Submitted to: Swiss Archives of Veterinary Medicine
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/2/2003
Publication Date: 2/3/2003
Citation: Albini, S., Zimmermann, W., Neff, F., Ehlers, B., Häni, H., Li, H., Hüssy, D., Casura, C., Engels, M., Ackermann, M. Diagnostic findings in pigs with porcine malignant catarrhal fever. Swiss Archives of Veterinary Medicine. 2003. v. 145. p. 61-68. Interpretive Summary: Malignant catarrhal fever occurred in several gilts in a Swiss farm where pigs shared stables and meadows with sheep. Sheep-associated MCF virus, naturally carried by domestic sheep, was identified as a causative agent in the outbreak. The study detailed description of clinical signs, histopathology, and serology of affected pigs. Using a variety of specific PCR techniques, the study discriminated between infections with either the sheep-associated MCF virus, or other porcine gammaherpesviruses in pigs with clinical MCF.
Technical Abstract: For the first time Ovine Herpesvirus 2 (OvHV-2) was identified in Swiss pigs as the causative agent of Porcine Malignant Catarrhal Fever (MCF). Diseased animals from two farms were observed to show weakness, anorexia, fever up to 41°C, and neurological symptoms, i.e. ataxia, convulsions and hyperesthesia, erosion on the snout and in the oral and nasal mucosa, as well as multiple skin lesions. Histopathological findings included severe non-purulent inflammation with round cell infiltration in several organs. Most dominant were meningo-encephalitis, disseminated nephritis as well as purulent catarrhalic bronchopneumonia. The findings were quite reminiscent of the lesions due to MCF in cattle and give therefore substantial proof to use Porcine Malignant Catarrhal Fever as the term for the disease. Identification of the causative agent was done with a quantitative PCR specific for OvHV-2. Different tissues from diseased animals were positive. Furthermore, one animal which had been ill for more than five days tested positive for antibodies against an epitope conserved among MCF viruses. Serum samples from diseased animals reacted negative towards Classical Swine Fever- and Pseudorabies virus antigen. An only weakly positive reaction against porcine enterovirus type I argued against the involvement of enteroviruses in the observed disease. Moreover, by the means of different conventional PCRs, we detected the relatively newly discovered porcine lymphotropic herpesviruses for the first time in Switzerland and could at the same time exclude their involvement in Porcine malignant catarrhal fever.