Vet. Res. 35 (2004) 283-290
DOI: 10.1051/vetres:2004010

Finding of Neospora caninum in the wild brown rat (Rattus norvegicus)

Chiu-Chen Huang^a, Chen-Hsiung Yang^b, Yuko Watanabe^a, Yung-Kung Liao^c and Hong-Kean Ooi<sup>a

a</sup>  Department of Veterinary Medicine, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, Taiwan
^b  Livestock Disease Control of Taichung County, Taiwan
^c  Bureau of Animal and Plant Health Inspection and Quarantine, Taiwan

(Received 15 July 2003; accepted 15 December 2003)

Abstract - Nine rats (16.4%) out of 55 (Rattus norvegicus) from cattle farms were seropositive to Neospora caninum. Two of the seropositive rats were also PCR positive but all were negative by immunohistochemistry and PAS staining. The brains of all the captured rats were homogenized and initially inoculated intraperitoneally into nude mice or into SPF ICR mice, which had been immunosuppressed with prednisolone. One mouse that was inoculated with brain material from a seropositive rat became infected with N. caninum, as demonstrated by the presence of a tissue cyst in the brain and confirmed by immunohistochemistry and PCR. This is the first finding of N. caninum in naturally infected farm rats. The findings show that natural N. caninum infection occurs in wild brown rats and thus rats may serve as a reservoir for the protozoan on the cattle farm.

Key words: Neospora caninum / rat / cattle farm / natural infection

Corresponding author: Hong-Kean Ooi hkooi@mail.nchu.edu.tw

© INRA, EDP Sciences 2004