A vaccine combining a turkey herpes virus (HVT) vaccine for Marek's disease and part of the virus for infectious laryngotracheitis (ILT) has picked up Canadian registration for use in day-old chickens at the hatchery.
Intervet/Schering-Plough Animal Health said its Innovax-ILT product now has Canadian registration for vaccination of healthy one-day-old chickens by subcutaneous route as an aid in the prevention of Marek's and ILT.
Because the vaccine does not contain live ILT virus, it provides birds with life-long protection against Marek's Disease and ILT without the potential respiratory reactions or house-to-house spread that can be associated with live chick embryo origin (CEO) vaccines.
The ILT virus affects mainly chickens, causing conjunctivitis and "severe" respiratory disease, causing birds to have trouble breathing and to hack up blood from the trachea. It can also cause decreased egg production.
According to Intervet/Schering Plough, an ILT infection in a broiler flock can cause "excessive mortality and negatively impact performance," The virus can lead to morbidity rates ranging from 50 to 100 per cent, with a mortality rate of 10-20 per cent, but sometimes as high as 70. The disease can also lead to export restrictions and, possibly, production problems from vaccination reactions to live ILT vaccines.
Marek's disease, the other poultry disease covered on Innovax's registration, is a "highly contagious" gallid herpes virus which generally hits birds after four to six weeks of age, according to the Canadian Food Inspection Agency.
Internally, the virus infiltrates lymphoid cells, forming tumours in organs such as the liver, kidneys, heart, gonads and spleen, and/or lesions or enlargements of peripheral nerves. Carcasses of infected birds are condemned at slaughter; the infection can also cause paralysis or death.
HVT has been used for over 30 years in vaccines against Marek's disease. An HVT vaccine won't prevent infection with the virus causing Marek's, but will impede development of lymphoma in infected chickens, according to CFIA.
According to Intervet Schering-Plough, Innovax-ILT also gives producers the option of using an infectious bursal disease (IBD) vaccine such as Univax-BD at the hatchery.
The two products would thus protect birds against Marek's, ILT and IBD easily, but "without the risk associated with other vaccination strategies.