bluuebunny/crossref_metadata_2025 huggingface dataset:
Spring rise in faecal worm-egg counts of housed sheep, and its importance in nutritional experiments
Authors: Field A. C. , Brambell M. R. , Campbell J. Allan
Published: June 2009

1. A spring-rise in faecal strongyloid egg count is described in sheep housed under conditions designed to prevent reinfestation. Large rises were observed in the majority of 3-year-old breeding ewes and primiparous ewe-hoggs, and occasional small rises occurred in nulliparous ewe-hoggs and wether-hoggs.

2. Falls were observed in the packed red-cell volumes of ewes during the period of spring-rise and a close inverse correlation was found between packed-cell volumes and transformed worm egg counts. No evidence was obtained to attribute the falls in packed-cell volume to factors other than worm burden.

3. The fall in packed-cell volume was partially alleviated by feeding of one type of perennial rye-grass, but no direct effect of feeding on the worm-egg output was found.

4. Theories of spring-rise are discussed and the conclusion reached that latent overwintering larvae must play a major part generally in the phenomenon.
Polysaccharides in the different stages of the life-cycles of certain sporozoa
Authors: Dasgupta B.
Published: June 2009

Glycogen proved to be absent in the malaria parasites (Plasmodium and Hepatocystis) by applying cytochemical methods; while in the piroplasms (Theileria and Babesia), and in Hepatozoon glycogen could be demonstrated by using the same methods. A strong positive reaction for polysaccharides was obtained in the residual masses of Hepatozoon sciuri, and H. balfouri; while a negative reaction was obtained in the residual mass of Plasmodium. A positive reaction for polysaccharides was obtained in the following structures: the wall of the oocysts of Plasmodium, the gametocyte capsules of Hepatozoon sciuri and Hepatozoon sp., the sporoblast capsule of H. sciuri, and the polar areas of the gametocyte of H. balfouri.
Enzymic Proteolysis byEntamoeba histolytica; biochemical characteristics and relationship with invasiveness
Authors: Neal R. A.
Published: June 2009

The proteolytic activity of extracts ofEntamoeba histolyticahas been further investigated. Casein and gelatin, but not haemaglobin, were hydrolysed. Activity was observed in the pH range 5·8 to 8·5 with optimal activity at pH 7·5 to 7·9. Activity was optimal at 37° C. and sulphydryl groups were not required. Concomitant bacteria showed no proteolytic activity. Hyaluronidase, collagenase and lecithinase could not be detected.

An inhibitor of proteolytic enzyme was present in sera of all animals tested and in egg yolk. All culture media prepared from eggs were inhibitory, but inspissation or dilution of serum inactivated the serum inhibitor. Purified trypsin inhibitors from lima and soy bean were not active against the amoebic enzyme. Proteolytic enzymes were not secreted extracellularlyin vitro.

High proteolytic activity was found in two out of five invasive, freshly isolated, strains ofE. histolyticaand after two series of liver passages of a single strain. The significance of these observations is discussed. It is concluded that the present evidence does not convincingly demonstrate that high proteolytic activity is required for tissue invasion by amoebae, but may accompany another factor.
Notes on the occurrence of Acanthocephala in Pacific fishes
Authors: Ekbaum Ella
Published: June 2009

Echinorhynchus gadi (Zoega) Müller has been found parasitic in various species of Pacific salmon. The amphipod Cyphocaris challengeri Stebbing serves as an intermediary host for this parasite in the region in which the investigations were carried out.

Echinorhynchus lageniformis sp.nov. and Corynosoma strumosum (Rudolphi) both parasitic in the Starry flounder (Platichthys stellatus (Pallas)) and the Two-lined flounder (Lepidopsetta bilineata (Ayres)) are recorded with data on their occurrence.
The generative organs of the blow-fly, Calliphora erythrocephala L., with special reference to their musculature and movements
Authors: Graham-Smith G. S.
Published: June 2009

In Part I the musculature of the internal organs of the male blow-fly, C. erythrocephala, testis, vas efferens, accessory gland, vas deferens, and ejaculatory sac and duct, is described, together with the movements observed in them and the passage of secretions down the system. It is suggested that the testicular and accessory gland secretions are ejaculated separately. The musculature, mechanics and co-ordinated movements of the external organs and associated structures are also described.

In Part II the generative organs of the female, except the ovaries, with special reference to their musculature and movements, and the musculature of the ovipositor are described and compared with those of M. domestica. It is suggested that the male accessory gland secretion is kept separate from the testicular secretion, the former passing into the lateral sacs of the female and the latter into the spermathecae.

