8/3/2019 Morrow Present
1/19
2006 IDEXX Laboratories, Inc. All rights reserved.
SEROPREVALENCE OF SARCOCYSTIS NEURONA IGG IN UNITED STATES SUBMISSIONS TO
EQUINE BIODIAGNOSTICS (EBI):
A RETROSPECTIVE ANALYSIS OF 2000-2005.
JK Morrow*, SM Reed** and DE Granstrom***
* Equine Biodiagnostics/IDEXX, Lexington KY,
** The Ohio State University College of Veterinary Medicine,
Columbus OH
*** USDA Animal and Natural Resources Institute, Beltsville
MD
8/3/2019 Morrow Present
2/19
2 2006 IDEXX Laboratories, Inc. All rights reserved.
QUALIFYING STATEMENTS
The results from non-US submissions were excluded from analysis.
The results of all known infection studies were excluded fromanalysis.
The results were counted in the state of the submitting veterinarian.
Geographic regions within states were not distinguished.
States in which 100 sera or less were submitted during the 6 yearreview period were Alaska, Hawaii, Idaho, North Dakota, Nevada,Rhode Island and West Virginia.
States in which 200 sera or less were submitted during the 6 yearreview period were Maine, New Hampshire, New Mexico, SouthDakota, Utah, Vermont and Wyoming.
8/3/2019 Morrow Present
3/19
3 2006 IDEXX Laboratories, Inc. All rights reserved.
Serum POSITIVE Results for Central Region
63%
N= 1252
31%
N = 180
24%
N = 17 47%
N = 471
73%
N = 338
70%
N= 975
72%
N = 1113
72%
N = 434
80%
N = 759
68%
N = 2687
61%
N = 2632
CENTRAL REGION RESULTS
8/3/2019 Morrow Present
4/19
4 2006 IDEXX Laboratories, Inc. All rights reserved.
NORTHEAST REGION RESULTS
Serum POSITIVE Results for Northeast Region
30%
N = 107
NH32%N = 186NH
VT
VT32%N = 169
MA MA47%N = 742CT
CT49%N = 1065
56%N = 3808
57%N = 2172
81%N = 100 62%
N = 1850
NJ NJ48%N = 2100
DE DE
65%N = 221
MD
MD46%N = 1404
8/3/2019 Morrow Present
5/19
5 2006 IDEXX Laboratories, Inc. All rights reserved.
35%N =5518
31%N=483
55%N =291
38%N = 1014
36%N = 73
21%N = 42
33%N =137
33%N = 745
33%N = 168
31%N = 105
WEST REGION RESULTS
Serum POSITIVE Results for West Region
36%N = 112
8/3/2019 Morrow Present
6/19
6 2006 IDEXX Laboratories, Inc. All rights reserved.
75%N= 548
68%N = 4961
80%N = 913
75%N = 558
80%N = 718
85%N = 318
SOUTHWEST REGION RESULTS
Serum POSITIVE Results for Southwest Region
80%N = 731
8/3/2019 Morrow Present
7/19
7 2006 IDEXX Laboratories, Inc. All rights reserved.
57%N=2066
72%N = 500
76%N = 270
65%N=540
75%N = 1083
73%N=758
SOUTHEAST REGION RESULTS
Serum POSITIVE Results for Southeast Region
8/3/2019 Morrow Present
8/19
8 2006 IDEXX Laboratories, Inc. All rights reserved.
Seroprevalence
21-40%41-60%
61-85%
8/3/2019 Morrow Present
9/19
9 2006 IDEXX Laboratories, Inc. All rights reserved.
Seroprevalence
21-40% 41-50%
51-60% 61-70%
71-85%
8/3/2019 Morrow Present
10/19
10 2006 IDEXX Laboratories, Inc. All rights reserved.
Seroprevalence
41-40% 41-55%
56-65% 66-75%
76-85%
8/3/2019 Morrow Present
11/19
11 2006 IDEXX Laboratories, Inc. All rights reserved.
