Download IDEXX APV Ab Test Effective tool for monitoring avian pneumovirus

IDEXX APV Ab Test
Test With Confidence™
Effective tool for monitoring avian pneumovirus
in chicken and turkey flocks
The IDEXX APV Ab Test is an indirect ELISA
for the detection of APV antibodies in
chicken and turkey serum. This test has been
developed as a flock-screening tool to aid in
the diagnosis of APV.
•Detects A, B and C avian pneumovirus types
•Detects vaccine immune response
16 days after vaccination
•Chicken and turkey serum samples
•98% specificity in SPF populations
•Indirect—quantitative ELISA
DRAFT
GD1R
9.9.10
GD2R
9-13-10
RF1R
FNP
FNSO
Avian pneumoviruses (APV) can cause damage to the upper respiratory tract
(trachea), such as, lack of cilia movement and/or cilia loss—damage that may
lead to respiratory clinical signs such as coughing, sneezing, swollen head
and more complicated respiratory problems. This stress on the cilia and upper
respiratory tract can facilitate the multiplication of E. coli and other bacterial
infections such as Mycoplasmas, Bordetella sp, etc. that lead to a respiratory
syndrome called swollen head syndrome (SHS).1 APV plays a role in the
multiplication of infectious bronchitis virus (IBV) in the upper respiratory tract.
APV can also affect the reproductive tract, impacting egg formation in turkey
breeders, broiler breeders and egg-type chickens, resulting in an increase in
the percentage of egg abnormalities and a drop in egg production.2,3
The most prevalent types of APV are A and B, but type C is present in
some poultry states in the United States.3 For this reason, it is important for
monitoring purposes to have a diagnostic test that is able to detect any of the
potential APV strains in the commercial chicken and turkey industries.
The IDEXX APV Ab Test is a quantitative test for the detection of A, B and/or
C APV-specific types in specific pathogen-free (SPF), as well as commercial,
chicken and turkey flocks that could be exposed to field or vaccine viruses.
This test and xChek* software can help to screen SPF populations or monitor
flocks that have been vaccinated with live or inactivated vaccine against
A, B and/or C APV types. IDEXX recommends building a baseline for
each company.
References:
1 Jones RC. Viral respiratory diseases (infectious bronchitis, infectious laringotracheitis and avian pneumovirus). Proceedings from:
XIII Congress of the World Veterinary Poultry Association; Denver, Co; July 20–23, 2003:39–41.
2 Cook JK. Avian pneumovirus infections of turkeys and chickens. Vet J. 2000;160(2):118–125.
3 Cook JK, et al. Infectious bronchitis virus vaccine interferes with the replication of avian pneumovirus vaccine in domestic fowl. Avian
Pathology. 2001;30:233–242.
4 Goyal SM. Seroprevalence of avian pneumovirus in Minnesota turkeys. Avian Dis. 2003;47(3):700–6.
IDEXX APV Ab Test
Graph 1
IDEXX APV Ab Test
German SPF chicken population
n=612
Specificity = 98.4%
MEAN S/P = 0.058
STD = 0.047
STDs from cutoff = 3.0
160
This study consisted of 18 chickens. The first group was vaccinated
with inactivated type A vaccine, another two groups with type B
vaccines and the fourth was a nonvaccinated control group. Serum
samples were taken from the day of vaccination up to 43 days after
vaccination. The percentages of seroconversion and mean titers for
each group are shown in graphs 5 and 6.
Cutoff = 0.2
140
120
Frequency
The IDEXX APV Ab Test (graph 1) performed
better than the gold-standard competitive, or
blocking, ELISA (graph 2), with 98.4% specificity
vs. 96.9%, respectively. The cutoff in graph 1
for the IDEXX APV Ab Test is 0.2, whereas, the
arrows in graph 2 indicate the suspect zone for
the blocking ELISA test .
Sensitivity: Chickens with type A and B vaccines
100
80
60
40
20
4
46
0.
0.
0.
34
28
0.
0.
22
0.1
6
0.1
2
04
0.
8
.0
.0
-0
.14
-0
-0
-0
.2
0
S/P
Vaccine B1
Vaccine B
Control
90%
80%
70%
60%
50%
40%
30%
20%
Suspect
Zone
50
40
A decline in antibodies was seen 43 days after vaccine application in all
of the groups.
between
30% to 40%
30
0%
0
16
23
30
35
43
Days post-vaccination
Graph 6: Mean titers with the IDEXX APV Ab Test—in chickens
vaccinated with inactivated product containing A or B antigen
Vaccine A
Vaccine B1
Vaccine B
Control
3000
20
2500
Mean titer
Specificity = 96.9%
MEAN = 12%
STD = 10%
STDs from cutoff = 1.9
Vaccine A
100%
10%
The group vaccinated with type B vaccine reached up to 100% of
seroconversion with mean titers between 1,500 and 2,500. The groups
vaccinated with A and B1 had a seroconversion between 80% and 100%,
and mean titers between 1,000 and 2,000.
60
Frequency
Graph 2
Competitive
Blocking ELISA
German SPF chicken population
n=612
The IDEXX APV Ab Test detects antibodies from the three commercially
available inactivated vaccines against avian pneumovirus 16 days postvaccination and up to 43 days post-vaccination.