In Part III the relation of the parts of the two sexes during coitus is discussed.
The development ofMoniezia expansain the intermediate host
Authors: Stunkard Horace W.
Published: June 2009

When eggs ofMonieza expansaare fed to galumnid mites, the onchospheres emerge in the intestine and migrate to the body cavity. Here they undergo metamorphosis and develop into cysticercoids. The dissection of mites, at various intervals after exposure, has yielded a successive series of developmental stages. Protocols of the experiments and photographs of living larvae are presented. These results demonstrate that mites serve as intermediate hosts ofMoniezia, and probably also of other anoplocephaline cestodes.
Studies on a virus found in the roots of certain normal-looking plants
Authors: Smith Kenneth M.
Published: June 2009

An account is given of a virus which is present in the roots of a number of different plants. Plants which have been shown, so far, to contain the infective principle in the roots are several members of the Solanaceae, tomatoes, tobacco, etc.; of the Primulaceae, Polyanthus sp. and Primula obconica; of the Geraniaceae, zonal Pelargonium; and of the Compositae, the aster. Such plants show no indication of infection with the exception of Nicotiana tabacum and N. glutinosa, which may develop natural disease symptoms. These symptoms are usually confined to the two lowermost leaves and develop most frequently under conditions of low temperature and low light intensity. The virus never becomes completely systemic in any host plant and is generally restricted to the inoculated leaves. Experiments are described which show the virus to be present in the roots of tobacco plants which had given a negative virus reaction a few weeks earlier. The virus is found in the roots of tobacco plants arising from seed which has been heated to a temperature of 75° C., the thermal death-point of the virus in expressed sap being 72° C. All attempts to demonstrate the presence of the virus in the seed have proved negative.

Although no systematic study has been made, the range of plants susceptible to local infection in the leaves, by artificial inoculation, seems wide. Tests have shown that about 25 species of plants belonging to 10 families respond to inoculation with the virus.

Three possible explanations of the origin and spread of the infection are discussed.
The life history and pathogenicity of Eimeria meleagridis Tyzzer, 1927, in the turkey poult
Authors: Clarkson M. J.
Published: June 2009

A description is given of the life history and pathogenicity of a species of Eimeria, derived from a single oocyst infection in a coccidia-free bird, and subsequently identified as E. meleagridis.

There are two asexual generations followed by the sexual generation. The first schizogony cycle occurs in the small intestine and the second and sexual generations are restricted to the caeca.

The organism is not pathogenic but the sexual stages produce marked caseous lesions in the caeca. It is immunologically distinct from a pure strain of E. adenoeides and cannot be transmitted to chickens.
Seasonal variations in the incidence and development of the cestodeProteocephalus filicollis(rud. 1810) inGasterosteus aculeatus(L. 1766)
Authors: Hopkins C. A.
Published: June 2009

1. The incidence, intensity of infection, rate of growth and genital development inProteocephalus filicollishas been studied by the monthly examination of approximately 60Gasterosteus aculeatusover a period of 2 years.

2. The existence of an annual cycle, commonly reported for cestode parasites of fish in a temperate climate, is clearly established. The most advanced stages commonly occurring are: plerocercoids (0·25–5mm.) July-November; strobilate worms with genital primordia (58mm.) December-April; mature worms (1 cm.) April-May; gravid (2 cm.) June-July.

3. No tissue phase occurs between the time the procercoid is swallowed and the mature worm develops, but there is a migration from the rectum to the anterior part of the intestine.

4. From a consideration of the seasonal variation in incidence it is deduced that the parasitic population is in dynamic balance and that approximately 1 % of worms present are lost daily.

5. No evidence to support the existence of immunity was found. The lower incidence in 1+ than in 0+ fish was attributed to feeding habits.

6. Other aspects discussed are the interrelationship of proglottid formation and appearance of genital rudiments; the structure of the egg-shell; and the intensity of infection ofCyclopswith procercoids as calculated from the numerical distribution of worms in the fish host.

7. Reference is made to intercurrent helminth and protozoan infections and the effect of an epidemic ofIchthyophthiriussp. on the fish population.

I wish to thank Prof. C. M. Yonge for granting every facility for this work. My thanks are also due to Mr Archer, Miss Bell, Mr Berrie, Miss Spence and Miss Wyllie for help in collecting fish, and to Mr Gray who showed me the lochan.
Anthelmintic studies: II. A double entero-nemacidal anthelmintic test covering a wide range of activities
Authors: Steward J. S.
Published: June 2009

A technique is described of the use of two infections in the rat which respond to the anthelmintics acting on a very wide range of gastro-intestinal nematodes. It can be used as a routine screening test for anthelmintics or for the study of variations in the degree of activity caused by alterations in formulation or presentation.
Anthelmintic studies: III. A taeniacidal testing technique
Authors: Steward J. S.
Published: June 2009

1. A controlled taeniacidal technique is described using mice artifically infected with Hymenolepis nana var. fraterna.

2. The method of interpretation is based upon a form of computation relating to the number and sizes of worms left in the treated animals as well as the proportion of mice rendered negative by the treatment as compared with untreated controls.
The identification and estimation of acetylcholine in three parasitic nematodes (Ascaris lumbricoides, Litomosoides carinii, and the microfilariae of Dirofilaria repens)
Authors: Mellanby Helen
Published: June 2009

1. Extracts made from whole nematode worms, Litomosoides carinii, and from Ascaris ‘heads’ and body wall tissue, contain a substance similar to acetylcholine.

2. In the case of extracts from Litomosoides whole worms, this substance was shown to be probably acetylcholine itself.

3. Tissue from the anterior end of Ascaris (including the nerve ring), contains about 15 times as much acetylcholine as the body wall preparations; i.e. 0·39μg./g. as compared with 0·025μg/g. of wet weight.

4. There appeared to be rather more acetylcholine present in the Litomosoides males than in the females; 0·92μg./g. as compared with 0·63μg./g. of wet weight.

