Feline haemoplasma species vary in pathogenicity. Mycoplasma haemofelis is the most pathogenic, and can cause moderate to severe, Coombs-positive, haemolytic anaemia (feline infectious anaemia) in immunocompetent cats. ‘Ca. M. haemominutum’ and ‘Ca. M. turicensis’ are less pathogenic, but can result in a decreased haematocrit, which may or may not be clinically significant. Co-infections with all three feline haemoplasma species have been described frequently. The whole genome sequences of M. haemofelis and ‘Ca. M. haemominutum’ have been determined.