Journal of Clinical Virology 38 (2007) 64–69 Serological evidence for Borna disease virus infection in humans, wild rodents and other vertebrates in Finland Paula M. Kinnunen a,b,* , Christian Billich c , Christine Ek-Kommonen d,1 , Heikki Henttonen e,2 , Eva R.K. Kallio a,e,f,3 , Jukka Niemimaa e,4 , Airi Palva a,5 , Peter Staeheli c,6 , Antti Vaheri b,g,7 , Olli Vapalahti a,b,g,8 a Division of Microbiology and Epidemiology, Faculty of Veterinary Medicine, P.O. Box 66, 00014 University of Helsinki, Finland b Department of Virology, Haartman Institute, P.O. Box 21, 00014 University of Helsinki, Finland c Department of Virology, Institute of Medical Microbiology and Hygiene, University of Freiburg, 79104 Freiburg, Germany d Finnish Food Safety Authority, Mustialankatu 3, 00790 Helsinki, Finland e Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, 01301 Vantaa, Finland f Department of Biological and Environmental Science, P.O. Box 35, University of Jyv¨ askyl¨ a, FIN-40014, Finland g Helsinki University Central Hospital Laboratory (HUSLAB), P.O. Box 400, 00029 HUS, Finland Received 1 December 2005; received in revised form 30 May 2006; accepted 12 October 2006 Abstract Background: Borna disease virus (BDV) can infect many vertebrate species, including humans. BDV infection may lead to meningo- encephalomyelitis in animals. An association with human neuropsychiatric diseases has been reported, but the causal relationship between BDV and human disease remains unclear. Objectives and study design: To find out whether BDV is present in Finland and to look for a potential reservoir, we examined a large panel of blood samples from different vertebrate species with immunofluorescence assay. Samples from horses, cats, dogs, sheep, cattle, large predators, grouse, wild rodents and humans were included. Most positive results were confirmed by other specific methods and in other laboratories. Results and conclusions: BDV-specific antibodies were detected in 10 horses, 2 cats, as well as 2 horses and 1 dog from farms housing a previously detected seropositive horse. Interestingly, BDV-specific antibodies were further detected in three wild rodents. In humans, BDV- specific antibodies were detected in a veterinarian and in two patients suspected to have a Puumala hantavirus infection. Our serological analysis suggests that BDV infects various vertebrates in Finland, including humans. Furthermore, our data indicate for the first time that BDV infects also wild rodents. © 2006 Elsevier B.V. All rights reserved. Keywords: Antibody; Borna disease virus; Finland; Human; Rodent; Serology * Corresponding author at: Department of Virology, Haartman Institute, P.O. Box 21, 00014 University of Helsinki, Finland. Tel.: +358 9 191 26706/57049; fax: +358 9 191 26491. E-mail address: Paula.Kinnunen@helsinki.fi (P.M. Kinnunen). 1 Tel.: +358 50 514 3926. 2 Tel.: +358 10 211 2430. 3 Tel.: +358 50 354 2232. 4 Tel.: +358 10 211 2682. 5 Tel.: +358 9 191 57058. 6 Tel.: +49 761 203 6579. 7 Tel.: +358 9 191 26490. 8 Tel.: +358 9 191 26604. 1386-6532/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jcv.2006.10.003