States with the highest # serum submissions and seroprevalence:
State #submitted %positive
California 5518 35%
Connecticut 1065 49%
Florida 2066 57%
Illinois 1113 72%
Kentucky 2687 68%
Maryland 1404 46%
Nebraska 1252 63%
New Jersey 2100 48%
New York 3808 56%
Ohio 2632 61%
Pennsylvania 2172 57%
Tennessee 1083 75%
Texas 4961 68%
Virginia 1850 62%
Washington 1014 38%
8/3/2019 Morrow Present
12/19
12 2006 IDEXX Laboratories, Inc. All rights reserved.
PUBLISHED SEROPREVALENCE STUDIES
EBI EBI
State Reference #Horses %Positive #Tests %Positive
California Vet Parasit (2001) 95:273-282 93 27% 5518 35%
Colorado J Equine Vet Sci (1999) 19:122-126 608 34% 745 33%
Florida Vet Parasit (2001) 95:273-282 40 28% 2066 57%
Michigan JAVMA (2001) 48:113-128 1121 60% 434 72%
Missouri Vet Parasit (2001) 95:273-282 39 54% 718 80%
Montana Vet Parasit (2001) 95:273-282 15 0% 168 33%
Ohio JAVMA (1997) 210:519-524 1056 54% 2632 61%
Oklahoma J Vet Diag Invest (2003) 15:597-600 798 89% 913 80%
Oregon JAVMA (1997) 210:525-527 334 45% 291 55%
Pennsylvania JAVMA (1997) 210:517-518 117 45% 2172 57%
Wyoming J Parasit (2003) 89:716-720 276 7% 112 36%
8/3/2019 Morrow Present
13/19
13 2006 IDEXX Laboratories, Inc. All rights reserved.
SUMMARY
The overall seroprevalence from US submissions was 58%.
The seroprevalence ranged from a low of 31% in Arizona toa high of 85% in Arkansas.
The seroprevalence tended to be lower in the western statesand the far northeast while higher in the southeastern centralstates.
In states with moderate seroprevalence rates, 22-42% testnegative and even in those with higher seroprevalence, up to20% test negative.
The western blot continues to be a useful diagnostic tool witha negative result essentially ruling out S. neuronacausedEPM.
8/3/2019 Morrow Present
14/19
14 2006 IDEXX Laboratories, Inc. All rights reserved.
Commercially Available Sarcocystis neurona IgG Tests
Source Since Reference Validation Samples Test Format Antigen Used Variation Interpretation
EBI/IDEXX June 1995 (1) J Vet Diagn Invest (1993) 5:88-90 (1) 7 necropsy positive horses, serum western blot merozoite lysate none 14.5 kDa
(2) Vet Parasit (1997) 68:199-213 (2) 5 infected and 2 uninfected foals, serum and csf
(3) Proceedings International Equine (3) 295 necropsy cases, serum and csf ~40% were
Neurol Conf (1997) p.4 positive for EPM
Neogen November 1996 not published not published western blot merozoite lysate quantification of csf IgG 17 kDa
based on serum levels
Mic higan St ate ~fall 1998 J Vet Diagn Inves t (2000) 12: 28-32 Serum only: 6 necropsy positive wes tern blot meroz oite lysate pre-block ing of blot with 16 and 30 kDa
University 45 from India anti-S. cruzi IgG12 from Germany
UC Davis ~ early 2004? (1) J Vet Diagn Inves t (2003) 15:8-13 (1) 48 sera: 7 nec rops y pos it ive, neurologic IFA whole meroz oit es indirec t fluores cent ant ibody endpoint tiit er= las t
(2) J Parasit (2004) 90:379-386 2 necropsy positive, non-neurologic dilution showing whole
(2) 20 OSU infected horses, serum and csf parasite fluorescence
(4 non-infected horses not tested) titer gives "probability"
8 UFL infected horses, serum and csf of EPM
2 non-infected control horses
20 vaccinated (several pre-exposed) and
6 non-vaccinated horses, s erum and csf110 Necropsied horses, serum and csf
8 EPM positive
8 EPM suspect
94 EPM negative
E llis on/Antec h ~ late 2004 J App Res Vet Med (2003) 1:318-327 6 hors es infec ted wit h E llis on model, s erum and c sf ELISA rec ombinant SAG1 ELISA c orrelates a given t it er
8/3/2019 Morrow Present
15/19
15 2006 IDEXX Laboratories, Inc. All rights reserved.
