For example, suppression of astrogliosis in glial fibrillary acidic protein (GFAP) knockout mice substantially facilitates the penetration of Staphylococcus aureus or Toxoplasma gondii into the brain, which results in vasculitis, purulent ventriculitis and severe brain oedema (Stenzel et al., 2004). The gene discussed is GFAP; the disease is vasculitis.