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CVM Research Aids Poultry Industry
MISSISSIPPI STATE -- The fight against a costly virus affecting the state's billion dollar poultry industry recently got a boost when researchers improved the testing procedure.
Dr. Chinling Wang, a researcher with Mississippi State University's College of Veterinary Medicine, has found a way to shorten the time needed to run the RT-PCR (reverse transcriptase polymerase chain reaction) test. This test accurately and now quickly detects and identifies infectious bronchitis virus in poultry.
Infectious bronchitis is a major problem in the poultry industry around the state and country, said Dr. Tom Smith, MSU extension poultry specialist. The poultry industry loses an estimated $1.7 million yearly to the virus.
Smith said about 1.5 percent of the birds produced in Mississippi are condemned at the processing plants, and of these, about 15 percent are due to respiratory problems such as infectious bronchitis. In an industry worth $1.14 billion in 1996, that represents about $1.7 million lost to the virus.
"Any test that more accurately and quickly identifies this virus so the birds can be vaccinated properly saves the industry money," he said.
Wang's research is doing just that.
"It used to take six to seven days to run the PCR test, but we've gotten it down to three to four days," Wang said. "The poultry industry always wants to know the results quickly, and this test allows for a faster response."
The PCR test is also more sensitive than the IFA test (indirect fluorescent antibody) used by some to detect the virus. With more than 20 known strains of infectious bronchitis, the IFA test can only detect three types, even if more are present. The PCR test can identify most strains.
Wang said all broilers in the United States are vaccinated against infectious bronchitis and other diseases, but some still get infectious bronchitis.
"The virus mainly causes respiratory problems where the bird sneezes and coughs," Wang said. "But once the bird has bronchitis, it's easier to get a secondary infection, such as E. coli, which can lead to airsaculitis."
Birds with airsaculitis are condemned at the processing plant, causing the producers to lose money. Even when airsaculitis does not develop, infectious bronchitis can be deadly and lowers egg production, Wang said.
To run a PCR test, a sample of the virus must be taken and injected in an egg so the virus can replicate. The genes of the virus are then taken from the egg and amplified so they can be identified.
Once identified, the results can be used to recommend the appropriate vaccine for this particular strain of the virus.
Industry losses can be reduced if the proper vaccine are given to infected birds.
The CVM is the only location in Mississippi that offers the PCR test for infectious bronchitis, Wang said. Many in the poultry industry request the PCR test, but until last year when Wang started her research, testing was done out of state.
Wang's research is focusing on finding what strain of the infectious bronchitis virus is prevalent in Mississippi broilers. She is trying to determine how long the virus stays in the bird and what tissue works best for diagnosis. She is also working to determine why so many types of infectious bronchitis exist.