bluuebunny/crossref_metadata_2025 huggingface dataset:
Further observations on the malaria parasite of the Himalayan flying squirrel
Authors: Dasgupta B. , Chatterjee Amal
Published: June 2009

Two types of exflagellating bodies of the malaria parasite are described in the infected blood of the Himalayan flying squirrel (Petaurista magnificus). The first type, which is larger, is characterized by a blue-staining cytoplasm. These produce blue-microgametes with red chromatin dots. The second type, which is smaller, stains red, and also produces red microgametes. Certain large schizonts occurring in the peripheral blood are described. It is speculated that these might represent the primary tissue stage of Rayella rayi.
The effect of host lactation on the self-cure of Nippostrongylus brasiliensis in rats
Authors: Connan R. M.
Published: June 2009

The primary infection of breeding female rates with N. brasiliensis was examined as an experimental model for the study of the effect of lactation on host-parasite relationships.

Self-cure was inhibited when the period of infection corresponded with lactation, and a majority of worms could persist to day 34 when lactation was prolonged. A normal self-cure occurred during pregnancy, when litters were removed at birth or when the suckling litter was reduced to 3 young.
Preliminary studies on the karyotypes of five species ofGlossina
Authors: Maudlin I.
Published: June 2009

The karyotypes of five species ofGlossinaare described.

Differences were found between karyotypes of different species, and also between different populations of the same species. These differences are discussed in relation to the phylogeny of the genus.
Egg size and desiccation survival in Trichostrongylus colubriformis (Nematoda: Trichostrongylidae)
Authors: Waller P. J. , Donald A. D.
Published: June 2009

It has been shown that in samples of the eggs of T. colubriformis, the smaller eggs (i) have a greater probability of survival when incubated at fixed temperature and saturation deficit; (ii) require less time to develop and hatch when incubated in water at constant temperature, and (iii) have a greater surface area relative to volume, than do the larger eggs.

A hypothetical basis for the relation between egg size and desiccation survival is briefly discussed.
Comparative account of the merocysts seen in the Himalayan flying squirrels, with a note on the identity of the parasites
Authors: Dasgupta B. , Chatterjee Amal , Ray H. N.
Published: June 2009

Merocysts in P. inornatus are found in the liver, spleen and lungs, while in P. magnificus the liver is the only site. In the former the protoplasmic rim is narrow and the merozoites are sparsely distributed within it; in the latter the protoplasmic rim is irregular, quite thick and broken in places. In the former, the colloidal mass is scanty, and is in the form of tenuous matrix enclosing irregular interspaces; in the latter form, the colloidal mass is in the form of homogeneous substance with little vacuolation. In view of the wide differences in the structure and the site of occurrence, the merocysts found in the two different species of flying squirrels are considered to belong to two separate parasites. The parasite occurring in P. inornatus is identified as H. rayi rayi Tokura & Wu, sensu stricto, while the other parasite occurring in P. magnificus is designated H. rayi wui, a new subspecies, named in honour of Dr Wu Chen-Lan who worked on flying squirrel malaria in Formosa.
Localization, length and reproduction in single- and multiple-worm infections of Echinostoma revolutum (Trematoda) in the chick
Authors: Fried B. , Alenick D. S.
Published: June 2009

Mono-metacercarial infections of Echinostoma revolutum in the domestic chick yielded 14- or 15-day-old worms that produced viable eggs, indicating that this species can self-fertilize under conditions which preclude cross-fertilization. In multiple infection studies, chicks were fed either 5 or 10 cysts and each infected chick contained 2–7 worms at necropsy 14 or 15 days later. Worms from multiple infections were mainly paired or clustered and they tended to locate more posteriorly in the intestine than single worms. Length measurements of single and multiple worms were similar. Both the number of eggs and the percentage of hatched eggs were considerably greater in multiple than in single infections.
Schistosoma mansoni: the sustentacular cells of the testes
Authors: Otubanjo O. A.
Published: June 2009

Studies on the multiple compact testes of Schistosoma mansoni have revealed 2 principal cell types: germinal and non-germinal cells. Two morphological forms representing different stages in the cytomorphosis of the sustentacular cells have been considered. The polymorphic sustentacular cells which are conspicuously stained with potassium permanganate contain abundant ribosomal endoplasmic reticulum, glycogen particles and ribosomal masses in comparison with the germinal component of the testes. Golgi complexes with associated secretory bodies and vacuoles are present in the cells. The cytoplasm of the sustentacular cells interdigitate between other cells in the testes. Based on their morphology, nutritive, supportive and phagocytic functions have been attributed to the sustentacular cells. The possible recycling of nutrients by the cells is discussed. It is suggested that the cells regulate the production of spermatozoa from a nutritive viewpoint and also that the translocation of nutrients from the parenchyma to the testes is facilitated by these cells whose cytoplasm extends directly adjacent to the basal lamina.
Protective heterologous immunity between Plasmodium atheruri and other Plasmodium spp. and Babesia spp. in mice
Authors: Cox F. E. G.
Published: June 2009

