·9 µm, 95% confidence limits) wide, with posterior nuclei exhibit three distinct types of movement. (a) An active flexion of the body which is thought to occur during the intracellular phase. (b) A flicking action by both ends of the body. This is thought to occur during the free phase. (c) A spiralling motion which is thought to aid the entry of the merozoite into the cells.The nucles of the intracellular merozoite divides several times, forming a multinucleate body. The merozoites of the 2nd schizogony form in groups at the poles of the schizont. The merozites are indistinguishable from each other until after a period of growth has ensued, when they are differentiated as macro- and microgametocytes. The pear-shaped macrogamete 44·3 µm (± 4·5 µm, 95% confidence limits) long, 21·6 µm (± 3·2 µm, 95% confidence limits) wide, which contains a crescent-shaped structure in the nucleus. The microgametocyte grows to 40·3 µm (± 2·7 µm, 95% confidence limits) long, 16·7 µm (± 1·5 µm, 95% confidence limits) wide and then attaches itself lengthwise to the macrogamete. A membrane is then secreted around both partners. Nuclear division produces 4 microgametes, one of which fertilizes the female. The 1st and 2nd oocyst membranes are deposited before cytoplasmic shrinkage and meiosis. The zygote is 44·6 µm (± 4·2 µm, 95% confidence limits) long and 33·7 µm (± 4·1 µm, 95% confidence limits ) wide. Cytoplasmic condensation around the nuclei forms the sporoblasts which mature into sporocysts each containing 1 sporozoite. The zygote may be expelled from the larvae at any juncture after fertilization.
Studies on enzyme variation in the murine malaria parasitesPlasmodium berghei,P. yoelii,P. vinckeiandP. chabaudiby starch gel electrophoresis
Authors: Carter Richard 
Published: June 2009

SummaryElectrophoretic variation of the enzymes glucose phosphate isomerase, 6-phosphogluconate dehydrogenase, lactate dehydrogenase and glutamate dehydrogenase (NADP-dependent) has been studied in the African murine malaria parasitesPlasmodium berghei,P. yoelii,P. vinckeiandP. chabaudiand their subspecies. Horizontal starch gel electrophoresis was used throughout. The number of isolates examined in each subspecies varied from 1 (P. y. nigeriensis) to 24 (P. c. chabaudi). Extensive enzyme variation was found among isolates of most of the subspecies from which more than two such isolates were available for study. It is clear that the phenomenon of enzyme polymorphism is of common occurrence among malaria parasites. With the exception ofP. bergheiandP. yoelii, of which all isolates share an identical electrophoretic form of lactate dehydrogenase, no enzyme forms are shared between any of the 4 species of murine plasmodia. By contrast, within each species common enzyme forms are shared among each of the subspecies. The subspecies are, nevertheless, distinguished from each other by the electrophoretic forms of at least one enzyme.The distribution and reassortment of enzyme variation among isolates of a single subspecies is in accordance with the concept of malaria parasites as sexually reproducing organisms. The study of variation among parasites present in individual wild-caught rodent hosts demonstrates that natural malarial infections usually comprise genetically heterogeneous populations of parasites. Nevertheless, the number of genetically distinct types of parasite of any one species present in a single infected host appears to be small. Generally not more than 2 or 3 clones of parasite of distinct genetic constitution are present in a single infected animal.
The metabolic profile of adultFasciola hepaticaobtained from rafoxanide-treated sheep
Authors: Prichard R. K. 
Published: June 2009

SummarySheep infected with adultFasciola hepaticawere drenched with rafoxanide. At 4, 8, 16 and 24 h after drenching the sheep were killed and the flukes removed, washed and rapidly frozen in liquid nitrogen. The content of key metabolites in the fermentation pathway were determined and compared with those in controlF. hepatica, whose hosts were not treated with rafoxanide.Rafoxanide decreased glycogen, malate, NADH and ATP levels. The level of other metabolites in the pathway increased for the first 8–16 h after rafoxanide treatment. The marked decrease in ATP and glycogen, and the increase in total [NAD+]/[NADH] and [oxaloacetate]/[malate], together with the changed content of other metabolites, led to the conclusion that the mode of action of rafoxanide againstF. hepatica in vivois by uncoupling oxidative phosphorylation.
Antibody dependent cell-mediated cytotoxicity of Trypanosoma cruzi: the release of tritium-labelled RNA, DNA and protein
Authors: Sanderson C. J. , Moreno Marlene M. Bunn , Lopez Angel F. 
Published: June 2009

SummaryThe cytotoxicity of normal rat spleen cells to antibody-coated Trypanosoma cruzi epimastigotes has been studied by assaying the release of [3H]-labelled macromolecules from the parasites. The release of thymidine (DNA) is slower than the release of uridine (RNA), suggesting that the nucleus is broken down more slowly than the cytoplasmic membrane. Less than 50% of the leucine (protein) is released when the parasites are lysed, whereas uridine (RNA) is almost totally released. In practical terms these results show that the release of incorporated radioisotope-labelled uridine can be used as a sensitive assay for cytotoxicity of T. cruzi. Cytotoxicity by normal rat spleen cells is antibody dependent and proportional to the logarithm of effector cell number. The lag phase and the rate of RNA release is not altered by centrifuging the parasites and effector cells to enhance contacts between them.