Thesis
Eradication of Theileria equi from a ranch in Texas
Washington State University
Master of Science (MS), Washington State University
2017
Handle:
https://hdl.handle.net/2376/103002
Abstract
In October 2009, Theileria (Babesia) equi infection was confirmed in a herd of domestic Quarter Horses on a large ranch in south Texas. There were 2,500 horses ultimately tested for equine piroplasmosis (EP) as part of the traceback and epidemiological investigation with a total of 413 T.equi-positive horses disclosed in connection with the outbreak. Active natural transmission of T. equi to horses on the index ranch was confirmed to have been occurring via Amblyomma cajennense and Dermacentor variabilis ticks. Epidemiological investigation and testing of the horses sold from the premises indicates that T. equi infection had been present in horses on the ranch since prior to 1990. The original source of the infection is likely to have been from longterm periodic movement of horses between the Texas ranch and another premises owned by the ranch and located in Brazil. The epidemiology and regulatory response to the outbreak is described which included extensive trace-back and testing of potentially exposed horses, longterm quarantine of infected premises, acaricide mitigation of tick vectors, culling of selected infected horses, and treatment of 163 T. equi-infected horses with a published high-dose imidocarb dipropionate protocol under the USDA-APHIS-VS and USDA-ARS EP treatment research program. The combined response measures ultimately resulted in successful eradication of T. equi from the index ranch. This is the only known outbreak of natural tick-borne transmission of T. equi on the U.S. mainland.
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Details
- Title
- Eradication of Theileria equi from a ranch in Texas
- Creators
- Angela Maria Pelzel
- Contributors
- Donald P. Knowles (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Veterinary Medicine, College of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525198001842
- Language
- English
- Resource Type
- Thesis