Mice which have recovered from infections with P. atheruri are immune to challenge with the homologous parasite and are also strongly resistant to challenge with P. v. chabaudi and, to a lesser extent, B. rodhaini, B. microti and P. b. yoelii. There is little protection against P. v. vinckei and none against P. b. berghei. In the reciprocal experiments, the greatest degree of protection against P. atheruri occurs after P. v. chahaudi infections but over two-thirds of mice are protected by B. rodhaini or B. microti, half by P. v. vinckei or P. b. berghei but hardly any by P. b. yoelii. The considerable degree of cross-protection which exists between P. atheruri and P. chabaudi can be correlated with some antigenic similarities between these parasites but these are not greater than those of parasites which do not protect against one another.
Immunity to malaria and piroplasmosis in mice following low level infections with Anthemosoma garnhami (Piroplasmea: Dactylosomidae)
Authors: Cox F. E. G.
Published: June 2009

Mice which have recovered from infections with A. garnhami do not succumb to; challenge with the piroplasms B. rodhaini or B. microti and over half such animals are protected against the malaria parasites P. v. vinckei and P. v. chabaudi. This protection does not extend to the malaria parasites P. b. berghei or P. b. yoelii. Mice which have recovered from infections with the piroplasms are protected against A. garnhami, as are those which have recovered from infections with P. v. vinckei or P. v. chabaudi. About half the mice which have recovered from infections with P. b. berghei or P. b. yoelii are also protected against A. garnhami. This interaction between intra-erythrocytic protozoa may influence the incidence of these parasites in the wild. A. garnhami is unlikely to be of any use in the immunization of humans against malaria but could be of use in the protection of cattle against piroplasmosis.
Prevalence of Trypanosoma otospermophili (Protozoa: Trypanosomatidae) in five species of Spermophilus (Rodentia: Sciuridae)
Authors: Hilton Donald F. J. , Mahrt Jerome L.
Published: June 2009

During the summers of 1969–71, 554 ground squirrels belonging to six species (115 Spermophilus columbianus, 46 S. franklinii, 13 S. lateralis, 327 S. richardsonii, 20 S. tridecemlineatus and 33 S. undulatus) were sampled for trypanosomes. Natural infections were recorded in all but S. lateralis.
In 1969 and 1970 the prevalences of infection were approximately equal within, but varied between each species of ground squirrel. In 1971 the prevalences of infection increased for all host species sampled. Trypanosomiasis was detected in twice as many ground squirrels when the haematocrit centrifuge technique was used for diagnosis instead of stained thin blood films.
In S. richardsonii the prevalences of infection varied from month to month but showed the same trends in both 1969 and 1970. Prevalence was lowest in May and highest in June. It is suggested that susceptible juveniles accounted for the high prevalence in June.
Culture ofPlasmodium falciparum in vitro: a subculture technique used for demonstrating antiplasmodial activity in serum from some Gambians, resident in an endemic malarious area
Authors: Phillips R. S. , Trigg P. I. , Finnigan-Scott T. J. , Bartholomew R. K.
Published: June 2009

A technique is described for obtaining consistent reinvasion and multiplication of the erythrocytic stages ofPlasmodium falciparumfrom humansin vitro. Subsequent to this,P. falciparumwas subcultured through almost three cyclesin vitro, during which multiplication of the parasite was obtained in the first but maintenance or only slight increase in numbers was obtained in the second subculture. The effect of sera from adult Gambians on the reinvasion ofP. falciparumwas measuredin vitroboth morphologically and by the incorporation of [14C]isoleucine into parasite protein and by the incorporation of [3H]adenosine into parasite DNA and RNA. Two sera reduced the amount of reinvasion.
Microsporidan parasites of Simulium ornatum Mg. in South England
Authors: Gassouma M. S. S.
Published: June 2009

(1) Simulium ornatum larvae were regularly collected from the River Lea (Hertfordshire) and from Tilling Bourne (Surrey) during 1967–9. Preliminary surveys revealed no parasitism in pupal and adult stages of S. ornatum but several parasites, some common, occurred in the Simulium larvae. These were studied by dissection, smears and histologically.
(2) Microsporida were well represented by two genera - Thelohania and Plistophora. Infection rates never exceeded 9% of larvae. Spore measurements statistically evaluated from different larval infections justified recognition of five species of Thelohania (T. minuta sp.nov., T. bertrami sp.nov., T. canningi sp.nov., T. simulii sp.nov., and T. avacuolata sp.nov.), and two species of Plistophora (P. tillingbournei sp.nov. and P. leasei sp.nov.).
(3) Intra-epithelial organisms of the larval gut wall, referred to provisionally as Microsporidan-like bodies, caused light infections.
(4) With the exception of the slight Microsporidan-like infections, all species of Microsporida were found parasitizing the fat body of the larva, causing its disintegration. Delay in larval growth and pupation occurred, followed by death.
(5) Seasonal cycles of abundance of infection were related to summer and overwintering populations of Simulium larvae.
(6) Transmission of infection was attempted by exposing apparently uninfected wild-caught Simulium larvae to spores of Thelohania but no evidence of active infection being established in the exposed larvae was obtained.
(7) Although the pathogenic Microsporida taken in this study must have exerted control on natural larval densities, too little is known of their biology, mode of transmission or methods of culture to envisage their development, for biological control of simuliids, at present.
Sexual differentiation of merozoites of Eimeria tenella
Authors: Klimes B. , Rootes D. G. , Tanielian Zabel
Published: June 2009

