From University of California - Berkeley
Exotic Newcastle disease LIVERMORE-- Newly developed rapid diagnostic assays to detect exotic Newcastle disease developed by a partnership of researchers at Lawrence Livermore National Laboratory and other institutions have "significantly aided" containment of the poultry disease.
That's the view of professor Alex Ardans, director of the California Animal Health and Food Safety Laboratory based at the UC Davis School of Veterinary Medicine.
Design and development of the assays have been done by a team from the Laboratory, the California Animal Health and Food Safety Laboratory (or CAHFS) at UC Davis and the U.S. Department of Agriculture.
At the time of the outbreak of exotic Newcastle disease last October in California, available assays to identify the disease required 6 to 12 days, according to Ardans.
A key signature that allows identification of the virus within four hours of receiving the sample was facilitated by a genomic-approach developed by an eight-member LLNL team, led by Paula McCready.
"The ongoing collaboration between LLNL and UC Davis doesn't only benefit the state of California, but also the nation," Ardans said. "The Livermore approach to developing assays for microbial diseases is being embraced nationwide."
The rapid tests are being used to assist state and federal exotic Newcastle disease task force personnel in disease detection and control efforts.
During the past five months, almost 3 million commercial egg-producing chickens have been euthanized in California because of exotic Newcastle disease. Additionally, more than 100,000 game birds and backyard poultry also have been euthanized.
Currently, seven counties, all in Southern California, are under quarantine, with a prohibition on moving poultry such as chickens, turkeys, geese, partridges and other birds.
Ardans believes federal and state agriculture officials are making headway in the fight against exotic Newcastle disease. During the past two weeks, the number of new cases of infected "backyard birds" seems to be decreasing in some areas, he noted.
A highly lethal viral ailment, exotic Newcastle disease affects poultry, causing respiratory problems and lethargy. Chickens are particularly susceptible to the disease and usually die within a few days.
"With the faster detection method, we can rapidly identify the affected animals and isolate them before the disease spreads further," said McCready.
"If an outbreak is not quickly contained, it spreads rapidly, affecting the state's poultry industry and its ability to trade with other states and countries."
Laboratory researchers were contacted by CAHFS on Oct. 13, and within days had generated possible target signatures for development of a rapid assay.
LLNL biomedical scientist Evan Skowronski worked with CAHFS staff at UC Davis over the next two months to optimize performance of the assays and pioneer ways to rapidly process hundreds of samples per day. Skowronski was instrumental in sequencing the first viruses isolated from commercial flocks to confirm the accuracy of the assay.
In addition to disease identification in affected birds, the rapid test is now being used routinely in surveillance efforts in unaffected commercial flocks to assure their disease-free status.
These efforts involving nearly 600 different poultry houses will continue after the outbreak is contained as a disease surveillance program to demonstrate that the state is free of the disease.
"We were able to make a rapid response to an outbreak of an emerging disease," said McCready, who is associate program leader for biology in the Chemical and Biological National Security Program.
The team's computations group, led by Tom Slezak, used unique software developed by Laboratory researchers to identify a target sequence to distinguish the highly virulent forms of the virus from other forms.
This has been extremely useful in the rapid differentiation of exotic Newcastle disease virus from closely related Newcastle disease viruses used in vaccines or those causing less severe disease.
"To the best of our knowledge, this is the first working rapid assay for Newcastle disease to be adapted for routine diagnostic and surveillance use," McCready said.
The development of this exotic Newcastle disease signature and the additional work required to ready it for use was paid for with Laboratory Directed Research and Development money, a Laboratory fund for cutting-edge research.
In addition to McCready, Skowronski and Slezak, other members of the Laboratory assay development team include bioinfomatics scientists Beth Vitalis, Tom Kuczmarski and Shea Gardner, along with biomedical scientists Shanavaz Nasarabadi and Jason Olivas.
Funded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by the University of California for the U.S. Department of Energy's National Nuclear Security Administration.