Diagnostic survey of bovine abortion with special reference to Neospora caninum infection: Importance, repeated abortion and concurrent infection in aborted fetuses in Southern Brazil Luis G. Corbellini a , Caroline A. Pescador a , Fernanda Frantz a , Elsio Wunder a , David Steffen b , David R. Smith c , David Driemeier a, * a Laboratory of Veterinary Pathology, Veterinary Faculty, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonc ¸alves 9090, CEP 91540-000, Porto Alegre, RS, Brazil b Veterinary Diagnostic Center, University of Nebraska-Lincoln, P.O. Box 82646, Fair Street and East Campus Loop, Lincoln, NE 68501-2646, USA c Veterinary and Biomedical Sciences, University of Nebraska-Lincoln, P.O. Box 830907, Lincoln, NE 68583-0907, USA Abstract The protozoa Neospora caninum is an important cause of bovine abortion world-wide. The objective of this survey was to deter- mine the distribution pattern of infectious abortion in Southern Brazil with special reference to N. caninum infection. A total of 161 bovine aborted fetuses from 149 farms were analysed during a 1.5 year period. The cause of abortion was identified in 51.5% of cases. Overall, 23% (37/161) of the fetuses were considered to be infected with N. caninum. Bacterial infection accounted for 17.4% (28/161) of cases, fungal infection for 3.1% (5/161) of cases and viral aetiology for 1.8% (3/161). Six fetuses had concurrent infection with N. caninum and Leptospira spp. Data from 111 fetuses and the respective aborted cows were analysed to investigate the association between previous abortion and current N. caninum infection. The prevalence of N. caninum-infected fetuses from cows with and without a history of previous abortion was 44% (11/25) and 24.4% (21/86), respectively. Cows aborting a N. cani- num-infected fetuses were 2.4 times more likely to have aborted previously than cows aborting for other reasons (95% CI of odds ratio = 0.9–6.8, P = 0.06). Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Neospora caninum; Bovine abortion; Diagnostic survey; Leptospira spp. infection; Repeated abortion 1. Introduction Determining the cause of bovine abortion is difficult as abortions are caused by numerous infectious and noninfectious factors (Miller, 1987; Kirkbride, 1991; Jamaluddin et al., 1996). It has been demonstrated in numerous surveys that many abortions occur due to endemic infectious agents such as bovine viral diar- rhoea virus (BVDV), bovine herpesvirus (BHV)-1, var- ious bacteria and Neospora caninum, which are normally present in cattle populations world-wide (Hubbert et al., 1973; Anderson et al., 1991; Kirkbride, 1992; Jamaluddin et al., 1996; Kim et al., 2002). Among the infectious agents, the Apicomplexan proto- zoan N. caninum (NC) has been implicated as the most important cause of bovine abortion in many countries (Dubey, 2003). A previous survey of NC infection in Southern Brazil revealed that 39.1% of aborted bovine fetuses were infected with this protozoon (Corbellini et al., 2002). Dogs and coyotes are definitive hosts for NC and shed NC-oocyst in faeces (McAllister et al., 1998; Gondim et al., 2004). NC-seropositive cows are reported to have a higher abortion risk than seronegative cows (Pare ´ et al., 1997; 1090-0233/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.tvjl.2005.03.006 * Corresponding author. Tel.: +55 51 3316 6107; fax: +55 51 3316 6116. E-mail address: davetpat@ufrgs.br (D. Driemeier). www.elsevier.com/locate/tvjl The Veterinary Journal 172 (2006) 114–120 The Veterinary Journal