Acta Veterinaria Scandinavica Brief communication The moose throat bot fly Cephenemyia ulrichii larvae (Diptera: Oestridae) found developing in roe deer (Capreolus capreolus) for the first time Arne C Nilssen1, Marja Isomursu2 and Antti Oksanen*2 Address: 1Tromsø University Museum, NO-9037 Tromsø, Norway and 2Finnish Food Safety Authority Evira, Fish and Wildlife Health Research Unit (FINPAR), P.O. Box 517, FIN-90101 Oulu, Finland Email: Arne C Nilssen - ArneC.Nilssen@tmu.uit.no; Marja Isomursu - Marja.Isomursu@evira.fi; Antti Oksanen* - Antti.Oksanen@evira.fi * Corresponding author BioMed Central Open Access Published: 2 June 2008 Acta Veterinaria Scandinavica 2008, 50:14 doi:10.1186/1751-0147-50-14 This article is available from: http://www.actavetscand.com/content/50/1/14 Received: 21 February 2008 Accepted: 2 June 2008 © 2008 Nilssen et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract About fifty larvae of Cephenemyia ulrichii Brauer (Diptera: Oestridae), some of them nearly full- grown third instars, were found in the throat of a roe deer (Capreolus capreolus) in June 2007 near Helsinki in Finland. The parasite is considered to be host specific, occurring only in the moose (Alces alces), and this paper is apparently the first report of a successful infestation in an aberrant host. Background Larvae of throat, or nose or pharyngeal, bot flies in the genus Cephenemyia (Diptera: Oestridae) are obligate para- sites that inhabit the nasal cavity, pharynx and throat of cervids [1]. In Europe there are four known species: Cephenemyia trompe (Modeer) in reindeer Rangifer taran- dus; Cephenemyia stimulator (Clark) in roe deer Capreolus capreolus; Cephenemyia auribarbis (Meigen) in red deer Cer- vus elaphus; and Cephenemyia ulrichii Brauer in moose or European elk Alces alces [1-4]. In Finland, Sweden and Norway only C. trompe and C. ulrichii have been reported [3], with the result that Cervus elaphus and Capreolus capre- olus are generally not infested by throat bot flies in Fenno- scandia (see also [5]). Even though the roe deer population has increased in Finland in the recent decades [6], throat bots have never been reported in roe deer in Fennoscandia. The moose throat bot fly C. ulrichii was first reported in Finland in 1910 and 1913 [7], and has subsequently become increasingly common in southern Finland [8,9]. In Sweden, C. ulrichii was first reported in 1988 [10], but has since increased its distribution [11]. In 1987, the spe- cies was reported for the first time in Norway (first instars in Pasvik in northeastern Norway) [3,4]. We here report a finding of moose throat bot fly larvae in roe deer. Methods About 50 throat bot fly larvae were seen in an adult roe deer buck shot on 4 June 2007, in Kirkkonummi near Hel- sinki by the southern coast of Finland. The population consisted of different sized larvae, and three of the bigger ones were collected for laboratory examination. The other larvae were not collected. Before we could do a proper investigation of the larvae, we considered three species possible: 1) C. stimulator (of roe deer), 2) C. trompe (of reindeer), and 3) C. ulrichii (of moose). As mentioned, C. stimulator has never been found in Finland, whereas C. trompe is common in the northern Finland where there are domestic reindeer, and in the east and central Finland where the wild forest reindeer (Rang- ifer tarandus fennicus) has a restricted distribution. Cephen- emyia ulrichii, on the other hand, is seemingly abundant in Page 1 of 3 (page number not for citation purposes)