Rhipicephalus microplus (formerly Boophilus microplus) is considered to be the most important tick parasite of livestock in the world. R. microplus is a hard tick that can be found on many hosts including cattle, buffalo, horses, donkeys, goats, sheep, deer, pigs, dogs and some wild animals. Heavy tick burdens on animals can decrease production and damage hides. R. microplus can also transmit babesiosis (caused by the protozoal parasites Babesia bigemina and Babesia bovis) and anaplasmosis (caused by Anaplasma marginale). Under experimental conditions, this tick can transmit Babesia equi, the cause of equine piroplasmosis.

Babesiosis or “cattle fever” was eradicated from the United States between 1906 and 1943, by eliminating its vectors R. microplus and Rhipicephalus annulatus. Before its eradication, babesiosis cost the U.S. an estimated $130.5 million in direct and indirect annual losses; in current dollars, the equivalent would be $3 billion. R. microplus and R. annulatus still exist in Mexico, and a permanent quarantine zone is maintained along the Mexican border to prevent their reintroduction into the U.S. Within this zone, the USDA’s Animal and Plant Health Inspection Service (APHIS) conducts a surveillance program to identify and treat animals infested with these exotic ticks. Recently, increased numbers of infestations have been recorded in the quarantine zone.