Redescription of Besnoitia tarandi (Protozoa: Apicomplexa) from the reindeer (Rangifer tarandus) * J.P. Dubey a, * , C. Sreekumar a , B.M. Rosenthal a , M.C.B. Vianna a , M. Nylund b , S. Nikander c , A. Oksanen b a United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal and Natural Resources Institute, Animal Parasitic Diseases Laboratory, Building 1001, BARC-East, Beltsville, MD 20705-2350, USA b National Veterinary and Food Research Institute, Oulu regional Unit, P.O. Box 517, FIN-90101 Oulu, Finland c Department of Basic Veterinary Sciences, University of Helsinki, P.O. Box 57, FIN-00014, Helsinki, Finland Received 4 May 2004; received in revised form 5 July 2004; accepted 5 July 2004 Abstract Besnoitia tarandi tissue cysts were found in naturally-infected reindeer (Rangifer tarandus) from Finland. Infectivity of its tissue cysts, bradyzoites, and tachyzoites to animals and cell culture was studied. The bradyzoites and tissue cysts were not infectious to out-bred mice, rabbits or gerbils. When fed tissue cysts, neither cats nor dogs excreted oocysts. However, the parasite was lethal to interferon-gamma gene knock out mice irrespective of the route of inoculation. The parasite was grown successfully in African Green Monkey cells from tissues of two reindeer for the first time. Non-dividing, uninucleate tachyzoites from smears from cell cultures were 5.6!1.4 mm (4.5–7.4!1.0–1.9, nZ50) in size. Longitudinally-cut bradyzoites in tissue sections measured 7.4!1.3 mm (6.5–7.8!1.0–1.6, nZ30). Ultrastructurally, tachyzoites and bradyzoites were similar to those in other Besnoitia species, and in particular to parasites described from cattle (Besnoitia besnoiti) and equids (Besnoitia bennetti) in that their bradyzoites lacked enigmatic bodies. Based on comparative analysis of three portions of nuclear ribosomal DNA (the small and large subunits and the first internal transcribed spacer) B. tarandi was found to be more closely related to the other congeners described from ungulates. The parasite was formally redescribed and specimens deposited in the US National Parasite Collection. Published by Elsevier Ltd on behalf of Australian Society for Parasitology Inc. Keywords: Besnoitia tarandi; Finland; Mice; Gerbils; Cell culture; Ultrastructure; Sequence analysis 1. Introduction Species of the coccidian genus Besnoitia parasitise cattle, goats, equids, reindeer, caribou, opossums, rabbits, rodents, and lizards (Leighton and Gajadhar, 2001; Dubey et al., 2003a). To date, nine species in the genus have been named: Besnoitia bennetti, Besnoitia jellisoni, Besnoitia wallacei , Besnoitia tarandi , Besnoitia darlingi, Besnoitia caprae, Besnoitia besnoiti (type species), Besnoitia akadoni and Besnoitia oryctofelisi (Dubey et al., 2003a, 2003c). However, considerable uncertainty exists regarding the identity of some of these species because the life cycles of only three (B. darlingi, B. wallacei, and B. oryctofelisi) of these species are known, and morphologi- cal differences among the remaining species are poorly defined (Dubey et al., 2003a). Although parasites isolated from distinct intermediate host species have traditionally been presumed to represent distinct parasite taxa, it will be difficult to test their actual host specificity until natural definitive hosts are identified. Besnoitia tarandi was first reported from reindeer (Rangifer tarandus tarandus) and caribou (Rangifer tarandus caribou) from Alaska, USA by Hadwen (1922), who named it as Fibrocystis tarandi n. sp. Levine (1961) transferred it to the genus Besnoitia. Subsequently, infections 0020-7519/$30.00 Published by Elsevier Ltd on behalf of Australian Society for Parasitology Inc. doi:10.1016/j.ijpara.2004.07.002 International Journal for Parasitology 34 (2004) 1273–1287 www.parasitology-online.com * Nucleotide sequence data reported in this paper are available in the Genbank, EMBL and DDBJ databases under the accession numbers: AY616163, AY616164, AY665400. * Corresponding author. Tel.: C1-301-504-8128; fax: C1-301-504- 9222. E-mail address: jdubey@anri.barc.usda.gov (J.P. Dubey).