Equine Biodiagnostics/IDEXX Sarcocystis neurona IgG western blot
ACVIM EPM Society SIG panel, Louisville KY Jennifer Morrow, PhD 5/31/06
Developed in the research laboratory of Dr. David Granstrom while on the faculty of Gluck Equine
Research Center, University of Kentucky
Commercialized by the University of Kentucky as Equine Biodiagnostics, Inc. in 1995 (acquired by
IDEXX Laboratories in October 2003)
References on method and validation:
J Vet Diagn Invest (1993) 5:88-90
Vet Parasit (1997( 68:199-213
Proceedings International Equine Neurol Conf (1997) p.4
8/3/2019 Morrow Present
16/19
16 2006 IDEXX Laboratories, Inc. All rights reserved.
Equine Biodiagnostics/IDEXX Sarcocystis neurona IgG western blot
ACVIM EPM Society SIG panel, Louisville KY Jennifer Morrow, PhD 5/31/06
Original validation samples (respective to above publications):
7 necropsy positive EPM horses, serum
5 infected and 2 uninfected foals, serum and csf
295 necropsy cases, paired serum and csf:
123 were EPM necropsy positive
3 western blot false negatives were due to acute onset
6 western blot false positives were due to cases in which blood brain barrier breach was
likely
specificity = 89% for CSF and 71% for serum
sensitivity = 89% for CSF and 89% for serum
8/3/2019 Morrow Present
17/19
17 2006 IDEXX Laboratories, Inc. All rights reserved.
Equine Biodiagnostics/IDEXX Sarcocystis neurona IgG western blot
ACVIM EPM Society SIG panel, Louisville KY Jennifer Morrow, PhD 5/31/06
The test format is a standard western blot and uses whole merozoite lysate as the antigen. The
interpretation of a positive result is based on the presence of a 14.5 kDa antigen specific for S.
neurona. Although the western blot format is not meant to be a quantitative test format, it is
possible to visually compare the level of reactive specific S. neuronaIgG when samples collected
from the same horse at different times (for example, pre and post treatment) are analyzed side-by-
side on the same blot. This service is provided (at no extra fee) when requested.
8/3/2019 Morrow Present
18/19
18 2006 IDEXX Laboratories, Inc. All rights reserved.
Equine Biodiagnostics/IDEXX Sarcocystis neurona IgG western blot
ACVIM EPM Society SIG panel, Louisville KY Jennifer Morrow, PhD 5/31/06
This assay has been used to test several hundred thousand sera and csfs, from clinical
submissions, at least five different infection studies and clinical trials for all the currently FDA
approved EPM drugs.
The test is performed daily M-F with 24 hour turnaround time. Our staff has a combined ~40 work
years experience performing and interpreting this test. Each result is read by two independent
observers with greater than 95% agreement. A third person resolves any discrepant reads (usually
those with equivocal immunoreactivity) and a repeat test may be performed to further confirm the
result.
Contact info: (800) 621-8378 or at www.ebiky.com
8/3/2019 Morrow Present
19/19
19 2006 IDEXX Laboratories, Inc. All rights reserved.
EQUINE BIODIAGNOSTICS/IDEXX
SERUM WESTERN BLOT
Controls 1 2 3 4
Pos
WkPos
Neg
Pre
Post
Pre
Post
Pre
Post
Pre
Post
The arrows on the left side define bands of immunoreactivityto S. neuronaantigens.>> point out two crossreactive (nonspecific) bands of ~ 65
kDa and 30 kDa> point out three S. neuronaspecific bandsKnown positive, weak positive and negative control sera arein the far left lanes.Pre and Post designate the vaccination status.Representative results from four horses are:
Horse # Pre Post1 negative negative2 negative positive3 positive equivalent
positive4 positive increased
positive
>>
>>
>>
>