bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study ofTrypanosoma cruziwith the electron microscope
Authors: Meyer Hertha , Porter Keith R. 
Published: June 2009

Trypanosoma cruzihas been examined with the electron microscope. Crithidia and metacyclic forms of a blood agar culture have been studied and compared with the adult tissue forms, obtained in tissue cultures, from the same strain.In all the forms studied, the internal structure of the body is not revealed because it is too thick for electron penetration. In places where a good penetration has been obtained the cytoplasm shows a fine striation in spiral or parallel arrangement. This striation can be digested with trypsin or by prolonged osmic acid fixation.Dense spherical bodies of variable size can also be observed in the body portion. They can be dissolved with xylene.The whole body of the trypanosome is covered by a fine, transparent sheath.The flagellum is formed by the axoneme which consists of five or nine fibres. It can be followed throughout the whole length of the metacyclic and of the adult tissue forms. In the crithidia forms of the blood-agar culture, it disappears in the anterior part of the body. The whole flagellum is covered by a fine sheath. The axial fibre bundle can be digested with trypsin or by prolonged osmic-acid fixation. Both, the striation and the fibre bundle are contractile structures which could explain the movements of the trypanosome.Some dividing forms are also described.
Rhipicephalus hurti n.sp. (Ixodidae) from Kenya game and domestic animals
Authors: Wilson S. G. 
Published: June 2009

A new species of Rhipicephalid tick, Rhipicephalus hurti, is described from game animals from the Rift Valley of Kenya. The new species is compared with R. capensis, R. serranoi and R. jeanneli.My thanks are due to Dr G. Theiler, Onderstepoort, who confirmed that R. hurticould be correctly regarded as a new species and has been most generous in her assistance. My thanks are also due to Dr Santos Dias and Dr Hoogstraal for their most helpful criticisms; to Lieut.-Col. Hurt for his interest and care in sending me numerous tick-collections from the Naivasha area of Kenya; to Mr Alex Wiley and Mr Guggesburg for their careful drawings; and to Miss Walker, E.A.V.R.O., and
my colleague Mr Pollard, for their generous help at all times.
The life cycle of Paramphistomum microbothrium Fischoeder, 1901 (Trematoda, Paramphistomidae)
Authors: Dinnik J. A. , Dinnik N. N. 
Published: June 2009

The whole life cycle of Paramphistomum microbothrium Fischoeder, 1901, found in cattle of Kenya, East Africa, has been established experimentally.In laboratory conditions, the eggs hatched miracidia on the 14th to 16th day, if they were kept in water at a temperature of 26–28° C.In a snail, Bulinus alluaudi (Dautzenberg), kept at the temperature of 18–20° C., the miracidium developed into a sporocyst, the elongated body of which, containing young rediae, reached a length of 3·6 mm. in about 2 weeks.The first rediae which emerged from a sporocyst were observed on the 14th day, and on the 20th day the first generation rediae began to produce second-generation rediae. From the 28th day onward the first-generation parent rediae ceased to produce daughter rediae and began to develop cercariae only. This period of production of cercariae by the redia lasted about 30 days, and when the life of the first-generation rediae drew to its close, the old rediae developed a few daughter rediae again.Cercariae began to emerge from the first-generation rediae 30 days after exposure of the snail to miracidia. The cercariae left the parent redia in a very immature state and further development occurred in the liver of the snail. The emergence of cercariae from the infected snail began on the 43rd day after exposure to miracidia. Shortly after emerging from the snail, the cercariae attached themselves to vegetation and encysted.Development of rediae of the second, third, fourth and apparently more successive generations followed an identical course to that outlined for the rediae of the first generation. As a result the successive generations of rediae maintain the infection going in an intermediate host and the infected snails were continually shedding cercariae as long as they lived. In the laboratory experiments the life span of some of the infected snails exceeded a year.In cattle infected experimentally P. microbothrium reached maturity and began passing out the eggs about a 100 days after the encysted cercariae were fed to the animals.
Amoebae found in the intestine of lizards from the Sudan
Authors: Neal R. A. 
Published: June 2009

