Experimental infection of swine and cat central nervous systems by the pig paramyxovirus of the blue eye disease

This study analyses whether the pig paramyxovirus of blue eye disease (PPBED) infects the central nervous system (CNS) utilizing anterograde and retrograde peripheral nerve transport systems. The virus was injected into muscle and skin, and inoculated per nasum. The presence of PPBED was detected by an immunohistochemical method using polyclonal mouse antibodies against the whole inactivated virus, and was revealed with polyclonal rabbit antibodies against mouse immunoglobulin G (IgG) labelled with peroxidase. The PPBED injected into the pig medial gastrocnemius (MG) muscle was detected in a terminal branch innervating the MG muscle, in neural fibres of the sciatic nerve, in fibres of the ventral and dorsal spinal roots and in ventral horn neurones of the spinal cord. When PPBED was injected into the skin area innervated by the sural nerve, it was detected in neural fibres of the sural and sciatic nerves and in spinal cord dorsal horn neurones. The per nasum inoculum rapidly invaded the CNS through the olfactory nerve. The study concluded that, in order to invade the CNS, PPBED was transported retrogradely by peripheral cutaneous and muscular nerves, and anterogradely by the olfactory nerve. No PPBED was detected in either cat peripheral nerves or in cat CNS.