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Wise LN, Kappmeyer LS, Silva MG, White SN, Grause JF, Knowles DP. Verification of post-chemotherapeutic clearance of Theileria equi through concordance of nested PCR and immunoblot. Ticks Tick Borne Dis 2017; 9:135-140. [PMID: 28887100 DOI: 10.1016/j.ttbdis.2017.08.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 07/24/2017] [Accepted: 08/17/2017] [Indexed: 11/27/2022]
Abstract
Certain countries including the United States remain non-endemic for particular infectious diseases such as equine piroplasmosis through import restrictions and surveillance. Endemic regions often employ premunition as the primary method to control disease, however in non-endemic countries, chemosterilization combined with methods to confirm parasite elimination are required to maintain disease-free status. The ability of imidocarb diproprionate (ID) to clear persistent Theileria equi infection from infected horses has been shown through the inability of treated horses to transmit via blood transfer. However, the common lengthy persistence of anti-T. equi antibody causes regulatory tests such as cELISA or IFA to remain positive for extended periods. Persistence of positive testing creates challenges for regulatory veterinary medicine and international trade. Concordance between nested polymerase chain reaction (nPCR) targeting the ema1 gene and immunoblotting (IB) measuring declination in anti-EMA1 and anti-EMA2 antibody were used to verify clearance of T. equi from 179 ID-treated horses. These data support the use of IB to demonstrate declining anti-EMA1 and EMA2 titers in T. equi-infected horses subsequent to successful ID treatment. Such data provide concordant support to a negative nPCR and allow for a more timely determination of effective ID clearance of T. equi. The post ID treatment results indicate that while nPCR was consistently negative by 14 days and cELISA generally remained positive after 1 year, immunoblot was on average negative after 4 months and 100% in agreement with nPCR.
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Affiliation(s)
- L N Wise
- Animal Disease Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Pullman, WA, USA; School of Veterinary Medicine, St. George's University, True Blue, Grenada, W. I..
| | - L S Kappmeyer
- Animal Disease Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Pullman, WA, USA
| | - M G Silva
- Animal Disease Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Pullman, WA, USA; Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - S N White
- Animal Disease Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Pullman, WA, USA; Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - J F Grause
- Animal and Plant Health Inspection Service, Veterinary Services, Science, Technology and Analysis Services, National Veterinary Services Laboratories, Ames, IA, USA
| | - D P Knowles
- Animal Disease Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Pullman, WA, USA; Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
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