Histological lesions in the CNS <*> were mild
Immunohistochemically , the distribution of PTV antigens corresponded closely with the distribution of brain lesions .
Histological lesions in the CNS caused by oral or intranasal inoculation of the virus were mild compared with those induced by intravenous infection .
Immunohistochemically , the distribution of PTV antigens corresponded closely with the distribution of brain lesions .