Nosema algerae: Infection of the white mouse by a mosquito parasite

Undeen, Albert H.; Alger, Nelda E.

doi:10.1016/0014-4894(76)90068-0

Cited by 43 publications

(31 citation statements)

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“…A recent study of B. algerae spores (Cali et al 2002) provides details of the changes of the internal spore morphology, polar tube location in association with membranes, translocation, eversion, and the release of the sporoplasm during the activation process. Additionally, a number of in vivo experimental studies of the infective process of B. algerae, in a variety of host organisms, support the in vitro observations (Vavra and Undeen 1970, Canning and Sinden 1973, Undeen and Alger 1976, Avery and Anthony 1983, Trammer et al 1999, Koudela et al 2001.…”

mentioning

confidence: 75%

The early events of Brachiola algerae (Microsporidia) infection: spore germination, sporoplasm structure, and development within host cells

Takvorian¹,

Weiss²,

Cali³

2005

FOLIA PARASIT

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Abstract. Brachiola algerae (Vavra et Undeen, 1970) Lowman, Takvorian et Cali, 2000, originally isolated from a mosquito, has been maintained in rabbit kidney cells at 29°C in our laboratory. This culture system has made it possible to study detailed aspects of its development, including spore activation, polar tube extrusion, and the transfer of the infective sporoplasm. Employing techniques to ultrastructurally process and observe parasite activity in situ without disturbance of the cultures has provided details of the early developmental activities of B. algerae during timed intervals ranging from 5 min to 48 h. Activated and nonactivated spores could be differentiated by morphological changes including the position and arrangement of the polar filament and its internal structure. The majority of spores extruded polar tubes and associated sporoplasms within 5 min post inoculation (p.i.). The multilayered interlaced network (MIN) was present in extracellular sporoplasms and appeared morphologically similar to those observed in germination buffer. Sporoplasms, observed inside host cells were ovoid, contained diplokaryotic nuclei, vesicles reminiscent of the MIN remnants, and their plasmalemma was already electron-dense with the "blister-like" structures, typical of B. algerae. By 15 min p.i., the first indication of parasite cell commitment to division was the presence of chromatin condensation within the diplokaryotic nuclei, cytoplasmic vesicular remnants of the MIN were still present in some parasites, and early signs of appendage formation were present. At 30 min p.i., cell division was observed, appendages became more apparent, and some MIN remnants were still present. By two hours p.i., the appendages became more elaborate and branching, and often connected parasite cells to each other. In addition to multiplication of the organisms, changes in parasite morphology from small oval cells to larger elongated "more typical" parasite cells were observed from 5 h through 36 h p.i. Multiplication of proliferative organisms continued and sporogony was well underway by 48 h p.i., producing sporonts and sporoblasts, but not spores. The observation of early or new infections in cell cultures 12-48 h p.i., suggests that there may also exist a population of spores that do not immediately discharge, but remain viable for some period of time. In addition, phagocytized spores were observed with extruded polar tubes in both the host cytoplasm and the extracellular space, suggesting another means of sporoplasm survival. Finally, extracellular discharged sporoplasms tightly abutted to the host plasmalemma, appeared to be in the process of being incorporated into the host cytoplasm by phagocytosis and/or endocytosis. These observations support the possibility of additional methods of microsporidian entry into host cells and will be discussed.

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mentioning

confidence: 75%

The early events of Brachiola algerae (Microsporidia) infection: spore germination, sporoplasm structure, and development within host cells

Takvorian¹,

Weiss²,

Cali³

2005

FOLIA PARASIT

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“…With respect to taxonomy, recent molecular phylogenetic analyses of the small subunit rDNA sequences of mosquitoparasitic microsporidia (Baker et al 1998, 2004a confirm the relatedness of the "true" mosquito microsporidia and suggest that mosquitoes and their parasites have co-evolved. Finally, B. algerae and V. culicis isolated from and studied in mosquitoes has provided crucial foundational information that have become highly relevant to studies of microsporidia in vertebrates and specifically man (Vavra and Undeen 1970, Undeen 1975, Undeen and Alger 1976.…”