5. The microfilariae of the filariid nematode of the dog, Dirofilaria repens, contain as much as 2·4;μg./g. of acetylcholine. In this respect it resembles some other motile parasites of the blood, such as trypanosomes.
Excystment and in vitro cultivation of Echinoparyphium serratum
Authors: Howell M. J.
Published: June 2009

Seventy-five per cent of Echinoparyphium serratum metacercariae excysted within 10 min in a trypsin/sodium cholate solution after successive pretreatments with pepsin and sodium dithionite. Excystment appears to be an active process as the cyst wall is unaffected by the treatment except in the vicinity of the ‘escape aperture’.

Optimum development to sexual maturity in vivo required 72 h and was divided into six easily recognized stages against which development in vitro could be judged. These were undifferentiated (excysted metacercariae), cell multiplication, organogeny, gametogeny, vitellogenesis and oviposition. Migration of the juveniles from the lower regions of the intestine to the duodenum in the first few hours after infection was noted.

Cultures were prepared from excysted metacercariae and a variety of media were used. The beneficial effects of shaking cultures were apparent. No development took place in media containing saline, Parker 199 medium, homologous and heterologous sera, chicken embryo extract, albumen and glucose, either alone or in various combinations, although, relative to saline or Parker 199 medium controls, survival times were increased in some and decreased in others. Survival in some media above pH 7 was longer than below pH 7. Serum substrates in culture vessels, and the presence of additional glucose, did not increase longevity.

Development to organogeny was achieved using a yolk/albumen/saline or 199 medium, and addition of yeast extract to this favoured the later stages of development up to and including vitellogenesis. In general only a small percentage of juveniles in each culture reached vitellogenesis, and the amount of egg-shell protein formed and the size of the worms was always less than in vivo. Furthermore, development in vitro was much more prolonged than in vivo. Variability in development in vitro may be due to failure of the excystment procedure to satisfy completely the physiological ‘triggers’ which are probably necessary for normal development.

In some specimens vitellogenesis was reached without production of sperm. In others, production of eggs was thought to be inhibited by either a general deterioration of the juveniles or premature ‘tanning’ of the egg-shell protein, as significant amounts of egg-shell protein, sperm, and apparently normal ova were present.

The results of culturing E. serratum are compared briefly with those of D. phoxini.

I should like to record my sincere thanks to Professor J. D. Smyth for his advice and comments on the manuscript.
Lymnaea natalensis laboratory culture and production of Fasciola gigantica metacercariae
Authors: Bitakaramire P. K.
Published: June 2009

A method of breeding and maintaining L. natalensis cultures in the laboratory is described.

The infection of snails with F. gigantica miracidia and the collection of metacercariae is discussed. The mean number of metacercariae arising from cercariae produced by each snail was 652·6, over a period of 8·2 days.

It is shown that after 3 months storage F. gigantica metacercariae are still viable when excysted in vitro by using artificial pepsin and trypsin enzymes.

The author wishes to express his thanks to Dr G. M. Urquhart of the Wellcome Laboratories for Experimental Parasitology, University of Glasgow, Veterinary Hospital, Bearsden Road, Bearsden, Glasgow, who has read through this paper and made the necessary corrections.
Experiments on the Action of Emetine in Cultures of Entamoeba Coli.
Authors: Bishop Ann
Published: June 2009

1. Two pure strains of Entamoeba coli, differing in their accompanying bacterial flora and experimental history, but identical morphologically, have been tested with emetine hydrochloride in vitro.

2. In a buffered and wholly liquid medium, with a pH varying between 6·8 and 7·2, emetine hydrochloride was found to be toxic to E. coli in dilutions between 1 : 300,000 and 1 : 600,000, the toxicity increasing with the alkalinity of the medium.

3. It is therefore concluded that emetine is about 16 times as toxic in vitro to E. histolytica as it is to E. coli.
A comparison of malarial antigens from human and Aotus monkey blood infected with Plasmodium falciparum
Authors: Wilson R. J. M. , Voller A.
Published: June 2009

An extract of blood from Aotus monkeys infected with Plasmodium falciparum contained all the clones of malaria precipitins so far identified in human blood.

We are grateful to the Medical Research Council and Overseas Development Administration of Great Britain and to the World Health Organization for their financial assistance.
Influence of male and femaleNippostrongylus brasiliensison each other's distribution in the intestine of the rat
Authors: Gimenez Alba , Roche Marcel
Published: June 2009

Nippostrongylus brasiliensisof either sex, 216 h old, were injected directly in the intestinal lumen of 10-week-old laparotomized male rats in the duodenum or near the ileocaecal valve and their position ascertained 24 h later. Males migrated anteriad farther when females were placed in the duodenum than when they were alone or when 32P tagged males were in the duodenum. Females migrated anteriad similarly when they were alone or when males were in the duodenum or when 32 P tagged females were injected in the duodenum. The findings are consistent with the idea that females attract males anteriad at a distance.
The distribution and abundance of the ectoparasites of the wild rabbit, Oryctolagus cuniculus (L.), in New South Wales, Australia
Authors: Williams R. T.
Published: June 2009

In the winters of 1969 and 1970 a total of 64 rabbits was shot at 11 sites covering diverse climatic regions in the western, central and eastern districts of New South Wales. The ectoparasites of these rabbits were identified and counted. The flea Echidnophaga myrmecobii was most frequently found in western districts; the louse Haemadipsus ventricosus was prevalent in the central districts; the mite Listrophorus gibbus was very abundant on rabbits from the eastern districts, whilst the mite Cheyletiella parasitivorax was prevalent on rabbits from central and eastern districts.