1. The morphology of an Entamoeba from the Sudanese lizards Mabuya quinquetaeniata, M. striata and Tarentola annularis is described. It was similar to Entamoeba coli of man.2. It is referred to the species E. flaviviridis, Knowles & Das Gupta (1935).3. An ‘Amoeba’ was observed in Tarentola annularis which was similar in size to the Entamoeba. The nuclear structure, however, was distinctive, with a very large karyosome and no peripheral chromatin. The cysts were uninucleate.4. It is very similar to the organism described as Vahlkampfia reynoldsi by McFall (1926).
On the Biology and Life History of Rhabditis Pellio (Nematoda)
Authors: Otter G. W. 
Published: June 2009

1. Accurate measurements were made of adults, larvae and eggs of Rhabditis pellio, representing an average selection for comparison with Johnson's figures.2. The most satisfactory method of culturing the nematodes was in hanging drops, in a medium free from an excess of putrefying bacteria.3. A medium poor in food was found to prolong life (up to 40 days), while a rich medium quickened up the life processes thereby causing death sooner. It is probably partial starvation which prevents the larvae from becoming mature while in the living earthworm.4. In a medium favourable for prolonging life, the males were found to live about one-third as long as the females (F generation). It is probable that the females only live for about 4–8 days in a decaying earthworm after attaining maturity.5. The maximum number of eggs laid per female was 257 (F generation) and 197 (F1 generation). It is probable that between 150 and 300 eggs are laid per female in the natural state. No information was obtained regarding the effect of the various media on egg production.6. In most cases the females died when spent of eggs.7. Vivipary is considered to be due to a favourable environment probably aided by a high temperature.8. Larvae were found to be more susceptible to cultural conditions than the adults, especially those (F generation) which were not bred from females in culture media. The growth-rate of F1 generation larvae was found to be slightly faster in a natural medium, such as earthworm broth, than in peptone.9. The chief food is considered to be bacteria.10. During this work R. pellio behaved entirely as a bisexual species. A few cases of copulation were observed, showing that some of the males had not lost their “sexual instinct.”11. Rhabditis pellio is considered to be a species in which hermaphroditism is just commencing and in which true males and females exist together with hermaphrodite females whose numbers fluctuate, the degree of hermaphroditism possibly bearing some relation to the sex ratio.12. The sex ratio was about 1 ♂: 2 ♀♀, in both the F and F1 generations, but varied considerably. There were a few cases in which the male proportion was equal, or higher, than the female.13. Four different species of British earthworms were examined, each being infected by Rhabditis pellio to a varying extent. Eisenia foetida was, however, rarely infected. Size of the earthworm, in proportion, played no part regarding the degree of infection. There is an indication that the head (segment I to the beginning of the clytellum) is the most heavily infected region.14. A few specimens (larval stage) of an Ascarid, a species of Porrocaecum, a parasite of small mammals and birds, were found in three of the species of earthworms examined.15. A probable course of the life history is given, based on this work and that of Johnson (1913).
The Life History of Onesia accepta Malloch (Diptera, Calliphoridae)
Authors: Fuller Mary E. 
Published: June 2009

The life history of Onesia accepta Mall. is described. This species is parasitic on the earthworm Microscolex dubius Fletcher. The first and second larval instars are passed under the skin and the third instar in the body cavity of the host. The feeding period of the maggot is approximately 20 days, and the pupal stage about 12 days.The external morphology of the three larval instars and of the puparium is described in detail.
Studies on some New Ophidian and Avian Coccidia from Uganda, with a Revision of the Classification of the Eimeriidea
Authors: Hoare Cecil A. 
Published: June 2009

