Ceva Poultry Vector Vaccine Symposium

Poultry vaccination is mass vaccination but the poultry industry demands for simpler, more efficacious and cheaper vaccines. Farmers can chose between live and killed vaccines but also biotechnology derived vaccines such as vector vaccines. Ceva Animal Health organised a dedicated symposium to this topic.

Dr Sylvain Comte, corporate marketing director poultry at Ceva, officially opened the symposium. "We are delighted to have an excellent selection of speakers and experts in the audience, I am looking forward to a lively discussion on vector vaccines", Comte said.

Dr Arnoud Bourgeois from Ceva in the USA kicked off the meeting by saying that "the poultry industry has a big challenge for the future". He addressed that besides animal health, genetics and management, implementing new technologies for disease control are taking off quickly".

Dr Robert Webster from St Jude Children's Research Hospital in Tennessee, USA gave an excellent overview on human and avian influenza and how the virus evolved over the years and still is.

Dr Webster looked back at the history of different pandemics with the influenza virus, starting with the Spanish Influenza, which whiped out 20-50 million people. He addressed that during this pandemic H1N1 was the cause, the same virus type that caused the recent Mexican Influenza outbreak and therefore created so much hystery around the world.

Dr Webster further showed the spread of the current H5N1 virus in the world, with North and South America and Australia being free of reported cases of bird flu caused by H5N1.

Different types of vaccine strategies are currently being implemented to fight avian influenza. They can be oil based or DNA derived and all prevent mortality in the birds. Dr Webster addressed that different influenza strains require different vaccine strategied and because the virus can change so quickly, current strains should be kept in a databank to safe them.

Dr Jean de Foucauld from Ceva in Hungary updated the attendees on the regulatory aspects of biotechnology derived vaccines. He explained that a quality dossier, safety trials in animal and environment and efficacy of the product are the main issues to consider when applying for registration of the vaccine.

Dr Gregg Cutler from the USA explained some pratical experience from using new types of vaccines in the US market. He addressed that getting the vaccine to the bird at the right time is most critical. He also mentioned that Vaccine Associated Clinical Disease can be minimised by using new types of vaccines.

Whether the vaccination has been succesful can be told by looking at the skin where the vaccine has been applied. In this picture it is clear that an immune response was initiated because the skin shows red papules.

Dr Andrew Rohrer from the National Poultry Improvement Plan (NPIP) in the US. The NPIP is part of the US Department of Agriculture. Dr Rohrer talked about the need to fill the Salmonella Enteritidis (SE) gaps. He mentioned that we have to focus on broilers, not eggs, as the primary source for SE.

According to Dr Rohrer, raising backyard poultry, hobby chickens and interaction with chickens at shops or other consumer events or fairs could reduce the change to control avian and human influenza succesfully.

Rick van Oort, Poultry Corporate Product Manager at Ceva gave an excellent overview on Salmonella control and the EU regulations and experiences with this topic. Van Oort emphazised that besides vaccination other measurements such as rodent control programs, hygiene protocols, visitors/personnel protocols, disinfection after depletion of flock among others are equally important. "Fighting Salmonalla is a complete programme of several measures" van Oort said.

The total Salmonella control program excists of three pillars: Biosecurity, Monitoring and Vaccination. Only when farmers, veterinarians and government are consistent with these measures, Salmonella in poultry can be targeted effectively.

The level of vaccination is not the same around the world. Some countries have a low vaccination rate (green), other countries vaccinate more against Salmonella (dark blue). The experience with vaccination is that it is a major factor in reducing Salmonellais in hens and also egg-related human Enteritidis infections.

Mr. Eliot Hoff from APCO New York in the US shared a refreshing insight to the audience on how to deal with a crisis in agriculture, such as the recent Salmonella egg crisis in the US. He explained the key components of crisis management such as establish an infrastructure/task force, gather facts quickly, develop key messages, control information flow and above all: be prepared!

Mr Eliot explained that the media landscape is evolving: use of consumer weblogs, twitter, camera phones and other online tools. Therefore, the need for good communciaton is more important then ever. Once a wrong message appears on the web, it is circulated, copied and pasted by others at a great pace.