The probable consequences of these variations are discussed in relation to their possible effects on the epidemiology of myxomatosis.

This investigation was carried out as part of the study of the biology of the wild rabbit undertaken by the Division of Wildlife Research, CSIRO, under the general supervision of Mr K. Myers. The author is indebted to P. Haycock and Miss S. Stephens for invaluable technical assistance. Messrs I. Parer, M. Stranger, G. Richards, H. Bults, J. Libke and P. Haycock shot the rabbit samples.
Studies on the immunity of albino mice to Trichuris muris
Authors: Wakelin D.
Published: June 2009

The immunogenicity of larval Trichuris muris in Schofield strain albino mice has been studied using infections abbreviated by chemotherapy. When mice were exposed to an initial infection lasting from 7 to 14 days their immunity to reinfection increased progressively, but the immunity stimulated by abbreviated infections was less than that stimulated by uninterrupted immunizing infections which last for approximately 16–18 days. The immune response of mice to T. muris appears to be stimulated by, and effective against, larvae of all ages and does not show stage specificity.
Transmission of Theileria annulata by the crushed infected unfed Hyalomma dromedarii
Authors: Mazlum Z.
Published: June 2009

In two experiments in which two different strains of T. annulata were used it was possible to induce theileriasis by injection of the crushed infected unfed H. dromedarii. The nature of the disease corresponded with that transmitted naturally by the feeding of the tick vector.
The effect of cortisone on the worm burdens of calves infected daily withOstertagia ostertagi
Authors: Michel J. F. , Sinclair I. J.
Published: June 2009

Of two groups of calves, one was regularly treated with the cortisone-derivative, β-methazone. This treatment greatly reduced the ability of the calves to produce antibody and gave rise to a number of side effects. Calves of both groups were given 1500 infective larvae ofOstertagia ostertagidaily. A milder régime of cortisone administrations using prednisolone was employed in a second experiment in which two comparisons were made. Worm burdens of calves infected with 1500 larvae daily and receiving cortisone were compared with those of control calves infected at the same rate and cortisone-treated calves receiving 1500 larvae per day were compared with cortisone-treated calves infected at twice this rate.

By periodicpost-mortemexamination it was shown that even in cortisone-treated animals the worm burden was regulated at a level only slightly higher than in control calves, apparently by a density-dependant loss of worms. A more rapid loss of worms which occurred for a period in the control calves was prevented in cortisone-treated animals unless the infection rate was high.

The limit set by the normal host to the total egg output of its worm population was raised by cortisone treatment, very greatly in the first experiment, rather less in the second in which the cortisone treatment was less severe. The effect of host resistance on the length of worms and on the incidence of females without vulval flaps was greatly reduced by cortisone. The inhibition of development was not affected.
The use of parasympathomimetic drugs to stimulate salivation in the tick Rhipicephalus appendiculatus, and the transmission of Theileria parva using saliva obtained by this method from infected ticks
Authors: Purnell R. E. , Branagan D. , Radley D. E.
Published: June 2009

Various parasympathomimetic drugs were injected per anus into female R. appendiculatus, previously fed for 5 days on rabbits, in attempts to induce the ticks to salivate. Pilocarpine nitrate and arecoline hydrobromide gave the best results and these drugs were therefore injected into ticks of various weight ranges and at various concentrations of the drug and the diluent, saline. The drugs were most effective at a concentration of 10% in 6% sodium chloride solution. If ticks salivated, the amount of saliva they produced could be positively correlated with their weight.

Sections of salivary glands from 5-day-fed female ticks in the corresponding weight ranges were examined for infection with T. parva. There appeared to be an inverse relationship between the infection rate of the ticks, and the number of infected acini observed, with increase in their weight. It was established that the greatest numbers of infective particles of T. parva should be obtained by the injection of 1 μl of 10% pilocarpine nitrate in 6% sodium chloride solution into ticks weighing between 3.1 and 13.0 mg. Twenty-five infected ticks in this weight range were injected, and the resultant saliva added to concentrated autologous leucocytes in phosphate-buffered saline before injection into a steer. The animal underwent a typical East Coast fever reaction and died, thus indicating that infective particles had been harvested by our methods.

Acknowledgements are due to many colleagues for assistance in a variety of ways. Mr M. P. Cunningham, Mr C. G. D. Brown, Dr J. K. H. Wilde, Dr R. Tatchell, Mr M. L. Burdin and Dr G. H. Freeman have given us a great deal of helpful advice. Mr C. Boarer and Mrs D. Backhurst supervised and carried out the processing and staining of the tick sections. Mr B. Wood carried out the weighing of the ticks and prepared the photographs.
‘Host’ antigens associated with schistosomes: observations on their attachment and their nature
Authors: Clegg J. A. , Smithers S. R. , Terry R. J.
Published: June 2009

Further investigations have been carried out on the nature of ‘host’ antigens associated with the adult worms of Schistosoma mansoni. These investigations show:

1. The ‘host’ antigens are not removed from the surface of the worms by thorough washing and prolonged incubation in Hanks's balanced salts solution. The antigens must be firmly bound or even incorporated at the surface.

