pil distribution in Y. pseudotuberculosis strains in relation to their ecological niche (A) and O-antigen type (B). The number of strains in each class is given in parentheses. Water sources: mountain water (20), well water (5), river water (2), unknown origin (11). Wild mammal sources: raccoon dog (32), marten (7), hare (6), deer (5), reindeer (2), fox (2), mole (2), wild boar (1). Breeding animal sources: pig (29), rabbit (8), ruminant (7). Rodent sources: wild mouse (11), guinea pig (2), house rat (4), wild rat (1), unspecified (1). Miscellaneous sources: fish (2), plant (2), soil (1), unknown (2). Bird sources: pet birds (8), duck (2), pigeon (2), unspecified (3). Other mammal sources: monkey (3), goat (2), horse (2).