Week of July 15, 2006; Vol. 170, No. 3 , p. 45 Mad cow disease might linger longer Nathan Seppa A rare but deadly human illness spread by cannibalism has an incubation period in some individuals of about 4 decades, researchers in New Guinea have discovered. The finding implies that a related human illness caused by eating beef from cattle with mad cow disease could also lie dormant for many years. HEADS UP. The box shows the area in New Guinea where until the 1950s, people practiced cannibalism, a ritual that spread the prion disease kuru. S. Norcross Scientists have...