2. Monkeys cannot be immunized against ‘mouse worms’ with mouse IgG immunoglobulins. Accordingly it is unlikely that the ‘host’ antigens are mouse anti-worm antibodies.

3. The ‘host’ antigens are certainly associated with the membranes of mouse erythrocytes. They may also be associated with the ‘soluble protein’ fraction of the erythrocytes.

4. Immunization with sheep erythrocytes failed to protect monkeys against challenge with ‘mouse’ worms. Therefore it is unlikely that the ‘host’ antigens are Forssman antigen.

5. The mouse ‘host’ antigens associated with ‘mouse’ worms are not major histocompatibility antigens. Consequently it is likely that they are species-specific mouse antigens.
In vitro cultivation of Echinococcus granulosus, Taenia hydatigena, T. ovis, T. pisiformis and T. serialis from oncosphere to cystic larva
Authors: Heath D. D. , Smyth J. D.
Published: June 2009

A technique for the hatching and subsequent in vitro cultivation of the oncospheres of Echinococcus granulosus, Taenia hydatigena, T. ovis, T. pisiformis and T. serialis to cystic larvae is described. The cytology and histology of developing larvae were also studied.

The basic culture medium consisted of medium 858 containing additional glucose and K+ supplemented with the appropriate host sera. Fresh sera from young animals was generally more successful in promoting growth than sera from commercial sources. Cultivation was carried out at 37°C in roller tubes with a gas phase of 10% O2+5% CO2 in N2.

The most successful results were obtained with T. pisiformis, oncospheres of which were grown to the cystic stage with development of hooks and suckers. During the later culture period, the bladder, although morphologically normal, ‘collapsed’ and did not retain its cystic shape.

In culture, larvae of T. pisiformis became motile at 3 days and at 5 days began secreting droplets from a glandular apical region; this region stained differentially in alcian blue.

Some larvae of T. pisiformis showed a tendency to undergo transverse or longitudinal fission, an effect possibly associated with the centrifugation applied during the early cultivation procedures.

Early cystic development was obtained with the other species studied, but experiments carried out were only of a preliminary nature. However, the development rate in these experiments approximated that recorded in vivo.
Growth and development of Strongyloides venezuelensis Brumpt, 1934 in the albino rat
Authors: Wertheim Guta
Published: June 2009

Growth and development of S. venezuelensis in percutaneously infected albino rats was studied and compared with S. ratti. The development of S. venezuelensis was found to last longer than that of S. ratti, the difference resulting mainly from the longer sojourn of the L3 larvae in skin and lungs. The growth rate was found to differ in each developmental stage, being higher in L4 than in L3 larvae. The adult females continued to increase in size for 6–7 days postexposure. The increase in body width, oesophagus length and tail length was found to be allometric bradyauxetic.
Experimental concurrent infections with Strongyloides ratti and S. venezuelensis in laboratory rats
Authors: Wertheim Guta
Published: June 2009

The distribution of S. ratti and S. venezuelensis in the intestine of albino rats was studied in experiments with single species infections and in mixed infections.

The majority of S. ratti were found in the anterior 20 cm of the intestine and in decreasing numbers in the remaining 60 cm. The larvae of S. ratti settled in the Lieberkühn crypts where they matured and laid eggs in convoluted tubes.

The parasitic females of S. venezuelensis were concentrated in the anterior 15 cm of the intestine, with over 50 % in the anterior 5 cm, and a few worms 20–25 cm posterior to the pylorus. The larvae settled in the villi, close to the surface of the mucosa. The straight egg strands were laid on this site.

It was concluded that, although occurring together, the two species can coexist in the intestine without interfering with each other.
A muscle-domain hypothesis forAscarispostural waves
Authors: Jarman M.
Published: June 2009

A hypothesis to explain some features ofAscarisflexures is given. It is based on the co-operation of muscle cells in domains which may assume two states. In one state the muscles are long and it is mainly the non-contractile parallel elements that are in tension. The other state has short muscles exerting tension mainly in the contractile elements. The living animal changes shape if new domains are formed or if domain boundaries move. The hypothesis is applied to laboratory experiments and observations.
Analysis of antigenic types appearing in first relapse populations of clones of Trypanosoma brucei
Authors: Miller E. N. , Turner M. J.
Published: June 2009

Variant antigenic types (VATs) represented in a total of 47 first relapse populations of 6 clones of Trypanosoma brucei LUMP 227 were identified by immunofluorescent staining of living trypanosomes, using antiserum raised against purified surface antigens. The relative growth rates of these 6 clones were measured both individually and when grown together in a mixed population, and were found to be different under these two sets of conditions. A pattern emerged in the VATs represented in relapses of each clone, with some types being expressed more frequently than others and certain VATs being only very rarely expressed. It is suggested that new VATs are expressed according to a statistically definable order of priority which is different for each parent VAT, and that some VATs may be able to change to certain others only after passing through an intermediate VAT. The order of priority of appearance of VATs does not appear to correlate with growth rate measured either in individual clones or when clones are grown in a mixed population.
Mites of the hedgehog Erinaceus albiventris Wagner in Kenya: observations on the prevalence and pathogenicity of Notoedres oudemansi Fain, Caparinia erinacei Fain and Rodentopus sciuri Fain
Authors: Gregory M. W.
Published: June 2009

