Anaplasmosis is a isease caused by a rickettsial parasite of ruminants, Anaplasma spp. The organism occurs in the erythrocytes and is transmitted by natural means through by a number of haematophagous species of ticks and flies. It can also be transmitted iatrogenically by the use of surgical, dehorning, castration, and tattoo instruments and hypodermic needles that are not disinfected between uses.