Theileria

Mehlhorn, Heinz; Schein, E.; Ahmed, Jabbar S.

doi:10.1016/b978-0-12-426017-7.50009-8

Cited by 38 publications

(19 citation statements)

References 125 publications

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“…Theileria are important intracellular parasites of ruminants in tropical and subtropical regions. Two species -T. parva and T. annulata -induce the lympho-and myeloproliferative disorders East Coast Fever and tropical Theileriosis in cattle, and thereby constitute the two most pathogenic variants (Mehlhorn et al, 1994). Pathogenesis is caused by massive, parasite-dependent amplification of infected lymphoid and myeloid cells and of their concomitant spread inside the infected host animal.…”

Section: Introductionmentioning

confidence: 99%

“…Pathogenesis is caused by massive, parasite-dependent amplification of infected lymphoid and myeloid cells and of their concomitant spread inside the infected host animal. Inside the cell, the parasite resides free as a syncytium (schizont) within the host cell cytoplasm, not surrounded by a parasitophorous vacuole like some other better-known apicomplexan parasites, such as Toxoplasma or Plasmodium (Mehlhorn et al, 1994;Dobbelaere and Baumgartner, 2009) but similar to Babesia (Lobo et al, 2012). Theileria parasites transform their host cells.…”

Section: Introductionmentioning

confidence: 99%

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Actin-mediated plasma membrane plasticity of the intracellular parasiteTheileria annulata

Kühni-Boghenbor

Lemgruber

et al. 2012

Cell Microbiol

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SummaryPathogen-host interactions are modulated at multiple levels by both the pathogen and the host cell. Modulation of host cell functions is particularly intriguing in the case of the intracellular Theileria parasite, which resides as a multinucleated schizont free in the cytosol of the host cell. Direct contact between the schizont plasma membrane and the cytoplasm enables the parasite to affect the function of host cell proteins through direct interaction or through the secretion of regulators. Structure and dynamics of the schizont plasma membrane are poorly understood and whether schizont membrane dynamics contribute to parasite propagation is not known. Here we show that the intracellular Theileria schizont can dynamically change its shape by actively extending filamentous membrane protrusions. We found that isolated schizonts bound monomeric tubulin and in vitro polymerized microtubules, and monomeric tubulin polymerized into dense assemblies at the parasite surface. However, we established that isolated Theileria schizonts free of host cell microtubules maintained a lobular morphology and extended filamentous protrusions, demonstrating that host microtubules are dispensable both for the maintenance of lobular schizont morphology and for the generation of membrane protrusions. These protrusions resemble nanotubes and extend in an actin polymerization-dependent manner; using cryo-electron tomography, we detected thin actin filaments beneath these protrusions, indicating that their extension is driven by schizont actin polymerization. Thus the membrane of the schizont and its underlying actin cytoskeleton possess intrinsic activity for shape control and likely function as a peri-organelle to interact with and manipulate host cell components.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Actin-mediated plasma membrane plasticity of the intracellular parasiteTheileria annulata

Kühni-Boghenbor

Lemgruber

et al. 2012

Cell Microbiol

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“…Theileria and Babesia species, the causative agents of theileriosis and babesiosis, respectively, are tick‐borne parasitic protozoa and a number of them are highly pathogenic for cattle, sheep, and goats. The economic losses due to theileriosis and babesiosis are enormous in tropical and subtropical areas 1, 2 …”

Section: Introductionmentioning

confidence: 99%

Phylogenetic Position of Small‐Ruminant Infecting Piroplasms

Ahmed

Luo

Schnittger

et al. 2006

Annals of the New York Academy of Sciences

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Theileria and Babesia are tick-transmitted protozoa that cause great economical losses in livestock. Recently, interest has risen in sheep-infecting piroplasms and a number of previously unidentified pathogens were described, particularly in China. To address the phylogenetic relationship of Theileria and Babesia species infecting sheep, the complete sequences of the 18 S small subunit ribosomal RNA genes of a panel of piroplasm isolates, including T. lestoquardi, T. ovis, T. separata, B. ovis, B. motasi, B. crassa, and several novel species, were compared. The classification based on the established phylogenetic tree corresponded with traditional systematics and revealed that sheep/goat piroplasm species are of a polyphyletic origin. In addition, these studies revealed the existence of at least two novel sheep/goat piroplasm species, designated Theileria sp. (China 1) and Theileria sp. (China 2).

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“…Apicomplexan parasites that are transmitted by ticks comprise Babesia and Theileria spp. Due to the existence of pear-shaped intraerythrocytic stages, they have been referred to as piroplasms (1,2). Traditional morphological and recent molecular investigations have substantiated that Babesia and Theileria spp.…”

Section: Introductionmentioning

confidence: 99%

“…A unique morphological characteristic shared by piroplasmids with other apicomplexan protozoans is the presence of an apical complex: a rather intricate cellular apparatus consisting of conoid, rhoptries, micronemes (Babesia) or microspheres (Theileria), and other subcellular organelles (1,2). For Babesia spp.…”

Section: Introductionmentioning

confidence: 99%

Piroplasmids and ticks: a long-lasting intimate relationship

Florín-Christensen¹

2009

Front Biosci

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The tick-transmitted Babesia and Theileria spp. parasites are detrimental for animal health and cattle production in vast tropical and subtropical areas of the world. Additionally, human babesiosis increasingly raises public health concern. Most of the research on these piroplasmids has been focused on mammal-infecting stages, while the interaction with their tick vectors has been widely neglected. For millions of years, piroplasmids have been able to effectively exploit the tick milieu to carry out critical parts of their life cycle; including self propagation, sexual reproduction and recombination, development of infective forms capable of returning to their mammalian hosts through tick saliva, and in many cases, perpetuation into the next tick generation. Although piroplasmid colonization can seriously damage tick tissues and organs, innate immune mechanisms seem to be able to control these effects. This paper reviews the molecular interactions between ticks and piroplasmids from different perspectives. A deeper understanding of this interface might lead to the design of new control strategies.

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Theileria

Cited by 38 publications

References 125 publications

Actin-mediated plasma membrane plasticity of the intracellular parasiteTheileria annulata

Actin-mediated plasma membrane plasticity of the intracellular parasiteTheileria annulata

Phylogenetic Position of Small‐Ruminant Infecting Piroplasms

Piroplasmids and ticks: a long-lasting intimate relationship

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