The occurrence of 3 mites (Acari: Astigmata) is reported, from the Central African hedgehog Erinaceus albiventris Wagner, in the Nairobi area of Kenya. Notoedres oudemansi Fain (Sarcoptidae) showed sporadic incidence, affected males particularly and caused high mortality. A description of the male mite is given. Caparinia erinacei Fain (Psoroptidae) was found on 72% of animals on capture but showed very low pathogenicity. Rodentopus sciuri Fain (Hypoderidae) was found in the hair follicles of 46% of 43 animals examined; adverse effects were slight.
Immunity to coccidiosis: effect of serum antibodies on cell invasion by sporozoites ofEimeria in vitro
Authors: Long P. L. , Rose M. Elaine
Published: June 2009

A method for detecting antibody activityin vitroagainst the invasive stages ofE. tenellaandE. maximais described. Treatment of cultured chick kidney monolayers with serum (or a globulin fraction thereof) from immunized birds caused a reduction in the numbers of intracellular stages 24 or 48 h after inoculation of sporozoites. This reduction was seen when serum was incorporated in the culture medium at the time of sporozoite inoculation and also, but to a lesser extent, when the monolayers had been pretreated with the antibody-containing medium which was washed off prior to infection. The results correlated reasonably well with those obtained when the sera were tested in embryo (E. tenella) orin vivo(E. maxima). Similar treatment of cultured CAM monolayers in which infection withE. tenellawas well established (101 h), did not greatly affect the development of the parasite. This suggests that the anti-coccidial activity is either effective against the sporozoite stages only, or is unable to affect parasites within cells.
Protein composition and protein synthesis in the surface membranes of Schistosoma mansoni
Authors: Kusel J. R.
Published: June 2009

Saponin treatment of cercariae and schistosomula alters the surface membrane so that it may be sheared from the organism and isolated as fragments by centrifugation. Saponin-calcium chloride treatment or freezing and thawing of adult worms removes the surface membrane, which can be washed from the bodies and collected by centrifugation. The small quantities of material available necessitated the development of a sensitive technique for detecting the proteins in the membranes. The surface membranes were radioiodinated after butan-1-ol extraction and electrophoresed in polyacrylamide gel.
Adult surfaces prepared by the saponin-calcium chloride and by the freezing and thawing technique had identical protein components, detected as gel-cut profiles or in autoradiographs. The quantity of a rapidly migrating PAS-positive amido black negative component was greater in the surfaces prepared by saponincalcium chloride than in the frozen and thawed surfaces. This component contains lipid, some of which may be glycolipid. It was largely absent from the surface membranes of cercariae and schistosomula.
Cercarial surface membranes contained a major protein component which was absent from the surface membranes of schistosomula. Otherwise the surface membranes of the cercariae were identical to those of the schistosomula in their protein components.
The rate of incorporation of freshly synthesized protein per unit area of surface membrane of schistosomula was very low in the first 5 days in culture, after which there was a very rapid increase to a maximum rate on the 15th day. After this time, the rate of protein synthesis decreased to a low level at 26 days. In these studies the activity per unit area was measured and this would not be expected to vary greatly during growth. The biological significance of the observed variation in protein incorporation into the membrane is unclear.
The growth ofHymenolepis microstomain the laboratory rat
Authors: Goodall R. Ian
Published: June 2009

The growth ofHymenolepis microstomain weanling (21–23 days old) and adult (> 10 weeks old) rats has been investigated. Growth proceeded normally until the worms were about 9 days old. They then destrobilated, leaving only the scolex attached to the duodenum or bile duct. In only 1% of the rats did growth of the worms continue beyond 10 days and these large worms caused the bile ducts of their hosts to become distended. Immuno-suppressants had no effect on the growth of the worms, and tests suggested that there was no serological reaction to infection. It was concluded that the rat is a poor host forHymenolepis microstomabut that it is not completely refractory.
Effect of mating on oogenesis and oviposition in the tick Argas persicus (Oken)
Authors: Leahy Mary Gerald , Galun Rachel
Published: June 2009

The initial pattern of oogenesis after a feed is similar for mated and unmated A. persicus. The peak number of mature oocytes within the females occurred on the seventh day at 30 °C. Both groups ovulated but only mated females oviposited.
At the end of the first week the mature eggs of unmated females began to undergo dissociation and resorption. The early onset of this process seems to exclude the presence of unlaid eggs as a factor inhibiting ovarian maturation.
Many more eggs matured within the mated than the unmated female. After oviposition, the ovaries appear as in the unfed virgin except oocytes are fewer.
When the male was mated consecutively to the 7–8th virgin female, there was a decrease in the number of eggs laid. This indicates that the male factor(s) effecting oogenesis and oviposition act on a quantitative rather than an ‘all or none’ basis.
To determine whether a female was effectively mated, the ampulla must be checked for sperm. The reason for this is that the spermiophore capsules may be resorbed or may lack sperm.
Spermless spermiophores enhanced fecundity but did not effect oviposition.
There was evidence of mechanical influence on oocyte maturation when beads were introduced into the vagina of A. persicus. An increase in the number of beads increased the number of mature oocytes.
Chemical influence on oogenesis was demonstrated by injection of male gland complex into the body cavity of unmated females.
Nippostrongylus brasiliensis: observations on factors affecting the establishment of secondary worm populations in rats
Authors: Jenkins D. Conwil
Published: June 2009

