title: Course of induced infection by Eimeria krijgsmannni in immunocompetent and immunodeficient mice.
abstract: Recently, we have demonstrated the utility of Eimeria krijgsmanni as a novel mouse eimerian parasite for elucidating the biological diversity. The parasite showed notable infectivity to mice with various levels of immune status and susceptibility to antimicrobial agents including coccidiostat. However, the detailed lifecycle of E. krijgsmanni had not yet been determined and this information was lacking in discussion of previous findings. In the present study, we clarified the morphological characteristics of E. krijgsmanni and its lifecycle in normal mice, and examined the effects in immunodeficient mice and lifecycle stage for challenge infections after the primary inoculation. In immunocompetent mice, the lifecycle consisted of four asexual stages and the sexual sages followed by formation of oocysts during the prepatent periods. Interestingly, the second-generation meronts were detected in all observation periods after the disappearance of the other stages. For the challenge infection of immunodeficient mice, all developmental stages except for the second generation meronts were temporarily vanished. This finding suggests a "rest" or marked delay in development and a "restart" of the promotion toward the next generations. The second generation meronts may play an important role in the lifecycle of E. krijgsmanni.
authors.affiliation: Laboratory of Parasitology, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, 890-0065, Japan.
authors.forename: Yuina
authors.initials: Y
authors.lastname: Ono
authors.affiliation: Laboratory of International Prevention of Epidemics, Department of Veterinary Science, Graduate School of Life and Environmental Science, Osaka Prefecture University, Izumisano, Osaka, 598-8531, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Matsubayashi
authors.affiliation: Laboratory of Veterinary Histopathology, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, 890-0065, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kawaguchi
authors.affiliation: Laboratory of Anatomy, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, 890-0065, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Tsujio
authors.affiliation: Laboratory of Parasitology, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, 890-0065, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Mizuno
authors.affiliation: Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, 890-0065, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, 890-0065, Japan.
authors.forename: Tatsunori
authors.initials: T
authors.lastname: Masatani
authors.affiliation: Seisen University, Higashi Gotanda, Tokyo, 141-8642, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Laboratory of Parasitology, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, 890-0065, Japan. thmatsuo@vet.kagoshima-u.ac.jp.
authors.forename: Tomohide
authors.initials: T
authors.lastname: Matsuo
mesh_terms: D000818:Animals; D003048:Coccidiosis / Q000276:immunology / Q000469:parasitology*; D004195:Disease Models, Animal; D004539:Eimeria / Q000254:growth & development* / Q000276:immunology / Q000648:ultrastructure; D005260:Female; D007121:Immunocompetence; D016867:Immunocompromised Host; D008018:Life Cycle Stages; D051379:Mice; D008819:Mice, Nude; D016513:Mice, SCID; D033661:Oocysts
keywords: Challenge infection; Eimeria; Lifecycle; Meront; Mouse