This paper contains an account of four new Coccidia from Uganda: Caryospora legeri sp.n., from a snake, Psammophis sibilans; Isospora dirumpens sp.n., from a snake, Bitis arietans; Wenyonella africana gen.n., sp.n., from a snake, Boaedon lineatus; and Eimeria urnula sp.n., from a bird, Phalacrocorax carbo lugubris. Eimeria dukei. Lavier 1927, is recorded from a new host, Chaerephon (= Nyctinomus) limbatus (bat).The characters of the new Coccidia are summarised in the diagnoses (pp. 364, 369, 373, 378). There is a list of all the known species of Isospora found in snakes and lizards. It is noted that I. coelopeltis Galli-Valerio 1926, is actually an Eimeria, and its name is amended to E. coelopeltis. The diagnostic characters of the three species of Caryospora are given in tabular form.The discovery of a new type of Coccidia, with oocysts containing sixteen sporozoites, divided between two sporocysts in Dorisiella Kay 1930, and between four in Wenyonella gen.n., necessitated a revision of the systematics of the Eimeriidea.When the genera comprising this suborder (with a few exceptions) are arranged in the ascending order of the number of structural elements (sporocysts and sporozoites) contained in their oocysts, they form parallel series or groups in the horizontal and vertical directions, which consist of homologous members, as represented graphically in Fig. VI (p. 383). The oocyst characters of each genus are determined by those of its four neighbours in the horizontal and vertical groups.This scheme serves as the basis for the new classification proposed, which is represented in Table III (p. 385). The higher systematic units (subfamilies) are distinguished from each other by the number of sporocysts within the oocyst, while the genera of each subfamily differ from each other in the number of sporozoites within each sporocyst, thus forming a homologous series.
Coccidia of the Felidae
Authors: Yakimoff W. L. , Matikaschwili I. L. , Rastegaïeff E. F. , Lewkowitsch E. N. 
Published: June 2009

Two species of coccidia have been found in captive Felidae examined by us in Russia:(1) Isospora felis Wenyon 1923, in lion, tiger and lynx.(2) Isospora rivolta (Grassi 1879), in tiger, leopard and jungle cat.
Protozoa in Termites of the Genus Amitermes
Authors: Kirby Harold 
Published: June 2009

1. Six species of Amitermes, one from Panama and five from California, have been examined for protozoa. Certain protozoa have been found in many or all individuals examined of all species, but they are much less abundant than are flagellates in termites of the three xylophagous families below the Termitidae.2. Trichomonas lighti n.sp. has been found in all species, but not in all individuals.3. Chilomastix minuta n.sp. occurs in Amitermes beaumonti.4. Embadomonas termitis n.sp. is described from Amitermes beaumonti.5. Endamoeba beaumonti n.sp. has been observed in five host species. In its size and nuclear structure it resembles Endamoeba disparata of Mirotermes hispaniolae.6. Nyctotherus silvestrianus n.sp. has been found in three of the Californian species. It resembles N. termitis and N. ovalis, but is larger than the former and smaller than the latter. A long filament is attached to the end of the cytopharynx. A thickened, V-shaped structure lies against the cyto-pharynx. Several deeply staining fibrils arise from this V.7. A coccidian has been found in one individual of Amitermes minimus. This forms sixteen banana-formed merozoites and three sporoblasts as in Chagasella.8. Micro-organisms other than protozoa are very abundant in the intestines of all six species of Amitermes, and they are similar in all.
New species of Ixodes ticks from eastern Africa, with a description of the male and nymph of Ixodes oldi Nuttall, 1913
Authors: Arthur D. R. 
Published: June 2009

The following new species of Ixodes from eastern Africa are described and figured: I. rotundatus, I. auriculaelongae, I. nchisiensis, I. latus, I. loveridgei, I. spinae, and I. euplecti.The female of I. oldi is redescribed and the hitherto unknown male and nymph are described and figured. Some consideration is given to two specimens from Uganda which differ in certain particulars from typical specimens from East and West Africa.
Experimental Eimeria mitis infections in chickens
Authors: Joyner L. P. 
Published: June 2009

1. Methods are described for the isolation and maintenance of a pure strain of Eimeria mitis.2. The prepatent period of the infection in chicks was 101 hr. The mean dimensions of the oocysts were 15·38 × 13·83μ, and sporulation occurred after 48 hr. at 60° F. (15·5° C.). The production of oocysts following infection with known numbers of oocysts is recorded.3. When 500,000 or more oocysts of E. mitis were given to chicks aged 6, 17 or 26 days the growth rate of the birds was markedly reduced. Young chicks were most susceptible and a few deaths occurred when 6-day-old chicks received 2·5 million oocysts. E. mitis is unlikely to be of pathological importance under normal conditions of good husbandry practice.4. Pathological lesions due to this species of Eimeria were not found in sections of intestinal tissues.5. Developmental stages of this parasite were found throughout the whole of the small intestine.6. The growth-retarding effects and oocyst production by E. mitis were controlled when 0·2% sodium sulphadimidine was given in the drinking water.
The effects of trematode metacercariae (Brachylaemidae) on the slugsMilax sowerbiiFérussac andAgriolimax reticulatusMüller
Authors: Foster R. 
Published: June 2009

