Advanced Technology Vaccines: Feed-Back from Years of Use in the US

Dr Gregg J. Cutler of Cutler Associates International shared his experience of field use of vector vaccines in poultry in California with delegates at the Vector Vaccines Symposium organised by Ceva Santé Animale in San Diego in October 2010.
calendar icon 28 January 2011
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Vector vaccines are available in the US since several years in order to control several poultry diseases such as IBD, Infectious Laryngotracheitis, Newcastle disease and Mycoplasma gallisepticum, said Dr Cutler. These vector vaccines are based either on fowl pox (FP) or herpes virus turkey (HVT) vectors.

He added that his personal experience is with the use of HVT IBD vector and FP LT vector in commercial layers.

Dr Gregg Cutler

HVT IBD vector vaccine was first foreseen in a way to overcome the water or spray application of infectious bursal disease (IBD) live vaccines during rearing period and to bring a possible better protection. The vector vaccine has been able to perform at least as well as conventional IBD vaccine in USA field conditions where very virulent IBD virus (vvIBDV) was not present.

In Sonoma County in California, Dr Cutler explained that they have been faced with some breaks of vvIBDV which was previously unknown in the USA in a very dense poultry growing zone. The breaks were observed on commercial layer pullets.

The decision was made to use a combination of Vector HVT IBD vaccine at the hatchery with several applications of live 2515 and D78 vaccines in the field in order to maximise the protection and preventing any spread of the vvIBDV virus. After several rounds of intensive vaccination, they have been able to prevent further vv IBDv breaks, the vvIBDV virus has not been recovered from specific pathogen-free (SPF) sentinels placed in the farms.

Dr Cutler said they used less live vaccines after each round, and are considering using only the Vector HVT IBD for upcoming flocks.

Infectious laryngotracheitis (ILT) is an endemic disease in California, for which CEO vaccines were used for a long period of time to prevent the disease symptoms.

But due to the spreading capacity of these CEO vaccines to other pullets or broiler flocks, and the rolling vaccine reactions observed in pullets flocks and international trade issues with ILT disease, the vectored Pox ILT or HVT ILT vaccines have been perceived of great interest.

The large use of pox ILT vaccine in commercial pullets has shown the interest of such vaccine in field conditions by preventing vaccine ILT post vaccination reactions, eliminates eye drop administration and the capacity to diagnose ILT disease identification by serology. The protection has been measured in field conditions when a multi-age layer site vaccinated with a vector FP LT vaccines faced ILT challenge. Slight respiratory symptoms without mortality was observed during a few days and disappeared without any treatment.

Subsequent flocks show fewer symptoms with the reduction of ILT virus circulation in the farms vaccinated with the vector vaccine.

Vector vaccines are new solutions proposed to the poultry industry that can be of interest to reduce birds handling and safety issues with some conventional live vaccines, concluded Dr Cutler.

Further Reading

- You can view other papers presented at the Vector Vaccines Symposium by clicking here.

Further Reading

- Find out more information on the diseases mentioned in this article by clicking here.

February 2011
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