Regional distribution of lesions in the central nervous system of cats infected with feline immunodeficiency virus.

Neuropathological examination of the central nervous system of 13 naturally and 13 experimentally feline immunodeficiency virus (FIV)-infected cats revealed diffuse gliosis of gray and white matter and vacuolar myelinopathy in a large proportion of infected animals, sometimes associated with lymphocytic meningitis. Multinucleated giant cell formation, the hallmark of multifocal giant cell encephalitis in HIV infection, was never observed. Morphometric analysis confirmed a marked increase of GFAP reactivity in infected cats. Gliosis was mainly present in cortical structures of frontal, parietal, and occipital lobes. Only one naturally infected animal evidenced clinical symptoms of neurological damage. This study confirms that FIV provides an interesting model for studying HIV-induced cortical and subcortical brain pathology believed to be the cause of the neurological manifestations frequently observed in AIDS patients.