The narrator's brother runs off and probably dies after Minami kills the dog he named Leo, whose digging had unearthed diseased corpses that infected the boys after the villagers abandoned them.  
The narrator of this novel contracted an STD from the girl from the toy factory, whom he met after stabbing a fellow student.  Its author wrote a short story sequel to it about the "trial" of it. One character in this work, who often speaks longingly of the south, has a morning ritual in which he assumes an undignified posture to medicate his hemorrhoids.  That character, Minami, is beaten with a hoe early in this novel after trying to escape.  The narrator's brother runs off and probably dies after Minami kills the dog he named Leo, whose digging had unearthed diseased corpses that infected the boys after the villagers abandoned them.  FTP, name this novel in which a group of juvenile offenders are confined to a remote, plague-stricken village, a work by Kenzaburo Oe.
The narrator of this novel contracted an STD from the girl from the toy factory, whom he met after stabbing a fellow student.  
Nip the Buds, Shoot the Kids (or Memushiri kouchi)