In chickens kidney-cell culture gametogony of E. tenella usually occurs in a limited number of selected cells in the form of nests of gametocytes. Some cells contain only macrogametocytes, others only microgametocytes and some cells contain both sexes together.
Mixed nests of gametocytes are evidence for genetic sex determination.
By using PAS staining the origin of macrogametocytes and microgametocytes can be retraced to the merozoites and schizonts of the last generation, which are differentiated by this technique.
An endogenous circadian hatching rhythm in the monogenean skin parasiteEntobdella soleae, and its relationship to the activity rhythm of the host (Solea solea)
Authors: Kearn G. C.
Published: June 2009

When the eggs of the skin parasitic monogeneanEntobdella soleaeare subjected in the laboratory to alternating periods of light and darkness (LD 12:12, LD 6:18 or LD 18:6) at constant temperature (selected from the range 12–16 °C), hatching is rhythmical, most of the oncomiracidia emerging during the first 4 h of the period of illumination on each successive day.

Rhythmicity in response to alternating 12 h periods of light and darkness persists in a wide range of lighting conditions including natural daylight and in dim blue light, the latter being similar in intensity (65 nW/cm2) and in spectral quality to light at the depths where the hostSolea solealives.

The hatching rhythm persists with a periodicity of about 24 h in constant darkness and in constant light, provided that the eggs have been exposed previously to LD 12:12 until hatching begins. This indicates that there is a strong endogenous component to the rhythm.

Eggs laid and maintained in total darkness develop and hatch, but the oncomiracidia may emerge at any time during each 24 h period and there is little evidence of rhythmicity.

When alternate 12 h periods of light and darkness are reversed after the commencement of hatching, the hatching pattern also reverses after 24 h, so that emergence of larvae occurs at the beginning of the new illumination period.

Mechanical disturbance plays little or no part as a hatching stimulus.

Larvae, which had emerged from their eggs at some time between 20 and 80 min previously, responded to host skin, suggesting that an initial uninfective period is of short duration or absent.

Hatching soon after dawn may have high survival value forE. soleaein view of the host's activity pattern; soles are active at night and partly bury themselves in the sediment (where the eggs of the parasite lie) at dawn, and the fish is inactive and a stationary target during the day.
The effect of parasitism by the trematode Cryptocotyle lingua (Creplin) on digestive efficiency in the snail host, Littorina saxatilis (Olivi)
Authors: Davis D. S. , Farley J.
Published: June 2009

The efficiency of assimilation of carbon and nitrogen by Littorina saxatilis, as calculated from the carbon and nitrogen content of food and faeces, showed that the efficiency of snails infected with rediae of Cryptocotyle lingua did not differ significantly from that in non-infected snails.

Similarly, the rate of ingestion and the rate of assimilation of infected snails did not differ significantly from those of non-infected snails.

It is suggested that this harmonious relationship reflects the longterm strategy of Cryptocotyle lingua infections.
Immunity toPlasmodium bergheiin rats: maximum levels of protective antibody activity are associated with eradication of the infection
Authors: Phillips R. S. , Jones Valerie E.
Published: June 2009

Maximum levels of protective antibody activity were reached in the circulation of rats given a primary infection or one or two re-infections ofPlasmodium bergheiat the time the infection was finally eradicated. This association of maximum protective antibody activity with complete clearance of the parasite was also found in recipients of lymphoid cells from immune donor rats and suggests that a high level of protective antibody activity is one essential factor in complete elimination of the parasite.

Excellent technical assistance was given at different times by Mrs J. Page, Mr A. J. Edwards and Miss D. Leader.
The extraction, characterization andin vitrotranslation of RNA from adultSchistosoma mansoni
Authors: Tenniswood M. P. R. , Simpson A. J. G.
Published: June 2009

We have extracted RNA fromSchistosoma mansoniusing the lithium chloride–urea method which gives good yields of undegraded RNA. The results of agarose gel electrophoresis of RNA extracted by this procedure suggest thatS. mansonihas anin vivonick in the large rRNA sub-unit. Translation of the RNA in a rabbit reticulocyte lysate gave significant incorporation of [35S]methionine into synthesized proteins. Immuno-precipitation of these translation products using a hyperimmune monkey serum sedimented between 5 and 8% of the radioactivity, which appeared to be present in approximately 13 proteins of molecular weights 18, 20, 21, 22, 23, 35, 40, 54, 60, 70, 74, 78 and 105 K Daltons.
Schistosoma mansoni: quantification of skin penetration and early migration by differential external radioassay and autoradiography
Authors: Georgi Jay R.
Published: June 2009

