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PubMed1980

Development of Theileria mutans (Theiler, 1906) in the gut and the haemolymph of the tick Amblyomma variegatum (Fabricius, 1794).

The development of Theileria mutans in the gut and haemolymph of its tick vector, Amblyomma variegatum, was studied by Giemsa-stained smears after the nymphal tick had completed engorgement on parasitaemic calves. Sexual stages occurred in the gut between five and seven days after repletion. The zygotes were observed in the gut from day 29 and the kinetes from day 30, i.e. three and four days after the nymphs moulted to adults. From day 34 kinetes were observed in the haemolymph. The developmental stages of T. mutans in the tick were compared with those of other Theileria spp. of cattle.

Animals↗
PubMed1978

Haemoproteus columbae: course of infection, relapse and immunity to reinfection in the pigeon.

Studies were performed on the course of infection, relapse, and immunity to reinfection in 11 young pigeons infected with the avian malaria parasite Haemoproteus columbae Kruse. The prepatent period in our experiments varied between 22 and 37 days. The intensity and length of the initial infection period showed wide variations. During this period an initial periodicity of gametocyte production of about 12 days with peaks at about 6-8 and 18-20 days after patency was observed. The various modes of infection (fly bite, intramuscular, intravenous, or intraperitoneal inoculation of sporozoites) did not influence the intensity of the initial infection. No pathogenicity due to heavy infection with the parasite was observed. There was no periodicity of relapse occurrence, nor any correlation between the frequency of relapse and the intensity of the initial infection, and the phenomenon was not influenced by seasonal changes. Pigeons (Columba livia) that had recovered from previous infections were susceptible to reinfection, whereas pigeons with chronic infection acquired immunity (premunition).

Animals↗
PubMed1978

[Comparative review of the developmental biology of the genera Sarcocystis, Frenkelia, Isospora, Cystoisospora, Hammondia, Toxoplasma and Besnoitia (author's transl)].

A review is given of the advances in our knowledge of the developmental biology of the so-called cyst-forming coccidia in the years from 1974 to 1978. Until 1970 only 6 Isospora species were known to occur in cats, dogs and men. After the discovery of the coccidian nature of the genera Toxoplasma, Sarcocystis, Besnoitia and Frenkelia, and after the discovery of the new genus Hammondia the number of known species rose to over 30. In addition it could be shown that also birds of prey, owls and reptiles serve as final hosts for several Sarcocystis and Frenkelia species. The coccidia with isosporoid oocysts can be classified into two major groups: Species with gamogony and sporogony in the final host (Sarcocystis, Frenkelia) and species with schizogony and gamogony in the final host and sporogony on the ground (Isospora, Cystoisospora, Hammondia, Toxoplasma, Besnoitia). The subdivision of the first group into the genera Sarcocystis and Frenkelia based on the localization of their cysts in the musculature and in the brain, respectively, cannot be upheld in the future. Their classification into organisms with small cystozoites of about 7 microm with birds or reptiles as final hosts (Sarcocystis and Frenkelia species of rodents) and those with large cystozoites of about 15 microm and mammals as final hosts (Sarcocystis spp. of domestic animals and rodents) would be more significative. The second group can be subdivided into monoxenous species (Isospora), species with an optional intermediate host in which no or only slight multiplication occurs (Cystoisospora) and in genera with a multiplication in two phases in the intermediate host (Hammondia, Toxoplasma, Besnoitia). The nomenclature of single species is very controversial. As an example the controversial apprehension of the taxonomy of the Sarcocystis species of cattle is discussed. An application has been submitted to the International Commission for the Zoological Nomenclature to delcare a number of names as nomina dubia and to introduce unambiguous names for those organisms for which type specimens are available.

Animals↗
PubMed1979

The erythrocytic entry- and exit-mechanism of Aegyptianella pullorum Carpano, 1928.

The erythrocytic entry- and exit-mechanisms of Aegyptianella pullorum were investigated and characterized by scanning (SEM) and transmission electron microscopy (TEM) using for TEM ruthenium red as a marker of the red cell plasmalemma. The scanned Aegyptianella preparations produced static evidence of an endocytosis followed by an erythrocytic vesiculation as the possible mode of entrance of initial bodies into erythrocytes. The presence of ruthenium red only coating the membrane around the parasitophorous vacuole during the whole invasive process and the complete absence of the stain inside the host cell indicate that the entry of aegyptianellas is accomplished by invagination of the host cell plasmalemma and is not preceded nor followed by its breakage, furthermore unequivocally proving the intracellular parasitism of A. pullorum during its reproductive cycle. One possible mode of exit of initial bodies from parasitized erythrocytes appeared to be the invasive mechanism in reverse order, an exocytosis. Generally, however, the affected erythrocytes are parasitogenically injured, resulting in release of the parasites into the plasma and, subsequently, in host cell lysis.

Animals↗
PubMed1981

Besnoitia in a palaearctic lizard (Lacerta dugesii) from Madeira.

