Equine babesiosis (piroplasmosis) is an acute, subacute, or chronic infectious hemolytic disease caused by the intraerythrocytic parasites Babesia equi and Babesia caballi. The former parasite is considered more pathogenic..
The disease is endemic in most tropical and subtropical regions of the world and occurs in horses, mules, donkeys, and zebras and is transmitted by various species of ticks; Dermacentor, Rhipicephalus, and Hyalomma.
Horses become infected when they are parasitized by feeding ticks that harbor the sporozoites in their salivary secretions.
Additional features that may or may not be seen include sweating, colic, lacrimation, incoordination, cardiac murmurs, and subcutaneous edema around the head and eyelids.
Rarely, a peracute form of the disease occurs in which horses die within 24 - 48 hours of the onset of clinical signs. Clinical signs of equine babesiosis generally follow a variable incubation period of 5 to 21 days.
Subacute cases are characterized by intermittent fever, anorexia, weight loss, tachycardia, tachypnea, with variable degrees of icterus, hemoglobinuria, and bilirubinuria.
Diagnosis is based on clinical signs and laboratory evidence of hemolytic anemia, together with identification of the parasitized erythrocytes. I
A definitive diagnosis requires PCR, ELISA, serology, complement fixation and indirect fluorescent antibody tests.
Treatment is usually effective with imidocarb, however, Babesia equi infections are known to be more refractory to treatment than those caused by Babesia caballi. .
Prevention of babesiosis requires control of tick infestations and avoiding iatrogenic transfer of infected blood during routine surgical and medical procedures. Vaccines are not commercially available at this time to prevent disease or boost immunity to Babesia spp infections.
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