title: Babesia equi-induced anemia in a Quarter Horse and subsequent regulatory response.
abstract: METHODS
  A 7-year-old Quarter Horse gelding used for unsanctioned racing was examined because of fever and anorexia.
  
  
  RESULTS
  Physical examination revealed fever, tachycardia, and tachypnea. Results of a CBC indicated anemia and mild thrombocytopenia. Results of microscopic examination of a blood smear indicated piroplasms in erythrocytes, consistent with Babesia spp. Regulatory authorities were contacted, and results of serologic testing at the National Veterinary Services Laboratories confirmed acute Babesia equi infection.
  
  
  RESULTS
  Equids on the home premises of the index horse were placed under quarantine. Those equids were tested for piroplasmosis, and 6 of 63 horses had positive results for B equi. Another horse that had previously been housed on the index premises also had positive results for B equi. Competent tick vectors for piroplasmosis organisms were not identified. All 8 horses with piroplasmosis were Quarter Horses that participated in unsanctioned racing and were trained by the same person. Two of the horses were illegally removed from the index premises; these 2 horses and the other horse with piroplasmosis that was previously housed on the index premises could not be found. The other 5 horses with piroplasmosis were euthanized. Investigators concluded that transmission of B equi among horses was most likely iatrogenic.
  
  
  CONCLUSIONS
  The United States has been considered piroplasmosis free. However, veterinarians should consider piroplasmosis in horses with signalments and clinical signs similar to those of the index horse of this report. Regulatory authorities should be contacted regarding horses in which piroplasmosis is suspected.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA. lbeard@vet.k-state.edu
authors.forename: Laurie A
authors.initials: LA
authors.lastname: Beard
authors.forename: Angela M
authors.initials: AM
authors.lastname: Pelzel
authors.forename: Bonnie R
authors.initials: BR
authors.lastname: Rush
authors.forename: Abra M
authors.initials: AM
authors.lastname: Wright
authors.forename: Bradley I
authors.initials: BI
authors.lastname: Galgut
authors.forename: Steven G
authors.initials: SG
authors.lastname: Hennager
authors.forename: Alison O
authors.initials: AO
authors.lastname: King
authors.forename: Josie L
authors.initials: JL
authors.lastname: Traub-Dargatz
mesh_terms: D000740:Anemia / Q000209:etiology / Q000382:microbiology / Q000662:veterinary*; D000818:Animals; D001403:Babesia / Q000145:classification*; D001404:Babesiosis / Q000150:complications / Q000382:microbiology / Q000662:veterinary*; D006734:Horse Diseases / Q000209:etiology* / Q000382:microbiology / Q000473:pathology; D006736:Horses; D008297:Male; D012420:Running; D013177:Sports