Besnoitia cysts in the heart of a lizard (Lacerta dugesii) from the islands of Madeira are the first record of besnoitiosis in a poikilothermic animal in the Old World. The size of the cysts corresponds to those found in lizard genera (Basiliscus and Ameiva) from Panama which belong to B. darlingi. Up to now nothing is known concerning the life cycle of this species from Madeira but it seems possible that cats function as definitive hosts as well as in the other species.

Animals↗
PubMed1989

Some ultrastructural data on the spore development in a Henneguya sp. parasite of the gill of a Brazilian fish.

A myxosporean Henneguya sp. was found in the gill filaments of a freshwater fish, Hoplosternum littorale, from the lower Amazon river near Belém, Brazil. Plasmodia were represented by numerous vegetative nuclei, generative cells and sporogony stages. The spore body was ellipsoidal and each valve presented a tapering tail approximately 45.2 microns in length. The spores differed from those of previously described species in their shape and size. The developmental stages are described and discussed. This histozoic species is reported to be pathogenic, inducing great mortality in the host.

Animals↗
PubMed1989

Phenotypic characterization of Theileria parva schizonts by two-dimensional gel electrophoresis.

Biosynthetically radiolabelled Theileria parva schizonts were purified from bovine lymphoblastoid cells and their proteins were analyzed by two-dimensional gel electrophoresis and autoradiography. The protein spot patterns of schizont proteins from three stocks of T. parva parva indicated that the phenotypic diversity among the stocks was minimal, with the Mariakani and Uganda stocks being identical and the Muguga stock showing only a few differences in minor spots. Comparison of the spot patterns of schizonts of three T. parva subspecies showed that T.p. parva and T.p. bovis differed in only one protein and thus could not be reliably distinguished on the basis of their protein differences. However, T.p. lawrencei showed several protein differences and could be distinguished easily from the other subspecies. Differences in schizont-protein spot patterns were also seen when two different cell lines were infected with the same Theileria stabilate, when one cell line was infected with two different stabilates of the same stock and when uncloned and cloned infected cell lines were used. These results suggest the possibility that selection of phenotypically different parasites could occur in vivo or in vitro.

Animals↗
PubMed1992

Characterization of anti-Neospora caninum hyperimmune rabbit serum by western blot analysis and immunoelectron microscopy.

The antigens recognized by hyperimmune rabbit serum raised against tachyzoites of the NC-1 isolate of Neospora caninum were characterized using chemiluminescent Western blotting, immunogold-silver staining and immunoelectron microscopy. Approximately 20 immunodominant antigens whose relative rates of migration were 16-80 kDa were recognized by the serum in Western blots using reduced or nonreduced parasite antigen preparations. The nonreduced parasite antigens were more strongly recognized by the serum than were the reduced antigen preparations. Immunoelectron microscopy revealed that the rabbit-serum-labeled antigens were localized to some organelles of N. caninum tachyzoites and to the parasitophorous vacuole surrounding them. In particular, antigens found in the dense granules, in the micronemes, and in the posterior portion of the rhoptries were strongly labeled by an indirect immunogold-labeling technique.

Animals↗
PubMed1978

[Light microscopic studies on the development of Theileria annulata (Dschunkowsky and Luhs, 1904) in Hyalomma anatolicum excavatum (Koch, 1844). II. The development in haemolymph and salivary glands (author's transl)].

Fully differentiated kinetes, average length 17.6 micrometer, appeared in the haemolymph of engorged nymphs usually 17 to 20 days after repletion. Kinetes were observed at first in the salivary glands on day 18 after repletion. The kinetes then transformed into fission bodies of about 10 micrometer in diameter, mainly in type III alveoli and less frequently in type II alveoli. The fission bodies grew up to a size of about 20 micrometer after several divisions of their nucleus. At this time the ticks moulted and no further development occurred until activation. Shortly before infestation the salivary glands began to proliferate, and rapid growth of the fission bodies was observed, especially in young ticks where development of 'infective particles' ('sporozoites') was concluded within two days. Development in feeding adult ticks apparently occurred in four major steps: (1) Division of primary fission bodies (sporonts) into numerous secondary fission bodies ('primary sporoblasts'), (2) division of secondary fission bodies into tertiary fission bodies ('secondary sporoblasts'), (3) production of particles ('sporozoites') by tertiary fission bodies and release of particles into the saliva, and (4) degeneration of fission bodies and their host cell but further release of particles. The host cell was stimulated to giant growth, thus its diameter increased, on average, from 15 to 110 micrometer. Heavy infections resulting from parasitaemias of greater than 40% caused disease and mortality in the tick population. Development was much retarded by aging. In ticks starved for six months 'sporozoites' did not develop before day five to seven of infestation. 'Sporozoites' did not develop before day five to seven of infestation. 'Sporozoites' may not develop at all in six to nine month old female ticks during the infestation period. The significance of the described developmental stages of T. annulata was discussed and a sexual generation postualted. The hypothetic development of T. annulata in its tick vector was illustrated.

