TITLE : Effects of experimental exclusion of scavengers from anthrax - infected 4 herbivore carcasses on Bacillus anthracis sporulation , survival and distribution 5 6 Steve

24 Scavenging of anthrax carcasses has long been hypothesized to play a critical role 25 in the production of the infectious spore-stage of Bacillus anthracis after host death, 26 though empirical studies assessing this are lacking. We compared B. anthracis spore 27 production, distribution and survival at naturally occurring anthrax herbivore carcasses 28 that were either experimentally caged to exclude vertebrate scavengers or unmanipulated. 29 We found no significant effect of scavengers on soil spore density (p > .05). Soil stained 30 by terminally hemorrhaged blood and by non-hemorrhagic fluids exhibited high levels of 31 B. anthracis spore contamination (ranging from 10-10 spores per gram) even in the 32 absence of vertebrate scavengers. At the majority of carcass sites, we also found that 33 spore density in samples taken from hemorrhagic-fluid stained soil continued to increase 34 for longer than 4 days after host death. We conclude that scavenging by vertebrates is not 35 a critical factor in the life cycle of B. anthracis and that anthrax control measures relying 36 on deterrence or exclusion of vertebrate scavengers to prevent sporulation are unlikely to 37 be effective. 38 39