1. Infestation of the kidney ofM. sowerbiiandA. reticulatusby unencysted brachylaemid metacercariae led to a widespread necrosis of the organ. The necrotic debris was ingested into the gut crura of the parasites.2.M. sowerbiiis considered to be a natural intermediate host of the parasite andA. reticulatusto be an unnatural host, because inA. reticulatusparasitization led to a host mortality closely related to the degree of infestation, whereasM. sowerbiiwithstood the damaging effects of parasitization until the parasites reached maturity.3. InA. reticulatusthe rate of ingestion of food and the rate of egg production were reduced during parasitization.4. No further effects were observed in either host species.5. The possibilities and difficulties of using unencysted metacercariae to control pests are discussed.
The vector of Hepatozoon sciuri
Authors: Dasgupta B. , Meedeniya Kamani 
Published: June 2009

A description is given of the stages of sporogony of Hepatozoon sciuri, which have been found in three wild fleas (Orchopeas wickhami) out of a total of nearly sixty specimens collected from squirrels in England. Although an attempt to infect the fleas in the laboratory, by feeding them on infected squirrels, failed, the above findings indicate that these fleas may act as vectors of the squirrel parasite.We wish to record our thanks to Professor P. C. C. Garnham for his kind interest and constructive suggestions regarding this work. We are specially indebted to Mrs M. Vizoso and to Dr J. F. D. Frazer for sending us fleas and squirrels from time to time. Our thanks are due to the authorities of the British Museum of Natural History for the identification of the flea.
Digestion in Leidynema appendiculata (Leidy, 1850), a nematode parasitic in cockroaches
Authors: Lee D. L. 
Published: June 2009

1. A study of the digestive enzymes present in the nematode Leidynema appendiculata, parasitic in the cockroach, gave the following results.2. An amylase with optimum activity at pH 4·5, is present. Sodium chloride increases activity by 29 % at this pH.3. A maltase, with maximum activity at pH 5·0–6·0, is present. It is completely inhibited by 15 % glycerin.4. Lactase and invertase were not detected.5. A protease, capable of clotting calcified milk, and of splitting gelatin and edestin, with maximum activity at pH 6·0, is present. KCN does not increase activity.6. Peptidases splitting glycyl-glycine, dl-leucyl-glycine and dl-leucyl-glycyl-glycine, and a prolidase splitting glycyl-l-proline are present.7. A lipase hydrolysing glycerol tributyrate, with maximum activity at pH 7·0 is present. Hydrolysis of olive oil and ethyl butyrate was not detected.8. It is concluded that these enzymes are quite distinct from those of the host and that digestion probably takes place over the range of pH 5·5–6·0.
The epidemiology of the infestation of the honeybee, Apis mellifera L., by the mite Acarapis woodi Rennie and the mortality of infested bees
Authors: Bailey L. 
Published: June 2009

The proportion of young honeybees which became infested with Acarapis woodi Rennie rose with an increased degree of infestation of the older bees and increased temperatures. But the most important influence controlling infestation seems to be the frequency with which young and old bees come into contact; this is probably determined by the foraging activity of the bees and the ratio of young bees to old bees; the percentage of infested bees in colonies diminished rapidly during nectar-flows and rose in periods of little nectar-flow.The mortality of infested bees was only slightly greater than that of non-infested bees and became evident only after the bees had been in prolonged unfavourable circumstances. There were no obvious signs of disease in heavily infested colonies in summer. Colonies with more than about 30 or 40 % of infested bees seemed more likely to die in winter than non-infested colonies, but few colonies became so heavily infested even after a very poor season.
Researches on the intestinal protozoa of monkeys and man
Authors: Dobell Clifford 
Published: June 2009

