title: Spiroplasma spp. from transmissible spongiform encephalopathy brains or ticks induce spongiform encephalopathy in ruminants.
abstract: Spiroplasma, small motile wall-less bacteria, are linked by molecular and serological studies to the transmissible spongiform encephalopathies (TSEs), which include scrapie in sheep, chronic wasting disease (CWD) in deer and Creutzfeldt-Jakob disease in humans. In this study, two experiments were undertaken to determine the role of spiroplasma in the pathogenesis of TSE. In experiment 1, Spiroplasma mirum, a rabbit tick isolate that had previously been shown to experimentally induce spongiform encephalopathy in rodents, was inoculated intracranially (IC) into ruminants. S. mirum-inoculated deer manifested clinical signs of TSE after 1.5 to 5.5 months incubation. The deer, as well as sheep and goats, inoculated with S. mirum developed spongiform encephalopathy in a dose-dependent manner. In experiment 2, spiroplasma closely related to S. mirum were isolated from TSE-affected brains via passage in embryonated eggs, and propagated in cell-free M1D media. Spiroplasma spp. isolates from scrapie-affected sheep brain and from CWD-affected deer brain inoculated IC into sheep and goats induced spongiform encephalopathy closely resembling natural TSE in these animals. These data show spiroplasma to be consistently associated with TSE, and able experimentally to cause TSE in ruminant animal models, therein questioning the validity of studies that have concluded the prion, a miss-folded protease-resistant protein that builds up in TSE brains during the course of the disease, to be the sole causal agent. The spiroplasma infection models reported here will be important for investigating factors involved in the pathogenesis of TSE since ruminants are the natural hosts.
authors.affiliation: Department of Veterinary Science, Louisiana State University Agricultural Center, 111 Dalrymple Building, Baton Rouge, LA 70803, USA.
authors.forename: Frank O
authors.initials: FO
authors.lastname: Bastian
authors.affiliation: Idlewild Research Station, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Dearl E
authors.initials: DE
authors.lastname: Sanders
authors.affiliation: Idlewild Research Station, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Will A
authors.initials: WA
authors.lastname: Forbes
authors.affiliation: Department of Veterinary Science, Louisiana State University Agricultural Center, 111 Dalrymple Building, Baton Rouge, LA 70803, USA.
authors.forename: Sue D
authors.initials: SD
authors.lastname: Hagius
authors.affiliation: Department of Veterinary Science, Louisiana State University Agricultural Center, 111 Dalrymple Building, Baton Rouge, LA 70803, USA.
authors.forename: Joel V
authors.initials: JV
authors.lastname: Walker
authors.affiliation: Department of Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, LA, USA.
authors.forename: William G
authors.initials: WG
authors.lastname: Henk
authors.affiliation: Department of Veterinary Science, Louisiana State University Agricultural Center, 111 Dalrymple Building, Baton Rouge, LA 70803, USA.
authors.forename: Fred M
authors.initials: FM
authors.lastname: Enright
authors.affiliation: Department of Veterinary Science, Louisiana State University Agricultural Center, 111 Dalrymple Building, Baton Rouge, LA 70803, USA.
authors.forename: Philip H
authors.initials: PH
authors.lastname: Elzer
mesh_terms: D000818:Animals; D001921:Brain / Q000382:microbiology*; D003670:Deer; D015511:Goat Diseases / Q000382:microbiology; D006041:Goats; D009096:Multi-Institutional Systems; D017096:Prion Diseases / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D012418:Ruminants / Q000382:microbiology*; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology; D013149:Spiroplasma / Q000302:isolation & purification* / Q000472:pathogenicity*; D013987:Ticks / Q000382:microbiology*