Comparative studies of viral infections of the developing forebrain: I. Pathogenesis of rat virus and bluetongue vaccine virus infections in neonatal hamsters

The pathogenesis of rat virus and bluetongue vaccine virus (BTW) infections were studied in the forebrains of newborn hamsters. Both infections were initially confined to cells of the subventricular zone (SVZ) and comparable amounts of infectious virus were replicated, yet these infections led to different sequelae. BTW infection eventually spread outward from the SVZ to the cortex, dentate gyrus and internal granule cells of the olfactory bulbs. Bat virus infection remained confined to the SVZ. BTW infection produced an intense inflammatory response, whereas rat virus infection evoked almost no inflammation. Based on the maturational changes in the germinal cells of the forebrain and on the different biological properties of the two viruses, the reasons for the contrasting effects of these viruses on the forebrain are discussed.