While Eperythrozoon species are common all over the world, In Turkey, they are detected only in cattle and mice. Eperythrozoon species propogate in blood by dividing into two. They are found on erythrocyte surfaces or in plasma in high numbers in different shapes including, circular, rod, ring, rectangular or multiform shapes. Commonly seen latent infections are characterized with a weak parasitemia, light anemia, weak fever, and icterus. Splenectomy results in high level of parasitemia. Disease should be considered in animals with anemia, enlarged spleen and animals with splenectomy. Arthropoda are responsible for natural transmission of parasites. It is well known that bloodsucking fleas are the most important vectors. Parasites can be transported by oral or parenteral routes. Tetracycline, oxytetracycline, chlortetracycline, neosalvarsan, aureomycine and arsenic are very effective in the treatment.