ILT also causes a drop in egg production in laying birds – both breeders and layers – and can affect broilers as well.

Currently, birds may be treated for ILT using a live vaccine, so mounting a respiratory tract challenge in the birds. But this can have side effects and live vaccines can also be transmitted to other birds.

The new vector vaccine – called Innovax®-ILT – is administered in a single, subcutaneous shot in the hatchery and offers at least 60 weeks’ protection.

It works by utilising the herpesvirus of turkey (HVT) as a vector for ILT antigens.

“HVT has a good safety profile for chickens and also immunises against Marek’s disease, another herpesvirus that causes tumors, immunosuppression and sometimes mortality,” said an MSD statement.

“The vaccine allows birds to develop immunity against ILT and Marek’s disease before they are exposed to the viruses that cause these diseases.”

The prescription-only medicine will be delivered to hatcheries towards the end of October.