Eleven gamma-emitting radionuclides (49Sc, 54Mn, 59Fe ( + 2 and + 3), 60Co, 65Zn, 75Se (as selenomethionine, selenocystine, selenite and selenate), 109Cd, 125Sb, 133Ba, 137Cs and 203Hg) were screened as labelling agents for Schistosoma mansoni cercariae by incubation of infected Biomphalaria glabrata snails in radioactive solution according to the technique of Christensen (1977). Only [75Se]methionine yielded satisfactorily labelled cercariae. Multiple regression analysis of volume, number of cercariae and radioactivity from a series of 10 aliquots of unwashed cercarial suspensions yielded estimates of unbound and cercarial-bound radioactivity that were equivalent or superior to estimates based on assay of washed cercariae and eliminated loss of cercariae. Washing of cercarial suspensions over 8 μm pore diameter Millipore filters was found to result in entanglement of 60–90% of the cercariae on the filter disc. Differential external radioassay, a new technique employing partial body shielding within a total body counter, permitted separate estimation of tail and body radioactivity of conscious mice previously exposed by tail immersion to 75Se-labelled cercariae, with measurements repeated as often as desired. Approximately 39% of the 75Se present in emergent cercariae was retained by schistosomula transformed in vitro but this was subject to considerable variation, especially in schistosomula transformed in vivo. Secreted or catabolized label from penetrant cercariae and schistosomula was rapidly removed from the skin by the bloodstream. Numbers of schistosomula in tail skin were directly proportional to the number of reduced silver foci counted on tail autoradiograms; only a very small fraction of tail radioactivity represented unbound (‘spurious’) label. Migration of schistosomula away from skin was 50% complete at 3·8–4·3 days, as determined by probit analysis of autoradiographic data.
Comparative migration, growth and development of Typhlocoelum cucumerinum sisowi in dabbling ducks and Typhlocoelum cucumerinum cucumerinum in diving ducks
Authors: Scott Marilyn E. , Rau M. E. , McLaughlin J. D.
Published: June 2009

Experimental infections of mallards (Anas platyrhynchos L.) with Typhlocoelum cucumerinum sisowi (Skrjabin, 1913) and of canvasbacks (Aythya valisineria (Wilson)) with Typhlocoelum cucumerinum cucumerinum (Rudolphi, 1809) revealed significant differences in various parameters of the life-cycle in the definitive host. Both T. c. sisowi and T. c. cucumerinum migrate to the trachea via the abdominal cavity, air sacs and lungs, although T. c. cucumerinum migrate more quickly and more synchronously than T. c. sisowi. Typhlocoelum c. sisowi has a shorter expected life-span than T. c. cucumerinum but grows and reaches maturity more quickly than T. c. cucumerinum. Evidence suggests that T. c. cucumerinum has a higher fecundity than T. c. sisowi. These differences in the patterns of migration, growth and development are related not only to differences between the two host species but also to differences intrinsic to the parasites, and serve to provide biological support for considering them as separate sub-species.
The effect of host age on the course of infection ofRaillietina cesticillus(Molin, 1858) in the fowl
Authors: Gray J. S.
Published: June 2009

The effect of host age on the course of infection ofRaillietina cesticillusin the chicken has been investigated. It was found that male hosts become resistant to the cestode with increasing age. This resistance manifests itself in an increased rate of destrobilization and consequent loss of scolices and in a decreased rate of growth of the worms. The cestodes are distributed over a greater length of intestine in old than in young birds. In female hosts age resistance develops more rapidly than in males until the birds are 84 days old and from this age onwards the manifestations of resistance decline. The possible factors responsible for age resistance toR. cesticillusare discussed.
Studies on the course of infection of the poultry cestode Raillietina cesticillus (Molin, 1858) in the definitive host
Authors: Gray J. S.
Published: June 2009

The course of infection of Raillietina cesticllus in the chicken has been studied and information is presented on proglottid output, the dynamics of infection and the distribution and growth of the cestode.
A posterior migration of young cestodes during the first 7 days of infection was confirmed and a progressive destrobilization of the worms was observed with complete destrobilization occurring 70 days after infection. No regeneration of strobilae occurs and the scolices are eventually eliminated. A marked difference in the rate of destrobilization in the two host sexes was noted.
Effects of variations in temperature on infective larvae and their relationship to inhibited development of Obeliscoides cuniculi in rabbit
Authors: Hutchinson G. W. , Lee E. H. , Fernando M. A.
Published: June 2009

The relationship between changes in the temperature of storage of infective O. cuniculi larvae and the proportion that become inhibited in a subsequentinfection was studied. Prolonged storage at 5°C resulted in an initial inhibitionfollowed by acclimation to this temperature and subsequent normal developmentin the host. After acclimation to low temperature raising the temperature ofstorage produced no appreciable increase in the proportion of worms inhibited atthe early 4th stage. Maintenance of infective larvae at 15°C followed by a suddendecrease in storage temperature to 5°C resulted in rapid onset of inhibition. This inhibition was not reversed even after 25 days at the lower temperature. These temperature variations and the consequent pattern of arrested development werecompared to seasonal changes of spring and autumn occurring to nematode larvaeon pasture. An increase in the number of larvae given from 5000 to 15000 perrabbit had a slightly significant effect upon the proportion that remained inhibited. The need for careful assessment of the methods used for determining the extentof such inhibition is discussed.
The life-cycle of Bucephaloides gracilescens (Rudolphi, 1819) Hopkins, 1954 (Digenea: Gasterostomata)
Authors: Matthews R. A.
Published: June 2009