Graph 5: Percentage of positive samples with the IDEXX APV Ab Test—
in chickens vaccinated with inactivated product containing A or B antigen
% Positive birds
Specificity: German chicken population
10
1500
1000
46
42
38
34
30
26
22
18
14
6
10
2
-2
-6
-1
0
0
2000
500
Blocking
0
x
0
x
x
x
x
x
16
23
30
35
43
Days post-vaccination
Specificity: U.S. turkey population
60
50
40
30
20
10
e
between 0.083 to 0.126
16
14
Vaccine B: Graphs 7 and 8 show a large percentage of positive serum
samples from turkeys vaccinated at one-day old with the live vaccine type
B. The percentage of seroconversion remains high at six weeks of age, and
then starts to decline at 12 weeks of age.
12
10
8
6
4
2
S/P
e
or
4
0.
m
34
0.
28
0.
22
0.
0.1
6
0.1
2
04
0.
.0
8
.14
.0
-0
-0
.2
0
-0
Specificity = 51.3%
MEAN S/P = 0.09
STD = 0.048
STDs from cutoff = -0.116
Suspect Zone
18
Frequency
Graph 4
Indirect ELISA
U.S. turkey population
n=80
Mean titers for both groups reached levels between 9,000 and 12,000 after
the inactivated vaccine was applied.
Vaccine B
90%
80%
70%
60%
50%
40%
30%
20%
or
4
0.
Vaccine A: Graphs 7 and 8 show that there is low seroconversion at
three weeks of age with vaccine A, most likely due to maternal antibodies
interference. But after the booster with a live vaccine type A, the percentage
of turkeys showing titers increases at six weeks of age, as well as at 12
weeks of age.
S/P
20
Vaccine A
100%
10%
m
34
0.
28
0.
22
0.
0.1
6
04
2
0.1
0.
8
.0
.14
.0
-0
-0
-0
-0
.2
0
The IDEXX APV Ab Test detects antibodies in turkeys vaccinated with live
and inactivated avian pneumovirus vaccines against serotype A or B.
Graph 7: Percentage of positive samples with the IDEXX APV Ab Test—
in turkeys vaccinated with type A or B antigen
% Positives
Turkey flocks were vaccinated at one day of age with either type A or
type B live vaccines. Serum samples (sample size = 23) were taken at
three weeks of age. After an additional live vaccination (booster), new
serum samples were taken at six weeks and 12 weeks of age, and the
last serum sampling occured after an inactivated vaccination at 33
week of age.
Cutoff = 0.2
70
0%
3w (1x live)
6w (2x live)
12w (2x live)
33w+
(2x live, 1x killed)
Age of sampling (vaccination)
Graph 8: Mean titer with the IDEXX APV Ab Test—in turkeys
vaccinated with type A or B antigen
Vaccine A
Vaccine B
14000
Mean titer
Specificity = 100%
MEAN S/P = 0.021
STD = 0.018
STDs from cutoff = 10.0
80
Frequency
Graph 3
IDEXX APV Ab Test
U.S. turkey population
n=192
-0
The IDEXX APV Ab Test (graph 3)
displayed better specificity in a negative U.S.
turkey population vs. another commercial indirect
ELISA (graph 4). The IDEXX APV Ab Test has
an excellent population distribution. The cutoff
in graph 3 for the IDEXX APV Ab Test is 0.2,
whereas, the arrows in graph 4 indicate the
suspect zone for the other indirect ELISA test .
Sensitivity: Turkeys with type A and B vaccines
12000
10000
8000
6000
4000
2000
0
3w (1x live)
6w (2x live)
12w (2x live)
33w+
(2x live, 1x killed)
Age of sampling (vaccination)
IDEXX APV Ab Test
Sensitivity: Chickens with type C vaccines
Conclusion
Seven birds were vaccinated intramuscularly/
subcutaneously with a type C vaccine against
avian pneumovirus. Serum samples were
taken twice a week for four weeks postvaccination.
•The IDEXX APV Ab Test has better specificity than the blocking format or
competitive ELISA, which is considered the gold-standard reference for
negative populations. Now, poultry producers will have more confidence
in monitoring SPF or naïve populations.
Graph 9: Percentage of positive samples and mean titers with the
IDEXX APV Ab Test—in chickens vaccinated with type C antigen
100%
8000
90%
7000
•The IDEXX APV Ab Test can detect immuno response to a commercially
available live or inactivated vaccines against avian pneumovirus that
contain A, B or C antigens.
6000
70%
60%
5000
50%
4000
40%
3000
30%
Mean titers
% Positives
80%
2000
20%
1000
10%
0%
0
0
4
7
11
14
17
21
•The IDEXX APV Ab Test can detect the presence of A, B or C avian
pneumovirus.
28
Days post-vaccination
•The IDEXX APV Ab Test has a good balance of sensitivity for the detection
of A, B or C avian pneumovirus serotypes.
•The IDEXX APV Ab Test can be used with xChek* software to generate
baselines and to monitor vaccination programs and field challenge
interaction.
•The IDEXX APV Ab Test has the same sample diluent and same test
protocol as the other IDEXX poultry ELISA test kits.
The IDEXX APV Ab Test detects antibodies
against type C avian pneumovirus 11 days postvaccination. The rate of seroconversion and mean
titers are shown in graph 9. At day 14, all birds had
seroconverted with a mean titer of 1,400, which
increased over time to 7,400 at day 28.
For more information about the IDEXX APV Ab Test, please
contact your IDEXX representative or visit idexx.com/apv.
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