Fig 1.
Independent but interconnected life cycles of Bordetella bronchiseptica.
B. bronchiseptica (red rods) can infect a range of mammalian species as a respiratory pathogen. Alternately, it can associate with predatory amoeba to expand in numbers and disperse in the environment via their complex life cycle.
Fig 2.
A Bordetella metacycle of transmission: The source of host-restricted species.
Schematic of a progenitor Bordetella species involved in a complex metacycle of transmission involving alternative cycles in environmental protists or animal host species. Phylogenetic relations strongly indicate that host specializations of transmission restricted species, including B. pertussis, evolved from a metacycle of transmission of a B. bronchiseptica-like ancestor. [Image by: Danielle Brittany Vanbrabrant ©2019—University of Georgia Research Foundation, Inc.].