The cercaria and sporocyst of Bucephaloides gracilescens are described from Abra alba (Wood). Observations were made on the behaviour of the cercaria and the mechanism of release from the first intermediate host. The metacercaria was obtained experimentally for the first time using Ciliata mustela (L.), a species of Gadidae from rock pools, as second intermediate host. It has not previously been recorded from this fish. Unsuccessful attempts were made to infect species of fishes from three other families, namely, Bothidae, Pleuronectidae and Gobiidae, confirming the high degree of host specificity of the metacercaria to Gadidae. The metacercaria, its development and effect on the host are briefly discussed. It was linked with the adult on the basis of comparative morphology and ecology of the hosts.
A study of the effect of temperature on the growth of Fasciola hepatica in Lymnaea truncatula
Authors: Nice Nigel G. , Wilson R. A.
Published: June 2009

The growth rates of the intramolluscan stages of the parasite Fasciola hepatica were determined at three temperatures 16°, 20° and 25°C. A graphical relationship of growth rate with respect to temperature was produced and a growth array was calculated from this. Meteorological data were summarized in the form of a temperature array. These arrays were then used in conjunction with a simple equation to simulate parasite growth within the snail host. A digital computer was employed to solve iteratively the simulation equation, initially by checking its application against experimentally determined results. It was then employed with the meteorological data to simulate growth with respect to environmental temperatures and the results obtained were compared with those derived from field collections. Estimates were also made of the duration of the shortest life-cycle under field conditions.
Energy utilization of infectiveAncylostoma tubaeformelarvae
Authors: Croll Neil A.
Published: June 2009

It has been demonstrated that under prolonged experimental conditions lipid is utilized most quickly under optimal conditions of tonicity, gaseous exchange, pH and sensory stimulation. There is good evidence that activity may be an appreciable energy-consuming process. It has been deduced, however, that the low Reynold's number means viscous forces dominate locomotory energy consumption, and work done is proportional to the square of the velocity. Osmoregulation in hypotonic media and tolerance of hypertonic media do not require appreciable energy.

Locomotion is only possible in limited environmental conditions, and these may also be conditions of peak basal metabolism. Larvae are able to enter quiescence which is not energy-demanding, in poor conditions. Larvae can survive anaerobiasis, but finally die without reduction in lipid and cannot convert lipid to carbohydrate for anaerobic metabolism.

The help of Mrs Helen Foreman in staining the larvae and for statistical analyses, and of Mr J. M. Smith is greatly appreciated. I would like to thank Dr Elizabeth U. Canning for kindly providing the microdensitometer and Professor G. S. Nelson and Dr D. A. Denham for enabling us to establishA. tubaeformein our cats. The generous support of the British Medical Research Council is much appreciated.
Feeding and lipid synthesis of Ancylostoma tubaeforme preinfective larvae
Authors: Croll Neil A.
Published: June 2009

The growth curve, rate of neutral unbound lipid synthesis, and relationship between morphogenesis and lipid reserve have been studied at 30 °C. The feeding process, including a theoretical calculation of bacterial requirements of preinfective larvae, is presented, together with some measurements of the most important variables in ingestion, expulsion of water through the anus, and its dependence on larval posture is described.

Larval stages have been tracked on agar; L1 are so inactive that no tracks were obtained; L2 show short, irregular tracks, and infective larvae strong, long and straighter tracks. The locomotory activity of L2s is primarily for feeding, whereas L2s are adapted for dispersion and host location.

I thank Mr J. M. Smith for tracking the larvae and Mrs Helen Foreman for staining them, Dr Elizabeth U. Canning for making available the scanning microdensitometer and Professor G. S. Nelson and Dr D. A. Denham for enabling us to establish A. tubaeforme in cats. Finally the generous support of the British Medical Research Council is appreciated.
Short-interval absorption and metabolism of some amino acids in Trypanosoma gambiense
Authors: Chappell L. H. , Southworth G. C. , Read C. P.
Published: June 2009

During 2 min incubations of Trypanosoma gambiense (bloodstream form) with [U-14C]glucose (1 mM) over 60% of absorbed label was detected in free alanine. In the presence of 12·5 mM unlabelled alanine, the amount of alanine synthesized from glucose was reduced by less than 10%. These data support previous observations on the high level of transaminase activity in African human trypanosomes.

Alanine, aspartate and glutamate were metabolized to various other free amino acids whereas a significant amount of label derived from [14C]arginine could not be accounted for by amino acid assay.

The sulphur containing amino acids, cysteic acid and taurine, were apparently synthesized from alanine, glutamate and arginine. The significance of these syntheses is poorly understood.

Following incubations of trypanosomes for 2 min in exogenous amino acids the internal free pool became imbalanced due to accumulation and metabolism of the substrate amino acid.

Evidence obtained indicated that the level of free endogenous glutamate may be rate limiting for the glutamate-pyruvate transaminase system.
An analysis of the course of infection of Moniliformis dubius (Acanthocephala) in rats
Authors: Crompton D. W. T. , Walters D. E.
Published: June 2009

An analysis of the course of infection of mixed oral infections of 12 cystacanths of Moniliformis dubius in 174 male and 179 female Wistar rats has been undertaken.

There was a marked decline in the average recovery rate of worms of both sexes from hosts of both sexes during the course of the infection.

Female worms from both male and female rats showed, on average, a greater power of survival than male worms from the third period (10–13 weeks) onwards.

Male rats were found to retain, on average, a greater number of worms of both sexes than female rats.