Section: Discussionmentioning

confidence: 99%

Review of microsporidia-mosquito relationships: from the simple to the complex

Becnel

White²,

Shapiro³

2005

FOLIA PARASIT

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Abstract. Microsporidia in mosquitoes can be divided into two categories based on their life cycles and host-parasite relationships. Some species of microsporidia exhibit simple life cycles with one spore type responsible for oral (horizontal) transmission. They affect only one generation of the mosquito and are not usually host or tissue specific. Brachiola algerae (Vavra et Undeen, 1970) and Vavraia culicis (Weiser, 1947) are examples of species isolated from mosquitoes with relatively straightforward life cycles (one spore type) and simple host-parasite relationships. B. algerae and a close relative of V. culicis have also been isolated from a vertebrate (human) host but sources for these infections are unknown. In contrast to B. algerae and V. culicis, polymorphic (heterosporous) microsporidia in mosquitoes are characterized by complex life cycles involving multiple spore types responsible for horizontal and vertical transmission. They affect two generations of the mosquito and some involve an obligate intermediate host. These microsporidia are generally very host and tissue specific with complex develop-mental sequences comprised of unique stages and events. The microsporidium Edhazardia aedis (Kudo, 1930) is a pathogen of Aedes aegypti and does not require an intermediate host. The developmental cycle of E. aedis is characterized by four sporulation sequences, two in the parental host and two in the filial generation. Recent speculation relative to the source of B. algerae human infection have implicated infected mosquitoes and raised concerns about the safety of mosquito microsporidia in general. The subject of this review is to compare and contrast three species of microsporidia from mosquitoes, two with broad host ranges (B. algerae and V. culicis) and one specific to mosquitoes (E. aedis). This review describes features that distinguish mosquito-parasitic microsporidia with simple life cycles and broad host ranges from truly mosquito-specific microsporidian parasites with complex life cycles.

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“…Hence, this microsporidial species was shown to proliferate in mammalian cell lines, initially only at temperatures of below 37°C (294) but later also after adaptation to 37°C (207,289). Intravenous injection of spores failed to induce infections in immunocompetent and immunocompromised mice, and subcutaneous injections led to limited development close to the infection site in extremities only (290,295). Furthermore, ocular, but not oral, intraperitoneal, intramuscular, or subcutaneous, inoculation of SCID mice with spores of B. algerae led to severe infection of the liver as the only affected internal organ (164).…”

Section: Brachiola Sppmentioning

confidence: 99%

Zoonotic Potential of the Microsporidia

2005

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Microsporidia are long-known parasitic organisms of almost every animal group, including invertebrates and vertebrates. Microsporidia emerged as important opportunistic pathogens in humans when AIDS became pandemic and, more recently, have also increasingly been detected in otherwise immunocompromised patients, including organ transplant recipients, and in immunocompetent persons with corneal infection or diarrhea. Two species causing rare infections in humans, Encephalitozoon cuniculi and Brachiola vesicularum, had previously been described from animal hosts (vertebrates and insects, respectively). However, several new microsporidial species, including Enterocytozoon bieneusi, the most prevalent human microsporidian causing human immunodeficiency virus-associated diarrhea, have been discovered in humans, raising the question of their natural origin. Vertebrate hosts are now identified for all four major microsporidial species infecting humans (E. bieneusi and the three Encephalitozoon spp.), implying a zoonotic nature of these parasites. Molecular studies have identified phenotypic and/or genetic variability within these species, indicating that they are not uniform, and have allowed the question of their zoonotic potential to be addressed. The focus of this review is the zoonotic potential of the various microsporidia and a brief update on other microsporidia which have no known host or an invertebrate host and which cause rare infections in humans

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Nosema algerae: Infection of the white mouse by a mosquito parasite

Cited by 43 publications

References 4 publications

The early events of Brachiola algerae (Microsporidia) infection: spore germination, sporoplasm structure, and development within host cells

The early events of Brachiola algerae (Microsporidia) infection: spore germination, sporoplasm structure, and development within host cells

Review of microsporidia-mosquito relationships: from the simple to the complex

Zoonotic Potential of the Microsporidia

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