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  [RC] FW: Spinal Taps Unnecessary for EPM Diagnosis? - Kristen A FisherCarla - I would be very cautious about a spinal tap too. 
Very expensive [a few hundred $s] and risky. See the CSU article 
below. 
We suspected by gelding had EPM a couple years ago and it 
turned out to be stifle OCD which was surgically corrected. If I was facing that 
again, I would find a vet experienced with EPM to standard neurological 
tests of his physical symptoms [circling, backing the horse, 
etc]  - AND I would also find a vet that would write me an RX for Marquis 
for approx $700 vs whatever the vet was going to charge you. 
Good luck. 
Kristen From: Kristen A Fisher [mailto:kskf@xxxxxxxxxxxxx] Sent: Wednesday, July 12, 2006 5:09 PM To: 'Kristen A Fisher' Subject: Spinal Taps Unnecessary for EPM Diagnosis? Spinal Taps Unnecessary for EPM 
Diagnosis? 
by: Erin Ryder, Editorial Assistant July 2006 Article # 7190 While cerebrospinal fluid (CSF) testing for equine protozoal myloencephalitis (EPM) is widely regarded as the only definitive way to diagnose the disease, the difficult, expensive, and potentially dangerous test might not be necessary, according to new research from Colorado State University. This study compared different 
testing schemes for EPM including assessment of the value of indirect 
fluorescent antibody testing (IFAT) of the combination of blood serum and CSF 
tests in relation to that of blood serum testing alone. In a previous study, 
using naturally exposed, experimentally infected, and vaccinated horses the 
researchers demonstrated that the IFAT has good accuracy in serum, and CSF 
correctly determined the infectious status of the horse more than 80% of the 
time. 
The difficulty of diagnosing EPM is 
that a horse exposed to Sarcocystis neurona (the parasite that most frequently 
causes EPM) will retain antibodies whether the horse is actually displaying 
symptoms of EPM or not. The western blot test, which is currently the most 
accessible and affordable test for owners, can only return a positive or 
negative response. This has resulted in a number of false 
positives. 
Indirect fluorescent antibody 
testing (IFAT) of either CSF or blood serum offers a higher specificity than the 
western blot. These tests can show not only the presence of antibodies to S 
neurona, but also quantify the concentration of antibodies, giving a far more 
specific result. 
"Because we can quantify the 
antibodies in serum with the IFAT, and because when there is such a high 
concentration of antibodies in serum, it is likely that the horse will have 
antibodies in CSF, even if the parasite is not in their brain or spinal cord, 
there will be less need to use CSF to make a final diagnosis." says Paulo C. 
Duarte, DVM, MPVM, PhD, assistant professor at Colorado State."Hence, we can 
potentially reduce the risk associated with CSF collection and the costs for 
horse owners." 
The researchers suggest that only 
horses that are already undergoing a spinal tap for other diagnostic procedures 
should be CSF tested for EPM. For those not requiring CSF testing for other 
issues, a blood serum IFAT might reveal as much information without the 
associated costs and risks. 
Researchers for this study, 
published in the May 5 edition of the American Journal of Veterinary Research, 
included Duarte, Eric D. Ebel, DVM, MS; Josie Traub-Dargatz, DVM, MS; W. David 
Wilson, BVMS, MS; Patricia A. Conrad, DVM, PhD; Ian A. Gardner, BVSc, MPVM, 
PhD. 
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