We wish to thank Miss Susan Arnold and Mr David Barnard for excellent technical help.
Babesia pantherae sp.nov., a piroplasm of the leopard (Panthera pardus)
Authors: Dennig H. K. , Brocklesby D. W.
Published: June 2009

A large Babesia species was found in a leopard (Panthera pardus) in Kenya. It was established in domestic cats but no other animal was found to be susceptible. The parasite has been compared with other piroplasms of felids and it was found to differ from them in some significant characters. It was established as a new species and named Babesia pantherae.

We would like to thank Miss B. O. Vidler for her assistance, Dr S. F. Barnett for many helpful discussions and Professor N. D. Levine for pointing out the need for this description.

The parasite was isolated when we were working at the East African Veterinary Research Organization at Muguga in Kenya and we are most grateful to that organization for facilities.
The influx of purines and pyrimidines across the brush border of Hymenolepis diminuta
Authors: Pappas Peter W. , Uglem Gary L. , Read Clark P.
Published: June 2009

The kinetics of uracil, thymine, 5-bromouracil, hypoxanthine, guanine and adenine uptake by Hymenolepis diminuta were studied using shortterm (2 min) incubations. The effects of other purines and pyrimidines on the uptake of these compounds was determined. The data suggest that the purine-pyrimidine transport system of H. diminuta contains at least three distinct transport loci and that two of these loci contain multiple substrate binding sites. The three loci are characterized as follows: (1) A thymine-uracil locus which is responsible for the absorption of thymine and uracil via allosteric mechanisms and, therefore, apparently contains two binding sites for these pyrimidines. Adenine and hypoxanthine are non-productively bound to this locus; purine and 6-methyluracil are also bound to this locus, but it is unknown if binding is productive. (2) A locus which transports hypoxanthine (denoted as hypoxanthine locus no. 1), guanine, and adenine. The latter purine is apparently transported by an allosteric mechanism and, therefore, this locus apparently contains two adenine binding sites. Uracil and 5-bromouracil also bind to this locus, however, the nature of binding is uncertain. (3) A second hypoxanthine locus (hypoxanthine locus no. 2) can also be demonstrated which nonproductively binds adenine. Purine is also bound to this locus, but it is unknown if this binding is productive.
East Coast fever: correlation between the morphology and infectivity of Theileria parva developing in its tick vector
Authors: Purnell R.E. , Brown C. G. D. , Cunningham M. P. , Burridge M. J. , Kirimi I. M. , Ledger M. A.
Published: June 2009

Rhipicephalus appendiculatus ticks, infected with Theileria parva, were fed on rabbits and removed at daily intervals for 9 days. Half of the ticks removed were dissected and their salivary glands processed and examined for parasites. The remaining ticks which had been removed were ground up and aliquots of the supernatant fluid thus obtained were injected into East Coast fever susceptible cattle. Cattle injected with supernatant fluids from ticks fed for 4–9 days became infected, and this could be correlated with the histological detection of mature parasites in the corresponding ticks. The most highly infective supernatant fluids were prepared from 5-day-fed ticks. In a second experiment it was shown that female ticks of a variety of weights contained infective particles of T. parva.
Effects of mebendazole on the encysted phase of Trichinella spiralis in the rat: an electron-microscope study
Authors: Nollin Sonja De , Borgers M. , Vanparijs O. , Van Den Bossche H.
Published: June 2009

The ultrastructural changes in the encysted phase of Trichinella larvae, during and after treatment of the rat with mebendazole, were studied.

The earliest modifications in the infected area concerned the immediate larval environment (matrix). These degenerative changes in the matrix were seen before any alteration could be observed in the larvae.

Subsequently, oedematous swelling, intracellular vacuolization and loss of glycogen were noted in the larval cells.

Together with the progressive involution of the larvae and their matrix, inflammatory and immunocompetent cells invade the infected area and penetrate the altered capsule. Calcification of the larvae and massive infiltration of mononuclear phagocytes with subsequent elimination of the calcified remnants were the prominent features in the first weeks after treatment. The infected areas were completely cleared from larval and matrix residues 50 days after the end of treatment and a nearly normalized tissue was seen from day 111 after treatment.
The propulsion of the cercariae of Himasthla secunda (Nicoll) and Cryptocotyle lingua
Authors: Chapman H. D. , Wilson R. A.
Published: June 2009

The locomotion of two species of cercariae has been studied by cinematography. The ability of the tail to generate bending waves providing the force to drive the cercaria forward has been demontrated. The waveform of the tail and its relation to the pattern of movement has been described and evidence is presented that the tail is capable of propagating complicated swimming movements in the absence of the body. The pattern of propulsion is related to the functional organisation of the tail musculature of the cercaria.
Chondracanthid copepods parasitic on platycephalid fishes of Australia, with discussion of known species occurring on flatheads
Authors: Ho Ju-Shey
Published: June 2009

Two species of chondracanthid copepods Acanthochondria platycephali Heegaard, 1940 and Pterochondria alatalongicollis Heegaard, 1940 are described. The latter was described by Heegaard as Acanthochondria platycephali f. alata-longicollis. However, it is placed in a new genus, based on the studies of type specimen and new material. A discussion on the other species of Acanthocondria parasitic on the flathead is given. It is suggested that A. bulbosus Heegaard, 1943, is synonymous with A. tchangi Y¨, 1935, and A. diastema Kabata, 1965, with Pterochondria alatalongicollis.
The measurement of the relative turnover rates of proteins of the surface membranes and other fractions ofSchistosoma mansoniin culture
Authors: Kusel J. R. , Mackenzie Pamela E.
Published: June 2009

