Tick-borne diseases (TBDs) pose a major constraint of livestock production and have considerable economic impact
to rural people affecting not only their food supply, but also
their daily income and other agricultural activities [1]. In
1997, the annual global losses associated to ticks and TBDs
in cattle was estimated to amount between US$ 13.9 billion
and US$ 18.7 billion [2]. Four groups of TBDs are of importance to the livestock production: theileriosis, babesiosis,
anaplasmosis and heartwater (also called cowdriosis), posing major health and management problems of cattle and
small ruminants in affected areas. In cattle, East Coast
fever (ECF), tropical theileriosis and babesiosis are caused
by protozoan parasites (Theileria parva, Theileria annulata
and Babesia bovis or Babesia bigemina, respectively), whereas
heartwater and anaplasmosis are caused by the Rickettsiales
Ehrlichia ruminantium and Anaplasma marginale, respectively.
In endemic areas, indigenous cattle have developed resistance to ticks and to tick-borne pathogens (TBPs) [1]. However, susceptibility of exotic breeds presents a major obstacle
to the improvement of cattle production.