Previously immunized rats of different ages were exposed either to one large, or several small challenge infections with the nematode, Nippostrongylus brasiliensis. The number of secondary worms harboured by each of these rats was then determined on the fourteenth day after exposure to challenge. It was found that worms adapted more efficiently to host immunity when both (a) the rats were less than 11 weeks old when challenged and (b) the challenge was given in small repeated doses over a period of weeks. The age of the rats on exposure to the immunizing primary infection, however, had little or no affect per se on the subsequent establishment of immune-adapted worms. It is tentatively suggested that the failure of worms to adapt effectively to the acquired immunity of older rats resulted from the acquisition by these rats of a fully competent cellular immune response.
The structure and development of the spermatozoon of Dipetalonema viteae (Nematoda: Filarioidea)
Authors: McLaren Diane J.
Published: June 2009

The structure and development of the spermatozoon of Dipetalonema viteae has been studied by means of electron microscopy.
Spermatogonia are developed from a syncytium in the terminal region of the reproductive tract. The syncytium grows along the length of the testis as an anucleate rachis, carrying with it the developing germ cells. The gametes become detached from the rachis when they have become secondary spermatocytes. The chromosomes which appear in the primary spermatocytes at the onset of meiosis persist throughout all subsequent stages of development. The nucleus is not reconstructed. Cytophores are produced by the spermatids at the end of the second meiotic division. The spermatid is an elongated cell, but the mature spermatozoon, within the male tract, is amoeboid. There are only minor differences between the sperm found in the male and female tracts. The male gametes contain complex membraneous organelles which are developed from the Golgi bodies and endoplasmic reticulum of the primary spermatocytes. These organelles are suggested to have similar origins and functions to the acrosome of the typical mammalian spermatozoon.
Eimeria weybridgensis sp. nov. and Eimeria ovina from the domestic sheep
Authors: Norton C. C. , Joyner L. P. , Catchpole Janet
Published: June 2009

Eimeria weybridgensis sp.nov. is described from pure infections in experimental lambs. The characters by which it can be distinguished from E. ovina and E. crandallis, which it resembles, are described. Cross-infection experiments confirmed its distinction from E. ovina. Oocysts of E. weybridgensis are the same size as those of E. crandallis, measuring 24 × 17 μm. The prepatent period of E. weybridgensis, however, is much longer and the morphology of the sporocysts of the two species is different.
Studies on the effects of cercarial concentration and length of exposure on the infection of mice by Schistosoma mansoni
Authors: Upatham E. S. , Sturrock R. F.
Published: June 2009

Groups of mice were exposed to Schistosoma mansoni cercariae in a large volume of water. A factorial design was used to investigate the effects of cercarial concentration and length of exposure on infection rates and worm burdens. Low exposure times and cercarial concentrations gave no infections, but prolonged exposure to high concentrations gave high infection rates and worm burdens. Prolonged exposure to low concentrations gave low worm burdens and moderate infection rates: short exposure to high concentrations gave moderate infection rates and worm burdens.
Statistical analysis showed that both infection rates and mean worm burdens were significantly related to the two main factors, but the relationship was complicated in each case by curvilinear effects and by a significant interaction between the main factors.
Field cercarial concentrations are generally low on St Lucia, a fact suggesting that brief human water contacts, such as fording and filling domestic water containers, play little part in transmission. Prolonged contact during swimming, bathing and washing clothes may produce significant infection rates accompanied by low worm burdens. However, on the rare occasions when high cercarial concentrations occur, even the briefest exposure may produce significant infection rates and moderate worm burdens.
Growth and respiration throughout the life-cycle ofNematospiroides dubiusBaylis, 1926 (Nematoda: Heligmosomidae)
Authors: Bryant Victoria
Published: June 2009

The growth of the three free-living stages ofN. dubiuswas measured in terms of dry and fresh weight. Changes in body water content during moulting were demonstrated by variations in dry weight when expressed as a percentage of fresh weight. The respiration rate of the larvae increased until they became infective, after which time it decreased until five days later no oxygen consumption could be recorded. The inability of all larval stages to withstand anaerobic conditions indicated that their metabolism was essentially aerobic. The relationship between body size and metabolic rate was established for each stage and its significance in relation to the life-cycle discussed.
Scanning electron microscopy of the duodenal mucosa of lambs infected with Trichostrongylus colubriformis
Authors: Barker I. K.
Published: June 2009