1. This memoir amplifies my accounts ofEndolimax nanapublished in 1919 and 1933. The complete life-history, as observable in cultures, is now described—special attention being devoted to the nuclear structure at all stages.2. Additional information is also given about methods of cultivation, viability of the cystsin vitro, the ‘nucleal reaction’, natural parasites (Sphaerita, etc.), and other details.3. The life-history has been found to comprise trophic, precystic, cystic, and metacystic stages, comparable with those described inEntamoeba histolytica(1928) andE. coli(1938).4. The trophic amoeba is redescribed, with special reference to the polymorphism of its karyosome.5. Division of the trophic amoeba (by binary fission) has been studied, and the mitosis of its nucleus is now first described in detail. It is characterized by the formation of an intranuclear spindle, with well-developed centrioles and centrodesmus. The granular chromosomes are 10 in number, and arranged in a ring on the equatorial plate.6. Precystic amoebae are smaller than trophic forms —the reduction in size being effected during the last two divisions before encystation.7. The cyst is formed by a precystic amoeba in the usual way. Inside the cyst, the nucleus undergoes two successive mitotic divisions similar to those seen in trophic forms. The ripe cyst is therefore 4-micleate, though supernucleate specimens—which are viable— occur occasionally. Glycogen is normally present in young (1- and 2-nucleate) cysts, but not in those which are mature.8. The process of excystation is described for the first time, and closely resembles that seen inE. histolytica. The entire protoplasmic contents emerge as a single 4-nucleate amoeba through a minute pore in the cyst wall.9. Metacystic development—not previously studied —consists in simple division, by successive cytoplasmic bipartitions without division of the nuclei, into 4 uninucleate amoebulae. These grow into trophic amoebae once more.10. The whole life-history is thus asexual, with no gametes, conjugation, or autogamy, at any stage.
The development of symptoms, parasitic infection and immunity in human scabies
Authors: Mellanby Kenneth 
Published: June 2009

1. Scabies is usually transmitted by intimate personal contact.2. The young, newly fertilized adult female Sarcoptes is the stage usually responsible for transmission.3. Patients with a high parasite rate (over 100 adult female mites) are much more likely to spread scabies than those with few parasites.4. The distribution of the parasites in clinical scabies gives no clue to the original sites of infection.5. When a volunteer is infected for the first time he gives no reaction for about a month. During this period he may be quite unaware that the parasites are burrowing in his cuticle.6. After a month the patient becomes sensitized, itching and other symptoms develop.7. In a first infection the mites increase in numbers far less rapidly than is theoretically possible. A parasite rate of about 25 may be reached in 50 days and of up to 500 in 100 days; after this the number of mites decreases rapidly.8. The second time an individual has scabies he itches at the sites of infection within 24 hr. His mite population seldom rises to a fraction of the height reached in his first infection.9. Reinfection of cured cases is much more difficult than infection for the first time.10. Sarcoptes causes antibody function in man. This causes a partial immunity.11. The mechanism of immunity is due to three reactions: (a) scratching by the host which removes the parasites mechanically; (b) oedema renders the cuticle unsuitable for colonization and causes the mites to vacate their burrows; (c) scratching produces sepsis which is fatal to Sarcoptes.12. The partial immunity obtained may account for fluctuations in the incidence of the disease.
The mechanism of the attachment ofKuhnia scombri(Kuhn, 1829) (Trematoda: Monogenea) to the gills of its hostScomber scombrusL. including a note on the taxonomy of the parasite
Authors: Llewellyn J. 
Published: June 2009

The manner by whichKuhnia scombri(Kuhn, 1829) Sproston, 1945, attaches itself to the gills ofScomber scombrusL. is described.The parasite lies between the primary gill lamellae with its posterior attachment organs ‘upstream’ with respect to the gill ventilating current of the host.The adhesive mechanism consists of two sets of organs which become attached to the secondary lamellae: a pair of hooks, provided with powerful muscles, perforates three or four secondary lamellae; and each of the members of four pairs of hinged clamps, operated by its own extrinsic muscle, grasps one or two secondary lamellae.The description of the adhesive mechanism given differs substantially from that given by Sproston. Sproston's classification of the Diclidophoroidea, being based mainly on her interpretation of the structure of the clamps ofKuhnia, is therefore open to criticism.