Similarly, early infection of the spinal cord was observed in IRF-1-/- mice with 20% (2 of 10) and 90% (9 of 10) having detectable viral loads at day 4 (103.1 PFU/g) and at day 6 (104.9 PFU/g, P<0.0001), respectively (Fig 1G), whereas infection in wild type mice was not observed at these times. The gene discussed is IRF1; the disease is infection.