Duodenal mucosae of uninfected lambs and lambs inoculated at least 16 days earlier with 85000–140000 Trichostrongylus colubriformis larvae were examined with the scanning electron microscope. Normal duodenum had tall spatulate villi with surface folds upon which goblet cells and a regular pattern of hexagonal enterocytes were seen. Micro villi on normal enterocytes were closely packed and imparted a granular surface texture. In heavily infected areas of gut the villi were atrophic, the mucosa sometimes being composed of irregular masses and ridges, with crypt mouths, often surrounded by collars of cells, opening into the surface. More severely affected mucosae were flat, with protuberant collars of cells surrounding crypt mouths. There were rounded bodies, interpreted as sloughing enterocytes, or inflammatory cells, on the mucosal surface. Apices of enterocytes were domed and microvilli were sparse and irregular. Micro-organisms were numerous on cell surfaces. Nematodes were located in sinuous thin-walled tunnels in the epithelium. The mucosal microtopography is compared with that of coeliac disease of humans, nippostrongylosis in rats and with villus atrophy in pigs.
Scanning electron microscopy of the duodenal mucosa of chickens infected with Eimeria acervulina
Authors: Michael E. , Hodges R. D.
Published: June 2009

The morphology of the duodenal mucosal surface of chickens infected with Eimeria acervulina has been studied on days 5, 6, 8 and 11 post-infection and compared with that of the normal duodenal mucosa using the scanning electron microscope. The normal duodenum possessed tall, spatulate villi with horizontally-arranged surface clefts upon which a regular pattern of hexagonal absorptive cells and goblet cell mouths was superimposed.

A maximum degree of villous atrophy was shown on day 5 post-infection, the villi being thickened and flattened with frequent adhesions and fusions between them. The general effects of the disease together with the physical presence of intracellular parasites caused considerable changes in size and shape of the cell apices. By day 8 the mucosa was clearly recovering, with a normal pattern of somewhat thickened and truncated villi beginning to re-appear and by day 11 post-infection the mucosa had regained an outwardly normal morphological pattern. The mucosal changes are discussed in relation to similar changes which occur in diseases of the alimentary tract of other animals, including man.
The cellular response of the fowl small intestine to primary and secondary infections of the cestode Raillietina cesticillus (Molin)
Authors: Gray J. S.
Published: June 2009

Infections of Raillietina cesticillus in the small intestine of the fowl caused a mononuclear leucocyte infiltration, which occurred in the tissues around the worm scolices and was especially prevalent in challenge infections. There was no evidence of vascular congestion or of a neutro-philic response, and the cellular reaction seemed to consist of a local proliferation of lymphoid tissue. Mast cell and pyroninophylic cell numbers increased in the intestinal mucosa of birds with longstanding primary infections and with secondary infections, but very little eosin-lophil infiltration was detected and the globule leucocyte response was minimal. The infections had no effect on the numbers of thelio-lymphocytes and goblet cells. Challenge infections did not result in an increased level of serum antibodies, but more cells containing globulin seemed to be present in the intestinal mucosa of these birds. The interrelationships of the various cell responses to the cestode and the origin of the globule leucocyte are discussed in the light of previous work on helminth infections.
Response of Haemonchus contortus cayugensis to a change in the ratio of smooth to linguiform
Authors: Jambre L. F. Le , Ractliffe L. H.
Published: June 2009

The equilibrium, of vulvar phenotypes in Haemonchus contortus cayugensis was changed by infecting lambs with either a selected strain of smooth or of linguiform worms. Subsequently the lambs grazed the same pasture and observations were made on changes in worm populations in the lambs, and on pasture it appeared that the seasonal change in the relative frequencies of A and B linguiform worms was related to density-dependent factors in the host. In the spring, when lambs first become infected, the worm population is small and the majority of linguiform worms are A-type. As the season progresses the density of the parasite population increases. Once the population becomes crowded selection begins to favour the B-type females. The effects of crowding on linguiform A females can be seen as a positive correlation between the percentage of linguiform A and their weight. Population density also affected the survival of A-type worms since there was a negative correlation of percentage A-type on total worm numbers. There was a similar negative correlation between percentage A-type and total worm numbers in both the continuously infected and tracer lambs.

Population density did not affect the proportion of smooth worms. However, smooth worms increased in the tracers from, approximately 10% at the beginning of the experiment to 55% at its conclusion 18 weeks later. The latter percentage is almost within range of the local subspecies, which has 60% or more smooth worms. It appears therefore that the proportion of smooth to linguiform worms is a stable equilibrium maintained by natural selection.
Studies on short-term application of drugs to Eimeria tenella in tissue culture
Authors: Wilson R. G.
Published: June 2009

The anticoccidial action of 6 drugs was studied by treating cell cultures with drug for 24 h after inoculation of the cultures with sporozoites of Eimeria tenella. A monitoring technique was used to confirm that the drug was being removed. Only monensin was shown to be coccidiocidal. Amprolium, lasalocid, methyl benzoquate, nicarbazin and robenidine were coccidiostatic at their minimum effective doses. Misleading coccidiocidal effects were observed when higher concentrations of methyl benzoquate, nicarbazin or robenidene were used.
Invasion of erythrocytes by Plasmodium falciparum in vitro
Authors: Trigg P. I.
Published: June 2009

The erythrocytic stages of Plasmodium falciparum from Aotus trivirgatus were grown in Mill Hill medium. Significant invasion of erythrocytes was obtained by a subculture technique. This invasion, by parasites grown in Aotus erythrocytes, was greater when human erythrocytes were added to the cultures than when parasites were allowed to invade Aotus erythrocytes. This difference appeared to be a function of the properties of the erythrocyte and was not serum dependent.