Dr Yannick Gardin from Ceva in France shared some information about the past and present in poultry diseases control. Dr Gardin addressed that with the global farming pratices and farms getting bigger, the need for better control of the sanitary risks is increased and better vaccine control is requested.

Dr Gardin addressed the need to make mass vaccination simpler, more efficacious and cheaper. One way to reach this goal is vaccinating the day old chicks in the hatchery. This is easier as the chicks are in the same unit.

Poultry vaccination is mass vaccination but the poultry industry demands for simpler, more efficacious and cheaper vaccines. Especially on large farms, applying vaccines can be a time consuming activity and effective injection of the product is sometimes compromised.

Scientists have learned a great deal about the advantages and limitation of vector vaccines since their first introdcution in 1994 said Dr Kristi Moore from Ceva in the US. One of the reasons to use vector vaccines is improved safety. The gene insert can not revert to virulence, the gene insert can not be transmitted (horizontal or vertical) and a reduction in vaccine reactions is seen, according to Dr Moore.

The fowl pox based vaccine (FPV) and the Turkey Herpes based vaccine (HVT) can both be administred in ovo or in live birds.

Dr Zoltan Penzes from Ceva Hungary explained that research is now focused on finding new type of inserts, multiple insert on one vactor and new type of vectors to be used as vector vaccines. For example, a gene insert for avian influenza type H5 is ready, but is there also a need to create vaccines that have a gene for H7 and H9 versions of the influenza virus?

Dr Jagdev Sharma from Arizona State University presented work that has been done in using the turkey herpes virus (HVT) as a vector. He explained that laboratory and field studies have shown that multiple vaccines may be combined with HVT for in ovo immunization.

Newcastle disease (ND) is a poultry disease with great economic impact, explained Dr Thierry van den Berg from Coda Cerva in Belgium. He addressed that especially in regions where ND is enzootic and where there is high pressure from the field, the need for very early immunization is hampered by the intereference of an important passive immunity.

In the presentation from Dr van den Berg, we quickly looked back at the basics of why we use vaccination. This is threefold: clinical protection, resistance to infection and reduction of shedding. According to van den Berg most classical attenuated/inactivated vaccines are satisfactory in laboratory conditions but have some limitations in the field.

Jack Rosenberger is Presendient of AviSerce LLC in the US and was invited to the symposium to highlight some of the laboratory expertise associated with HVT Newcastle vector vaccines. He explained a trial in which 2 HVT NDV vector vaccines were compared. Differences between the 2 vaccines were not so much seen in the protection against the disease, but more in the onset of immunity and the speed in which protection was induced.

Detection of the Newcastle virus can be measured by embryo mortality, embryo lesions and hemagglutination by allantoic fluid. In this picture it is clear how severe the damage is in the embryo when infected with the Newcastle virus.

Dr Tom Holder from Allan's Family Food in the US spoke about his field experience in using the HVT Newcastle vector vaccine. Allan's farm is the oldest broiler company in the US (1919) and produces 2 billion broilers a week, with 2 hatcheries, 2 feed mills and 2 processing plants. The farm moved towards vaccinating all the birds with a vector vaccines against Newcastle disease.

Dr Holder started with asking a few questions why a vector vaccine for Newcastle disease should be considered. These are: Would it replace the standard B1 program? Would it protect for both Marek's and Newcastle disease? Would a booster be needed? What dosage was needed for protection? Which of the two products to use? Is using a vector vaccine more cost effective?

Dr Deoki Tripathy from the University of Illinois in the US explained that the fowlpox virus was already used as a vector in the 1980s to develop recombinant fowlpox virus vaccines. Later, fowlpox virus vaccines expressing antigens of several viruses such as Newcastle diseae, Marek's disease, infectious bursal disease and infectious laryngothracheitis were developed.

There are different reasons to use fowlpoxvirus as a vector. The advantage is that the fowlpox virus has a large size genome and presence of non-essential genes.

Dr Carlos Barranon Jaled, General Director of PATSA in Mexico was the final speaker at the conference and shared some field experience using a vector vaccine against infectious laryngotracheitis (ILT). In December 2007, the farm of PATSA experienced its first outbreak of ILT in broilers at 5 weeks of age.

Intensive dicussions about vector vaccines were not restricted to the scientific programme. Also during the lunch breaks, the attendees discussed their work and possible research topics.