Anaplasma is a type of bacteria that resides in the blood cells. Once inside the host blood cells this species of bacteria will cause a disease known as anaplasmosis. Anaplasmosis is a disease that often occurs in areas of the world where ticks live - as they often pass from the tick to the organism a tick feeds on. This is often found in tropical parts of the world.
Anaplasma are transmitted specifically by Ixodes deer-tick vectors. The species A. marginale can also be transmitted by certain flies that bite. This is common in cows, and when bovine red blood cells are infected by A.marginale the animal will develop nonhaemolytic anaemia, that can be serious or even fatal for the animal as it stops the flow of oxygen around the body.
Anaplasma ovis and Anaplasma mesaeterum is common in both sheep and goats and will cause the same illness as in cows.
In dogs, cats and horses - Anaplasma phagocytophilum is a prevalent type of Anaplasma and this should be tested for if your pet is bitten by a tick.
In terms of genetic structure - Anaplasma is not particularly complex and the largest genome that has currently been sequenced only consists of 1335 proteins. Compared to the 25000 proteins present in the human body this is rather simplistic. The organism itself is only 1.1 to 1.2 MB in size.