The project was funded by USPOULTRY and the USPOULTRY Foundation and was run by Dr Maricarmen García.

The group found that deleting a gene from the ILT virus makes the virus less virulent and more useful as a vaccine. The new vaccine gives good protection against ILT, but is not safe enough to use in ovo in chicks with no maternal antibody against ILT, so efforts are continuing to make the vaccine safer.

The scientists said that performance of vectored vaccines that reduce clinical signs of the disease but fail to reduce viral shedding emphasise the need for the development of better attenuated live vaccines.

They said they believe that avoiding ILT field mass vaccination, by providing early robust immunity against it with the use of in ovo vaccination, is necessary to reduce the circulation of virus in the field.

According to the scientists, the research resulted in a much better understanding of the level of safety and protection necessary to properly control the disease, taking us a step closer to acquiring more efficient vaccines and implementing sounder control strategies against ILT.