Location: Animal Disease ResearchTitle: Validation of an improved anaplasma antibody cELISA kit for detection of anaplasma ovis antibody in domestic sheep at the U.S. Sheep Experiment Station in Dubois, ID
|GONZALEZ, MICHAEL - Washington State University|
|CHUNG, CHUNGWON - Washington State University|
|Taylor, Joshua - Bret|
Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2017
Publication Date: 5/8/2017
Citation: Mason, K.L., Gonzalez, M.V., Chung, C., Mousel, M.R., White, S.N., Taylor, J.B., Scoles, G.A. 2017. Validation of an improved anaplasma antibody cELISA kit for detection of anaplasma ovis antibody in domestic sheep at the U.S. Sheep Experiment Station in Dubois, ID. Veterinary Microbiology. https://doi.org/10.1177/1040638717709494.
Interpretive Summary: An accurate and easy to perform revised diagnostic kit was developed by VMRD and approved in 2015 by the USDA for use in testing for a disease (anaplasmosis) in cattle. In order to also benefit sheep researchers and sheep growers, we analyzed this cattle test kit to see if it could be used to test for a related anaplasmosis which occurs in sheep. We used blood samples from sheep at the United States Experiment Station (USSES) in Dubois, Idaho and our results showed that this test is 100% compatible for sheep anaplasmosis. We also determined that the unusually high rate of sheep infected with anaplasmosis at the USSES appears to be related to the presence of large numbers of ticks which transmit the disease.
Technical Abstract: An accurate and simple-to-perform new version of a competitive ELISA (cELISA) kit that became commercially available in 2015 for testing of cattle for antibody to Anaplasma marginale was validated for detection of Anaplasma ovis antibody in domestic sheep. True positives and negatives were identified using nested PCR (nPCR) as the gold standard. Negative bovine control sera supplied with the kit were used to calculate % inhibition (%I), designated bovine control ELISA (BcELISA), and this was compared to %I calculated from negative ovine sera derived from hand-raised, pathogen-free sheep, designated ovine control ELISA (OcELISA). The receiver operating characteristics area under the curve was 1.0 with a p value <0.001 regardless of the source of the control sera. The cutoff values for negative BcELISA and OcELISA were <30%I and <27%I, respectively. Our work confirmed that this Anaplasma antibody cELISA kit version 2 can be used with the serum controls supplied in the kit to test for A. ovis antibody in domestic sheep. Furthermore, this work confirmed the historically high infection prevalence (>93%) at the U.S. Sheep Experiment Station (Dubois, Idaho), in spite of efforts to reduce the possibility for iatrogenic transmission there, suggesting high levels of tick-borne transmission.