Virus-infected cells were detected in the mesothelial cells of the meninges of one H5N1infected animal on day 4 pi, most pronounced over the occipital lobes (Fig. 3a) , while neurons and glia cells were negative for virus antigen in all animals at all time points examined. Apart from the meninges, the only other extrapulmonary and non-lymphoid tissues with virusantigen-positive signals were the colon (macrophage or dendritic-like cells in lamina propria; Fig. 3b ) of one H5N1-infected animal on day 2 pi, and the abdominal mesothelium (mesothelial cells, most notably the lining associated with the kidney capsule) of one animal on day 4 pi. No extrapulmonary virus antigen was detected in any animal of any other group at any time point.