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IDEXX Animal Health Updates
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your timely update of animal health and diagnostics
information.
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January 2003 Worldwide Edition
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IN THIS ISSUE
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THE
LATEST NEWS
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 In Poultry Testing |
| Measuring IBD Passive and Active Immunity with
FlockChek* IBD and IBD-XR for Monitoring and Data Baselines.
Infectious bursal disease (IBD) or Gumboro disease is a viral
disease affecting chickens at various ages. In the first two weeks of
age, IBD variants can cause atrophy in the bursa and early immune
suppression. From 3—6 weeks of age, classical IBD strains and
very virulent IBD (vvIBD) can cause the bursa to become swollen and
sometimes hemorrhagic. The bursa then quickly regresses to a small
size, leading to suppression of the immune system or, in the case of
vvIBD viruses, a higher percentage of mortality. Symptoms include
anorexia, incoordination and depression. Affected birds are more
susceptible to a variety of infectious agents, such as E. coli,
Staphylococcus spp., Clostridium spp. and respiratory
viruses, including live respiratory vaccines (rolling reactions). Also
the clinical picture and immune suppression effect can be enhanced by
chicken anemia virus (CAV) coinfections. Economic losses may approach
20% in an infected flock, and subsequent flocks may become infected
from contaminated living quarters.
An assessment of immune status in the broiler breeders and/or
day-old progeny, as well as serologic identification and definition at
the processing plant, requires a measurement of antibodies to IBD in
serum. Enzyme immunoassay systems have proven efficacious in the
quantification of antibody levels to IBD, and facilitate the
monitoring of immune status in large flocks, helping to establish
baselines for a preventive medicine program on the farms.
A: Passive Immunity
Graph 1 shows that both IDEXX ELISA systems have an excellent
correlation with virus neutralization (VN) for the maternal antibodies
decay. The main difference between the two tests is the ability of
FlockChek* IBD-XR to detect more variant types of IBD viruses, which
is important when broiler breeder operations are using inactivated
vaccines that contain different IBD-variant types of immunogens.
The rate of decay of the maternal antibodies was the same for both
IBD and IBD-XR ELISAs. Therefore, both kits still accurately identify
the age when a flock becomes susceptible to field challenge or live
IBD vaccines. By measuring passive immunity with FlockChek IBD, you
can use the Deventer formula to predict the appropriate date(s) for
field vaccination.1
Graph 1
Study design:
Thirty chickens per group were included in this study. Serum samples
were taken from day 3 through day 21. These progeny were from broiler
breeders that received two inactivated IBD vaccines that included
variant immunogens in the antigen formulation.
B: Active Immunity
Graph 2 shows that both kits can detect active immunity
between seven and 14 days post-inoculation. Both kits detect classic
IBD viruses at similar S/P levels.
Graph 3 shows the expanded detection characteristics of the
coated plate in FlockChek IBD-XR ELISA as compared to FlockChek IBD
(such as shown for Delaware E).
Studies conducted at IDEXX Laboratories, Inc., Westbrook, Maine U.S.A;
data on file.
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JOB OPENINGS
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We currently have the following job opening:
- Senior Technical Service Representative, Holland
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PEOPLE
ON THE MOVE
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We have the pleasure of announcing the following new hires and
promotions in the IDEXX Production Animal Services (PAS) division:
Laurie Desrochers joins the PAS team as a reference
laboratory chemist, providing testing and results for IBD-PCR and
IDEXX ELISA products for the poultry and livestock industries.
Laurie earned her bachelor's degree in laboratory science and
medical biology from the University of New England. For the past six
years she has worked as a pharmacy technician at Maine Medical
Center.
Karen Prouty has been promoted to Research Associate III.
Karen received her bachelor and master of science degrees in animal
science from the University of Maine at Orono. Her master's thesis
involved the reproductive physiology of dairy cows, which included
development of an RIA for bovine progesterone. Since she began
working at IDEXX in February 1996, she has been a key contributor to
our technical manufacturing and PAS technical support groups.
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TECHNICAL
TIP OF THE MONTH
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This month's tip: High Optical Density Readings:
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Excessive color development in negative control wells can result
in an invalid assay (indirect ELISA format only). One potential
cause can be the use of poor-quality water to wash plates or to
prepare wash solutions. IDEXX recommends the use of deionized or
distilled water for these steps. The recommended action in this case
is to have the water quality analyzed for pH and the presence of
metal ions. Another approach is to repeat assays on a set of
characterized sera using an alternate water source, such as bottled
distilled water, to wash plates and prepare wash solutions.
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VISIT
US AT THE FOLLOWING EVENTS
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Atlanta, Georgia, the United States—January 22–24,
2003
The 2003 International Poultry Exposition to be held at the Georgia
World Congress Center.
Please join us for the Annual IDEXX Poultry Health Seminar, which
will be held at the 2003 IPE in Building C Room C201, and will
feature the following:
- Diagnosis and Control of Avian Influenza—David E.
Swayne, Laboratory Director, USDA-ARS-Southeast Poultry Research
Laboratory
- Use of a Chicken Anemia Virus Antibody Test for Monitoring
Protective Antibody Titers—Dr. Ricardo Muñoz, DVM,
MS, ACPV, Poultry and Swine Marketing Manager, IDEXX Laboratories,
Inc.
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Bangkok, Thailand—March 5–7, 2003
VIV Asia, Queen Sirikit National Convention Center. Booth CGB031.
Kissimmee, Florida, United States—March 8–11, 2003
The American Association of Swine Veterinarians (AASV) at the Hyatt Orlando.
Davis, California, United States—March 9–11, 2003
The 52nd Western Poultry Disease Conference (WPDC) at the University of
California, Davis.
Stendal, Germany—March 12–14, 2003
The International BHV 1/BVDV-Symposium, at the Landratsamt Stendal
main conference hall. IDEXX will present, Quality Control in IBR
Diagnostics.
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LEARN
MORE
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To learn more about our products and services, innovative
technologies, trusted service and support, and our global offices,
please visit our Web site.
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