The double isotope labelling method of Arias, Doyle & Schimke (1969) and Dehlinger & Schimke (1971) was used to determine the relative rates of turnover of proteins in various tissue fractions and in the culture medium of adultSchistosoma mansoni. The majority of proteins in the surface membrane turned over at about the same rate. This is consistent with a model for membrane assembly and degradation involving multi-protein units. The proteins in the other fractions examined, except frozen-thawed supernatant fluid, also turned over at about the same rate. In the frozen and thawed supernatant fluid, the higher molecular weight (>40000 daltons) proteins turned over at a much greater rate than the lower molecular weight proteins (<40000 daltons). The antigens in the culture medium, both particulate and soluble, had a higher turnover rate than the worm tissue proteins. It is concluded that the culture medium antigens are released as the result of two distinct processes: (a) surface membrane turnover and (b) a rapid secretory process. It is possible that the high molecular weight proteins found in the frozen-thawed supernatant fluid are involved in the rapid secretory process. The culture media of 6-day and 16-day schistosomula were also examined by the double isotope method. The culture medium of the adult worm and 16-day schistosomula contains more material presumed to be secreted than does that from the 6-day schistosomula. This may explain the poor immunogenicity of young schistosomula.
Seasonal abundance ofNeoechinorhynchus cylindratustaken from largemouth bass (Micropterus salmoides) in a heated reservoir
Authors: Eure H.
Published: June 2009

Samples of largemouth bass were collected from Par Pond located on the Energy Research and Development Administration's Savannah River Plant in Aiken, South Carolina, from June 1972 to May 1973 inclusive. The sampling stations reflected water temperatures which were both normal and greater than 10°C above normal for the area. The acanthocephalanNeoechinorhynchus cylindratuswas the dominant species found in the bass sampled. Incidences of infection for this parasite were generally greater than 95% regardless of location. A pronounced seasonal cycling pattern in the intensity of infection was noted in both thermal regions. Significant differences, however, in the mean density ofN. cylindratusper host in fish taken from the heated area as compared with unheated areas were noted.

Turnover in the acanthocephalan population was measured by following the percentage of individuals less than 2 mm long. Fall proved to be the most intense parasite recruitment season, followed by maturation of the parasite and subsequent loss from the fish host.

The principal factors responsible for the seasonal incidence and intensity patterns are considered to be changes in the fish feeding behaviour and annual temperature regimes.
Fasciola hepatica: a transmission and scanning electron microscopical study of the apical surface of the gastrodermal cells
Authors: Threadgold L. T.
Published: June 2009

The ultrastructure of the apical surface of the gastrodermal cells of Fasciola hepatica has been investigated by transmission (TEM) and scanning electron microscopy (SEM). The surface is composed of triangular or rhomboidal lamellae which may be subdivided at their margins. The lamellae may have a smooth or wrinkled surface and apical microvilli of varied length and number. Spherical bodies may be attached to the sides or tips of the lamellae.

The lamellae of individual cells are grouped to form either a series of overlapping, concentrically arranged leaflets or a series of sinuous lamellae running parallel with the cell's long axis. Lamellae may also divide, anastomose, or cross from one cell to an adjacent cell.

The lamellae have an internal skeleton consisting of laterally orientated ‘fibres’ which are more or less evenly spaced and parallel with the cell's apical plasma membrane. There is some evidence that the ‘fibres’ are composed of a number of very small tubules in a dense matrix. The ‘fibres’ are connected to the plasma membrane and to each other by dense amorphous material.
Cuticle formation and moulting in the egg ofMeloidogyne javanica(Nematoda)
Authors: Bird Alan F.
Published: June 2009

At a temperature of 27°C the external cuticular membrane of the first larval stage (L1) ofMeloidogyne javanicais formed within a day of the start of elongation of the embryo within the egg. The first and only moult within the egg starts to occur 50 h after the commencement of elongation. Thus the cuticle of the L1is shed approximately a day after its formation. It is much thinner than the cuticle of the L2, is not covered during its formation by a closely adherent cuticle in the process of being moulted and its outermost membrane may be formed differently.
Immunological interactions between Trichinella spiralis and Trichuris muris in the intestine of the mouse
Authors: Burce R. G. , Wakelin D.
Published: June 2009

In outbred (CFLP) and inbred (NIH) mice, the inflammatory response which is thought to be party responsible for the expulsion of Trichinella spiralis from the mid-region of the small intestine, also seemed to be largely responsible fo rthe simulataneous (i.e. early) expulsion of Trichuris muris from the caecum and large intestine during concurrent primary infections. The intractive explusion operated only when the concurrent infections were timed to produce T. Spiralis expulsion before T. muris expulsion would normally occur and the effect persisted for several days after T. Spiralis has been expelled.

Interactive expulsion wasss depressed during application of the nonsteroid, anti-inflammatory drug indomethacin and by T-cell expulsion of T. spiralis. These results indicate that a T-cell mediated inflammatory response was probably the basis of the interaction.

