 Brooks designed World War Z to follow the " laws " set up in his earlier work , The Zombie Survival Guide ( 2003 ) , and explained that the guide may exist in the novel 's fictional universe . The zombies of The Zombie Survival Guide are human bodies reanimated by an incurable virus ( Solanum ) , devoid of intelligence , desirous solely of consuming living flesh , and cannot be killed unless the brain is destroyed . Decomposition will eventually set in , but this process takes longer than for an uninfected body and can be slowed by effects such as freezing . Although zombies do not tire and are as strong as the humans they infect , they are slow @-@ moving and incapable of planning or cooperation in their attacks . Zombies usually reveal their presence by moaning . 
 Brooks designed World War Z to follow the " laws " set up in his earlier work , The Zombie Survival Guide ( 2003 ) , and explained that the guide may exist in the novel <a href='null_genetive' title='1'><mark>'s</mark></a>fictional universe . The zombies of The Zombie Survival Guide <a href='drop_aux' title='2'><mark>are</mark></a>human bodies reanimated by an incurable virus ( Solanum ) , devoid of intelligence , desirous solely of consuming living flesh , and cannot be killed unless the brain is destroyed . Decomposition will eventually set in , but this process <a href='uninflect' title='3'><mark>takes</mark></a> longer than for an uninfected body and can be slowed by effects such as freezing . Although zombies do not tire and <a href='drop_aux' title='4'><mark>are</mark></a>as strong as the humans they infect , they <a href='drop_aux' title='5'><mark>are</mark></a>slow @-@ moving and incapable of planning or cooperation in their attacks . Zombies usually reveal their presence by moaning . 
Brooks designed World War Z to follow the " laws " set up in his earlier wrk , The Zombie Survival Guide ( 2003 ) , and explained dat the guide may exist in da novel  fictional universe . The zombies of TdaZombie Survival Guide human bodies reanimated by an incurable virus ( Solanum ) , devoid of intelligence , desirous solely of consuming living flesh , and cannot b killed unless the brain is destroyed . Decomposition gon eventually set in , but dis process take longer than fir an uninfected body and can be slowed by effects such as freezing . Although zombies do not tire and as strong as thdaumans they infect , they slow @-@ moving and incapable of plannin or cooperation in their attacks . Zombies usually reveal their presence by moaning .