The significance of a positive PCR result should always be compared with clinical signs, pathological findings, haematological features and possible concurrent or complicating diseases. More severe clinical signs have occurred in cats experimentally dual-infected with Mhf and CMhm than in cats with mono-infection with either of the species and in cats spontaneously infected with both Mhf and CMhm [6, 28]. Based on PCR and sequencing of the PCR products, we found no samples with more than one haemoplasma species. The only CMhm positive cat in our study was diagnosed as FIV positive. The risk of infections with haemoplasma has previously been associated with concurrent diseases such as feline leukemia virus (FeLV) and FIV. Cats co-infected with FeLV develop a more severe anaemia than cats only infected with CMhm and FIV infection was shown to be associated with an increased risk of co-infection with CMhm and Mhf [7, 14, 29].