When the timing of the infections was altered such that the expulsion of T. spiralis there was no reciprocal ecpulsion of the latter. Mice immunized againest one or the other species did not show cross-immunity on heterologus challenge, confirming that the interaction did not involve similar antigens in the two species. The interactive expulsive response is considered as an example of an indirect cross-immunity.
The regulation of host population growth by parasitic species
Authors: Anderson R. M.
Published: June 2009

The nature of parasitism at the population level is defined in terms of the parasite's influence on the natural intrinsic growth rate of its host population. It is suggested that the influence on this rate is related to the average parasite burden/host and hence to the statistical distribution of parasites within the host population.

Theoretical models of host–parasite associations are used to assess the regulatory influence of parasitic species on host population growth. Model predictions suggest that three specific groups of population processes are of particular importance: over-dispersion of parasite numbers/host, density dependence in parasite mortality or reproduction and parasite-induced host mortality that increases faster than linearly with the parasite burden. Other population mechanisms are shown to have a destabilizing influence, namely: parasite-induced reduction in host reproductive potential, direct parasite reproduction within the host and time delays in the development of transmission stages of the parasite.

These regulatory and destabilizing processes are shown to be commonly observed features of natural host-parasite associations. It is argued that interactions in the real world are characterized by a degree of tension between these regulatory and destabilizing forces and that population rate parameter values in parasite life-cycles are very far from being a haphazard selection of all numerically possible values. It is suggested that evolutionary pressures in observed associations will tend to counteract a strong destabilizing force by an equally strong regulatory influence. Empirical evidence is shown to support this suggestion in, for example, associations between larval digeneans and molluscan hosts (parasite-induced reduction in host reproductive potential counteracted by tight density-dependent constraints on parasite population growth), and interactions between protozoan parasites and mammalian hosts (direct parasite reproduction counteracted by a well-developed immunological response by the host).

The type of laboratory and field data required to improve our understanding of the dynamical properties of host–parasite population associations is discussed and it is suggested that quantitative measurement of rates of parasite-induced host mortality, degrees of over-dispersion, transmission rates and reproductive and mortality rates of both host and parasite would provide an important first step. The value of laboratory work in this area is demonstrated by reference to studies which highlight the regulatory influence of parasitic species on host population growth.
Isolation of blood and intracellular forms ofTrypanosoma cruzifrom rats and other rodents and preliminary studies of their metabolism
Authors: Gutteridge W. E. , Cover B. , Gaborak Maria
Published: June 2009

Isolation of blood and intracellular forms ofTrypanosoma cruziwas made mainly from rats (90–110 g) which had received 580 rad of whole-body γ-irradiation not more than 24 h before subcutaneous inoculation with 107trypomastigotes of the Sonya strain ofT. cruzi. Unirradiated chinchillas (250–350 g) were, however, used for some experiments. Blood forms were isolated using a technique involving differential centrifugation to remove most of the erythrocytes and DEAE–cellulose chromatography to remove the remaining blood cells. Overall recoveries were usually in the range 30–70%. Parasites were mainly (approximately 98%) broad forms and were motile, metabolically active (as judged by respiratory and radio-tracer incorporation studies) and had lost none of their infectivity for mice. Intracellular forms were isolated from hind-limb muscle tissue. This was disrupted in an MSE tissue homogenizer and the homogenate incubated with DNase, collagenase and trypsin. Parasites, contaminated only by a few blood cells, were then obtained by differential centrifugation. For purer preparations, a terminal sucrose gradient step was used. Recoveries ranged between 40 and 70%. About 1–3% of the parasites isolated were epimastigotes and trypomastigotes; the remainder are probably best collectively termed ‘amastigotes’, though they were pointed and most had a short, free flagellum. They were undamaged as judged by light and electron microscopy and metabolically active as judged by respiratory and radio-tracer incorporation studies. However, the infectivity for mice of both these purified preparations and the initial cell homogenates could be accounted for by the epimastigotes and trypomastigotes present in them. Preliminary biochemical studies with isolated parasites have shown that blood, intracellular and culture forms ofT. cruzihave a respiratory system which is in part sensitive to CN- and that all forms synthesize nucleic acids and proteins when incubatedin vitro. There appears, however, to be a lack of DNA synthesis in blood stages, and thus it is not surprising that these forms do not divide.
Taxonomy ofSolenopotesEnderlein, 1904, with redescription ofLinognathus panamensisEwing (Linognathidae: Anoplura)
Authors: Kim Ke Chung , Weisser Christian F.
Published: June 2009

All the known species ofSolenopotesEnderlein, 1904 are discussed with a complete synonymy, major references, diagnoses, host associations and distribution; they areS. binipilosus(Fahrenholz, 1916a);S. burmeisteri(Fahrenholz, 1919);S. capillatusEnderlein, 1904;S. capreoliFreund, 1935a;S. ferrisi(Fahrenholz, 1919);S. muntiacusThompson, 1938;S. natalensisLedger, 1970 andS. tarandi(Mjöberg, 1915). The species ofSolenopotesare compared on the basis of major taxonomic characters.SolenopotesandLinognathusare compared and a key to the known species ofSolenopotesis also presented. Taxonomic relationships among the cervid-infesting species are quantitatively studied. The status ofLinognathus panamensisEwing, 1927, previously assigned toSolenopotes, is discussed and the species is redescribed and illustrated.