Previous research indicates that local and systemic infections with opportunistic microbes do not readily occur via uptake of the plant pathogen through intraarticular and gastric routes. Nevertheless, the common understanding within the medical an veterinary fields that plant pathogens are not causative agents of disease in humans and animals should be challenged. Recent massive metagenome and genomic studies associated previously unidentified and uncharacterized microbial species with known and unknown disease symptoms in animals and humans, suggesting that these infections should be re-evaluated.