Texas Equine Veterinary Association

www.texasequineva.com | 25 quantitative PCR assays including use of an internal control to help ensure that negative results are not caused by either failure of DNA extraction or inhibitors of the PCR reaction. Drs. Pam Ferro and Megan Schroeder at TVMDL further demonstrated that the test performed well by comparing the test with samples submitted to TVMDL to be tested by both culture and PCR for SEE. Among samples that amplified, all that were culture- positive were positive by the qPCR test. One sample failed to amplify the internal positive control DNA. e protocol for TVMDL is that a sample in which the internal control fails is retested, with dilution of the sample if necessary, to achieve amplification of the internal control. is eliminates the possibility that sample are falsely called negative that contain SEE. In addition, there were some samples that were negative by culture but positive for SEE and/or SEZ by PCR, demonstrating that the PCR assay is more sensitive than culture (a finding consistent with other PCR tests). is SEE-SEZ duplex PCR test is currently offered by TVMDL. e EIDL plans to publish their results so that they will be publicly-available for other laboratories to use. Serological testing to detect antibodies against SEE is useful to identify horses at risk of complications from SEE infection, have metastatic abscesses (so-called "bastard strangles"), or have been exposed to SEE. e latter is especially important because carrier horses are the reason this ancient disease has been able to persist even though it is restricted to a single host without being able to survive well in the environment and does not have reservoirs other than horses. A serological test for SEE infections is likely best used to identify carriers during the late stages or shortly aer an outbreak of strangles to differentiate horses that were not exposed and could be managed as usual from horses that have been exposed to SEE and might be persistently infected. Seropositive horses can be subsequently investigated by guttural pouch lavage, guttural pouch endoscopy, or both and then tested by microbiologic culture and PCR to identify carrier horses. It appears that titers wane even in some or most chronically infected carriers, possibly because the bacteria transform to a low-metabolic state that renders them largely "under the radar" of the immune system. In the U.S., a serological test is available that detects antibodies against the M protein of SEE. However, this SeM ELISA test has cross-reactivity with the M protein of SEZ resulting in false-positive diagnoses of strangles. A dual antigen serological test has been developed in the U.K. It has been demonstrated to perform better than the SeM ELISA, but it is not available in the U.S. Investigators from the EIDL are working to develop a novel serological test. ey have identified a promising candidate and are seeking serum samples from horses with strangles to further validate the test. Samples are greatly needed and would be greatly appreciated by the EIDL. If you are willing and able to help provide samples, please contact Dr. Noah Cohen at ncohen@tamu.edu. Back by popular demand! We are requesting submissions for the 2023 Summer CE Symposium, TEXAS TAKES! Abstracts must be submitted by February 1st for the 2023 Summer CE Symposium. They should include ideas for a one-hour lecture as part of the Texas Takes Series. They must be educational, unbiased and able to receive RACE accreditation. TO SUBMIT your Abstract, please email it directly to info@texasequineva.com with 2023 Texas Takes in the subject line. You do not have to be a TEVA member to submit an abstract! TEXAS TAKES requesting EXTENDED EXTENDED

• Cover