Scientists
for the United States Department of Agriculture have created a vaccine that is
effective against infectious laryngotracheitis (ILT) and Newcastle disease (ND)
– two of the most economically important infectious diseases of poultry.
By using
reverse genetics technology, microbiologist Qingzhong Yu, who works at the U.S.D.A.'s
Southeast Poultry Research Laboratory at Athens, Ga., generated new dual
vaccines by inserting a gene from the infectious laryngotracheitis virus (ILTV)
into the Newcastle disease virus (NDV) LaSota vaccine strain, which has been
used for more than 50 years to protect poultry.
Vaccines
were tested in more than 100 day-old chicks and 120 three-day-old commercial
broiler poults.
All
vaccinated birds were protected against both ILTV and NDV challenges. They
showed little or no clinical signs and no decrease in body weight gains.
The vaccines
were found to be stable and safe in chickens of all ages.
According
to Yu, the new vaccines are safer than the current live-attenuated ILT
vaccines.
They can
be safely and effectively given by aerosol or drinking water to large chicken
populations at a low cost.
