Thirty-one O serogroups of the international antigenic scheme and ten O ser
ogroups of the provisional "Schubert" antigenic scheme were found in Plesio
monas shigelloides strains of animal origin. Serovar O18:H2 and serovar O22
:H3 are probably exclusively feline serovars. Fish, water birds and reptile
s carry "Schubert" serovars (i.e. serovars originating from water and water
insects).