Isolation and characterization of pseudorabies virus from a wolf (Canis lupus) from Belgium

Abstract

Aujeszky’s disease is an economically important disease in domestic pigs caused by the alphaherpesvirus pseudorabies virus (PRV). However, also wild boars are a natural reservoir for the virus, and this can lead to infection of wildlife carnivore species. Three wolves held in the wildlife park of Han-sur-Lesse in the province of Namur in Belgium were suspected to be infected with PRV based on the nervous symptoms they showed after being fed with wild boar offal. The diagnosis was confirmed for a female wolf by a positive real-time PCR detecting PRV. The virus was isolated from the brain tissue of the wolf and characterized by restriction fragment length polymorphism analysis and phylogenetic analysis. The obtained BamHI restriction fragment pattern of the wolf isolate was similar to that of the reference strain Kaplan, thereby characterizing it as a type Ip isolate. Type I PRV strains, and particularly subtype Ip, are predominant in European wild boar. Phylogenetic analysis based on the sequence of a fragment of glycoprotein C showed that the Belgian isolate belonged to cluster B and that the sequence was identical to that of wild boar isolates from southwestern Germany, eastern France, and Spain. This study is the first report of Aujeszky’s disease in wolves and shows that they are susceptible to PRV by eating infected wild boar offal leading to fatal neurological disease. This illustrates the possible implications of PRV-infected wild boar for the conservation of wolves and other carnivore species.