You might want to re-read that part of cryptum starting on page 229. The growths on the pheru only arrived after [b]centuries[/b] of breeding after consumption of the powder which then lead to the effects later described with them eating each other at times. [quote] [b]What would soon become the Flood[/b] first [u]manifested itself as a peculiar growth[/u] found on roughly a third of all Pheru treated with the powder. [/quote] [quote] [b]Then [/b]humans began to manifest the growths. [u]Some humans, it seemed, fancied Pheru as food. These humans became vectors.[/u] Whatever they touched was also infected, and in time, what they discarded limbs, tissue could also spread infection. [b]Thus began the Flood.[/b][/quote] The powder Didn't have drastic effects on the pheru until hundreds of years later. In order to be controlled by the flood you need to have sufficient calcium deposits,a spinal cord, and a central nervous system. The Pheru don't necessarily demonstrate signs of an infection because they weren't constantly eating each other nor were they spreading the illness to anything else. The flood did not manifest until humans started eating the crazed animals.