Abstract
In 15 breeding and fattening pig herds, 85 mice (Mus musculus) and 40 rats (Rattus norvegicus) were captured and bacteria and viruses looked for. Bordetella bronchiseptica, Pasteurella sp., E. coli, Campylobacter jejuni and Treponema sp. were isolated from different samples. Rota-virus was also identified and neutralizing transmissible gastroenteritis antibodies were detected in the serum of one rat and mice from three different farms. Wild rats were also orally infected with Aujeszky's disease virus (ADV) and classical swine fever (CSF) virus. All the rats survived the ADV experimental infection and some of them showed ADV neutralizing antibodies in their sera. No multiplication of the SF virus was obtained.