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PubMedDate not supplied

Studies on the development of Theileria annulata Dschunskowsky and Luhs, 1904 in the tick--Hyalomma anatolicum anatolicum Koch, 1844.

The endogenous development of Theileria annulata in the vector tick--Hyalomma anatolicum anatolicum has been described. Parasites within and outside the erythrocytes were seen in the gut contents of larvae and nymphs immediately after their removal from the infected cattle but not after 24 hours. Two bodies resembling the intra-erythrocytic stage of the parasite, lying close to each other were seen near the gut epithelium of a larva on the 4th day of its dropping off the infected host. Neither multiplication nor union of the parasite resulting in zygote formation in the gut of the tick, was noticed. Next stage of the parasite was seen in the salivary glands of nymphs and adults. The pre-infective stage characterized by indistinct chromatin dots (nuclei) surrounded with cytoplasm was seen in alveolar cells of the salivary glands of nymphs and adult ticks from the first to the third day of their feeding of the host. This stage progressed to the infective stage consisting of distinct chromatin particles (the infective particles) surrounded with cytoplasm in the salivary glands of nymphs and adult ticks after the second and first day, respectively of feeding on the host. The infective particles were also seen within ducts of the salivary glands.

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PubMedDate not supplied

Eimeria nebulosa n. sp. and Klossia pachyleparon n. sp. from the monitor lizard Varanus nebulosus in Malaysia.

Eimeria nebulosa n. sp. and Klossia pachyleparon n. sp. are described from the monitor lizard Varanus nebulosus in Malaysia. The flask shaped oocysts of E. nebulosa average 20.7 by 12.6 mum. The oocyst wall is composed of a single layer. There is a single polar granule but no residuum. Ellipsoidal sporocysts average 11.1 by 5.6 mum. A sporocyst residuum is present. Endogenous stages develop in the epithelial cells of the small intestine. The splerical oocysts of K. pachyleparon average 33.6 mum in diameter. The wall is about 2.5 mum thick and is composed of 3 layers. The spherical sporocysts average 10.8 mum in diameter. Sporocysts contain 4 sporozoites and residuum. Developmental stages were not observed.

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PubMedDate not supplied

Ultrastructural observations on the merocyst and gametocytes of Hepatocystis spp. from Malaysian squirrels.

An immature merocyst of Hepatocystis malayensis and gametocytes of H. brayi were studied with the electron microscope. The merocyst consisted of a highly complex cytoplasmic reticulum ramifying through an amorphous matrix: the entire complex was enclosed by a simple unit membrane. The host cell was apparently destroyed completely during growth of the cyst. Immature gametocytes were highly amoeboid and showed extensive vacuolisation or attenuation of the cytoplasm. The nucleus contained one or two prominent nucleoli. Mature gametocytes had compact cytoplasm and contained pyriform osmiophilic bodies which were believed to function in the release of the parasites from the host cells. Macrogametocytes were distinguished from microgametocytes by cytoplasmic differences in numbers of ribosomes, and cristate mitochondria and in the extent of development of the smooth endoplasmic reticulum. The compact nuclei of the macrogametocytes had inconspicuous DNA but prominent nucleoli whereas those of the microgametocytes were irregular and showed a central aggregate of DNA. In microgametogenesis karyokinesis of the parent nucleus was delayed until axoneme formation was complete. Then the nuclear buds were extruded into emerging microgametes. At fertilisation the plasmalemmas of the two gametes fused and the single axoneme and nucleus of the microgamete moved into the cytoplasm of the macrogamete.

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PubMedDate not supplied

[Hepatocystis brosseti n. sp. Haemproteidae, parasite of Epomops franqueti, Pteropinae, in Gabon].

Epomops franqueti (Pteriopinae) trapped around Makokou (Gabon) are frequently infected with Hepatocystis brosseti n. sp. Blood smears and tissue sections were made; all schizonts were found in the liver except a single one in the spleen. In liver, near maturity the schizonts are extracellular, convoluted, medium sized (250 mu) and filled with abundant colloidal substance.

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PubMedDate not supplied

Microsporidian infection in the cyst wall of Trematode metacercariae encysted in fish.

Microsporidian infection is reported in Liza ramada (Risso), Mugilidae, from Bardawil Lagoon, Mediterranean coast of Sinai, in the fibroblasts of the metacercarial capsule of Heterophyes heterophyes (Siebold). Infection of the metacercarial cyst resulted in an hypertrophy of the cyst wall and degeneration and eventual death of the encapsulated metacercaria.

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PubMedDate not supplied

Sporozoan infection in cultured Sparus aurata L. and wild Siganus luridus.

White nodules containing intracellular ovoid Sporozoans were observed in internal organs (kidneys, liver and gut wall) of cultured Sparus aurata and in the liver of wild Siganus luridus in the gulf of Aquaba in the Red Sea. Nodules consisted of parasitised hypertrophic macrophage-like cells enclosed in a well-defined collagenous fibrous capsule. These parasites are evidently the cystozoite stage of a haemogregarine.

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PubMedDate not supplied

On Leucocytozoon parasites of Ardeidae and description of one species.

In peripheral blood of Nycticorax nycticorax and Egretta garzetta (Aves, Ardeidae), gametocytes of the genus Leucocytozoon (Protozoa, Sporozoa) were found. We describe this parasite and compare it with the past records of Leucocytozoon in Ardeidae. While only life cycle studies will give a definitive answer to these taxonomic problems, we put forward an hypothesis about taxonomy of Leucocytozoon in Ardeidae.

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PubMedDate not supplied

[Dionisia bunoi n. g. n. sp., Haemoproteidae parasite of the microchiropteran bat Hipposideros cyclops in Gabon (author's transl)].

Dionisia bunoi ng. g., n. sp. is characterized by:--a) sexual dimorphism of gametocytes, macrogametocyte of the falciparum type, microgametocyte of the type malariae:--b) schizonts developing in the lumen of liver blood vessels inside a greatly hypertrophied host cell; their size remains moderate and their cytoplasm is not intensely basophilic as is usually in the young stages of Haemosporidia of Mammals. The genus has morphological characters in common with each of the 4 other genera of Haemoproteidae of Mammals. The phyletic hypothesis concerning the morphology of gametocytes and schizonts suggests that Bioccala and Dionisia are primitive.

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PubMed1986

[Influence of the number of inoculated parasites on the in vitro infestation of HeLa cells by the coccidia Besnoitia jellisoni Frenkel].

The influence of the number of bradyzoites of the Coccidia Besnoitia inoculated in the culture medium of HeLa cells on their penetration rate was investigated. The intracellular penetration rate increased with the "size of inoculum", then seemed constant when a certain density is reached. Important densities of bradyzoites in the inoculum led to an unequal distribution of intracellular parasites among the cellular sheet. Multiple infective units in a same host cell did not occur randomly. It seems that some cells are more suitable than others to parasite invasion.

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PubMed1990

[Common characteristics of the invasion of host cells by sporozoa].

Sporozoan zoites contain specific organelles that are involved in host cell invasion, a process highly conserved within this phylum. The data obtained on different genera have shown high similarities in parasitophorous vacuole development, organelle exocytosis and integration of the organelle contents into the vacuole or the vacuolar membrane. Parallel investigations on invasion process in different genera will help sorting fundamental mechanisms of Sporozoan invasion out of the specific peculiarities.

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