WEST NILE VIRUS SURVEILLANCE IN MICHIGAN CORVIDS

WEST NILE VIRUS
SURVEILLANCE IN MICHIGAN
CORVIDS
Jamee A. Black-Moorman and Jon S. Patterson
Diagnostic Center for Population and Animal Health
Michigan State University
Submission of Dead Birds to
DCPAH: 2001-2003
Tissue Handling and Collection
„
„
necropsy of submitted
birds in biosafety
cabinet
appropriate personal
protective gear:
• gloves
• respirator mask
• gown/lab coat
„
collection of heart and
kidney for WNV testing
Testing by Immunohistochemistry
(IHC)
heart
kidney
Confirmation of IHC-positive Birds
by RT-PCR
Comparison of IHC to VecTestTM
„
„
„
„
study done by Jamee
Moorman, at DCPAH
tested 200 corvids
submitted between June
1 and September 1, 2003
oral swabs from corvids
tested by VecTestTM
IHC results compared to
VecTestTM results
TM
VecTest
Procedure
swab the bird’s oral cavity, including under the beak and under the
tongue
„ place the swab in buffer solution, agitate the tube, and allow the
swab to set for one minute
„ remove the swab from the tube, and pipette 250 µL of the solution
into a clean tube
„ place the dipstick indicator in the solution, and incubate for 15
minutes
„ test results are interpreted as:
• negative if only the control line is present
• positive if a pink to red line is present in the test zone, below the
control line
„
VecTestTM Rapid Antigen Detection
Assay
weak positive, strong positive, negative
Comparison of IHC and
Results (2003)
TM
VecTest
IHC
Positive
IHC
Negative
VecTestTM
Positive
35
2
VecTestTM
Negative
6
157
Specificity 99.00%
Sensitivity 85.37%
Corvid testing: 2002 vs. 2003
2003
2002
total # of birds
submitted
696
763
total # of corvids
submitted
540
734
total # of corvids tested
400
568
total # of WNV(+)
corvids
89
330
# of counties submitting
corvids
70
80
# of counties with (+)
corvids
33 (75 zip codes)
73
Positive corvids: 2002 vs. 2003
Bird testing: 2002 vs. 2003
Number of Birds Tested
250
221
Number of Birds
200
peak in
June 2003
150
100
peak in late July,
early Aug. 2002
141
89
50
39
0 0
2 0
1 4
5 5
1-15
April
16-30
April
1412
33
60
59
53
5049
40
40
30
29
23
17
6
6
1
5
1
5
0 1
0
1-15 16-30
March March
1-15
May
16-31
May
1-15
June
16-30
June
1-15
July
16-31
July
Two Week Block
2002
2003
2003
2002
1-15
Aug
16-31
Aug
1-15
Sept
16-30
Sept
1-15
Oct
16-31
Oct
1-15
Nov
Positive birds: 2002 vs. 2003
Number of Birds WNV Positive
180
180
peak in late July,
early Aug. 2002
160
140
Number of Birds
120
100
80
peak in
Sept. 2003
74
60
47
40
31
20
13
0 0
0 0
0 0
0 1
1 1
1-15
April
16-30
April
1-15
May
1
4
1 1
4
1
10
15
13
13
4
4
5
0 2
1 0
0 0
1-15
Oct
16-31
Oct
1-15
Nov
0
1-15 16-30
March March
16-31
May
1-15
June
16-30
June
1-15
July
16-31
July
Two Week Block
2002
2003
2002 2003
1-15
Aug
16-31
Aug
1-15
Sept
16-30
Sept