Anaplasmosis is an infectious, non-contagious, tick-borne hemoparasitic disease of sheep, goats and wild ruminants in the tropics and subtropics. The acute phase of the disease is characterized by severe anemia, fever, weight loss, abortion, lower milk production, pallor of mucous membrane, jaundice and often death. Ovine anaplasmosis is mainly caused by A. ovis and A. marginale. Anaplasmosis is transmitted by ticks. Recovered animals become carriers. Splenectomy and intercurrent infections lower the resistance of the animals and render them more susceptible to the disease. Other stress factors such as malnutrition and pregnancy also increase the susceptibility of animals to anaplasmosis.