Trachipleistophora extenrec n. sp. a New Microsporidian (Fungi: Microsporidia) Infecting Mammals

Abstract

A new microsporidian Trachipleistophora extenrec n. sp. was isolated from a muscle lesion of the streaked tenrec Hemicentetes semispinosus Cuvier, 1798 (Mammalia, Tenrecidae), an insectivore endemic to Madagascar. The spores isolated from the tenrec were infectious to severe combined immunodeficient (SCID) mice by intramuscular injection. Material obtained from muscular lesions in mice was used for the parasite description. All developmental stages of the microsporidian were covered by a dense coat, which during sporogony changed into the sporophorous vesicle wall. Eight, 16, 32, or more spores were formed inside the sporophorous vesicle as the result of the division by plasmotomy and sequential fission of a multinucleate sporogonial plasmodium. Spores were ovoid, 4.7 x 2.8 microm in size, had a large posterior vacuole, and had an isofilar polar tube with 15-16 coils. Although the fine structure and the developmental pattern of the organism were in some respects similar to the genus Vavraia, molecular phylogeny based on the gene sequences of the small subunit rRNA and RNA polymerase subunit II indicated that the organism belongs to the genus Trachipleistophora. The diagnostic characters of the genera Trachipleistophora and Vavraia are discussed as well as the discrepancies between the phylogenies of these two microsporidian genera based on morphology and molecules.

Opportunistic nature of the mammalian microsporidia: experimental transmission of Trachipleistophora extenrec (Fungi: Microsporidia) between mammalian and insect hosts

“…Based on their relationship to vertebrate and/or invertebrate hosts, microsporidia affecting mammals can be divided into two groups (Mathis et al 2005;Vávra et al 2006). For the first group, mammals (including man) are true hosts (i.e., Enterocytozoon bieneusi and species of Encephalitozoon), whereas microsporidia of the second group infect humans/mammals only accidentally (i.e., Anncaliia spp., Trachipleistophora spp., Pleistophora ronneaffiei, Nosema ocularum, Vittaforma corneae, and Microsporidium spp.).…”

“…Trachipleistophora extenrec is a recently described microsporidian species from mammals (Vávra et al 2006). So far, it is the third known member of the genus Trachipleistophora.…”

Vavraia culicis (Weiser, 1947) Weiser, 1977 revisited: cytological characterisation of a Vavraia culicis-like microsporidium isolated from mosquitoes in Florida and the establishment of Vavraia culicis floridensis subsp. n.

“…It also opened the way to consider V. culicis-like microsporidia as mosquito control agents (Reynolds 1972, Kelly et al 1981, Andreadis 2007. Another interest of Vavraia culicis-like microsporidia from mosquitoes is in the fact that the Florida isolate mentioned below is highly related in phylogeny trees to mammalian opportunistic microsporidia of the genus Trachipleistophora (Cheney et al 2000, Vávra et al 2006. Also the structural characters of both genera are very similar (Vávra et al 2006) and the human pathogen Trachipleistophora hominis is transmissible to mosquitoes (Weidner et al 1999).…”

“…Another interest of Vavraia culicis-like microsporidia from mosquitoes is in the fact that the Florida isolate mentioned below is highly related in phylogeny trees to mammalian opportunistic microsporidia of the genus Trachipleistophora (Cheney et al 2000, Vávra et al 2006. Also the structural characters of both genera are very similar (Vávra et al 2006) and the human pathogen Trachipleistophora hominis is transmissible to mosquitoes (Weidner et al 1999). It is therefore surprising that no in-depth study has been made in order to critically compare the individual isolates of V. culicis-like microsporidia with the type material, to determine whether they represent a single species or a complex of distinct species.…”

“…This Florida (FL) isolate represents the only culture of a species of Vavraia isolated from mosquitoes that is maintained and grown under standard conditions. As it is available to other scientists, it has been used under the name Vavraia culicis in molecular phylogeny (Cheney et al 2000, 2001, Vávra et al 2006, host-parasite relationship studies (Agnew et al 1999, Becnel et al 2005, Bedhomme et al 2005, Biron et al 2005) and as comparative material in microsporidia identification (Lobo et al 2006). The present paper describes the structural characters of the FL isolate and discusses its taxonomic status.…”