COLUMBUS, Ohio -- An Ohio State University researcher has been awarded a patent for a test that can detect the presence of antibodies for a chicken virus that can be economically devastating.
The test is an ELISA assay and detects antibodies to infectious bursal disease virus (IBDV), a disease that can make chickens susceptible to future illness and infection. The same researcher has a patent pending for an IBD-PCR test, which determines if chickens in a flock currently have the virus. Both tests are now commercially available.
Use of these tests can tell farmers if their chickens need to be vaccinated against IBDV, and if so, which vaccine to choose.
Chicken farming is a multi-billion dollar industry in the United States. IBDV is the second-leading cause of viral disease in chickens. The first is infectious bronchitis virus, a respiratory disease.
“Neither disease is deadly, but each is important from an economic standpoint,” said Daral Jackwood, principal developer of the two tests and professor of molecular virology at the Ohio Agricultural Research and Development Center.
“A producer won’t get the same performance out of his flock. It’s going to cost more to feed the birds and the birds will weigh less when they go to market. It can be economically devastating, resulting in the loss of tens of millions of dollars.”
The ELISA assay requires drawing blood samples from chickens. This test determines how well the chickens are protected from strains of the virus -- in other words, how much antibody they have in their system. Higher antibody levels mean greater protection. Jackwood said older ELISA tests weren’t able to detect antibodies to specific strains of IBDV.
“Our test correlates much better with protection,” he said. “The antibody concentrations we get reflect how well-protected those birds are.”
The IBD-PCR test is used to test for the presence of IBDV in a chicken flock. About six chickens are killed and cells are extracted from the bursa – a sac located inside the bird at the base of the tail. The virus can be found in cells of bursa tissue. The first of its kind, this test tells farmers which strain, or strains, of IBDV their flock has been exposed to.
“The farmer will then know what strain is causing problems on his farm so when the next group of chickens comes in, he can select the proper vaccine,” Jackwood said. Worldwide, there are currently about two dozen vaccines for IBDV and at least an equal number of viral strains.
IBDV, first discovered in this country in the late 1950s, affects the immune system of young chickens. Signs of the disease include loss of appetite and low weight gain.
The disease favors chickens younger than 7 weeks old because these animals have immature immune cells. The virus replicates in and destroys the immature cells.
“If two or three percent of chickens on a farm have the disease, 100 percent of the flock will have it within a couple of days,” Jackwood said.
IBDV received additional attention in 1997, when researchers discovered the virus had infected certain populations of Antarctic penguins. Jackwood is currently testing the tissues of penguins using the IBD-PCR test to determine which strains of virus are present in these animals.
Jackwood received the ELISA assay patent in July.
Renee Jackwood, formerly a research associate in veterinary medicine, helped develop the tests. IDEXX Laboratories, Inc., based in Westbrook, Maine, manufactures the ELISA assay and IBD-PCR test.