Animals↗
PubMed1988

Besnoitia besnoiti: studies on the definitive host and experimental infections in cattle.

Domestic cats, 11 other species of carnivorous mammals, 6 species of snakes, and white-backed vultures were tested for their possible role as definitive hosts of Benoitia besnoiti by feeding with cystic material from chronically infected bovines. None of the species tested is a definitive host; hence, the life cycle of this parasite remains obscure. In attempts to produce clinical cases of besnoitiosis by experimental infection, bovines were inoculated IV, SC, and IP with cystozoites or tachyzoites. Immunosuppression of the animals was essential for the development of severe cases and skin lesions; cystozoites proved to be more pathogenic than tachyzoites.

Animals↗
PubMed1991

Purification of merozoites of Theileria sergenti from infected bovine erythrocytes.

A simple and rapid method for purifying merozoites of Theileria sergenti from infected bovine erythrocytes was developed. Infected erythrocytes were lysed by the use of a cytolytic toxin produced by Aeromonas hydrophila and the lysate was subjected to ultracentrifugation in a Percoll discontinuous density gradient. Pure and morphologically intact merozoites free of erythrocyte membrane were recovered from a band formed at the interface of 40% and 60% (by vol.) Percoll solutions. In this merozoite fraction, contamination of erythrocyte membrane proteins was not detected as examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Aeromonas↗
PubMed1995

Parasitic apicomplexans harbor a chlorophyll a-D1 complex, the potential target for therapeutic triazines.

Ultrastructural evidence is presented for the presence of plastid-like organelles in Toxoplasma gondii, Sarcocystis muris, Babesia ovis, and Plasmodium falciparum. In addition, it was shown that merozoites of T. gondii contain protochlorophyllidae a and traces of chlorophyll a bound to the photosynthetic reaction centers I PS I and PS II. A psbA gene was isolated from merozoites of S. muris by the polymerase chain reaction (PCR). Partial sequencing of the PCR product revealed that the herbicide-binding region is highly conserved. Therefore, it is likely that the sensitivity of apicomplexans to the herbicide toltrazuril depends on the interaction of the herbicide with the D1 protein of the photosynthetic reaction center of the parasite's organelles.

Amino Acid Sequence↗
PubMed1979

Sarcocystinae: nomina dubia and available names.

Examination of the original descriptions of the species of Sarcocystis in cattle, sheep, and swine, and of isosporid oocysts shed sporulated by dogs, cats, man, and other carnivores, has shown that it is not possible in most instances to identify unambiguously recently recognized taxa. The original descriptions are insufficient, and because no type specimens exist, could apply to two or more of the presently recognized taxa. We consider the following nomina dubia: Sarcocystis hirsuta S. miescheriana S. tenella S. cruzi S. bertrami Isospora bigemina (S. bigemina) I. hominis (S. hominis) I. buteonis (Frenkelia buteonis) Because the former type species, Sarcocystis miescheriana, is an indeterminate nomen dubium, we are proposing S. muris as the new type species. Historically, it was the first species described clearly and unambiguously even in the light of present knowledge, and the stages of its life cycle are probably completely known; it was the second species to be named. Old and recent descriptions are reviewed, and definitions are proposed for the following taxa: S. bovifelis S. bovicanis S. bovihominis S. ovifelis S. ovicanis S. muris (type species) S. suihominis S. suicanis S. equicanis Frenkelia microti F. glareoli for which neotypes will be prepared and deposited with designated institutions and curators. A new subfamily, Cystoisosporinae, is created.

Animals↗
PubMed1979

Infectivity of ground-up tick supernates prepared from Theilerai annulata infected Hyalomma anatolicum anatolicum.

Groups of Theileria annulata infected Hyalomma anatolicum anatolicum adults prefed on a calf for 1 to 6 days were separately ground in tissue culture medium-199, supplemented with bovine albumin powder, Fraction-V. Supernatant fluid was collected, made up with additional medium, so that each millilitre represented material from 25 ticks, and was injected subcutaneously into groups of cross-bred male calves. The results indicated that ground-up tick supernate (GUTS) prepared from unfed ticks was not infective, whereas that prepared from 1 to 6 days prefed ticks was infective. GUTS prepared from 3 days prefed ticks appeared to contain highest infectivity and 1 ml of it induced fatal theileriosis.

Animals↗
PubMed1979

The production of nymphs of Hyalomma anatolicum anatolicum for experimental infection with Theileria annulata.

Methods are described for the production of nymphs of Hyalomma anatolicum anatolicum for later use in transmission experiments with Theileria annulata where the timing of the application of nymphs to infected cattle needs to be accurately controlled. Larvae are fed on the torsos of rabbits where approximately 98% undergo a two-host feeding cycle. This cycle is interrupted 2 days after the first larvae moult into nymphs by killing the rabbits and the nymphs are then collected with a suction pump. Nymphs produced by the interrupted larval feeding method feed well on cattle, in regard to timing of detachment and weight, compared with nymphs produced by interrupted feeding on rabbits.

Animals↗