New test to detect lethal poultry disease developed in US

22-06-2006 | |

Ohio State University’s Center for Diagnostic Assays (CDA) has come up with a first-of-its-kind test for the detection of very virulent infectious bursal disease virus (vvIBDV), a highly contagious disease of poultry that is causing major losses to┬áthe industry worldwide.

Daral Jackwood, a molecular biologist with the university’s Food Animal Health Research Program (FAHRP) on the Ohio Agricultural Research and Development Center’s (OARDC) Wooster campus, developed a validated real-time RT-PCR assay (patent pending) for the rapid detection of nucleotide sequences that are unique to vvIBDV strains affecting poultry operations all around the world. This new assay distinguishes vvIBDV strains from non-vvIBDV classic and variant strains.

“Until now, no validated rapid assay for the detection of all known vvIBDV strains existed,” said Jackwood, who heads CDA. “In countries with vvIBDV, this assay is necessary for the effective monitoring and control of this devastating disease. In countries without the virus, the assay would be a first line of defense needed to prevent vvIBDV from entering domestic poultry operations.”

According to the US Department of Agriculture (USDA), poultry is the fastest-growing component of global meat demand. The US is the world’s largest poultry producer and the second-largest egg producer and exporter of poultry meat, with an annual farm value exceeding $20 billion.

IBDV(which, unlike highly pathogenic avian flu, does not affect humans) is an immuno-suppressive disease that attacks young birds, killing them or making them more susceptible to other infectious agents. In addition, this disease can quickly produce mutated viruses that are resistant to vaccines. IBDV has troubled egg and broiler operations in the US since the 1950s, and recent studies show the incidence of variant IBDV strains is increasing throughout the country.

But the expanding threat of vvIBDV – a much more powerful version of the disease that can kill up to 80 percent of a flock – has made it a top concern among the poultry industry. Beginning with European outbreaks in the mid-1980s, vvIBDV has spread furiously. It has been identified in chicken flocks on nearly every continent, including cases in Europe, Asia, South America, Central America and the Caribbean.

“Our greatest challenge was to find a region of the vial genome that was stable and unique to all known vvIBDV strains,” Jackwood explained. “We were lucky enough to find two regions containing a total of six nucleotides unique to vvIBDV strains. The second major challenge was then to design an assay to reliably identify these six unique nucleotides. That process took us about six months. We then spent the next year validating our assay.”

The next step involves getting the test on the market. Ohio State is currently inviting inquiries from scientific companies interested in discussing a potential collaboration with the university to produce and market a vvIBDV real-time RT-PCR assay kit worldwide.

The prospects for commercialisation are very good, Jackwood said. A reliable and economical assay for vvIBDV is needed in many parts of the world to help control the destructive disease caused by this virus. And the countries that do not currently have vvIBDV, such as the US and Australia, are interested in keeping the disease at bay by monitoring imported poultry for vvIBDV. In 2004 alone, the US imported more than18 million chicks and 9 million hatching eggs.

“If vvIBDV does reach the US, this assay will be very important in the initial diagnosis and subsequent eradication of the agent from our chicken flocks,” Jackwood said. For Ohio, the test means a vital tool to safeguard its $3.3 billion poultry industry.